Disclaimer
The information contained in the Microwave Ore Research Database is provided for general reference purposes only. While we strive to ensure accuracy and completeness, the database is a work in progress and may contain errors, omissions, or outdated data. Users are advised to exercise discretion and verify any critical information independently.
Please note that only a portion of the data has been uploaded so far, and the database is continually being updated and expanded.
By accessing or using the information in this database, you acknowledge these limitations and agree to reference the source as: Microwave Ore Research Database.
Do you have a document you would like to add to the database?
Microwave Assisted Weakening of Rocks and Ores
| Database ID | Year | Title | Author(s) | URL | Material(s) Studied | Keywords | Abstract | DOI | Language | Country of Corresponding Author | Document Type | Journal/Conference Name | Volume | Issue | Pagination | Other Format Info |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| A001 | 2024 | Microwave Treatment of Copper–Nickel Sulfide Ore for Promotion of Grinding and Flotation | Fang, Xiaolei; Peng, Zhiwei; Yin, Tianle; Rao, Mingjun; Li, Guanghui | https://www.mdpi.com/2075-4701/14/5/565 | copper-nickel sulphide ore | microwave treatment; copper–nickel sulfide ore; thermodynamics; grinding indexes; flotation | The effect of microwave treatment on the grinding and flotation performance of a typical copper–nickel sulfide ore was evaluated, based on the determination of its microwave absorption capability, grinding and flotation indexes such as crack percentage, mineral liberation degree, particle size distribution, relative work index (RWI), metal enrichment ratio and recovery. There were obvious differences between the microwave absorption capabilities of the main minerals in the ore, as demonstrated by their different microwave penetration depths. They also induced temperature differences between sulfide minerals and gangue minerals which could reach 418 ◦C after microwave treatment for 20 s. It was shown that microwave treatment could effectively improve the grindability of the ore, as proven by the increase in fine particles smaller than 0.074 mm and the decrease in RWI after grinding due to the higher crack percentage and mineral liberation degree. Moreover, microwave treatment affected the ore floatability because of the generation of cuprite, retgersite, and rozenite with poor floatability when the treatment time was extended. By microwave treatment for a proper time, 20 s, an optimal balance between the grindability and flotation performance could be achieved. Compared with the untreated ore, the RWI of the ore decreased by 11.5%. After flotation, the Cu and Ni enrichment ratios of the flotation concentrate increased by 0.3 and 0.2, respectively. Meanwhile, their corresponding recoveries increased by 4.2% and 3.1%. This study provides new insights for the treatment of copper–nickel sulfide ore to enhance the grinding and flotation process. | 10.3390/met14050565 | English | China | Journal Article | Metals | 14 | 5 | 565 | |
| A002 | 2024 | Comparative Study of the Rosin-Rammler and Gates-Gaudin-Schuhmann Particle Size Distribution Models for Microwave-Assisted Crushing Analysis | Rasyid, Muhammad A.; Aslam, Azlan; Rafiei, Arash; Sasmito, Agus P.; Hassani, Ferri | https://www.e3s-conferences.org/10.1051/e3sconf/202454301001 | hypabyssal kimberlite | N/A | Microwaves selectively heat dielectric minerals within the ore particles during a relatively brief exposure period, inducing thermal stresses that generate cracks, thereby diminishing the structural integrity of the ore particles. The immediate effect of employing this technique is an alteration in the particle size distribution (PSD) of the comminution product. In this research, two types of diamond-bearing kimberlite ore underwent microwave irradiation before the crushing process. The microwave experimentation was carried out utilizing a multi-variable power system with a maximum capacity of 15 kW, within a singlemode cavity structure. The exposure time was adjustable to vary the input microwave energy, which ranged from 6 kJ to 270 kJ. Three distinct narrow feed size classes were examined: -31.5 +16 mm, -16 +6.7 mm, and -31.5 +6.7 mm. Each sample weighed five hundred grams. Both the microwave-treated samples and the untreated samples (as-received) were subjected to crushing using a single-roll crusher. The PSD of the crushed product was determined through a standard sieving test and subsequently analyzed using empirical PSD models. These models are advantageous for enhancing the accuracy of PSD analysis by linearizing datasets that often exhibit skewness towards the distribution's tail end. Two widely recognized empirical PSD models, the Rosin-Rammler (RR) and Gates-Gaudin-Schuhmann (GGS) models, were employed to assess how microwave pre-treatment influences the PSD of the crushed product. Various comparative parameters derived from these models, such as the P50, distribution uniformity (DP), and critical fine sizes, were evaluated for both untreated crushed samples and the samples treated with microwaves. The findings indicated that crushed products treated with microwaves generally displayed improved alignment with both PSD models in comparison to the untreated samples. Notably, the GGS model exhibited marginally higher overall r-squared values compared to the RR model. Moreover, the microwave-treated samples showcased a slightly coarser and more uniform PSD when contrasted with the untreated counterparts. Among the various microwave energy inputs tested, the lowest input at the highest power level yielded the most substantial increments in P50 and DP. Simultaneously, it led to the most significant reduction in fractions corresponding to critical fine sizes. | 10.1051/e3sconf/202454301001 | English | Canada; Indonesia | Journal Article | E3S Web of Conferences | 543 | N/A | N/A | 1.001 |
| A003 | 2024 | Study on the Evolution of Rock Pore Pressure Under Microwave Irradiation | Xiang, Yang; Li, Yang; Wang, Jiahao; Guo, Zixian; Li, Jingcheng | https://link.springer.com/10.1007/s13369-024-09687-y | basalt; granite; limestone; shale | microwave irradiation; wet porous media; phase transition; water vapor pressure | Microwave-assisted rock-breaking technology is a promising and innovative technique with significant potential for engineering applications. To delve into the variations in rock pore pressure after microwave irradiation, this study employs the theory of wet porous media as the foundation, using numerical simulations to analyze the evolution of pore pressure in different conditions. The research findings indicate that oil-based drilling fluids have a comparably lower influence on the effectiveness of microwave irradiation in comparison with water-based drilling fluids. Additionally, the high conductivity of a medium substantially impacts the irradiation efficacy of microwaves. Basalt exhibits superior microwave absorption and reflection properties compared to granite, limestone, and shale. Consequently, it demonstrates the highest pore pressure, while shale follows with the most rapid decrease in electric field intensity owing to its elevated conductivity. The water vapor pressure escalates with rising rock porosity. Diverse irradiation distances alter the electric field distribution pattern, resulting in various temperature hotspots on the heating surface. Optimal irradiation distances are 10 cm or 16 cm. Additionally, as microwave power rises and irradiation time lengthens, the water vapor pressure inside the rocks intensifies. The irradiation time should be selected to range from 60 to 80 s to avoid evaporative saturation phenomena, which lead to microwave energy loss. Upon microwave irradiation, the pore pressure within rocks may elevate to 4 MPa, inducing a localized imbalanced state at the irradiated surface. This results in a decrease in the rock’s triaxial strength, thereby effectively improving the rock-breaking efficiency of the drill bit. | 10.1007/s13369-024-09687-y | English | China | Journal Article | Arabian Journal for Science and Engineering | 50 | N/A | 5157-5174 | |
| A004 | 2024 | Microwave fracturing of frozen coal with different water content: Pore-structure evolution and temperature characteristics | Yang, Zairong; Wang, Chaolin; Zhao, Yu; Bi, Jing | https://linkinghub.elsevier.com/retrieve/pii/S0360544224007102 | coal | Microwave; water content; liquid nitrogen freezing; NMR; fracturing | Liquid nitrogen (LN2) freezing has widely been studied for the production of coal-bed methane (CBM) in coal reservoirs, but there is little study involving the thawing process. In this paper, the effects of microwave thawing on the LN2-freezing coals with different water content are studied through magnetic resonance imaging (NMR), p-wave velocity, and infrared thermal imaging (ITI). The results prove that the increase rates of the seepage pores of the air-thawing samples increase with the increasing water content. Compared with air thawing, the increase rates of the seepage pores after microwave thawing increase by 17.37%, 9.56%, and 9.32% for the dried, wet, and saturated conditions, respectively. The results of the wave velocity are similar to the increased rates of the seepage pores. The uniformity of the surface temperature of the samples thawed by microwave is related to the initial water content. The low initial water content contributes to the development of surface cracks during LN2 freezing. After microwave thawing, the pore water reduces by 21.46%, 44.85%, and 21.31% for the dried sample, wet sample, and saturated sample, respectively. The research shows that microwave thawing of the frozen coal not only enhances the pore structures but also removes the pore water. | 10.1016/j.energy.2024.130938 | English | China | Journal Article | Energy | 294 | N/A | 130938 | |
| A005 | 2024 | Study on the Mechanism of Rock Damage Under Microwave and Laser Irradiation Through Multiscale and Multiphysics Numerical Modelling | Rui, Fuxin; Zhao, Gao-Feng; Zhang, Yuliang; Fan, Lifeng; Zhao, Xiaobao | https://link.springer.com/10.1007/s00603-023-03608-5 | Modelling | rock thermal damage; microwave and laser irradiation; multiphysics numerical modelling; fine-grained; coarse-grained | High-energy microwaves and lasers are applied to assist mechanical rock breaking due to their advantages in rapid thermal damage to hard rocks. However, the quantitative evaluation of rock damage under microwave and laser irradiation has always been a difficult problem. In this study, a multiscale and multiphysics numerical modelling approach is developed to quantitatively describe rock thermal damage under microwave and laser irradiation. By coupling the concept of the grain-based model (GBM), electromagnetic-thermal solution of COMSOL, and thermo-mechanical fracture simulation of the four-dimensional lattice spring model (4D-LSM), a fine-grained multiphysics numerical model is developed to quantitatively investigate rock damage during muffle furnace heating and microwave heating. Through a full comparison between the fine-grained numerical simulations and experimental results, we concluded that the rock thermal damage functions of these two heating methods are dominantly influenced by the meso-structure and mineral composition of the rock rather than the temperature gradient. Moreover, the limitation of temperature measurement is the most likely reason for the experimentally observed difference in rock thermal damage between muffle furnace heating and microwave heating. For a coarse-grained multiphysics numerical model for larger scale analysis, the influences of meso-structure and mineral composition on the rock thermal damage can be considered by introducing thermal damage functions. Our numerical study indicates that rock thermal damage functions obtained by using experimental data from muffle furnace heating can be used for microwave or laser irradiation, and a calibration method using a weight function with a single correction coefficient is developed to further address the difference in experimental conditions, the change in simulated scale, and the discreteness of used experimental data. Our coarse-grained multiphysics numerical model with thermal damage functions calibrated by data from a single experiment is verified to be able to quantitatively predict the experimentally observed microwave-induced and laser-induced rock damage. This study provides the possibility and methodology to reuse experimental data for rock thermal damage by muffle furnace heating in the analysis of rock damage under microwave and laser irradiation. | 10.1007/s00603-023-03608-5 | English | China | Journal Article | Rock Mechanics and Rock Engineering | 57 | 2 | 1079-1102 | |
| A006 | 2021 | Microwave assisted limestone grinding | Bilen, Candan | https://www.tandfonline.com/doi/full/10.1080/02726351.2021.1924329 | limestone | limestone; microwave; particle size distribution; chemical composition; iron content | In this study, limestone samples were investigated in terms of grinding product particle size distribution (PSD) differentiations after microwave treatment. Initially, collected limestone samples (a total of 58 sample) were crushed and prepared for microwave treatment. In order to observe the effect of microwave treatment, 58 of these samples were ground directly while the other 58 samples were objected to microwave treatment (5 min, 180 W) prior to the grinding. In this paper, size parameters (D10, D50, D90, D32, and D43) and their corresponding differentiations after microwave treatment were evaluated. As regards to the finding of this study, microwave treatment prior to grinding can be claimed to ease the grinding, and finer size distribution can be obtained especially for lower Fe2O3 content samples. It was also found out the fact that MgO and CaO content of samples have influenced the abovementioned PSD differentiation to some extent. | 10.1080/02726351.2021.1924329 | English | Turkey | Journal Article | Particulate Science and Technology | 40 | 2 | 151-164 | |
| A007 | 2023 | Study on microwave heating in-situ treatment of wasted clayey soil | Hu, Qijun; Liu, Zhicheng; He, Leping; Gu, Yucheng; Zeng, Junsen; Li, Muyao | https://link.springer.com/article/10.1007/s11368-023-03554-3 | clayey soil | clayey soil; microwave energy; in situ treatment; waste soil utilization | Purpose Due to its poor performance, clayey soil needs to be replaced to meet the requirements of engineering projects, which causes environmental damage and resource waste. To avoid the aforementioned problems, this study aims to develop an in situ microwave treatment for clayey soil, investigate the effect of microwaves in different soil regions, and evaluate the feasibility of microwave heating in situ treatment of wasted clayey soil. Method A soil model was exposed to microwaves with a frequency of 2.45 GHz and a power of 1.25 kW for 72 h. The temperatures of various locations were monitored in several sections of the model. And the moisture content, macroscopic and microscopic properties, Vickers hardness, free swelling rate, and water stability were measured by a series of tests after irradiation. Results The effects of soil heating, drying, and performance improvement under in situ microwave irradiation are regional. It can be summarized as follows. (1) The soil can be divided into three areas: the microwave heating area, the heat transfer area, and the unaffected area under microwave radiation. (2) Water intensely evaporates in the microwave heating area and migrates in the heat transfer area and unaffected area under microwave irradiation. (3) The soil mechanical properties and water stability are evidently improved in the microwave heating area, and the improvement effect is better than that of traditional heating. Conclusion These findings make it possible to achieve environmental protection and resource conservation by the in situ microwave treatment of clayey soils. | https://doi.org/10.1007/s11368-023-03554-3 | English | China | Journal Article | Journal of Soils and Sediments | 23 | N/A | 3345-3361 | |
| A008 | 2023 | Loaded Failure Characteristics of Anthracite Derived from Microwave Irradiation: Acoustic Emission Evaluation | Gao, Yirui; Zhao, Yixin; Wang, Hao; Liu, Bin; Hartlieb, Philipp; Gao, Sen | https://link.springer.com/10.1007/s00603-023-03494-x | anthracite | anthracite; microwave; uniaxial compression; acoustic emission; failure characteristics | Microwave energy and in situ stress cooperatively influence the permeability of coal reservoirs in microwave-assisted coalbed methane (CBM) extraction. In this study, the combined influence of microwave energy and load on the failure characteristics of coal reservoirs was investigated using acoustic emission (AE) technology. The failure characteristics of anthracite derived from microwave irradiation during uniaxial compression was analyzed from aspects such as the correlation dimension (D) of the AE time series, b-value, and AF–RA correlation. Then the combined mechanism of microwave energy and in situ stress was explored. The results indicated that microwave energy significantly affected the AE activity of anthracite under loading. Moreover, microwave irradiation lessened the damage intensity and increased the crush degree during loading. After lowenergy microwave (≤ 90 kJ) irradiation, the AE signals of anthracite were active only in the unstable crack growth stage, with less damage under load, and mainly characterized by the rapid expansion of large fractures. In contrast, after highenergy microwave (> 90 kJ) irradiation, AE signals penetrate the entire loading process, and the required energy for damage decreased, mostly manifested as small-scale microcracks. Additionally, microwave irradiation changed the failure mode of anthracite under loading from shear failure to tensile failure. In summary, microwave thermal effect reduced the stress threshold for fracture propagation by improving the physical structure of coal reservoirs. Cracks initiated by microwave irradiation could cause in situ stress redistribution, forming stress reduction areas and stress concentration areas, thereby accelerating the expansion of fracture networks. Therefore, the results of this study have great significance for optimizing the scheme of microwave-assisted CBM extraction and improving the CBM production rate through effective utilization of in situ stress. | 10.1007/s00603-023-03494-x | English | China | Journal Article | Rock Mechanics and Rock Engineering | 56 | 12 | 8809-8831 | |
| A009 | 2023 | Failure behavior and energy evolution characteristics of deep roadway sandstone under different microwave irradiation modes | Tang, Mao-ying; Gao, Ming-zhong; Li, Shu-wu; Yang, Ben-gao; Tang, Rui-feng; Li, Fei; Liu, Jun-jun | https://link.springer.com/10.1007/s11771-023-5237-4 | sandstone | microwaves; sandstone; acoustic emission; energy; brittle-ductile transformation | Efficient breaking of hard rock and prevention and control of rock burst disasters are two key concerns for construction in deep areas with high in-situ stresses and are two of the most important ways to ensure the safe and efficient construction of deep engineering. Therefore, this study considers microwave weakening and fracturing of hard rock, taking the duration of a single microwave irradiation treatment as a variable, and synchronously combines mechanical testing and acoustic emission monitoring methods to demonstrate the possibility of rock burst disaster prevention and the control with this treatment method. The result shows that under microwave irradiation, the proportion of crack damage stress decreased from 77% to 62%; the proportion of dissipated energy increased from 6% to 20%, and the energy-based brittleness index also decreased from 0.94 to 0.72; acoustic emission monitoring found that after microwave irradiation, the quiet stage of the rock was greatly reduced from 56.2% and 59.6% to 11.5% and 8.6% with the monitoring time. In this test, the threshold of the duration of 1 kW microwave irradiation is 2 min; beyond this threshold, the rock is irreversibly damaged. The research results can provide necessary theoretical support and technical guidance for efficient and safe rock breaking in deep areas with high in situ stresses. | 10.1007/s11771-023-5237-4 | English | China | Journal Article | Journal of Central South University | 30 | 1 | 214-226 | |
| A010 | 2023 | Influences of Microwave Irradiation on Rock-Breaking Efficiency of a Reduced-Scale TBM Cutter | Lu, Gaoming; Ding, Cong; Zhou, Jianjun; Liu, Haining; Liu, Chaoyin | https://www.mdpi.com/2076-3417/13/8/4713 | basalt | microwave irradiation; TBM; reduced-scale TBM cutter; specific energy consumption; rock breaking efficiency | To explore the influences of microwave irradiation on the rock-breaking efficiency of tunnel boring machine (TBM) cutters, a multimode cavity with a microwave power of 2100 W was used to conduct microwave irradiation tests on Chifeng basalt for different durations. A combined abrasion test device for the reduced-scale SP3-I TBM cutter was adopted to conduct cutter wear and rockbreaking tests on basalt samples before and after microwave irradiation. Influences of microwave irradiation on the wear loss of the reduced-scale TBM cutter, rock removal, cutting force, and specific energy were investigated. The results show that the wear loss of the reduced-scale TBM cutter linearly reduces while the rock removal linearly increases with increasing exposure to microwave irradiation. When the penetration depth and the cutter spacing are fixed, the cutting force and the work done by the cutting force exerted by the reduced-scale TBM cutter decrease linearly with increasing exposure to microwave irradiation. The rock-breaking specific energy decreases with increasing exposure to microwave irradiation in an exponential manner. These results indicate that microwave irradiation can prolong the service life of the TBM cutter in the rock-breaking process, reduce the required thrust and torque of the cutter, and improve the rock-breaking efficiency of the TBM. | 10.3390/app13084713 | English | China | Journal Article | Applied Sciences | 13 | 8 | 4713 | |
| A011 | 2022 | Experimental study on improving mechanical mining efficiency of deep banded iron ore by microwave presplitting | Lin, Feng; Feng, Xia-Ting; Yang, Cheng-Xiang; Li, Shi-Ping; Zhang, Jiu-Yu; Su, Xiang-Xin; Tong, Tian-Yang | https://linkinghub.elsevier.com/retrieve/pii/S136516092200199X | iron ore | true triaxial; banded ore; microwave cracking; mechanical mining | Microwave-assisted mechanical mining is a new mining method with great potential. A self-developed true triaxial system for microwave-induced fracturing and cutting of hard rocks was used to study the microwave cracking process, cracking mechanism, and its effects on subsequent cutting, grinding and mineral dissociation by taking Sishanling banded iron ore as the research object. The results show that compared with microwave irradiation alone, the failure mode and mechanism of ore samples were more complex under the combined action of true triaxial stress and microwaves. Large cracks that were parallel to the bedding plane appeared in the sample under microwave irradiation without triaxial stress. When true triaxial stress and microwave irradiation were used simultaneously, the surface of the sample was subject to spalling or spalling and cracking. Additionally, the correlation (parallel or vertical) between the direction of σ1 and the direction of the bedding plane affected the fracture characteristics. Microwave irradiation could promote subsequent mechanical mining, grinding, and beneficiation of samples. Compared with no microwave treatment, under the action of stress and microwaves, the total amount of rock breakage of samples was increased by 55.1%, the powder content of the product after grinding of cut particles was increased by 21.9%, and the degrees of dissociation of cutting products (<0.1 mm and <0.2 mm) were increased by 11.6 and 12.7%, respectively. The influence of the strip width of magnetite on the microwave cracking effect of ore was estimated. At a given magnetite content, the microwave absorption was worse for wider strips, and the reflection performance was similar for strips of various widths. | 10.1016/j.ijrmms.2022.105233 | English | China | Journal Article | International Journal of Rock Mechanics and Mining Sciences | 159 | 105233 | ||
| A012 | 2024 | Optimization of Microwave Presplitting Iron Ore to Improve Mechanical Mining Efficiency | Lin, Feng; Feng, Xia-ting; Li, Shi-ping; Zhang, Jiu-yu; Su, Xiang-xin; Tong, Tian-yang | https://link.springer.com/10.1007/s00603-023-03665-w | iron ore | true triaxial stress; microwave; reflection; mechanical mining; optimization | Optimizing the microwave parameters adopted in microwave-assisted mechanical mining is of great significance to improving the efficiency of the deep resource development. The effects of varying the type of microwave antenna, microwave power, and working distance on the reflection coefficient and heating characteristics of Sishanling iron ore were studied. The optimized microwave operating parameters were proposed, and microwave irradiation and mechanical cutting tests were then carried out on the ore samples under true triaxial stress conditions to verify the feasibility of the optimized parameters. The results show that the ore’s reflection coefficient increased at first and then decreased as the working distance (2–8 cm) was increased. The reflection coefficient increased as the microwave power was increased. Compared with other distances, the temperature and temperature gradient of the irradiated surfaces of samples were maximized when the working distance was 2 cm. The optimum microwave parameters of iron ore were: a microwave antenna format of horn antenna/standard waveguide antenna, a working distance of 2 cm. Under true triaxial stress conditions, samples suffered no macroscopic damage when irradiated for 300 s at a working distance of 8 cm. When the working distance was reduced to 2 cm, however, samples broke apart after just 10 s (failure mainly taking the form of intermittent spalling). Arcing readily occurred under true triaxial stress conditions when the working distance was 2 cm. This phenomenon occurred on the irradiated surface of the sample and the baffle of the antenna could also be ignited. Ways of optimizing the antenna were put forward and discussed. | 10.1007/s00603-023-03665-w | English | China | Journal Article | Rock Mechanics and Rock Engineering | 57 | 3 | 1897-1914 | |
| A013 | 2024 | Microwave assistance effect for rock breaking of TBM disc cutter using the coupled method of continuum and grain-based model | Wang, Yunlong; Gao, Yanan; Yu, Liyuan; Shao, Xiaoshuang; Hou, Peng | https://linkinghub.elsevier.com/retrieve/pii/S095579972300588X | granite | microwave-assisted rock breaking; penetration test; crack evolution; grain-based model; coordination number | Microwave-assisted rock breaking technique can significantly weaken the strength and the stiffness of hard rock, and can consequently enhance TBM efficiency as well as relieve wear of disc cutters. Understanding the mechanism of microwave-assisted rock breaking requires knowledge of the intersection and connectivity properties of freshly formed fractures below the cutter and the fracture network resulting from microwave-induced damage. In this study, a numerical approach, coupled with the grain-based model (GBM) and continuum based microwave electromagnetic analysis, for simulating the microwave-treated granite is proposed firstly. Subsequently, the numerical experiment of TBM cutter penetration is conducted with the consideration of five levels of microwave power irradiation as well as two waveguide arrangements. The temperature field and fracture behavior are analyzed to investigate the thermal damage of the granite after the treatment of the microwave. Furthermore, the reduction of peak normal force and variation of average coordination number are examined to evaluate the impact of waveguide position on the effectiveness of microwave-assisted rock breaking. The simulation results indicate that the suitable power of microwave irradiation (≥ 30 kW) can promote the rise of granite temperature directly below the waveguide, further resulting in an increase in the quantity of microcracks and noticeable damage to the rock block. When the microwave power exceeds 30 kW, the peak normal force and average coordination number progressively start to decline for the case of a waveguide port facing the centerline of a single cutter. In the case of waveguide facing the gap between double cutters, the decreasing trend of the peak normal force is similar to that under the condition of single cutter, but the starting threshold has been raised to 45 kW. When the microwave power is below 60 kW, the average coordination does not change significantly. After comparing the improvement effects of microwave-assisted rock breaking under the two waveguide arrangements, a preferred condition of the microwave for breaking is determined. The waveguide port facing the centerline of a single cutter, and the microwave power of 30 ~ 60 kW can lead a success in a satisfactory effect in term of the reduction rate of peak normal force and average coordination number. | 10.1016/j.enganabound.2023.12.020 | English | China | Journal Article | Engineering Analysis with Boundary Elements | 159 | 466-484 | ||
| A014 | 2014 | Microwave Assisted Liberation of High Phosphorus Oolitic Iron Ore | Omran, Mamdouh; Fabritius, Timo; Abdel-Khalek, Nagui; El-Aref, Mortada; Elmanawi, Abd El-Hamid; Nasr, Mahmoud; Elmahdy, Ahmed | http://www.scirp.org/journal/PaperDownload.aspx?DOI=10.4236/jmmce.2014.25046 | iron ore | microwave treatment; high phosphorus oolitic iron ore; liberation | The influence of microwave treatment on the liberation of iron ore from the high phosphorus oolitic iron ore from Aswan region, Egypt was studied. The effect of microwave power, exposure time and grain size on the liberation of iron ore was investigated. The microfractures and cracks of the samples were characterized before and after microwave treatments. The heating rate of high phosphorus oolitic iron ore was studied. Crystallinity of hematite was characterized before and after microwave pretreatment. The results indicated that intergranular fractures formed between the gangues (fluorapatite and chamosite) and hematite after microwave treatment, leading to improved liberation of iron ore and a significant reduction in comminution energy. Percentages of fraction ≤ −0.125 mm increased from 46.6% to 59.76% with increased exposure time from 0 to 60 seconds. The heating rate of iron ore showed that microwave treatment was less efficient at smaller particle sizes for a fixed applied power density. Crystallinity of hematite increased with the microwave exposure time. | 10.4236/jmmce.2014.25046 | English | Egypt, Finland | Journal Article | Journal of Minerals and Materials Characterization and Engineering | 2 | 5 | 414-427 | |
| A015 | 2024 | Failure characteristics of microwave heat-treated stressed sandstone: Implications for deep rock breakage using TBM cutting | Tao, Ming; Yang, Zheng; Zhao, Yan; Wu, Xingyu; Wu, Chengqing | https://linkinghub.elsevier.com/retrieve/pii/S0360544224002603 | sandstone | TBM cutting; initial stress; microwave-assisted rock breaking; rock breakage efficiency; crack evolution; sandstone | Microwave-assisted rock fragmentation is a clean, safe, and economically viable method in deep energy development. The innovation of this study lies in the first investigation of rock breaking under initial stress using microwave-assisted tunnel boring machines (TBM) cutters. To overcome the problem of inaccurate monitoring of crack information in laboratory tests, a new concept was adopted to simulate the failure process of microwaveirradiated sandstone caused by a TBM cutter. The microscopic parameters of the model were calibrated based on the laboratory test results. The results showed that an increase in the microwave power led to an increase in the damage level of the sandstone. The dominant failure modes at a low initial stress were vertical and diagonal cracks. At a high initial stress, the failure modes were a combination of vertical, diagonal, and subhorizontal cracks. The critical range of the initial stress to inhibit crack expansion was 10–20 MPa. The rock-breaking efficiency was negatively correlated with initial stress and positively correlated with microwave power. The assisted rock-breaking effect of microwave power was evident at 30 MPa. These results serve as a guide for selecting the appropriate microwave power for rock-breaking under initial stresses. | 10.1016/j.energy.2024.130489 | English | Australia, China | Journal Article | Energy | 292 | 130489 | ||
| A016 | 2024 | Experimental study on the effects of chemical or microwave treatment on the tensile strength of hot dry rock | Zhuang, Deng-deng; Yin, Tu-bing; Zhang, Zong-Xian; Aladejare, Adeyemi; Wu, You; Yang, Zheng | https://linkinghub.elsevier.com/retrieve/pii/S0960148124001046 | granite, sandstone | chemical erosion; microwave radiation; hot dry rock; tensile strength; differential effects | The Brazilian disc (BD) specimens were heated to high temperatures up to 100–500 °C followed by immersion in chemical solutions or irradiation in a microwave oven. The Brazilian splitting tests were then performed at high temperatures, and acoustic emission (AE) events were recorded. Meanwhile, the longitudinal wave velocity and open porosity of the rocks were measured, and the scanning electron microscope (SEM) was applied to identify the influence of chemical or microwave treatment on the microstructure in specimens. The experimental results show that: (1) the chemical or microwave treatment exacerbates the damage to the heat-treated rocks and that either treatment has significant effect on heat-treated rocks with diverse lithologies. (2) The specimens with a high proportion of soluble minerals are chemically dissolved and the specimens with a high percentage of powerful microwave absorption minerals were irradiated by the microwaves, resulting in lower longitudinal wave velocity, lower tensile strength, higher open porosity, and more severe microstructural damages. (3) Rock tensile strength is closely related to the breakdown pressure of hydraulic fracturing, implying that chemical or microwave-assisted fracturing techniques have significant impact on various hot dry rocks, and these auxiliary fracturing techniques considering rock lithology are novel and important for EGS projects. | 10.1016/j.renene.2024.120039 | English | China, Finland | Journal Article | Renewable Energy | 223 | 120039 | ||
| A017 | 2021 | The Temperature and mechanical damage investigation of shale with various dielectric properties under microwave irradiation | Sun et al. | https://www.sciencedirect.com/science/article/abs/pii/S1875510021001268 | shale | shale; microwave heating; temperature rise; p-wave velocity; damage factor F_T | Microwave stimulation technology is a potential effective method to improve shale gas recovery. It is very important to study the influence factors of microwave heating and evaluate the effect of microwave heating on promoting shale microstructure development. Infrared thermal imaging technology was used to study the influence of shale permittivity, saturation and microwave irradiation (MI) parameters on shale heating. The results show that the larger the permittivity is, the faster the heating rate of the sample is and the higher the final temperature is. Meanwhile, it was further confirmed that the contents of pyrite and siderite are positively correlated with the dielectric constant of the samples. The shale with higher saturation has better heating effect under the same microwave heating condition. In addition, when the microwave is used to heat the samples, there is a threshold effect of microwave power. When the microwave power is larger than the threshold, the samples will be heated rapidly. However, when the microwave power increased to a certain extent, better heating effect and higher microwave energy utilization efficiency can be obtained by extending the heating time rather than increasing the microwave power. The SEM images analysis shows that when the thermal stress are greater than the cementation strength between the minerals, micro-fractures will be produced. By analyzing the stress-strain curves of shale samples with different saturation, it is found that the peak stress and elastic modulus of the samples all decreased in different extent. In conclusion, the experimental results show that microwave heating can effectively improve the temperature of shale reservoir, weaken the shale strength, and induce effective fractures. Therefore, this technology has certain application potential in shale gas recovery. | 10.1016/j.jngse.2021.103919 | English | China | Journal Article | Journal of Natural Gas Science and Engineering | 90 | 103919 | ||
| A018 | 2022 | Combined effects of microwave irradiation and water cooling on the deformation and failure behaviours of CSTBD granite | Zhang, Yuliang; Sun, Qiang; Ge, Zhenlong; Rui, Fuxin; Li, Jiale | https://linkinghub.elsevier.com/retrieve/pii/S0013794422005665 | granite | granite; microwave; water cooling; failure pattern; fracture toughness | The low cutting rate and high cutting tool wear rate in hard rock tunnel excavation by a tunnel boring machine (TBM) are critical problems. By integrating microwave technology with water cooling into the TBM cutterhead, microwave-assisted mechanical rock breaking provides a promising solution. To reveal the deformation and failure behaviours of hard rocks after microwave heating and water cooling, this work experimentally conducted a series of tests on cracked straight-through Brazilian disc (CSTBD) granite specimens, where the crack angle was set to 0, 30, 60, and 90° and the microwave heating duration was set to 0.5, 1, 3, 5, and 7 min. During the experiment, digital image correlation (DIC) technology was employed to measure the deformation and failure process. The results show that microwave heating and water-based cooling facilitate the failure of CSTBD granite. The mode-Ⅰ fracture toughness linearly decreases with heating duration for pure tensile failure (crack angle: =0°), while it linearly increases with heating duration at other crack angles (30°, 60°, and 90°). The mode-Ⅱ fracture toughness linearly decreases with heating duration in the crack angle range of 0° to 90°. The mode-Ⅰ fracture toughness linearly decreases with the crack angle. The mode-Ⅱ fracture toughness increases with a crack angle of <24° and decreases in the crack angle range of 24° to 90°. The failure patterns are divided into five categories by different crack angles: pure tensile failure ( = 0°), tensile-shear mixed failure (0° < < 24°), shear failure ( = 24°), compressive-shear mixed failure (24° < < 90°), and compressive failure ( = 90°). The reasons for the main and second cracks during the failure process are revealed. The experimental results have significant implications for microwave-assisted mechanical rock breaking. | 10.1016/j.engfracmech.2022.108848 | English | China | Journal Article | Engineering Fracture Mechanics | 275 | 108848 | ||
| A019 | 2023 | Mechanical weakening behavior and energy evolution characteristics of shale with different bedding angles after microwave irradiation | Deng, Huchao; Yang, Bengao; Gao, Yanan; Xie, Jing; Tang, Ruifeng; Ye, Siqi | https://linkinghub.elsevier.com/retrieve/pii/S2949908923002698 | shale | microwave irradiation; shale; mechanical properties; energy | Microwave irradiation, as a novel, clean, and efficient rock-breaking technology, can be employed in shale gas exploitation to address the challenges of low fracture efficiency and environmental pollution. Therefore, it is essential to investigate the physico-mechanical properties of shale under microwave irradiation. Firstly, samples with different bedding angles (0◦, 30◦, 60◦, and 90◦) were subjected to microwave irradiation at a power of 1 kW and frequency of 2.45 GHz for durations of 0, 20, 40, 60, and 80 s. Additionally, measurements of mass, P-wave velocity, and porosity were taken before and after microwave irradiation, followed by uniaxial compression testing using acoustic emission (AE). The results demonstrated that with increasing microwave irradiation duration, the P-wave velocity and mass of shale gradually decreased, exhibiting anisotropic behavior for the Pwave velocity. The highest degree of weakening (24.75%) was observed for shale at 0◦, while the lowest (7.03%) occurred at 90◦. Both uniaxial compressive strength and elastic modulus weakened gradually. Notably, USC displayed more significant weakening at 30◦ and 60◦. The energy evolution pattern revealed increasing dissipated energy and decreasing brittleness index, enhancing anisotropy with duration, particularly at 60◦. Moreover, AE captured the transition of failure mode from tensile splitting to tensile-shear failure. The results indicated the significant and anisotropic weakening effect of microwave irradiation on shale. The increase in porosity and permeability also provided preliminary evidence for the enhanced permeability ability of shale, resulting in reduced hydraulic fracturing pressures and decreased environmental pollution. Furthermore, the changes of most parameters revealed threshold effect of microwave irradiation duration, which can be classified as weak or strong depending on whether it occurs before or after 40 s. Therefore, attention should be paid to the threshold conditions of microwave irradiation duration to achieve efficient extraction. This research provided initial theoretical support for microwave-assisted shale gas exploitation. | 10.1016/j.jgsce.2023.205141 | English | China | Journal Article | Gas Science and Engineering | 119 | 205141 | ||
| A020 | 2023 | Numerical modelling of microwave irradiated rock fracture | Pressacco, Martina; Kangas, Jari J.J.; Saksala, Timo | https://linkinghub.elsevier.com/retrieve/pii/S0892687523003321 | Modelling | rock fracturing; microwave irradiation; finite element method; compressive strength; numerical simulations | Rock fracturing through microwave irradiation has received significant attention recently as a viable pretreatment for improving the energy efficiency of comminution processes. This study presents a numerical analysis on the effects of microwave heating on the mechanical properties of hard rock. In particular, the reduction of the uniaxial compressive and tensile strength of granite-like rock due to microwave irradiation induced damage is numerically assessed. | 10.1016/j.mineng.2023.108318 | English | Finland | Journal Article | Minerals Engineering | 203 | 108318 | ||
| A021 | 2013 | Reduced grinding time: Effect of microwave heat treatment on the grindability of zircon in a planetary ball mill | Srikant, Satya Sai; Jayasankar, Kalidoss; Mukherjee, Partha Sarathi; Rao, Raghupatruni Bhima | https://www.at-minerals.com/en/artikel/at_Reduced_grinding_time-1852577.html | zircon | N/A | This paper deals with the microwave heat treatment effect on the grinding of zircon in a planetary ball mill for zirflor production. The results of the investigations reveal that the grindability characteristics of zircon samples, which have been heat treated by using both a microwave sintering furnace as well as a conventional muffle furnace followed by thermal shock treatment show a significant saving in grinding time compared to an un treated zircon sample. This is due to the fact that a thermal shock treated sample contains a few microcracks and fractures by which the grinding performance has been improved in a planetary ball mill. | English, German | India | Journal Article | AT Mineral Processing | 54 | 12 | 55-63 | ||
| A022 | 2023 | Dynamic Strength and Indentation Hardness of a Hard Rock Treated by Microwave and the Influence on Excavation Rate | Zou, Chunjiang; Quan, Xin; Ma, Zhongjun; Zheng, Yanlong; Zhao, Xiaobao; Li, Jianchun; Zhao, Jian | https://link.springer.com/10.1007/s00603-023-03243-0 | diorite | Microwave; Dynamic; Strength; Indentation hardness; Excavation rate; Hard rock | Mechanical excavation in hard or very hard rocks is still challenging in rock engineering. One plausible solution is to reduce rock strength prior to mechanical excavation to increase excavation and cost-efficiency. The present study utilizes a 6 kW microwave to irradiate rock specimens and evaluates the variation in rock strength and indentation hardness. Since the contact between the drill bits of roadheaders and the rock surface is a dynamic impact process, dynamic tests are conducted and compared with the quasi-static results. The experimental results demonstrate that short microwave irradiation (30 s) can produce substantial damage to the rock. The reduction of uniaxial compressive strength, Brazilian tensile strength, and indentation hardness under quasi-static loading can be about 39%, 43%, and 44%, respectively, and 33%, 26%, and 50%, respectively, under dynamic loading. In addition, it is found that the tensile strength is the most sensitive to microwave, while the crack density is the least sensitive. More importantly, this reduction is not linear and not monotonic to the irradiation time. The fast reduction of rock strength and indentation hardness after microwave irradiation implies the reduction in the drill-bit wear and increase in the excavation rate, and vigorously demonstrates the great potential of microwave-assisted mechanical excavation of hard or very hard rocks. | 10.1007/s00603-023-03243-0 | English | Australia, China | Journal Article | Rock Mechanics and Rock Engineering | 56 | 6 | 4535-4555 | |
| A023 | 2021 | Effects of Microwave Heating Paths on Pores and Cracks in Bituminous Coal | Yao, Junhui; Chen, Hui; Zhang, Junhui; Zhang, Xiaolei; Guan, Weiming | https://pubs.acs.org/doi/10.1021/acsomega.1c02922 | bituminous coal | coal; electromagnetic radiation; energy; morphology; water vapor | To follow the effect of the microwave heating path on the structure of coal, eight 50 mm diameter, 30 mm long dry coal cores from the same coal seam with similar pore structure characteristics were microwave-treated using 4 pathways. The T2 spectrum, pore-volume, temperature, mass, and visual changes of coal samples were analyzed before and after microwave heating. The microwave heating path affected the macropores and microcracks and the crack development mode. When the same microwave energy was applied, microwave heating on the coal was mainly manifested by the opening of closed pores, before the pyrolysis temperature of the coal was reached. Increasing the energy density caused the water vapor to move from constant pressure expansion to constant volume expansion. This resulted in an exponential growth of the mesopore and macropore volumes. Meanwhile, the micropore volume increased due to the collapse of pore structures. As a result, high-power microwave heating could accelerate the vaporization rate of water. The rapid expansion of water vapor volume brought about a microwave heating effect similar to the “steam explosion”. The resulting local tensile stress enabled the cracks to develop, expand, and connect to others continuously. Thus, it formed a complex crack network leading to the outside of the coal sample. | 10.1021/acsomega.1c02922 | English | China | Journal Article | ACS Omega | 6 | 38 | 24493-24501 | 0 |
| A024 | 2023 | Damage properties of basaltic rocks under multilevel stress loading and microwave irradiation | Liu, Hao; Sun, Huan; Liu, Xiaoli; Ye, Zhenni; Wang, Hui | https://linkinghub.elsevier.com/retrieve/pii/S0013794423003491 | basalt | damage properties; basaltic rocks; multilevel stress loading; microwave irradiation; x-ray digital radiography | The deterioration of mechanical strength and damage characteristics of rock under microwave is the primary focus in evaluating the applicability of microwave-efficient rock-breaking technology. This study analyzed the mechanical strength deterioration and damage characteristics of basalt under microwave irradiation and performed an X-ray digital radiography (DR) image analysis of the damage process of basalt under a multilevel stress loading (MSL) path. The research results show that basalt with a large porosity had a better thermal effect on microwave irradiation and significantly enhanced the resistance to deterioration. The microwave thermal effect of polar minerals is critical to plastic failure behavior. This study also proposes a rock damage characteristic evaluation model based on X-ray DR image quantitative analysis and X-ray absorption dose threshold segmentation. The image analysis model can accurately describe the evolution process of rock damage characteristics. A modified model for basalt damage characteristic analysis is provided. The elastic–plastic damage model based on the Cast3M finite element software was compared with the proposed damage model based on X-ray DR images. The calculated results show that the change in the damage zone was consistent with the damage crack propagation process of basalt. Therefore, the proposed damage evaluation model can provide guidance for the scientific evaluation of the adaptability of microwave-assisted tunnel boring machine (TBM) efficient rock-breaking technology. | 10.1016/j.engfracmech.2023.109391 | English | China | Journal Article | Engineering Fracture Mechanics | 289 | 109391 | ||
| A025 | 2023 | Mixed‐mode I/II fracture properties and failure characteristics of microwave‐irradiated basalt: An experimental study | Yang, Zheng; Yin, Tubing; Wu, You; Zhuang, Dengdeng; Yin, Jiewen; Ma, Jiexin | https://onlinelibrary.wiley.com/doi/10.1111/ffe.13897 | basalt | AE events; equivalent fracture toughness, microwave-assisted rock fragmentation; mixed-mode I-II loading, notched semicircular bending (NSCB) specimen | The notched semicircular bending samples with different microwave irradiations were subjected to 3-point bending fracture tests under mixed-mode I/II loading to investigate the effects of microwave irradiation on the fracture characteristics of basalt. Influences of the irradiation duration on the temperature, P-wave velocity, and mixed-mode I/II fracture characteristics under 2 kW power were studied. The acoustic emission device was utilized to monitor the acoustic emission signals during the destruction process. The P-wave velocity and equivalent fracture toughness are weakened by microwave irradiation, but the ductility of basalt is enhanced by microwave irradiation. The microscopic characteristics of the treated basalts were observed by scanning electron microscope. Microwave irradiation aggravated the creation and propagation of microcracks and pores. The study of the influence of microwave irradiation on mixed-mode I/II fracture characteristics of rock provides effective theoretical support for microwave-assisted rock fragmentation. | 10.1111/ffe.13897 | English | China, Finland | Journal Article | Fatigue & Fracture of Engineering Materials & Structures | 46 | 3 | 814-834 | |
| A026 | 2021 | Experimental and numerical investigations of microwave-induced damage and fracture formation in rock | Xu, Tao; He, Lei; Zheng, Yanlong; Zou, Xingxing; Badrkhani, Vahid; Schillinger, Dominik | https://www.tandfonline.com/doi/full/10.1080/01495739.2020.1865857 | diabase | Microwave-induced fracture;rock; thermal stress; discontinuous deformation analysis | Microwave technology is increasingly used in laboratory tests and field applications as an effective rock breaking technique. The underlying mechanism of rock fracturing induced by microwave energy, however, has not been well addressed. In this study, we employ experimental and numerical methods to investigate the global and local damage of rock in microwave radiation direction, including the fracture formation process. Our analysis focuses on three damage indicators under microwave irradiation, namely P-wave velocity attenuation, temperature distribution and fracture pattern. For a diabase sample, our experimental results indicate that the microwave power and irradiation time has a substantial influence on these three indicators. With increasing power level and irradiation time, we measured a lower P-wave velocity, higher temperature, and more fractures within the rock substrate. We observed that under the same energy, heating at higher power levels for shorter durations has a better weakening effect. Our numerical results show that thermal stress mismatch in the local high-temperature area is the main reason for crack initialization. Nucleation and propagation of microcracks depend on the thermal stress induced by global temperature increase, the geometry of the sample and existing fractures. | 10.1080/01495739.2020.1865857 | English | China, Germany | Journal Article | Journal of Thermal Stresses | 44 | 4 | 513-528 | |
| A027 | 2021 | Experimental Investigation on the Effect of Microwave Heating on Rock Cracking and Their Mechanical Properties | Lu and Zhou | https://www.intechopen.com/chapters/75087 | review book chapter | microwave heating; TBM excavation; temperature characteristics; crack propogation; mechanical properties | Due to various advantages including high efficiency, energy-saving, and having no secondary pollution (no dust or noise), the technology of microwave-induced fracturing of hard rock has been considered as a potential method for rock fracturing and breaking. Realizing microwave-assisted mechanical rock cutting using the microwave-induced hard rock fracturing technique can prolong the mechanical life and improve the efficiency of rock-breaking operations. For example, to realize microwave-assisted TBM excavation for hard rock tunnel. At present, this technology is still in the laboratory research stage. By summarizing the research results of relevant scholars in this field, this paper generalizes the mechanism of microwave heating of rock, microwave heating system, heating characteristics, and the effect of microwave heating on rock cracking and mechanical properties. Microwave heating causes microscopic cracks on the surface of the rock and microscopic cracks inside the rock. The higher the microwave power, the longer the irradiation time, the more serious the cracks propagation. Uniaxial compressive, Brazilian tensile, and point load strengths all decreased with increasing microwave irradiation time at rates that were positively related to the power level. The conventional triaxial compressive strength of basalt samples decreased linearly with microwave irradiation time, and the higher the confining pressure, the smaller the reduction in the strength of basalt samples after microwave treatment. In addition, the elastic modulus and Poisson’s ratio of basalts decreased in a quasi-linear manner with the growth of microwave irradiation time under uniaxial compression. While microwave irradiation has a slight influence on elastic modulus and Poisson’s ratio under triaxial compression. The cohesion decreases with increasing microwave irradiation time and shows an approximately linear decrease over time. | 10.5772/intechopen.95436 | English | China | Other | Microwave Heating - Electromagnetic Fields Causing Thermal and Non-Thermal Effects | ||||
| A028 | 2022 | Effect of microwave radiation on mechanical behaviors of tight fine sandstone subjected to true triaxial stress | Lu et al. | https://www.sciencedirect.com/science/article/abs/pii/S1365160922000314 | sandstone | true triaxial stress; microwave heating; deformation; strength; failure characteristics | During the exploitation of deep resources, rock masses are under three-dimensional anisotropic stress conditions owing to tectonic conditions and engineering disturbances. Owing to the advantages of high heating efficiency and selective volume heating, microwaves have broad application prospects in fields such as unconventional low-permeability reservoir fracturing. Therefore, it is of great significance to study the mechanical behavior of rocks under true triaxial stress after microwave irradiation. In this study, true triaxial tests of sandstone under different microwave irradiation conditions were conducted. The results showed that the strength of the irradiated sandstone first increased and then decreased. The strength of the irradiated sandstone was significantly lower than that of the unirradiated sandstone. The pre-peak brittleness of the sandstone gradually increased with an increase in σ₂. The brittleness of the irradiated samples was lower than that of the unirradiated samples. For the post-peak brittleness index of the sandstone, with the increase of σ₂, the microwave irradiated and unirradiated sandstone both gradually decreased first and then slowly increased. The residual strength of the unirradiated sandstone showed a trend of first increasing and then stabilizing, while the residual strength of the irradiated sample showed a greater dispersion and fluctuation. And, the residual strength of sandstone first increased and then decreased with the increase of microwave duration. In addition, a new double logarithmic linear strength model was proposed, which is in good agreement with the experimental results. The true triaxial stress induced anisotropic damage and deformation of sandstone are critical to rock fracture. The stress difference induced by water vapor expansion and mineral thermal expansion is the main factor for microwave breaking water-bearing sandstone. This work is of great significance to the research and application of microwave assisted breaking hard rock and fracturing deep low-permeability reservoir rocks. | 10.1016/j.ijrmms.2022.105063 | English | China | Journal Article | International Journal of Rock Mechanics and Mining Sciences | 152 | 105063 | ||
| A029 | 2022 | Fracture behaviour of microwave-heated granite under indentation: Experimental and numerical investigation | Li et al. | https://www.sciencedirect.com/science/article/abs/pii/S0013794422002739 | granite | racture behaviour; indentation; microwave heating; numerical simulation; hard rock breakage | Microwave-assisted rock breakage is a promising solution for drilling and crushing hard-rock formations. The fundamental mechanical and thermophysical properties of microwave-treated granite were obtained, and the factors affecting the fracture behaviour under indentation were investigated using experimental and numerical methods. The results show that the uniaxial compressive strength, tensile strength, brittleness index, thermal conductivity, and thermal diffusivity of microwave-heated granite are negatively correlated with temperature, whereas the specific heat capacity of treated granite is positively correlated with temperature. The fracture process of microwave-heated granite under indentation can be divided into three stages: elastic deformation, fluctuating penetration, and post-peak. The indentation damage zone near the indenter consists mainly of tensile cracks. Meanwhile, regression analysis shows that the peak indentation force, penetration depth, and consumed energy of the microwave-heated sample are linearly correlated with the brittleness index. In addition, microwave treatment can weaken the inhibitory effect of a high confining stress on the damage zone and is conducive to reducing the indentation force and penetration depth of rock fragmentation. The specific energy is more sensitive to temperature under high confining stress conditions, and the relationship between the specific energy, temperature, and confining stress can be described by a 2D poly function. | 10.1016/j.engfracmech.2022.108535 | English | China | Journal Article | Engineering Fracture Mechanics | 269 | 108535 | ||
| A030 | 2024 | Enhancing iron ore grindability through hybrid thermal mechanical pretreatment | Adewuyi, S. O.; Ahmed, H. A. M.; Anani, A.; Saeed, A.; Ahmed, H. M. A.; Alwafi, R.; Luxbacher, K. | https://www.mdpi.com/2075-163X/14/10/1027 | iron ore | microwave heating; thermal treatment; comminution energy; ore grinding; work index | Grinding is an important process of ore beneficiation that consumes a significant amount of energy. Pretreating ore before grinding has been proposed to improve ore grindability, reduce comminution energy, and enhance downstream operations. This paper investigates hybrid thermal mechanical pretreatment to improve iron ore grinding behavior. Thermal pretreatment was performed using conventional and microwave approaches, while mechanical pretreatment was conducted with a pressure device using a piston die. Results indicate that conventional (heating rate: 10 °C; maximum temperature: 400 °C), microwave (2.45 GHz, 1.7 kW, 60 s), and mechanical (14.86 MPa, zero delay time) pretreatments improved the studied iron ore grindability by 4.6, 19.8, and 15.4%, respectively. Meanwhile, conventional-mechanical and microwave-mechanical pretreatments enhanced the studied iron ore grindability by 19.2% and 22.6%, respectively. These results suggest that stand-alone mechanical pretreatment or microwave pretreatment may be more beneficial in improving the grinding behavior of the studied fine-grain iron ore sample. The results of the mechanical pretreatment obtained in this study may be used in a simulation of the HPGR system for grinding operations of similar iron ore. | 10.3390/min14101027 | English | Saudi Arabia | Journal Article | Minerals | 14 | 10 | - | 1.027 |
| A031 | 2024 | Experimental investigation and numerical modeling of effect of specimen size on microwave-induced fracturing of diorite | Ma, Zhongjun; Zheng, Yanlong; Rui, Fuxin; Zhao, Gaofeng; Li, Jianchun; Che, Ping | https://linkinghub.elsevier.com/retrieve/pii/S0892687524001067 | diorite | microwave treatment; fracturing behaviours; size effect; open-ended antenna; damage zone; fracture energy | The effect of specimen size on microwave-induced fracturing of rocks has not been well understood. In this study, the experimental tests using open-ended microwave and numerical simulations coupling COMSOL Multiphysics and four-dimensional lattice spring model (4D-LSM) were carried out to investigate the evolution process of microwave-induced cracks, and to elucidate the mechanisms responsible for size-dependent microwave-induced fracturing. The experiments show that with the increase of the specimen dimension, the number of microwaveinduced cracks is almost constant, and the total crack length first increases and then decreases, while the maximum crack width and maximum crack depth decrease gradually. A comparison of the experimental and numerical temperature characteristics as well as cracking characteristics indicates that the models established in this study are reasonable in the simulation of the rock fracturing behaviours. The numerical results show that the crack initiation time increases logarithmically with the increase of the specimen dimension. For the small-sized specimens, the microwave-induced cracks started from the outer boundary of the specimen and propagated toward to specimen center and into the depth. For the medium-sized and large-sized specimens, the microwaveinduced cracks initiated near the outer boundary of the antenna aperture, and then propagated toward to the center of the specimen and the outer boundary of the specimen. The main reason for the size-dependent of fracturing behavior is that the local fracture energy will dramatically decrease when the crack is approaching the specimen boundary. | 10.1016/j.mineng.2024.108677 | English | China | Journal Article | Minerals Engineering | 210 | - | - | 108.677 |
| A032 | 2024 | Effect of microwave heating on rock damage and energy evolution | Li, Tan; Wang, Wei; Chen, Guangbo; Li, Qinghai | https://cdnsciencepub.com/doi/10.1139/cgj-2024-0071 | coarse sandstone | microwave heating; mechanical properties; damage variables; brittleness index; impact energy index | Rock fragmentation efficiency can be increased by microwave heating. The mechanical properties and energy evolution characteristics of coarse sandstone specimens under different microwave heating conditions are compared in this paper. The effects of microwave heating time and power on coarse sandstone specimens of peak stress, elastic modulus, brittleness index, damage variable, and impact energy index are analyzed. The results indicate that the microwave heating power and microwave heating time are inversely proportional to peak stress and elastic modulus and directly proportional to peak strain. With the increase of microwave heating power and microwave heating time, the brittleness index and damage variable of rock specimens increase, the impact energy index decreases. The microwave heating power and microwave heating time increase the rock brittleness index. The energy absorption rate of rock specimens decreases with the increase of microwave heating time. The impact energy index is inversely proportional to microwave heating power and microwave heating time. High-power and long-time microwave heating can reduce the possibility of rockbursts and the intensity of potential dynamic disasters. The research conclusion can provide the theoretical and technical basis for breaking rock by microwave heating. | 10.1139/cgj-2024-0071 | English | China | Journal Article | Canadian Geotechnical Journal | 61 | 11 | 2523-2534 | 0 |
| A033 | 2024 | Influence of microwave irradiation and water-based cooling on the fracturing behavior and failure mode transition of CSTBD granite | Zhang, Yuliang; Gu, Yiming; Sun, Qiang; Rui, Fuxin; Ge, Zhenlong; Jia, Hailiang | https://linkinghub.elsevier.com/retrieve/pii/S0013794423007907 | CSTBD granite | granite; microwave; water cooling; failure patterns; fracture toughness | Utilizing microwave heating in conjunction with water-based cooling technology can effectively reduce the fracture toughness of hard rocks. However, the fracturing characteristics and failure modes of hard rocks following microwave heating and water-based cooling remain undisclosed. Granite, being one of the most common types of hard rocks, was selected for this study, employing Cracked Straight Through Brazilian Disc (CSTBD) specimens for laboratory testing. CSTBD specimens with various crack angles (0, 30, 60, and 90◦) underwent treatment with varying microwave durations (30, 60, 180, 300, and 420 s). Subsequently, Brazilian splitting tests were conducted on the damaged specimens. To simulate the entire process of microwave heating and mechanical testing of CSTBD specimens, we developed a coupled Finite Element Method –Distinct Lattice Spring Model (FEM-DLSM) approach. The results indicate that microwave heating with water-based cooling significantly influences the fracture toughness of CSTBD granite. Mode-I fracture toughness decreases with microwave heating temperature at a low crack angle (pure tensile failure and tensile–shear mixed failure) and increases at a high crack angle (compressive–shear failure and compressive failure). Mode II fracture toughness decreases with microwave heating temperature at any crack angle. Microwave heating with water-based cooling causes a decrease in the transition angles from tensile–shear failure to compressive–shear failure and from compressive–shear failure to compressive failure. Thermally induced microcracks in the rock specimen are responsible for changes in fracture toughness and failure mode transitions. After microwave heating and water-based cooling, numerous microcracks are induced in the rock interior. While macroscopic cracks predominantly control failure, growing microcracks, by weakening the rock matrix, shift the initiation position of the failure crack from the tip of the macroscopic crack to other positions, following the principle of the weakest failure path. | 10.1016/j.engfracmech.2023.109832 | English | China | Journal Article | Engineering Fracture Mechanics | 296 | - | 109832 | 0 |
| A034 | 2015 | Meso-mechanics simulation analysis of microwave-assisted mineral liberation | Qin Like; Dai Jun; Yuan Liqun | https://www.fracturae.com/index.php/fis/article/view/1612 | galena; calcite | microwave heating; assisted liberation; meso-mechanics simulation; irradiation time; energy consumption | Microwave-assisted crushing and grinding can improve efficiency and reduce energy consumption. This paper takes rock grains with galena and calcite as the research object to establish a two-dimensional computational model through the finite difference software FLAC2D. It analyzes the process and law of mineral boundary failure under microwave irradiation, and assesses the effects of four factors, namely, microwave irradiation time, power density, mineral crystal size, and mineral content, on mineral boundary failure. Results indicate an optimal microwave irradiation period for the rapid failure of mineral boundary. Moreover, irradiation time and energy consumption can be reduced by increasing the microwave power density. However, irradiation time and energy consumption are basically unchanged when the microwave power density is above a certain threshold. Mineral content slightly affects the microwave irradiation time, whereas mineral crystal size significantly affects the microwave irradiation time. In addition, a larger-sized mineral crystal requires less irradiation time and energy consumption to reach the same failure rate. However, irradiation time and energy consumption slightly change when the crystal size is larger than a certain value. | 10.3221/IGF-ESIS.34.60 | English | China | Journal Article | Frattura ed Integrità Strutturale | 34 | - | 543-553 | 0 |
| A035 | 2020 | Thermal response and crack propagation of mineral components in olivine basalt under microwave irradiation | Yuan, Yuan; Shao, Zhushan; Qiao, Rujia; Fei, Xinshuang; Cheng, Junxi | https://link.springer.com/10.1007/s12517-020-05494-5 | basalt | microwave; olivine basalt; mineral components; thermal responses; crack propogation | Microwave pre-treatment of mechanical rock breakage is an efficient technology to reduce bit wear and maintenance cost of the breaker. Thermal responses of basalt and its mineral components were tested using a multimode industrial microwave system. Different dielectric properties of the mineral components resulted in thermal stress within the basalt and hence crack propagation. Crack patterns of basalt after exposure were observed employing scanning electron microscope (SEM). Rock failure was induced by the unstable extension of radial cracks around the absorbing mineral grain boundary. A novel theoretical model containing initial micro cracks was established to investigate crack propagation behavior under microwave irradiation. A characteristic radius of cracks existed where the microwave energy required for crack growth was minimum. Cracks with radius shorter than characteristic radius would propagate in a kinetic manner. Most of the damage concentrated in an optimum exposure time range at the given power might be explained by the kinetic propagation of micro cracks. | 10.1007/s12517-020-05494-5 | English | China | Journal Article | Arabian Journal of Geosciences | 13 | 14 | 589 | 0 |
| A036 | 2022 | Mechanical responses of igneous rocks to microwave irradiation: a review | Bai, Guogang; Sun, Qiang; Jia, Hailiang; Ge, Zhenlong; Tang, Liyun; Xue, Shengze | https://link.springer.com/10.1007/s11600-022-00789-5 | granite, basalt, syenite, gabbro | microwave; microwave energy; heating rate; rock strength; rock crack | In order to explore the mechanism of microwave radiation damage to rocks and improve the efficiency of underground rock fragmentation, statistics have been conducted for nearly 40 years, and the heating effects of four types of igneous rocks (granite, basalt, syenite, and gabbro) after microwave irradiation have been analyzed. The attenuation of tensile and compressive strength, and the microwave response mechanism of igneous rocks are studied. The results show that under microwave energy of 0–50 kJ, the tensile and compressive strengths of rock do not change significantly; however, above 50 kJ, they decrease rapidly. With increasing contents of Fe-rich minerals in rock, such as pyroxene, microwaves have a greater fracturing effect, which is manifested as rapid attenuations in tensile and compressive strength. The wave velocity damage factor and tensile strength damage factor of igneous rocks increase with the increase of microwave energy. | 10.1007/s11600-022-00789-5 | English | China | Journal Article | Acta Geophysica | 70 | 3 | 1183-1192 | |
| A037 | 2022 | Porosity and mechanical strength of microwave-heated gabbro | Ding, Rui; Sun, Qiang; Geng, Jishi; Luo, Tao; Yuan, Shihao | https://link.springer.com/10.1007/s40948-022-00508-w | gabbro | gabbro; microwave; porosity; compressive strength; acoustic emission | The efficient fracturing of hard rock is a key factor for exploration and development of deep resource. Microwave induced rock fracture technology is an important tool to achieve continuous mining of hard rock without blasting. In this paper, gabbro was irradiated for different times (0–15 min) in a 0.9 kW microwave environment to investigate the changes in pore and compressive strength using NMR and uniaxial compression tests. The results show that microwave irradiation can be divided into three stages of 0 min, 5–10 min and 12–15 min, and the changes of porosity and compressive strength are closely related to these three stages. The surface temperature, porosity and permeability of gabbro increased and the compressive strength decreased with the increase of microwave irradiation time. This is due to the strong wave absorption of pyroxene and black mica in gabbro, and the uneven thermal expansion of the mineral composition generates thermal stress. The surface cracks of gabbro are dominated by intergranular cracks during the first 10 min of microwave irradiation and then by transgranular cracks. The results of this study are important to promote the future development of microwave-assisted rock-breaking technology. | 10.1007/s40948-022-00508-w | English | China | Journal Article | Geomechanics and Geophysics for Geo-Energy and Geo-Resources | 8 | 6 | 196 | 0 |
| A038 | 2024 | Experimental Study on Mechanical Damage characteristics of water-bearing tar-rich coal under microwave radiation | Yan, P.; Shan, P.; Xu, H.; Chen, J.; Li, Z.; Sun, H. | https://link.springer.com/article/10.1007/s40948-023-00726-w | tar-rich coal | microwave radiation; moisture content; tar-rich coal; energy evolution; crack expansion; fractal dimension | As a recognized special resource, tar-rich coal can extract the country's scarce oil and gas resources and generate semi-coke that can replace anthracite and coking coal. The tar-rich coal in northern Shaanxi is prominent, but due to the dense structure and high strength of tar-rich coal, it is easy to cause frequent dynamic disasters in coal mining. Therefore, the realization of pressure relief and disaster reduction has become the primary problem in mining tar-rich coal. There are many shortcomings in conventional pressure relief methods, so a new method of microwave-weakening coal is proposed. Through different water saturation treatments of tar-rich coal samples, the longitudinal wave velocity degradation trend and surface crack expansion law of water-bearing coal after microwave irradiation were analyzed, and the strength softening characterization and energy evolution relationship under the combined action of microwave and water were studied. Fractal dimension and its internal correlation based on the equivalent side length-mass of coal sample fragments. The experimental results show that: (1) Under the same microwave radiation condition, with the increase of water saturation, the deterioration trend of physical and mechanical parameters such as longitudinal wave velocity and peak strength is obvious. (2) After microwave radiation, the uniaxial compression results show that the coal sample is damaged by load, there is still a high residual strength, the ratio of elastic energy to dissipation energy decreases, and the possibility of rockburst of the coal sample decreases. The strength softening degree of coal specimen under the degradation of microwave and water is the highest, followed by microwave and water. (3) The fractal dimension is inversely proportional to the moisture content and microwave radiation intensity, and the fractal dimension has a significant positive correlation with the peak intensity and longitudinal wave velocity. The mechanical damage law of water-bearing tar-rich coal under microwave action is revealed, which aims to solve the problem of weakening and reducing the impact of hard coal on-site to a certain extent, ensure the safety of working face, and improve the mining efficiency of tar-rich coal. It provides basic theoretical support for microwave-assisted hydraulic fracturing technology and effective weakening measures for hard roof treatment. | https://doi.org/10.1007/s40948-023-00726-w | English | China | Journal Article | Geomechanics and Geophysics for Geo-Energy and Geo-Resources | 10 | 3 | - | 0 |
| A039 | 2024 | Variation in the electrical properties of gabbro after microwave heating | Ge, Zhenlong; Guan, Yuhua; Lyu, Chao | https://link.springer.com/10.1007/s00231-024-03502-y | gabbro | N/A | Microwave assistance has the potential to reduce the energy input required for mechanical rock breaking. This study systematically investigated the changes in electrical properties (specifically resistivity, capacitance, and impedance) of gabbro after microwave heating during the graded loading process, as well as its internal fracture mechanism. The findings indicate that the variations in resistivity, impedance, and capacitance of gabbro can be divided into three stages during the graded loading process: the compaction stage, elastic-steady cracking stage, and nonlinear crack propagation stage. When the strain level exceeds 70%, the resistivity and impedance start to increase, and the capacitance begins to decrease. The study also identifies a significant positive correlation between microwave power and the rate of temperature increase on the rock surface. A critical power threshold of approximately 2 kW is observed, below which achieving rapid temperature rise becomes challenging, but beyond which the temperature escalates swiftly with the energy input. Once the temperature exceeds 350 °C, rupturing mineral inclusions generate numerous microcracks, causing resistivity and impedance to exponentially increase. Furthermore, microwave heating induces a temperature differential exceeding 200 °C between the internal and external regions of the rock. Under the same radiation energy, high-power short-duration radiation is more likely to generate thermally induced cracks within the rock. The rapid expansion and heating of absorbent minerals, as well as the rupture of inclusions, further intensify the propagation of microcracks, greatly reducing the mechanical properties of the rock. This study will provide theoretical guidance for microwave-assisted mechanical rock excavation. | 10.1007/s00231-024-03502-y | English | China | Journal Article | Heat and Mass Transfer | 60 | 9 | 1485-1495 | 0 |
| A040 | 2024 | Thawing and Softening of Frozen Sandstone by Microwave Irradiation | Han, Li; Jia, Hailiang; Dong, Yuanhong; Wei, Yao; Tan, Xianjun | https://link.springer.com/10.1007/s00603-023-03559-x | sandstone | microwave irradiation; frozen quartz sandstone; saturation degree; thawing and softening laws; damage mechanisms | The strength and hardness of rock are much higher at freezing temperatures than at room temperature. This results in high excavation costs and low excavation efficiency in frozen rock layers. This study proposes a novel way to thaw porous and water-bearing rock by microwave irradiation. It is applicable to a wide range of strata and is not dependent on whether the rock contains wave-absorbing minerals. Quartz sandstone specimens free from absorbing minerals and of different saturation levels were used in an investigation of thawing and softening behaviors under microwave irradiation. The rock pore structures were observed before and after irradiation. The results show that (1) frozen quartz sandstone irradiated by microwaves undergoes three stages: (i) rapid melting of pore ice, (ii) intense vaporization of meltwater, and (iii) drying. (2) Microwave irradiation significantly reduces the strength of frozen quartz sandstone. (3) The mechanisms are vaporization expansion, which causes the propagation of intergranular cracks, and thermal expansion, which induces trans-granular cracking. (4) Softening of 40–100%-saturated frozen quartz sandstone is caused by both vapor and thermal expansion, while 0–40%-saturated sandstone is mainly affected by thermal expansion. This study provides theoretical and experimental support for microwave-assisted breakage of frozen porous and water-bearing rock. | 10.1007/s00603-023-03559-x | English | China | Journal Article | Rock Mechanics and Rock Engineering | 57 | 1 | 79-95 | 0 |
| A041 | 2024 | Numerical simulation of microwave-induced cracking and melting of granite based on mineral microscopic models | Su, Xiaoli; Li, Diyuan; Zhao, Junjie; Wang, Mimi; Su, Xing; Zhou, Aohui | https://link.springer.com/10.1007/s12613-023-2821-4 | granite | microwave; numerical modeling; microcracking; phase change; granite | This study introduces a coupled electromagnetic–thermal–mechanical model to reveal the mechanisms of microcracking and mineral melting of polymineralic rocks under microwave radiation. Experimental tests validate the rationality of the proposed model. Embedding microscopic mineral sections into the granite model for simulation shows that uneven temperature gradients create distinct molten, porous, and nonmolten zones on the fracture surface. Moreover, the varying thermal expansion coefficients and Young’s moduli among the minerals induce significant thermal stress at the mineral boundaries. Quartz and biotite with higher thermal expansion coefficients are subjected to compression, whereas plagioclase with smaller coefficients experiences tensile stress. In the molten zone, quartz undergoes transgranular cracking due to the α–β phase transition. The local high temperatures also induce melting phase transitions in biotite and feldspar. This numerical study provides new insights into the distribution of thermal stress and mineral phase changes in rocks under microwave irradiation. | 10.1007/s12613-023-2821-4 | English | China | Journal Article | International Journal of Minerals, Metallurgy and Materials | 31 | 7 | 1512-1524 | 0 |
| A042 | 2024 | Study on heating characteristics of granites with different sizes in microwave field | Zhang, Yang; Yang, Ben-Gao; Xie, Jing; Tang, Rui-Feng; Bai, Yan-Bo; Gao, Ming-Zhong | https://doiserbia.nb.rs/Article.aspx?ID=0354-98362404511Z | granite | microwave heating, sizes effect, numerical model, granite | Studying the heating characteristics of rocks in a microwave field is fundamental to exploring the mechanism of microwave rock breaking. Therefore, a heterogeneous granite model was established using COMSOL Multiphysics to deeply analyze the specific influence of rock size on rock heating characteristics in a microwave field. The results show that with the increase of rock size, the heating rate of rock exhibits a fluctuation characteristic. This phenomenon occurs because changes in rock size leads to variations in both the magnitude and spatial arrangement of electric field intensity. Further analysis of the electromagnetic loss of granite reveals that increasing rock volume can significantly enhance microwave energy utilization efficiency. Additionally, biotite occupying only 8% of the rock volume, absorbs over 55% of the microwave energy, highlighting the significant impact of biotite content on the heating characteristics of granite. | 10.2298/TSCI2404511Z | English | China | Journal Article | Thermal Science | 28 | 4 Part B | 3511-3516 | 0 |
| A043 | 2024 | Experimental observation on rock damage under microwave thermal shock | Teng, Teng; Yi, Peng; Jia, Wen-Jian; Wu, Xiao-Yan | https://doiserbia.nb.rs/Article.aspx?ID=0354-98362404457T | granite | heat shock; thermal damage; microwave; hard and brittle granite | Microwave thermal shock is an optimized means of crushing rocks in engineering, in order to investigate the effect of microwave thermal shock on granite, this paper adopts microwave irradiation and SEM experiments to investigate the mechanical behavior and microstructural evolution law of granite, and the main conclusions are: With the increase of the duration of thermal shock, granite exhibits the law of linear increase, and the peak strength and elastic modulus show the trend of rising first and then decreasing; After thermal shock the acoustic emission signal of granite is linearly rising, while the internal shear cracks expand to form larger transgranular cracks, the results of the study have great significance for the future development of traditional mining technology. | 10.2298/TSCI2404457T | English | China | Journal Article | Thermal Science | 28 | 4 Part B | 3457-3463 | 0 |
| A044 | 2024 | Doing Things Differently: Addressing the Comminution Energy Challenge | Batchelor, Andrew; Kingman, Sam; Craig, David; Purutyan, Herman; Bearman, Richard | https://store.smenet.org/22ocik7/262 | copper porphyry | N/A | As ore bodies age and grades decline, increasingly higher embodied energy input is required for comminution to maintain production, which increases costs and the carbon footprint of these operations. A step-change in energy reduction is required to meet the future demand of these processes. Indeed, several miners have made zero carbon commitments for the coming decades. Following haul trucks, comminution represents the highest percentage of CO2 emissions and a step change in the efficiency of comminution is required to significantly reduce overall mine -site emissions. In our work we present the state of the art in microwave processing of ores, an electrical technology which, after decades of development, now has the potential to be a key part of the step changes needed to deliver the zero-carbon outcomes required by the mining industry. The technology is now at the stage where commercial deployment can be considered, and we review routes to maximise the commercial and carbon reduction benefit of this technology. In particular, we consider the impact of induced fractures on conventional grinding/flotation circuits, on the performance of leach systems and on new flowsheets with the potential to deliver a paradigm shift in carbon emissions from mineral processing circuits. | N/A | English | UK | Conference Proceeding | IMPC 2024 | 0 | N/A | 248-260 | 0 |
| A045 | 2021 | Fracture behavior of concrete coarse aggregates under microwave irradiation influenced by mineral components | Yuan, Yuan; Shao, Zhushan; Qiao, Rujia; Fei, Xinshuang; Cheng, Junxi; Wei, Wei | https://linkinghub.elsevier.com/retrieve/pii/S0950061821007042 | garnite; basalt; olivine; pyroxene; K-feldspar; plagioclase; granite; honblende; quartz; ilmenite; biotite; basalt | concrete coarse aggregates; crack propogation; fracture behaviour; microwave irradiation; temperature gradient | Significant damage of some coarse aggregates due to microwave irradiation is neglected by most previous studies on microwave-assisted concrete recycling technique. Fracture behavior of commonly used coarse aggregates: granite and basalt were investigated by microwave heating tests. Heating rate of aggregates’ mineral components was tested respectively. Ilmenite was heated rapidly while other minerals were heated tardily. Larger temperature gradient was generated in basalt because of more ilmenite content to induce fracture, granite was not fractured yet. Most initial cracks in basalt extended along clockwise angle in Mode Ⅰ. Fracture of basalt occurred with more damage at higher power level. | 10.1016/j.conbuildmat.2021.122944 | English | China | Journal Article | Construction and Building Materials | 286 | - | - | 122.944 |
| A046 | 2014 | An application of microwave heating in treatment of selected minerals | Znamenackova, I.; Lovas, M.; Hredzak, S.; Dolinska, S. | https://www.proquest.com/openview/ef5dfa57c6a96abdb855851074f610ef/1?pq-origsite=gscholar&cbl=1536338 | quartz; barite; magnesite siderite; magnetite; galena; pyrite; chalcopyrite | heating; microwave; minerals; relative work index | The heating of minerals and ores in the microwave field depends on the dielectric properties and their ability to absorb the microwave energy. The temperature of samples was measured with a contactless infrared thermometer Raytek RAYMX4PG during microwave heating. The results of microwave heating of minerals during 1 and 5 minutes at power 900 W and the frequency 2.45 GHz are described. The sufficient penetration depth of microwaves to the material is needed at the heating of different types of materials in the microwave field. On the basic of the heating rate, irradiated minerals were divided into weakly heated minerals such as quartz, barite and well heated minerals, such as pyrite, chalcopyrite, magnetite, galenite and siderite. The temperature distribution in the sample of siderite and magnesite during microwave heating was described by COMSOL Multiphysic programme, on the basis of knowledge of their dielectric and physical characteristics, as well as the frequency and the intensity of the electric field. The submitted work described the influence of microwave energy on the intensification of the comminution processes. In consequence of microwave heating the stress and thermal dilatation at the interface of mineral grains arises. It increases the failure and following processes of irradiated specimens comminution. The rate of failure has been investigated on the basis of measurement of the elastic wave velocity by the impulse-dynamic method. The high degree of failure was observed after 2 minutes of microwave irradiation of siderite sample and after 5 minutes at magnesite sample at the power 900 W. The unpretreated and microwave pretreated samples of magnesite were crushed using the vibratory jaw crusher VČM-3. Consequently, the particle size distribution curves for crushed products were constructed. Finally, the relative work indexes according to the Berry and Bruce method were calculated and compared. After microwave heating of magnesite sample at the power 2500 W it was confirmed 18% decreasing of work index and 38% decreasing at the microwave power 5000 W. | 10.5593/SGEM2014/B13/S4.123 | English | Slovakia | Conference Proceeding | International Multidisciplinary Scientific GeoConference : SGEM | 3 | - | 965-972 | 0 |
| A047 | 2008 | Effects of Microwave Energy on Grinding of Colemanite | Eski, M F; Özkan, S G | https://nek.istanbul.edu.tr/ekos/MAKALE/M6190.pdf | colemenite | microwave treatment; colemanite; grinadability; characterization | Experiments were carried out on the samples of pure colemanite mineral samples supplied by Eti Mine Inc. 's Bigadic Boron Mines and classified according to partide size fractions of -8+4mm, -4+2mm and -2+1 mm. Grinding tests were performed on the samples using a conventional dry rod mill of which parameters kept constant during all tests. Material characterization tests including complete chemical, mineralogical by XRD and moisture analyses were also done in order to see the effect of microwave energy on colemanite surfaces. A kitchen type microwave oven with 2450 MHz frequency was used for surface modification by microwave pretreatment at five power levels before grinding. The effects of microwave pretreatment on the grindability of colemanite were determined by cumulative partide size distributions of the ground products. Microwave energy certainly affects grindability of colemanite due to loss of moisture near the surface and also some crystal water inside the lattice. Therefore microcracks due to this phenomenon ease the grindability of the mineral. | English | Turkey | Journal Article | 11th International Mineral Processing Symposium | 0 | - | 185-190 | 0 | |
| A048 | 2015 | Deriving the ideal ore texture for microwave treatment of metalliferous ores | Batchelor, A.R.; Jones, D.A.; Plint, S.; Kingman, S.W. | https://www.sciencedirect.com/science/article/pii/S0892687515301035 | nickel, copper, lead-zinc | microwave; ore; mineralogy; comminution | High power density microwave treatments on metalliferous ores have historically been shown to reduce ore competency prior to beneficiation at economically feasible energy inputs. However, the relationship between mineralogical textural features and the extent of the microwave-induced fracturing had previously been limited to qualitative descriptions or simplistic two-phase numerical models, which could not account for the complex mineral assemblages in real ores. In this paper, mineralogy, grain size, dissemination, textural consistency and mineral associations were determined for 13 commercially exploited nickel, copper and lead–zinc ores using a Mineral Liberation Analyser (MLA). The ores were subjected to high power density microwave treatments at up to 25 kW in a single mode cavity with microwave energy inputs of approximately 0.5–10 kW h/t, and the subsequent reductions in ore competency were measured by the Point Load Test. The ores that demonstrated the greatest reductions in strength typically contained between approximately 2 wt% and 20 wt% of highly microwave-absorbing minerals, with a native grain size d50 greater than approximately 500 µm, constrained by hard matrix minerals such as quartz and feldspar. Texturally consistent ores with a high proportion of amenable textures also demonstrated the highest average reductions in strength. These findings support the qualitative descriptions and numerical modelling results available in the literature and provide a baseline for selecting likely candidate ores for microwave treatments in the future. | 10.1016/j.mineng.2015.10.007 | English | UK | Journal Article | Minerals Engineering | 84 | - | 116-129 | 0 |
| A049 | 2018 | Enhancing mineral liberation of a Canadian rare earth ore with microwave pretreatment | Zhong, C.; Xu, C.; Lyu, R.; Zhang Z.; Wu, X.; Chi, R. | https://www.sciencedirect.com/science/article/pii/S1002072117300807 | rare earth ore | MLA; Bastnaesite; Strontianite; goethite; mineralogy; rare earths | Liberation, as an attribute of mineralogy characteristic, whose impacts on finely disseminated Canadian rare earth ore was studied with microwave pretreatment. Samples of a light rare earth ore along with mostly ankerite and biotite as dominant gangue minerals as well as bastnaesite, strontianite and goethite as dominated minerals were exposed to further comminution by ball mill and microwave pretreatment fragmentation. Mineralogical characteristics were analyzed by using a mineral liberation analyzer (MLA). The results indicated that tight association mutually penetrates among dominated minerals in the range size of -300 + 212 µm and -212 + 150 µm and gangue minerals in the form of adjacent type, fine vein type, shell type and packing type. Temperature in the ore samples pre-treated by microwave can rapidly rise to 250 °C with microwave power of 0–1.5 kW and microwave time of 0–2 min. Applying the microwave pretreatment merely reduces the hardness of the ore causing the fracture of rare earth ore, but this does not transform or change the original mineralogy characteristics of the ore samples. On the basis of above study, the liberation value of bastnaesite, strontianite and goethite with microwave pretreatment is greater than with conventional comminution when the liberation class is above 75%. The distribution of particle size of rare earth ore samples is better with microwave pretreatment than with conventional comminution for particle size of 7.4 × 10-5 m. With microwave pretreatment, the theoretical grade–recovery of bastnaesite, strontianite and goethite in the rare earth ore attains better results than with conventional comminution at a given grade. | https://doi.org/10.1016/j.jre.2017.08.007 | English | China | Journal Article | Journal of Rare Earths | 36 | - | 215-224 | 0 |
| A050 | 2001 | The effect of microwave radiation upon the processing of Neves Corvo copper ore | Vorster, W; Rowson, N.A; Kingman, S.W | https://linkinghub.elsevier.com/retrieve/pii/S0301751600000697 | copper ore | microwave; mineralogy; grindability; flotation; modelling; energy | An investigation into the effect of microwave radiation on the processing of a massive sulphide copper ore has been carried out. It is shown that significant reductions in the Bond work index can be achieved without any discernible adverse effect on the subsequent flotation process. A maximum reduction in work index of 70% was achieved after microwave exposure for 90 s. Microwave exposure followed by water quenching is shown to reduce the work index by up to 15% more than for unquenched samples. Initial trials on the effect of mass loading on the reduction in work index indicate that there exists an optimum mass of material that can be pretreated effectively by microwave radiation in any microwave cavity. Process simulation on the package USIMPAC showed significant flowsheet changes are possible as a result of exposure to microwave radiation and the subsequent reduction in work index. Conclusions are made regarding the economic implications of microwave pretreatment on the flowsheet. q 2001 Elsevier Science B.V. All rights reserved. | 10.1016/S0301-7516(00)00069-7 | English | UK | Journal Article | International Journal of Mineral Processing | 63 | 1 | 29-44 | 0 |
| A051 | 2017 | The influence of microwave irradiation on thermal properties of main rock-forming minerals | Lu, Gao-ming; Li, Yuan-hui; Hassani, Ferri; Zhang, Xiwei | https://www.sciencedirect.com/science/article/pii/S1359431116329763 | quartz; calcite; potassium feldspar; albite; black mica; white mica; enstatite; hornblende; olivine | thermal stress; thermal expansion; microwave-assisted rock fragmentation; rock-forming minerals; microwave absorption capacity; SEM-EDX elemental analysis | The sample will burst into fragment when the thermal stress induced by thermal expansion greater than the ultimate strength of the rock after microwave irradiation. Microwave-assisted rock fragmentation has been illustrated to be potentially beneficial for mineral processing, mining and geotechnical engineering. In order to have a comprehensive understanding on the influence of microwave on thermo-mechanical properties of rocks, it is necessary to investigate the interaction effect between microwaves and the main rock-forming minerals. In this work, eleven rock-forming minerals were tested in a multimode cavity at 2.45GHz with a power of 2kW, subsequently, the Scanning Electron Microscopy–Energy Dispersive X-ray (SEM-EDX) was used to determine the elemental distribution and mineralogical composition of the tested samples. It was observed that different rock-forming minerals present very different susceptibility induced by microwave treatment. Enstatite presents the strongest microwave absorption capacity by a large margin and most of the rock-forming minerals are weak microwave absorbers. It is significant that the results can be used to predict the heating behaviors of rocks subjected to microwave energy. Furthermore, the SEM-EDX elemental analysis demonstrates that the microwave absorption capacity of rock-forming minerals could link to the contribution of the ferrum, which may influence the interacting mechanisms between microwaves and the rock-forming minerals. | 10.1016/j.applthermaleng.2016.11.015 | English | China | Journal Article | Applied Thermal Engineering | 112 | - | 1523-1532 | 0 |
| A052 | 2019 | Production of high purity silica by microfluidic-inclusion fracture using microwave pretreatment | Buttress, A.J.; Rodriguez, J.M.; Ure, A.; Ferrari, R.S.; Dodds, C.; Kingman, S.W. | https://www.sciencedirect.com/science/article/pii/S0892687518305090?via%3Dihub | silica | silica; microwave processing; micro-fracture | Demand for high purity silica used in component manufacture is set to outstrip current supply in the near future. As such, alternative processing routes to feed-stock materials suitable for use in lighting and solar cell fabrication are required, without having to rely on reject material from semi-conductor manufacture. In this work, we report a facile, environmentally friendly method of producing quartz powder with a total residual impurity level of 30 ± 3 ppm from whole pebbles having an initial impurity level of 158 ± 22 ppm. This has been achieved using a metallurgical upgrading process incorporating microwave pre-treatment, crushing and milling, High Intensity Wet Magnetic Separation (HIWMS) and acid leaching. This process yielded a quartz powder having an 80% reduction in residual impurities compared to the untreated quartz pebbles. Pre-treatment of whole quartz pebbles in a multimode microwave cavity for 10 min yielded a reduction of the residual elemental impurity content associated with micro-fluidic inclusion sites containing calcium, potassium and sodium of 84, 78, and 50% respectively. Statistically significant reduction in residual aluminium phases was also observed (83%) compared to the as received material to below the IOTA® specification for Ultra High Pure Quartz produced by Sibleco. Mechanistically, this has been achieved by selectively heating impurity containing micro-fluidic inclusion sites. Resulting in their explosive decrepitation and enabling removal of the impurities in subsequent processing steps. It has been concluded that natural quartz pebbles can be upgraded through a combination of microwave treatment, magnetic and chemical refinement to produce a viable feedstock for the subsequent production of solar grade silicon. | https://doi.org/10.1016/j.mineng.2018.11.025 | English | UK | Journal Article | Minerals Engineering | 131 | - | 407-419 | 0 |
| A053 | 2020 | Dielectric properties of hard rock minerals and implications for microwave-assisted rock fracturing | Zheng, Y. L.; Zhao, X. B.; Zhao, Q. H.; Li, J. C.; Zhang, Q. B. | http://link.springer.com/10.1007/s40948-020-00147-z | albite; almandine; augite; biotite; calcite; diopside; galena; hematite; hornblende; microline; magnetite; muscovite; olivine; quartz | rock breakage and fracturing; microwave; dielectric properties; rock-forming minerals; resonant cavity; effective medium theory | Understanding microwave-assisted breakage and fracturing of hard rocks necessitates the characterisation of the dielectric properties of basic rock-forming minerals. In the literature, there is a significant discrepancy in the loss factors (i.e., the ability of minerals in absorbing microwave energy) of the gangue minerals due to the fact that different unsuitable and inconsistent measurement techniques are used. In this paper, the dielectric properties (i.e., the dielectric constant and loss factor ) of 14 high-grade minerals, including 11 gangue minerals and 3 ore minerals that form most of the commonly found igneous and metamorphic hard rocks, were obtained using a customised resonant cavity and the effective medium theory at 2.45 GHz and room temperature. These minerals could be classified into three categories (i.e., low, medium and high loss) based on the magnitude of their loss factors. For the low-loss and medium-loss gangue minerals, their loss factors hardly correlate to either one or a combination of the metal elements or the crystal system. The dielectric properties of minerals were then used to explain the behaviour difference of granite and basalt when exposed to microwave radiation. | 10.1007/s40948-020-00147-z | English | China | Journal Article | Geomechanics and Geophysics for Geo-Energy and Geo-Resources | 6 | 1 | 22 | 0 |
| A054 | 2018 | Reaction of different rock types to low-power (3.2 kW) microwave irradiation in a multimode cavity | Hartlieb et al. | https://www.sciencedirect.com/science/article/pii/S0892687518300037 | basalt; diabase; gabbro; copper ore; sandstone; granite | microwave irradiation; rock fragmentation; heat treatment; thermal behaviour of rock | This study deals with low-power (3.2 kW) microwave irradiation of a range of rocks and provide an indication of the suitability of certain rock types for this treatment method for rock fragmentation and mineral comminution. The influence of microwave irradiation was assessed physically by measuring rock properties and observing cracking phenomena and chemically by analysing the mineralogical and chemical composition before and after microwave irradiation. The results show that the reaction to microwave irradiation strongly depends on the mineralogy or the water content of the rock. Rocks with low content of microwave absorbers (like granite and sandstone) heat slowly and do not show strong physical changes, whereas rocks with better microwave absorption (basalt, mafic volcanites) heat quickly leading to significant physical changes. It is apparent that the presence of water either in the porous volume of the rock or in the mineralogical structure (e.g. clay minerals) adds to the destructive work with the help of the generated steam pressure. | 10.1016/j.mineng.2018.01.003 | English | Austria | Journal Article | Minerals Engineering | 118 | 37-51 | ||
| A055 | 2022 | Transforming Power Draw Trend of Ore Crushing by Applying Microwave Heating | Rasyid, A; Aslam, A; Rafiei, A.; Sasmito, P.; Hassani, F. | https://www.energy-proceedings.org/?p=10277 | kimberlite | microwave heating; crushing; power draw; energy; kimberlite ore | Microwave irradiation, as a heating source, has potential applications in mining industry. Microwave irradiation makes physical impacts on brittle rock particles that transform its power draw trend during comminution. This potentially improves the raw material supply. In this research, an instantaneous power draw analysis is applied to detect the microwave heating impact on the particle breakage mechanism during single-roll crushing. Microwave energy is reducing the duration of high resistance zone of crushing trend, which provides shorter crushing time as well as lower crushing energy saving. | 10.46855/energy-proceedings-10277 | English | Canada | Journal Article | Energy Proceedings | 29 | |||
| A056 | 1999 | Grindability Of Microwave-Heated Ores | Gungor, A; Atalay, U. | https://www.onemine.org/documents/grindability-of-microwave-heated-ores-565e34cf-e07a-4e92-899f-7ab25b1b8626- | copper ore | N/A | Thermal treatment can significantly improve industrial comminution operations by reducing energy requirements and increasing mineral liberation. The assistance of thermal pretreatment prior to grinding by microwave heating is scrutinized in this study. For this purpose three copper ore samples with different chemical composition were used. To see the effect of microwave heating on ore; work index, breakage rate and breakage distribution functions of original and heat treated samples were examined. The results obtained in this study did not show significant improvement in the grindability characteristics of the studied ores with microwave heat treatment. The inadequate amount of microwave transparent matrix was the main reason for the absence of cracks and micro-fractures in the microwave heated copper samples. | N/A | English | Turkey | Conference Proceeding | SME Annual Meeting, 1999 | ||||
| A057 | 2017 | Comparative analysis of the effect of microwave pretreatment on the milling and liberation characteristics of mineral matters of different morphologies | Singh, V.; Venugopal, R.; Tripathy, S.K.; Saxena, V.K. | http://mmp.smenet.org/abstract.cfm?articleID=7506&page=65 | coal; iron ore; manganese ore | microwave; minerals; grinding; morphology; ore | This study was carried out to understand the impact of variation in material morphology on the efficacy of microwave pretreatment. Three different types of mineral matter – coal, iron ore and manganese ore – were treated with microwaves at different energy levels, from 180 to 900 W, for different time durations of one to five minutes. The treated samples were subjected to microscopic, milling and liberation studies. Coal is a porous and amorphous material with low dielectric constant, and grinding of the microwave-pretreated coal samples resulted in an 18.18 percent reduction in the 80 percent of passing particle size, or d80, and a 17.1 percent increase in carbon recovery. The microwave-pretreated soft and friable manganese ore samples showed a 47.82 percent reduction in d80 during grinding and higher manganese recovery of 42.46 percent during liberation analysis. The microwave pretreatment and milling of hard and banded iron ore reduced the d80 by 20.83 percent, but no improvement was observed in mineral liberation. Coal showed better results during treatment at lower energy levels of 180 W for one to three minutes, whereas the minerals needed higher energy of 900 W for five minutes. Particle size analysis indicated rapid size reduction up to an energy input of 25 Wh. This effect diminished with increased energy input. | 10.19150/mmp.7506 | English | India | Journal Article | Minerals & Metallurgical Processing | 34 | 2 | 65-75 | |
| A058 | 2019 | Structural failure process of schistosity rock under microwave radiation at high temperatures | He, Leping; Gu, Yucheng; Hu, Qijun; Chen, Yuan; Zeng, Junsen | https://www.fracturae.com/index.php/fis/article/view/2587 | granite | microwave radiation; schistose granite; high temperature; thermal damage | The effects of high temperature induced by microwave radiation on the schistosity structural rock were investigated. A 1.45 kW commercial microwave system was employed to irradiate specimens to a designed temperature (300 − 800 °C) for 15 minutes. Cracking and local melting initially appeared in the biotite enrichment area at 500 °C. Macro-cracks in the dark area were parallel to the schistosity trend, owing to the weak connection in a direction perpendicular to the schistosity plane. The composition of the rock did not significantly change before and after microwave radiation. The diffraction peak intensity of the biotite decreased with temperature increase, owing to melting. The average peak stress decreased significantly with increasing temperature. It is concluded that the high temperature induced by microwave radiation promotes hard rock breakage and the schistosity structure of rock significantly affects the cracking pattern. | 10.3221/IGF-ESIS.50.55 | English | China | Journal Article | Frattura ed Integrità Strutturale | 13 | 50 | 649-657 | |
| A059 | 2008 | Microwave Assisted Drilling and its influence on rock breakage a review | Hassani et al. | https://onepetro.org/ISRMARMS/proceedings-abstract/ARMS508/ARMS508/ISRM-ARMS5-2008-007/37957?redirectedFrom=PDF | review paper | Various methods are currently used to increase penetration rate into hard rock for all kinds of applications such as drilling, tunneling, underground excavations and so on. Mechanical tools, because of their simplicity, have been the most popular for many years and have been developed to have the most efficient penetration rates. Other novel methods are being investigated, to assist mechanical tools as well. Microwave energy is one novel technique, generating in-depth heat which leads rocks to be highly fractured. It can also assist mechanical tools and allow the tool to penetrate more effectively by reducing the strength of rocks. A short summary of related methods will be discussed, followed by a brief explanation of experiments done to date, regarding the way. | English | Iran | Conference Proceeding | ISRM International Symposium - 5th Asian Rock Mechanics Syposium | ||||||
| A060 | 2019 | Analysis of the Dependence of the Break-Down Point on Temperature of Microwave Heating of Loaded Heterogeneous Materials (Rocks) Based on the Formation of Growth of Microcracks | Menzhulin, M. G.; Makhmudov, Kh. F. | http://link.springer.com/10.1134/S1063784219050153 | granite | N/A | Analysis of the dependence of the break-down point of granite on the temperature of microwave heating allows identification of the following characteristic areas: hardening is observed at low temperature heating up to 390 K; a decrease in strength appears in the temperature range from 390 to 460 K, which is due to generation, growth, and coalescence of smaller cracks and their redistribution to the boundaries of grains with the formation of intergranular microcracks; there is a significant decrease in the strength at the temperature range from 460 to 550 K, which is caused by the separation of grains into blocks with a small area of crack density as a result of their coalescence, and the destruction and splitting of granite samples occurs at temperatures above 593 K due to the development of all kinds of microcracks. The developed method of determining the rational parameters of the microwave energy impact on the softening of hard rocks in the field of standing electromagnetic waves allows justification of the effective parameters of the impact of microwave energy on quartz-containing hard rocks for their softening and destruction based on the study of the dynamics of induced microcracks. | 10.1134/S1063784219050153 | English | Russia | Journal Article | Technical Physics | 64 | 5 | 615-619 | |
| A061 | 2010 | Effect of Oxygen and Micro-Cracking on the Flotation of Low Grade Nickel Sulphide Ore | Muzenda & Afolabi | https://files.core.ac.uk/download/pdf/54186052.pdf | nickel sulphide ore | flotation; conventional air; oven micro-cracking; recovery | This study investigated the effect of oxygen and micro-cracking on the flotation of low grade nickel sulphide ore. The ore treated contained serpentine minerals which have a history of being difficult to process efficiently. The use of oxygen as a bubbling gas has been noted to be effective because it increases the pulp potential. The desired effect of micro cracking the ore is that the nickel sulphide minerals will become activated and this activation will render these minerals more susceptible to react with potassium amyl xanthate collectors, resulting in a higher recovery of nickel and hinder the recovery of other undesired minerals contained in the ore. Higher nickel recoveries were obtained when pure oxygen was used as a bubbling gas rather than the conventional air. Microwave cracking favored the recovery of nickel. | N/A | English | South Africa | Journal Article | World Academy of Science, Engineering and Technology | 70 | 723-728 | ||
| A062 | 2018 | The Impact of Microwave Pre-Treatment on the Liberation of Nb/Ta minerals from a tin oxide ore | Mutombo et al. | https://avestia.com/MCM2018_Proceedings/files/paper/MMME/MMME_123.pdf | cassiterite ore | cassiterite; microwave pre-treatment; niobium tantalum; liberation | Liberation of Nb/Ta minerals from Cassiterite ore during comminution is difficult. Microwave pre-treatment of cassiterite ore using batch multiple mode microwave was done. The ore was characterised and effects of various parameters affecting the liberation of Nb/Ta minerals were investigated. It was found that the ore contains 76. 1%wt of SnO2 and traces of Nb2O5 (0.62% wt) and Ta2O5 (0.81% wt). The major phases in the cassiterite ore after pre-treatment were Pyrochlore, Cassiterite, Sillimanite, Ferrotapiolite, Niobium Tantalum, Niobium Titanium, Iron Tin, Niobium Tin, Iron Tantalum and Niobium tin silicide. The ore displayed a significant liberation of the Nb and Ta minerals at 100% irradiation and a high temperature of 540 ̊C was achieved. Significant phase changes were observed from the SEM/EDS and the Mapping of the distribution of the Nb/Ta minerals showed that there was an improvement in the liberation of these minerals. It is concluded that the use of microwaves brings changes in the matrix pattern of the Cassiterite ore, favouring the liberation of microwave susceptible mineral phases. | 10.11159/mmme18.123 | English | South Africa | Conference Proceeding | 4th World Congress on Mechanical, Chemical, and Material Engineering (MCM'18) | 0 | |||
| A063 | 2018 | Effect of microwave treatment on the surface properties of chalcopyrite | Azghdi, S.M.S.; Barani, K. | http://mmp.smenet.org/abstract.cfm?articleID=8463&page=141 | chalcopyrite | chalcopyrite; microwave radiation; surface roughness, surface wettability; flotation | The effect of microwave treatment on the surface roughness and wettability of chalcopyrite (CuFeS2) and on the chemical composition of its surface was studied. The microwave source was a conventional multimodal oven with frequency of 2.45 GHz and maximum power of 900 W. Pure chalcopyrite specimens and purified chalcopyrite concentrate were used in this study. Analysis using atomic force microscopy showed a decrease in the surface roughness of the chalcopyrite after microwave radiation. This decrease may be due to oxidation of the surface and formation of iron oxide. Moreover, the surface wettability of the chalcopyrite mineral increased with increasing duration of microwave radiation, which was in good agreement with the micro-flotation mass recovery results. The increased wettability of the surface may be attributed to the decreased surface roughness by microwave radiation. Analysis using scanning electron microscope/ energy-dispersive X-ray spectroscopy indicate that after microwave radiation, the contents of sulfur and iron increased whereas that of copper decreased on the surface of the chalcopyrite, significantly changing the average atomic number of the chalcopyrite surface. | 10.19150/mmp.8463 | English | Iran | Journal Article | Minerals & Metallurgical Processing | 35 | 3 | 141-147 | |
| A064 | 2016 | Effect of microwave radiation on the processing of a Cu‐Ni sulphide ore | Marion, Christopher; Jordens, Adam; Maloney, Conor; Langlois, Ray; Waters, Kristian E. | https://onlinelibrary.wiley.com/doi/10.1002/cjce.22359 | copper-nickel sulphide ore | flotation; bond work index; microwave radiation; flotation kinetics | The need for fine grinding to liberate valuable minerals from low-grade ores has become a major concern due to the high energy requirements and low energy efficiencies of comminution processes. One method being studied to improve efficiencies is microwave pre-treatment. Microwaves can selectively heat certain minerals (absorbers) within an ore, causing internal stresses and forming fractures along grain boundaries. Microwave pretreatment of an ore containing microwave-absorbing minerals and microwave-transparent gangue can significantly reduce grinding energy. However, these improvements must not be detrimental to downstream processing. This work investigated the effects of microwave radiation on the grindability and flotability of a copper/nickel sulphide ore. A reduction in the Bond Work Index of 22 % was observed after microwave pre-treatment in a 3.0 kW multimodal microwave (2.45 GHz) for 60 s. Although a significant reduction in the required grinding energy was observed, the amount of energy required to treat the sample is significantly higher than the corresponding Bond Work Index reduction, indicating that the process remains some distance from being economically viable. Microwave pre-treatment also showed beneficial effects on the flotation of the ore. Copper recovery remained constant while nickel recovery increased by 33.6 % after 120 s of microwave exposure at 0.8 kW, and by 34.4 % after a 30 s exposure at 3.0 kW. Higher microwave exposure also showed an increase in concentrate grade and flotation kinetics of both copper and nickel. | 10.1002/cjce.22359 | English | Canada | Journal Article | The Canadian Journal of Chemical Engineering | 94 | 1 | 117-127 | |
| A065 | 2005 | Microwave Enhanced Recovery of Nickel-Copper Ore: Communition and Floatability Aspects | Henda, R.; Hermasa, A.; Gedyeb, R.; Islamc, M.R. | http://www.tandfonline.com/doi/full/10.1080/08327823.2005.11688522 | copper-nickel sulphide ore | microwave energy; mineral separation; comminution; flotation; process engineering | A study describing the effect of microwave radiation, at a frequency of 2,450 MHz, on the processes of communition and flotation of a complex sulphide nickel-copper ore is presented. Ore communition has been investigated under standard radiation-free conditions and after ore treatment in a radiated environment as a function of ore size, exposure time to radiation, and microwave power. The findings show that communition is tremendously improved by microwave radiation with values of the relative work index as low as 23% at a microwave power of1.406 kW and after 10 s of exposure time. Communition is affected by exposure time and microwave power in a nontrivial manner. In terms of ore floatability, the experimental tests have been carried out on a sample of 75 μm in size under different exposure times. The results show that both ore concentrate recoveries and grades of nickel and copper are significantly enhanced after microwave treatment of the ore with relative increases in recovered concentrate, grade of nickel, and grade of copper of 26 wt%, 15 wt%, and 27%, respectively, at a microwave power of 1,330 kW and after 30 s of exposure time. | 10.1080/08327823.2005.11688522 | English | Canada | Journal Article | Journal of Microwave Power and Electromagnetic Energy | 40 | 1 | 16-Jul | |
| A066 | 2004 | High powered microwave treatment of carbonate copper ore | Sahyoun et al. | https://www.911metallurgist.com/wp-content/uploads/2015/12/High-powered-microwave-treatment-of-carbonate-copper-ore.pdf | copper ore | microwave energy; copper ore; grindability; bond work index | The effect of microwave radiation on the grindability of Palabora ore has been investigated. Significant reductions in comparative Bond work index (kWh/t) were exhibited in microwave treated samples. The results were sensitive to applied power level and the mode of application of energy. Exposure at 2.6kW in a multimode cavity was found to reduce the relative work index but the energy expended to get this change was high. Experiments were also carried out using a Sairem 15kW industrial monomode microwave unit. With a microwave exposure time of 0.28 second at 10kW, a 61.3% reduction in Bond work index was obtained, compared to 0.78kWh/t of energy expended due to microwave pretreatment, which gives a more favourable energy balance. Finally, Quantitative Evaluation of Materials using Scanning Electron Microscopy (QEM*SEM) was employed to determine if any liberation at the grain boundaries and evidence of intergranular fracture could be observed. There was evidence of an increase in liberation of copper sulphide and iron oxide in the coarser size fractions for Palabora ore. | English | United Kingdom | Journal Article | The European Journal of Mineral Processing and Environmental Protection | 4 | 3 | 175-182 | ||
| A067 | 2016 | Increasing the grind size for effective liberation and flotation of a porphyry copper ore by microwave treatment | Batchelor, A.R.; Jones, D.A.; Plint, S.; Kingman, S.W. | https://linkinghub.elsevier.com/retrieve/pii/S0892687516301315 | porphyry copper ore | microwave; ore; mineralogy; liberation; flotation | In this paper, mineralogy, grain size, dissemination, textural consistency and mineral associations were determined for a commercially exploited porphyry copper ore using a Mineral Liberation Analyser (MLA). The ore was subjected to high power density microwave treatments in a single mode cavity at 15 kW and approximately 2 kW h/t. The untreated and microwave-treated samples were subsequently milled to two grind sizes near the nominal plant grind size and a size-by-liberation analysis performed. The analysis revealed that equivalent liberation could be obtained at a grind size approximately 50–60 lm coarser than the nominal plant grind due to the microwave treatment. Flotation testing indicated that an increase in copper recovery of approximately 1% could be achieved, or that a grind size increase of approximately 30 lm may potentially yield equivalent copper recovery due to the microwave-enhanced liberation observed. However, statistical analyses demonstrated that it is difficult to attain confidence in recovery increases of approximately 1% even when conducting batch flotation tests in triplicate. The ore under investigation had previously been shown to produce only modest average reductions in strength ( 8%) under similar microwave treatment conditions due to a prevalence of many unfavourable textures. However, the preferential association of copper minerals with a hard matrix mineral (quartz) and a hard microwave-absorbent mineral (pyrite) resulted in a significant change in liberation behaviour. | 10.1016/j.mineng.2016.05.011 | English | UK | Journal Article | Minerals Engineering | 94 | 61-75 | ||
| A068 | 2011 | Microwave heating of gold ores for enhanced grindability and cyanide amenability | Amankwah, R.K.; Ofori-Sarpong, G. | https://linkinghub.elsevier.com/retrieve/pii/S0892687510003298 | gold ore | microwaves; grindability; cyanide amenability; free-milling gold ore; selective heating | In leaching processes, the mass transport of lixiviants from the bulk of the solution to the site of the mineral of interest is usually the slowest step. Diffusion becomes slower when the particles to be leached are occluded in host minerals. Access to the mineral of interest is enhanced by micro-crack formation within the host minerals as it enhances percolation and migration of lixiviants. Micro-crack formation also augments grinding and allows size reduction and liberation at a lower stress level. In this research, microwave pretreatment was used to augment the grinding of a free-milling gold ore containing quartz, silicates and iron oxides. Under microwave irradiation, selective heating of the different mineral components resulted in thermal stress cracking. Microwave processing enhanced the grindability of the ore, and crushing strength was reduced by 31.2%. The presence of micro-cracks improved leaching rate, and over 95% extraction was achieved within 12 h as against 22 h for the non-microwaved sample. Such a strategy can be used to maximize recovery and man-hours on processing plants. | 10.1016/j.mineng.2010.12.002 | English | Ghana, United States | Journal Article | Minerals Engineering | 24 | 6 | 541-544 | |
| A069 | 2015 | Influence of microwave pre-treatment on the flotation of low- grade sulphide ore | Ola-Omole, Omoyemi; Adewuyi, B O; Borode, J O; Olubambi, P A | https://www.ajer.org/papers/v4(09)/ZB04901920197.pdf | lead-zinc sulphide ore | microwave treatment; flotation; sulphide ore; collectors; depressants | Sulphide ores are always difficult to process because of the complication in their mineralogical associations and the intergrown nature of their constituent minerals. These complexities usually result in a poor liberation of the associated minerals. Hence, full determination of comminution parameters relevant to the crushing and milling of these minerals will enhance higher recovery of the concentrate minerals as well as enable proper plant design to take place. Meanwhile, most high-grade deposits of the world have been depleted which give rise to the need to process low-grade ores. The conventional methods of mineral processing are also no longer effective for the processing of these low-grade ores. This work centres on understanding the effects of microwave pre-treatment on the flotation characteristics of the low grade-sulphide ores. The ore was characterized using JEOL JSM. 7600 SEM-EDX, Qurum150TE XRD-Ultima IV and XRF- ZSX Primus II. Microwave treatment was also carried out using 2.45 GHZ intellowave microwave oven at a power output of 750W. Comminution and particle size analysis of the ore shows that P80 for microwave treated sample is equal to -212µm +150µm while for the untreated sample P80 corresponds to -250 µm +212µm. Sodium Ethyl Xanthate, SEX was used as the collector, Methyl Isobutyl Carbinol, MIBC as the frother and three different depressants (Starch, sodium silicate and potassium dichromate). Particle sizes 150µm, 106µm, 75µm and 53µm were used for flotation experiment. The trend of the recoveries of both microwave treated and untreated samples shows that recoveries are higher for the microwave treated samples. | 30.0847/04901920197 | English | Nigeria, South Africa | Journal Article | American Journal of Engineering Research | 4 | 9 | 192-197 | |
| A070 | 2011 | Microwave Heating for Emolliating and Fracture of Rocks | Prokopenko, Aleksandr | http://www.intechopen.com/books/advances-in-induction-and-microwave-heating-of-mineral-and-organic-materials/microwave-heating-for-emolliating-and-fracture-of-rocks | review book chapter | N/A | None | 10.5772/14067 | English | Russia | Other | Advances in Induction and Microwave Heating of Mineral and Organic Materials | 313-338 | |||
| A071 | 2006 | Energy Reduction in ore comminution through microwave | Kumar et al. | https://app.knovel.com/hotlink/pdf/id:kt0110MYC5/advanced-processing-metals/energy-reduction-in-ore | lead-zinc sulphide ore | microwave; comminution; energy saving | Comminution is an essential mineral processing operation to liberate the minerals from the ore. This however, is an energy intensive step in mineral processing industries. This work highlights the possibility of saving in grinding energy for ore comminution reducing work index of the ore by effective utilization of microwave energy. This reduced work index results in increased throughput of the grinding circuit in mineral beneficiation plant in order not to shift the product size. The fundamental principle behind this application remains the ability of microwave to heat individual phases within the ore matrix. The constituents of the ore typically having different thermal and mechanical properties develop stress of sufficient magnitude to create intergranular and transgranular fractures during heating and subsequent quenching of the ore. The experiments conducted with the ore samples of Zawar Mines and Rampura Agucha Mine of Hindustan Zinc Limited, India (A member of Vedanta Resources Plc) reflect a substantial up-shift in cumulative weight percentage passing in finer sieve fractions under quenched conditions. Further, the experiments carried out on Rampura Agucha ore reveal 20-30% reduction in work index, which result in decreased milling time or saving in grinding energy. The simulation studies estimates a 2-4% increase in plant throughput. Moreover, preliminary flotation studies indicated a significant increment in total metal recovery and concentrate grade for the desired grade and recovery values respectively. This paper is a technical note on the laboratory investigations carried out at Central Research & Development Laboratory of Hindustan Zinc Limited. Results have been encouraging to progress the work further. It is also proposed to carry out modeling work for simulation so as to predict the changes in minerals. | English | India | Conference Proceeding | Sohn International Symposium Advanced Processing of Metals and Materials | 4 | 481-489 | |||
| A072 | 2022 | Numerical and experimental analysis of fully coupled electromagnetic and thermal phenomena in microwave heating of rocks | Shadi, Amin; Ahmadihosseini, Adel; Rabiei, Mahdi; Samea, Parham; Hassani, Ferri; Sasmito, Agus P.; Ghoreishi-Madiseh, Seyed Ali | https://linkinghub.elsevier.com/retrieve/pii/S0892687522000164 | basalt; kimberlite | numericalsimulation; finite element analysis; microwave; fragmentation; energy efficiency | Enhancement of mineral resources exploitation efficiency is one of the main targets identified by the mining industry. However, rock fragmentation, including excavation and comminution, is among the most energyintensive activities imposing a substantial economic burden on the industry. The microwave pre-treatment technique has offered promising solutions in pre-weakening rocks and ores. This paper investigates the fully coupled electromagnetic and thermal effects of microwave treatment of rocks. A numerical simulation tool based on the finite element method is developed to simulate the microwave-treatment process occurring within the microwave cavity. Temperature-dependent dielectric properties are employed to ensure a bi-directional coupling between the interfaces. The simulation results are quantitatively and qualitatively compared with experimental investigations and validated with less than 3% numerical error. | 10.1016/j.mineng.2022.107406 | English | Canada | Journal Article | Minerals Engineering | 178 | 107406 | ||
| A073 | 2020 | Energy analysis of the effectiveness of microwave-assisted fragmentation | Hassani, Ferri; Shadi, Amin; Rafezi, Hamed; Sasmito, Agus P.; Ghoreishi-Madiseh, Seyed Ali | https://linkinghub.elsevier.com/retrieve/pii/S0892687520304623 | basalt; kimberlite | microwave; fragmentation; energy effectiveness; calorimetry; uniaxial compressive strength; mine-to-mill | Enhancing the energy-effectiveness of microwave-assisted fragmentation is one of the overlooked areas in the published literature. A novel calorimetric technique is proposed to quantify the effect of inductive heating within a microwave cavity on subsequent rock/ore fragmentation. Two new parameters are introduced to identify, differentiate, and quantifiably evaluate the effects of microwave-induced energy and thermally induced fracturing on mechanical strength degradation. Additionally, the influences of sample geometry and position and orientation with respect to the microwave waveguide are experimentally investigated to determine optimum conditions for microwave treatment. Comparisons with published literature show that establishing optimum electromagnetic heating conditions significantly improves microwave-induced weakening. Microwave-assisted degradation has significant potential application to in-situ mining, tunnelling, rock breakage, and comminution. | 10.1016/j.mineng.2020.106642 | English | Canada | Journal Article | Minerals Engineering | 159 | 106642 | ||
| A074 | 2008 | Kimberlite fracturing by prompt microwave-heating | Didenko and Prokopenko | https://ieeexplore.ieee.org/document/5292853 | kimberlite | microwave heating; kimberlite; fracture process; estimation process; magnetron; microwave power; microwave energy; porous rock | The present paper concerns the study of kimberlite fracture processes by prompt microwave heating. The processes leading to kimberlite fracture are considered, and mechanisms of its fracture are defined. Results of research of kimberlite dielectric characteristics are presented. Results of researches of processes of the fracture carried out by resonator-type installation unit with capacity of SHF power supply of 600 W and 5 kW are represented. Power estimations of processes of kimberlite crushing by SHF energy, showing new method availability, are carried out. | English | Russia | Conference Proceeding | 19th International Crimean Conference Microwave & Telecommunication Technology | 855-856 | ||||
| A075 | 2022 | Microwave response characteristics and influencing factors of ores based on dielectric properties of synthetic samples | Lin et al. | https://www.sciencedirect.com/science/article/pii/S1674775521001104?via%3Dihub | sphalerite; hematite; galena; magnetite; pyrite; chalcopyrite; pyrrhotite; quartz; copper ore; iron ore; gold ore | metal minerals; electrical conductivity; metal mineral content; synthetic ore; prediction model | In order to understand the influence of different factors on the microwave response characteristics of ores, the effects of electrical conductivity, metal mineral content, compactness, metal mineral distribution, microwave frequency and temperature on the dielectric properties of synthetic ores (metal mineral and quartz) were studied. Microwave heating tests were carried out on three types of natural ores (Hongtoushan copper ore, Sishanling iron ore and Dandong gold ore) with significant differences in metal mineral contents. The test results showed that under microwave irradiation, the stronger the electrical conductivity of the metal minerals, the smaller the penetration depth in synthetic ore. For those metal minerals with lower electrical conductivity, the microwave absorption coefficient of the synthetic samples increases with increasing metal mineral content. For those metal minerals with higher electrical conductivity, the microwave absorption coefficient of the samples first increases and then decreases as the metal mineral content increases. When the metal minerals are distributed in layers, the penetration depth is much less than that given a uniform distribution. The penetration depth in the sample at microwave frequency of 915 MHz is greater than that at 2.45 GHz. The higher the electrical conductivity of metal minerals used in synthetic ores, the higher the high-temperature sensitivity of electromagnetic shielding coefficient (0 °C–500 °C). The Hongtoushan copper ore with high metal mineral content exhibits obvious size effect. The effects of ore structure and crystal particle size on the distribution characteristics of microcracks were discussed. Based on the test results, a quantitative prediction model of microwave sensitivity of ore was proposed, which provides guidance for the prediction of ore heating effect and the selection of microwave heating sequence of ore. | 10.1016j.jrmge.2021.08.002 | English | China | Journal Article | Journal of Rock Mechanics and Geotechnical Engineering | 14 | 2 | 315-328 | |
| A076 | 2023 | Experimental Study on the Damage Characteristics and Acoustic Properties of Red Sandstone with Different Water Contents under Microwave Radiation | Liu, Junjun; Xie, Jing; Yang, Bengao; Li, Fei; Deng, Huchao; Yang, Zundong; Gao, Mingzhong | https://www.mdpi.com/1996-1944/16/3/979 | sandstone | microwave rock breaking; red sandstone; different water contents; damage characteristics; acousitc properties | Rock breaking is one of the most basic issues in deep underground engineering. Water plays an important role in the rock response under microwave radiation. Consequently, microwave radiation experiments using red sandstone with different water contents were conducted. The damage characteristics and ultrasonic properties of red sandstone after microwave radiation were primarily investigated, and the representative conclusions were drawn as follows: With the increase in water content, the time of complete formation of the rupture surface of the rock sample gradually decreased, and the decreasing range gradually increased. When the fracture surface is completely formed, the samples with a higher water content have more powdery rock cuttings and less surface roughness. The damage degree of the samples does not increase significantly with the increase in the water content when the sample is radiated at the same time. As the microwave radiation time is increased, the damage degree of the sample will increase significantly. Through the ultrasonic velocity test, it can be suggested that the sample exhibits obvious zonal damage characteristics under the action of a microwave. Generally speaking, it is a very effective means of improving the degree of microwave attenuation of the rock by increasing the water content of the rock mass. | 10.3390/ma16030979 | English | China | Journal Article | Materials | 16 | 3 | 979 | |
| A077 | 2022 | Dynamic compressive strength and failure mechanisms of microwave damaged sandstone subjected to intermediate loading rate | Wang, Pin; Yin, Tu-bing; Li, Xi-bing; Konietzky, Heinz | https://linkinghub.elsevier.com/retrieve/pii/S1003632622660527 | sandstone | sandstone; microwave radiation; thermal cracking; dynamic compressive strength; failure patterns; split Hopkinson pressure bar | To investigate the influence of microwave heating on the dynamic behavior and failure mechanisms of rock, dynamic compression tests were conducted on microwave-irradiated sandstone specimens using a modified split Hopkinson pressure bar (SHPB) system. Experimental results show that microwave radiation can effectively weaken the compressive strength of sandstone. Rock specimens show three different failure modes under impact load: tensile failure, tensile−shear composite failure and compressive−shear failure. The dynamic Poisson’s ratio, calculated using the measured P- and S-wave velocities, is introduced to describe the deformation characteristics of sandstone. With the increase in microwave power and heating time, the Poisson’s ratio declines first and then increases slightly, and the turning point occurs at 244.6 °C. Moreover, the microstructural characteristics reveal that microwave radiation produces dehydration, pore expansion, and cracking of the rock. The damage mechanisms caused by microwave radiation are discussed based on thermal stress and steam pressure inside the rock, which provides a reasonable explanation for the experimental results. | 10.1016/S1003-6326(22)66052-7 | English | China, Germany | Journal Article | Transactions of Nonferrous Metals Society of China | 32 | 11 | 3714-3730 | |
| A078 | 2020 | Effect of Microwave Irradiation on Computed Tomography and Acoustic Emission Characteristics of Hard Rock | Lu, Gaoming; Sun, Zhenchuan; Zhou, Jianjun; Chen, Kui; Li, Fengyuan | https://link.springer.com/10.1007/s10706-020-01500-5 | basalt | microwave irradiation; hard rock; computed tomography (CT); acousitc emission (AE); damage law | Microwave-induced fracturing of hard rock can be used to assist mechanical rock breakage and release stress on rock masses in deep underground engineering operations. This is significant to those aiming to improve the construction efficiency and safety of underground tunnelling and ore extraction operations. The research was devoted to exploring the computed tomography (CT) and acoustic emission (AE) characteristics of hard rock subjected to microwave irradiation. For this purpose, microwave irradiation tests at a given power for different irradiation times were conducted on basalt collected from Chifeng, China by utilising a multimode cavity working at a frequency of 2450 MHz. By applying an infrared camera, the temperature distribution on the surface of samples during microwave irradiation was measured. Three-dimensional (3-d) microscopic CT was conducted on samples treated, and not treated, with microwave irradiation to explore the crack propagation regimes in such samples. Based on CT value and P-wave velocities, the damage characteristics of microwave treatment on basalt samples were evaluated. Afterwards, uniaxial compression strength tests were conducted and AE information in the loading process of samples was collected. After conducting microwave irradiation, internal cracks of samples propagated to generate fracture surfaces and surface temperatures of samples were found to have been non-uniformly distributed. The longer the irradiation time, the higher the degree of crack propagation in samples; P-wave velocities both decreased with increasing irradiation duration. With increasing irradiation time, the brittle failure characteristics of basalt shown in the time-dependent change curve of stress on basalt were gradually weakened while ductile failure characteristics were gradually strengthened. The uniaxial compressive strength, corresponding AE energy and cumulative AE energy at peak strength all gradually decreased with increasing irradiation time. The failure stress, the level of stress drop, AE energy, and cumulative AE energy of basalt after different irradiation times reflected consistent fracturing characteristics of basalt, which were interactively validated. | 10.1007/s10706-020-01500-5 | English | China | Journal Article | Geotechnical and Geological Engineering | 39 | 1 | 411-424 | |
| A079 | 2020 | Experimental investigation on the evolution of structure and mechanical properties of basalt induced by microwave irradiation | Yang et al. | https://pubs.rsc.org/en/content/articlelanding/2020/ra/d0ra04802j | basalt | N/A | Demand is growing for explosive-free and high efficiency rock breakage systems for mining, petroleum and civil engineering applications. Microwave irradiation is becoming a promising technique to deal with rock breakage due to its high efficiency, controllability and environmental friendliness. The cylindrical basalt samples with diameter of 50 mm and height of 100 mm and semi-disc specimens with diameter of 50 mm and thickness of 25 mm were irradiated using microwave apparatus (2.45 GHz, 2 kW). The mechanical properties of microwaved basalt have been tested and the micro fractures were quantitatively analyzed. The structural evolution and mechanical properties of basalt between 100 °C and 400 °C are assessed through the morphology, mineral characteristics and mechanical performance. It is found that the main damage modes of microwaved basalt are intergranular and transgranular fractures. Intergranular fractures generated rapidly at 100 °C, while transgranular fractures generated above 200 °C. Statistically, the length density of fractures grows fastest at 100 °C, while the width of fractures grows fastest at 200 °C. The intergranular and transgranular fractures develop rapidly and intersect each other over 400 °C, which results in rock failure. The length density of the fractures is the main factor inducing the decrease of compressive strength and fracture toughness of basalt which decrease fastest at 100 °C. The elastic modulus decreases fastest at 200 °C, which is closely related to the width of fractures. The Poisson's ratio of basalt is significantly improved by microwaves, and is not only affected by fractures size, but also closely relates to fracture type and distribution. | 10.1039/D0RA04802J | English | China | Journal Article | RSC Advances | 54 | 32723 | ||
| A080 | 2002 | Application of numerical modelling for prediction of the influence of power density on microwave-assisted breakage | Whittles, D.N; Kingman, S.W; Reddish, D.J | https://linkinghub.elsevier.com/retrieve/pii/S0301751602000492 | modelling paper | crushing; energy requirements; fracture mechanics; numerical modelling; microwave treatment | The influence of electric field strength on the microwave treatment of ore is elucidated. The ore consisted of a microwave-absorbing mineral in a low-absorbing matrix, and the influence of electric field strength was assessed by numerical simulation. Simulations were undertaken using finite difference modelling techniques for a theoretical 15 30 mm sample of calcite host rock containing 10 vol.%, 1-mm2 particles of pyrite. The simulations modelled the microwave heating, thermal conduction, expansion, thermally induced fracturing and strain softening and, finally, uniaxial compressive strength to predict the effect of microwave heating on the strength of the ore material. Standard correlations were then used to develop specific comminution energy verses t10 relationships for the treated and nontreated samples. It is shown that microwave power density is vital to the fracturing of the rock, and it is suggested that by utilising high power densities, the microwave fracturing of rock to reduce grinding energy requirements may be economically viable. | 10.1016/S0301-7516(02)00049-2 | English | United Kingdom | Journal Article | International Journal of Mineral Processing | 68 | 4-Jan | 71-91 | |
| A081 | 2023 | Energy Efficiency of Microwave-Induced Heating of Crushed Rocks/Ores | Shadi, Amin; Samea, Parham; Rabiei, Mahdi; Ghoreishi-Madiseh, Seyed Ali | https://www.mdpi.com/2075-163X/13/7/924 | basalt | microwave treatment; energy efficiency; comminution; liberation; numerical model | The interaction between electromagnetic waves and heat transfer phenomena due to microwave treatment is of utmost importance for an energy-efficient microwave-integrated grinding circuit. In this study, the effect of microwave irradiations on the heat absorptions of crushed particles is carried out by developing a numerical model. Crushed particles are simulated as diced-shaped geometries with different sitting arrangements but similar size distributions. The energy efficiency of the microwave treatment process is studied by introducing temperature-dependent dielectric properties and accounting for the convective heat loss from the particle boundaries to the surrounding environment. The simulations are quantitatively validated with the experimental results for heat over microwave efficiency. Heat absorption of larger particles is found to be significantly higher, and the arrangement of particles exerts a negligible effect on overall energy absorption. It is also found that ores with a larger average diameter can yield higher energy efficiencies, and the maximum absorption can be achieved by placing the particles at certain distances from the waveguide of the microwave. | 10.3390/min13070924 | English | Canada | Journal Article | Minerals | 13 | 7 | 924 | |
| A082 | 2021 | Mechanism of Increasing the Permeability of Water-Bearing Coal Rock by Microwave Steam Explosion | Qi, Qi; Guan, Weiming; Li, Xin; Ge, Yanyan; Nan, Senlin; Liu, Huabin | https://www.hindawi.com/journals/geofluids/2021/6661867/ | coal | N/A | Microwave heating of water-bearing coal can promote pore water evaporation. The pores are broken under the action of steam pressure, increasing the permeability of the coal. This study is aimed at investigating the mechanism of permeability improvement of water-bearing coal rock by microwave steam explosion. First, a microwave oven was used to irradiate and heat five groups of coal rock with different water contents; the NMR test was then conducted on the heated sample. Second, the internal vapor pressure and temperature changes during the heating process were obtained through the T-connector for samples with different water contents. Finally, a numerical experiment was used to explore the deformation characteristics of pores under three filling conditions. The experimental results showed that the total porosity increased significantly when the water content of coal increased from 0% to 8%, while the permeability increased by nearly 4.78 times. The extreme value of gas pressure inside the sample showed an increasing trend. The gas pressure and temperature were in line with the equation of state for an ideal gas during the rising phase. Numerical experiments showed that the pore boundary shrunk inward under vacuum conditions, and compressive stress appeared at the tip. The saturated humid air and liquid water conditions expanded the pore boundaries outward and caused tensile stress at the tip, with the latter being nearly 2.3 times larger than the former, making it more conducive to the development of pores. The findings of this study can be used as a reference value for the expansion of coalbed methane extraction technology. | 10.1155/2021/6661867 | English | China | Journal Article | Geofluids | 2.021 | 13-Jan | ||
| A083 | 2023 | Experimental Investigation on Failure Mechanism of Hot Dry Rock under Microwave Irradiation | He, Leping; Huang, Chengyi; Hu, Qijun; Zeng, Junsen; Wang, Haoyu | https://ascelibrary.org/doi/10.1061/IJGNAI.GMENG-7963 | granite | geothermal energy; hot dry rock; microwave irradiation; mechanical behavior | Hot dry rock (HDR) geothermal energy is clean energy that can meet people’s demand for low carbon. The traditional hydraulic fracturing method is challenging to break HDR dominated by granite, mainly because of HDR’s high temperature and hard characteristics. Microwave irradiation is considered a proven approach to breaking granite. This study investigates the failure mechanism of HDR at 500°C–800°C under microwave irradiation. The experiments cover preheating, uniaxial compression, granulometric analysis, binocular vision monitoring (BVM) technique, and X-ray powder diffraction. The result shows that the uniaxial compression strength of granite decreases the most at 500°C–600°C, which is 62.77% on average. The failure form is from the brittle failure (untreated) to ductile failure (800 °C) with the rise of the microwave irradiation temperature. The microwave makes a particle size in the range of 0.6–2.36 mm the most apparent particle size of granite after uniaxial compression. The BVM technique reconstructs the surface deformation with a 0.7% error. Microwaves cause heat accumulation near the rock near the magnetron, resulting in the formation of crack networks and a molten cavity. The possibility of microwave-assisted fracturing of HDR is discussed at the end of the article. DOI: 10.1061/IJGNAI.GMENG-7963. © 2023 American Society of Civil Engineers. | 10.1061/IJGNAI.GMENG-7963 | English | China | Journal Article | International Journal of Geomechanics | 23 | 4 | 4023021 | |
| A084 | 2020 | The influence of microwave treatment on the compressive and tensile strength of igneous rocks | Kahraman, Sair; Canpolat, A. Niyazi; Fener, Mustafa | https://linkinghub.elsevier.com/retrieve/pii/S1365160919302771 | granite, syenite, gabbro | igneous rocks; microwave treatment; compressive strength; tensile strength | Cutting hard rocks has some problems such as low penetration rate and high wear rate of cutting tools. These problems can be solved by the microwave treatment of hard rocks during cutting. In this study, the effects of microwave treatment were investigated on the strength of nine different igneous rocks. First, the uniaxial compressive strength (UCS) and Brazilian tensile strength (BTS) tests were carried out on the untreated samples. Then, the strength tests were performed on the microwave treated specimens. The results show that the rock strength decreases generally with increasing microwave power and treatment duration. The strength losses and the heating degrees are different for each tested rock type irradiated by microwave power due to the different the mineral content. When treating the specimens with microwave energy, crackings and/or meltings occur depending on the applied power, the exposure duration, and the mineral content. Even a small amount of metallic mineral can increase too much the temperature of a specimen. The UCS and the BTS values of granites decrease generally with increasing surface temperature after 200 �C and 100 �C, respectively. The significant losses in the UCS and the BTS values of syenite and gabbro specimens are generally observed below 100 �C due to their metallic mineral contents or high amount of microwave absorber minerals. It can be concluded that microwave irradiation has important influences on the strength of igneous rocks depending on the applied energy, the exposure time, and mineralogy. | 10.1016/j.ijrmms.2020.104303 | English | Turkey | Journal Article | International Journal of Rock Mechanics and Mining Sciences | 129 | 104303 | ||
| A085 | 2020 | The assessment of the factors affecting the microwave heating of magmatic rocks | Kahraman, Sair; Canpolat, Ahmet Niyazi; Fener, Mustafa; Kilic, Cumhur Ozcan | http://link.springer.com/10.1007/s40948-020-00197-3 | granite, syenite, gabbro | magmatic rocks; microwave irradiation; mineralogy; micro-structure | Low cutting rate and high tool wear are the important problems during excavating hard rocks. In order to find a solution for these problems, some investigations have been carried out by several researchers. One of the recent studies is the microwave assisted excavation of hard rocks. Revealing the impacts of microwave exposure on the minerals and micro-structures of rocks will be useful for the investigations on the microwave assisted hard rock excavation. In this research, the factors affecting the microwave heating of magmatic rocks were studied. First, the mineralogical analysis was carried out using the thin sections of the untreated specimens. Then, the specimens were exposed to microwaves at different power levels for varying durations. The surface temperature of the specimens was also measured using the infrared gun. After that, the mineralogical analysis was repeated for the treated specimens. The evaluation of the results shows that increasing microwave energy and radiation duration increases the surface temperatures of the tested specimens. The own mineral percentages of a specific specimen are the key factor for the heating degree. It was seen that the micro-structural changes in the specimens began at about the surface temperature of 100 °C. Very important micro-structural changes were observed in the specimens with metallic minerals and the minerals having metallic elements. It is concluded that the applied microwave power, the treatment time, and the mineral constitutes importantly influence the heating degrees of magmatic rocks irradiated with the microwave energy. The developed empirical equation can be used for the prediction of surface temperatures of the magmatic rocks using the percentages of quartz plus feldspar, the density and the porosity. | 10.1007/s40948-020-00197-3 | English | Turkey | Journal Article | Geomechanics and Geophysics for Geo-Energy and Geo-Resources | 6 | 4 | 66 | |
| A087 | 2023 | Strength Degradation and Fracture Mechanism of Sandstone Under Microwave Irradiation | Yao, Huayan; Yao, Jiali | https://link.springer.com/10.1007/s10706-022-02374-5 | sandstone | microwave irradiation; sandstone; wave velocity; tensile strength; scanning electron microscopy; microstructure | To study the strength deterioration and fracture mechanism of rock under the microwave irradiation, the experiments on the wave velocity and Brazilian splitting tensile strength of sandstones after different microwave irradiation time were carried out. The microstructural evolution of sandstone were studied by means of thermogravimetric (TG) analysis and electron microscope scanning (SEM). The results show that the surface temperature of sandstone increases rapidly under microwave irradiation. The P-wave velocity and tensile strength decreased continuously with the increase of irradiation time under 3 kW power. Considerable macroscopic cracks appeared on the surface of the sandstone after microwave irradiation for 6 min. The high temperature generated by microwave irradiation leads to physical and chemical changes of rock minerals, and the selective heating of microwave results in thermal stress. All these have caused damage to the rock, and led to the deterioration of macro physical and mechanical properties of sandstone. | 10.1007/s10706-022-02374-5 | English | China | Journal Article | Geotechnical and Geological Engineering | 41 | 3 | 2201-2209 | |
| A088 | 2005 | Influence of thermal pretreatment on quartz crushability | Hredzák, Slavomír; Lovás, Michal; Kušnierová, Mária | https://www.researchgate.net/publication/26412358_Influence_of_thermal_pretreatment_on_quartz_crushability?enrichId=rgreq-0e34d21b947ddbca1ef38ed2e32b3ad3-XXX&enrichSource=Y292ZXJQYWdlOzI2NDEyMzU4O0FTOjE4MDA2ODYwOTQzNzY5NkAxNDE5OTQzMTEwNTEx&el=1_x_2&_esc=publicationCoverPdf | quartz | quartz; crushing; thermal pretreatment; work index | The paper deals with an influence of thermal pretreatment on the crushability of quartz. The sample of lump quartz from the deposit of Švedlár (Eastern Slovakia) was subjected to primary crushing in the jaw crusher PS D-160 with a discharge of 10–20 mm to obtain a grain size fraction of 8 –12 mm. This fraction was thermally pretreated in microwave and muffle ovens. Subsequently, unpretreated and pretreated samples of quartz were crushed again in the secondary jaw crusher VCM-3 with a discharge of 0,2–3 mm. The products of the secondary crushing were been subjected to the grain size analyses. Finally, the results of the grain size analyses were plotted. The bond work index and the relative work index according to the Berry and Bruce method were calculated. The obtained results point to the fact that the thermal pretreatment results in a work index reduction by 5 – 21 %. | N/A | Slovak | Slovakia | Journal Article | Acta Montanistica Slovaca | 10 | 1 | 60-66 | |
| A089 | 1966 | Heating with Microwaves: Fundamentals, Components and Cicuit Technique | Puschner | https://archive.org/details/heatingwithmicro0000pusc/page/158/mode/2up?q=stone+shattering | N/A | N/A | N/A | N/A | English | Germany(?) | Textbook | N/A | 0 | N/A | N/A | |
| A090 | 2020 | Twenty years of experimental and numerical studies on microwave-assisted breakage of rocks and minerals—a review | Teimoori, Khashayar; Hassani, Ferri | https://arxiv.org/pdf/2011.14624 | review paper | single-mode microwave; multi-mode microwave; microwave-assisted rock breakage; microwave heating; mineral processing | Microwaves have been used for a variety of applications in the past two decades. However, there has been a significant and growing interest in the applications of microwaves in hard rock breakage and mineral processing industries. The purpose of this review paper is to focus on these applications and to present a careful review of the state-of-the-art experimental and numerical modeling techniques introduced in the literature from 2000 to 2020. The challenges involved in this research area are surveyed, and the efforts that should be made regarding the potential practical implementation of microwaves in industry are discussed. | N/A | English | Canada | Journal Article | N/A | 0 | N/A | ||
| A091 | 2020 | Influence of individual and combined pre-treatment of the strength properties of granite and sandstone | Bisai, R.; Palaniappan, S. K.; Pai, S. K. | https://link.springer.com/article/10.1007/s12517-019-5009-5 | granite, sandstone | microwave; cryogenic pre-treatment; liquid nitrogen; granite; sandstone | Temperature variation is one of the primary factors influencing the physical properties of rocks. Currently, research on improvement of energy efficiency in comminution of rocks using various pre-treatment methods is an important topic, worldwide. So, a proper pre-treatment for rocks reduces the energy required for comminution. In this paper, experimental data on strength properties of granite and sandstone using two different pre-treatments i.e., individual microwave and combined microwave/liquid nitrogen quenching are presented. The samples are treated with varying time duration of microwave and quenching. The obtained results indicate that pre-treatments in rocks show a decreasing trend in strength values of both the rock samples. Granite samples show a 54% drop in ultimate tensile strength and a 26% drop in ultimate compressive strength for individual pre-treatment, whereas a decrease of 67% in ultimate tensile strength and 33% in ultimate compressive strength are also observed for combined pre-treated samples. Similarly, sandstone shows the same decreasing trend in strength properties for the pre-treated samples. Scanning electron microscope analyses of untreated and treated samples are carried out to understand the fracture morphology of both the rocks. | 10.1007/s12517-019-5009-5 | English | India | Journal Article | Arabian Journal of Geosciences | 13 | 1 | ||
| A092 | 2020 | Dynamic tensile response of a microwave damaged granitic rock | Li, X.; Wang, S.; Xia, K.; Tong, T. | https://link.springer.com/article/10.1007/s11340-020-00677-3 | granite | microwave irradiation; SHPB; dynamic tensile response; digital image correlation (DIC); overload correction | Background: Understanding the dynamic tensile response of microwave damaged rock is of great significance to promote the development of microwave-assisted hard rock breakage technology. However, most of the current research on this issue is limited to static loading conditions, which is inconsistent with the dynamic stress circumstances encountered in real rock-breaking operations. Objective: The objective of this work is to investigate the effects of microwave irradiation on the dynamic tensile strength, full-field displacement distribution and average fracture energy of a granitic rock. Methods: The split Hopkinson pressure bar (SHPB) system combined with digital image correlation (DIC) technique is adopted to conduct the experiments. The overload phenomenon, which refers to the strength over-estimation phenomenon in the Brazilian test, is validated using the conventional strain gauge method. Based on the DIC analysis, a new approach for calculating the average fracture energy is proposed. Results: Experimental results show that both the apparent and true tensile strengths increase with the loading rate while decreasing with the increase of the irradiation duration; and the true tensile strength after overload correction is lower than the apparent strength. Besides, the overload ratio and fracture energy also show the loading rate and irradiation duration dependency. Conclusions: Our findings prove clearly that microwave irradiation significantly weakens the dynamic tensile properties of granitic rock. | 10.1007/s11340-020-00677-3 | English | Canada, China | Journal Article | Experimental Mechanics | 61 | 461-468 | ||
| A093 | 2020 | Analysis of the thermal mechanism and temporal and spatial evolution of the thermal field of deep sandstone under microwaves | Yang, Ben-Gao; Gao, Ming-Zhong; Xie, Jing; Liu, Jun-Jun; Liu, Yi-Ting | https://doiserbia.nb.rs/Article.aspx?ID=0354-98362006877Y | sandstone | deep; microwave; sandstone; mineral; heating | In the practice of the deep engineering, it is expected to improve engineering efficiency by introducing the microwave energy. Therefore, based on 1050 m deep sandstone, the heating characteristics of sandstone and its constituent minerals in the microwave field are comprehensively explored through experiments and nu?merical simulations. In the paper, the asynchronism of the temperature rise in different areas of the sandstone depends on the local characteristics of dielectric loss and maximum heat storage capacity. With increase of the temperature, the evaporation of the water leads to the decrease of the dielectric properties, the increase in the constant-pressure heat capacity and the increase in the heat dissipation coefficient, which suppresses the temperature growth trend. The temperature rise of the amplitude of the material is lower than that expected from the microwave power. The maximum temperature of dolomite, feldspar and quartz under the power of 2000 W is 1.86, 1.71, and 1.63 times that of the power of 1000 W, respectively. It is necessary to select the reasonable microwave power to maximize the engineering efficiency. The results are expected to provide the theoretical and technical supports for the electromagnetic heat generation in deep engineering. | 10.2298/TSCI2006877Y | English | China | Journal Article | Thermal Science | 24 | 6 Part B | 3877-3886 | |
| A094 | 2021 | Study on microwave-assisted grinding and liberation characteristics for Ludwigite | Huang, Weijun; Liu, Yajing | https://www.tandfonline.com/doi/full/10.1080/08327823.2021.1877245 | ludwigite (boron) | ludwigite; microwave treatment; particle size; lieration degree; locked particles | To effectively separate the valuable minerals in ludwigite, this study investigated the grinding fineness behaviour and liberation characteristics. The results indicated that the particle yield of 75 lm with a microwave power of 4 kW for 40 s was increased by 18.22% in comparison to that of raw ore. The D(50) and D(90) raw-ore grinding products reached 53.52 and 215.16 lm, both of which were larger than microwave-treated samples. The particlesize distribution of the grinding products for treated ore was more uniform, and the amount of coarse and over-ground particles decreased significantly. The specific surface area, pore volume and pore diameter of the large particles were effectively increased after microwave heating, which improved the crushing and grinding characteristics of the grinding products by lowering the relevant mechanical properties. The monomer liberations of magnetite, ascharite and serpentine of microwave-treated ore samples were 55.33%, 35.48% and 74.98%, respectively, which represented an increase of 12.06%, 9.37% and 6.22% in comparison to untreated ore samples. The bonding characteristics among different minerals were altered through microwave treatment to weaken the bonding force and reduce the proportion of interlocked minerals, which allows these complex minerals to easily liberate after secondary grinding. | 10.1080/08327823.2021.1877245 | English | China | Journal Article | Journal of Microwave Power and Electromagnetic Energy | 55 | 1 | 28-44 | |
| A095 | 2020 | A comparative study of the cooling-rate effect on rock strength reduction after microwave irradiation | Rafezi, Hamed; Deyab, Samir M.; Hassani, Ferri; Ghoreishi-Madiseh, Seyed Ali | https://www.cambridge.org/core/product/identifier/S2516712X20000325/type/journal_article | basalt | mining; microwave irradiation; rock preconditioning; rock excavation | A variety of machines are currently being used for mechanical excavation in mining and civil industries. A series of research works have been conducted at McGill University in the past decade to study the effects of microwave (MW) irradiation on rock mechanical properties. The idea is to enhance the excavation performance by improving the rate of penetration and decreasing the wear rate on the cutting tools. These two effects would eventually translate into economic benefits for mine operators. The effectiveness of MW on weakening rocks is proven, however the most efficient method to employ MW in mines is still under investigation. This article presents some experimental results on the effects of cooling- rate on rock strength. Brazilian Tensile Strength (BTS) of microwave treated samples were compared in natural air-cooled and water rapid-cooled conditions. | 10.1017/exp.2020.32 | English | Canada | Journal Article | Experimental Results | 1 | e36 | ||
| A096 | 1975 | The Development of a High-Power Microwave Circulator for Use in Breaking of Concrete and Rock | Okada, Fumiaki; Ohwi, Koichi; Mori, Makoto | http://www.tandfonline.com/doi/full/10.1080/00222739.1975.11688951 | equipment description, concrete | N/A | A high-power circulator at 915 MHz. has been developed. This three-port waveguide circulator has a power-handling capability of 30 kW CW and an insertion loss of 0.1 dB. The high-power circulator is useful for protecting high-power microwave sources from reflected power. A high-power microwave system describing the design of the circulator, and giving the results of preliminary experiments in breaking concrete and rock are presented. | 10.1080/00222739.1975.11688951 | English | Japan | Journal Article | Journal of Microwave Power | 10 | 2 | 171-180 | |
| A097 | 2020 | Microwave treatment of rocks: effect on specific gravity, whiteness, and grindability | Sefiu, O. A.; Hussin, A. M. A.; Haitham, M. A. A. | http://www.rudmet.ru/journal/1930/article/32671/?language=en | coral, quartzite | comminution; grinding; crushing; liberation; work index; energy; ore treatment | Heating of ores usually improves the liberation of minerals and reduces grinding energy consumption. One of the heating methods is using microwave electromagnetic radiation, which may change the rock’s physical properties. This paper investigates the effect of microwave heating of rocks on their physical properties. The physical properties monitored were specific gravity, whiteness, and grindability due to their importance for the downstream processes. Two rock types were investigated: coral as the soft rock and quartzite as the hard rock. The rock samples tested were treated for different time intervals in a microwave oven (frequency — 2.45 GHz, P = 1.7 kW). The results showed that specific gravity of the soft rock decreased by 1.82 % after the microwave treatment (150 s), while that of the hard rock was not affected. It was also found that the maximum change in rock whiteness for the soft rock is 8.65 % after the microwave treatment (150 s), while that of the hard rock was 6.02 % after a 120 s microwave radiation exposure period. Following a 60 s microwave radiation exposure, the soft rock demonstrated the work index of 20.99 % against the value of 45.03 % of the hard rock. The results of FTIR and XRD analyses suggest that changes in the physical property and a phase shift of minerals may be responsible for the improvement in the work index and whiteness of the rocks studied. | 10.17580/or.2020.03.02 | English | Saudi Arabia | Journal Article | Obogashchenie Rud | 2.020 | 3 | 8-13 | |
| A098 | 2018 | Microwave-Assisted Grinding of Bolkardag (Nigde, Turkey) Gold Ore and Enhanced Cyanide Leachability | Seflek, Cemaliye; Bayat, Oktay | https://www.metallurgical-research.org/10.1051/metal/2018039 | gold ore | gold ore; microwave; grindability; cyanide; leaching | This experimental work aims at studying the effect of particle size on the microwave pre-treatment for the grindability of Bolkardag (Nigde, Turkey) gold ore for cyanide leaching. Three different particle size batches ( 8 + 4.7 mm, 4.75 + 2 mm and 2 + 1 mm) were used for microwave treatment. Each sub-samples were exposed to four different power levels of microwave energy (0.09, 0.18, 0.36 and 0.6 kW) at exposure times of 5, 10, 15 and 30 minutes and then grindability characteristic of the treated samples were investigated with Berry and Bruce comparative grindability method. It was clearly seen that increasing power level and exposure time caused a reduction in comparative Bond Work index. A maximum reduction in Bond Work index (73.54%) was achieved by 0.6 kW at 30 minutes of microwave treatment. Compared to the untreated sample’s results, gold and silver extraction rates increased, using microwave-treated samples, about 7% and 9% after 77 hours cyanide leaching, respectively. Additionally, the hydrated lime added samples (after 0.6 kW at 30 minutes of microwave treatment) were used in the cyanide leaching tests to determine the possible effect. It was observed that there was no significant difference on leaching extraction rates using lime free or lime added samples. Applying microwave pre-treatment before cyanide leaching, the gold and silver extraction rates could be increased and also the cost of communition could be reduced due to easier breakage of the ore due to a significant decrease in Bond Work index. | 10.1051/metal/2018039 | English | Turkey | Journal Article | Metallurgical Research & Technology | 115 | 5 | 508 | |
| A099 | 2010 | The Effect of High Power Microwave Energy on the Grindability of Turkish Cayirhan Lignite | Toraman, O. Y. | http://www.tandfonline.com/doi/abs/10.1080/15567030902882976 | coal | microwave energy; single mode cavity; Turkish lignite coal; gridability; Hardgrove index | In this study, the effect of microwave radiation on grindability of Turkish lignite has been investigated. Turkish lignite ( 15 mm, 500 g) was treated by microwave (at a frequency of 2.45 GHz) in a Te010 single mode cavity using a pneumatic system to control the residence time of each sample in the cavity with high-electricfield-strength microwave energy at different power settings (in the range of 5–20 kW) for a short residence time (2 sec). In order to determine the grinding resistance of Turkish lignite samples treated by microwave ovens, the Hardgrove Grindability Test was applied for each treated and untreated sample and also the amount of fine product ( 74 m) was evaluated and compared with each other. Experimental results have shown that significant increases in grindability were achieved when the lignite samples were exposed to microwave radiation. The Hardgrove Grindability Index of samples and the amount of fine product increased up to 123 and 117%, respectively. | 10.1080/15567030902882976 | English | Turkey | Journal Article | Energy Sources, Part A: Recovery, Utilization, and Environmental Effects | 32 | 19 | 1794-1800 | |
| A100 | 2021 | A microwave fracturability index (MFI) of hard igneous rocks | Zheng, Y.L.; Ma, Z.J.; Yang, S.Q.; Zhao, X.B.; He, L.; Li, J.C. | https://linkinghub.elsevier.com/retrieve/pii/S1365160920309321 | Microwave has been regarded as a promising technique to break hard igneous rocks. However, there is no criterion to evaluate the ease with which commonly found hard rocks can be fractured by microwave. In this study, 15 hard rocks were treated by a 2.45 GHz single mode microwave cavity at 3 kW for 1 min. The effect of rock properties including the average grain size, the volume inhomogeneity coefficient, the effective dielectric loss factor and the initial P-wave velocity on the P-wave velocity reduction (which is defined as the microwave fracturability index-MFI) was investigated. The first three parameters can be obtained from the petrographic images whereas the last one is easy to assess. The results found positive linear relationships between MFI and the average grain size, the effective dielectric loss factor and the initial P-wave velocity, and a negative linear relationship between MFI and the volume inhomogeneity coefficient. In addition, the study revealed that the most significant factors according the entropy weight method are the effective dielectric loss factor and the average grain size, followed by the volume inhomogeneity coefficient, and finally the initial P-wave velocity. A multi-parameter linear regression model for MFI of igneous rocks was proposed and validated. This work provides an easy and straightforward method to assess the microwave fracturability of a specific rock based on petrographic photomicrographs and P-wave velocity measurement. | 10.1016/j.ijrmms.2020.104566 | English | Journal Article | International Journal of Rock Mechanics and Mining Sciences | 138 | 104566 | |||||
| A101 | 2020 | Coupled multiscale-modeling of microwave-heating-induced fracturing in shales | Cui, Guanglei; Chen, Tianyu; Feng, Xiating; Chen, Zhongwei; Elsworth, Derek; Yu, Hongwen; Zheng, Xu; Pan, Zhejun | https://linkinghub.elsevier.com/retrieve/pii/S1365160920308881 | shale | thermal stress; shear damage; tensile damage; intergranualr fracture; transgranular fracture | Microwave heating may be used to stimulate fracture formation and the release of hydrocarbons in gas shales. Although extensively studied experimentally and numerically, the microscopic observations are not fully explained in current work where the heating, at sample-scale, and fracturing, at the mineral-scale, are represented independently. Furthermore, the geometry, structure and mechanical interaction of different minerals are not fully considered in current approaches. We present a novel simulation approach to investigate the coupled electromagnetic-heating-stress-damage process. Microwave heating is simulated at sample-scale and the resulting stress-damage response is examined at micro-scale where minerals with contrasting thermo-mechanical characteristics are stacked as lamellae, instead of nested internally as in previous representations. A threestage temperature evolution profile is observed in the shale samples – although some stages may be absent in other rocks. The mathematical model accounts for the three modes of stress generated between minerals: horizontal stress (σh) (tensile stress parallel to the grain-grain interface) and the normal stress(σn) (tensile stress normal to the grain-grain interface) applied on the minerals, and the shear stress (τ) applied on the interface between different minerals. The minerals comprising the shale matrix are categorized into three types – ‘high’, ‘intermediate’ and ‘low’ – conversion efficiency based on their susceptibility to thermal stressing from microwave irradiation. Shear damage and intergranular fracture usually occurs for minerals with high dielectric permittivity. Transgranular fracture may feature both in high permittivity minerals, due to the larger induced horizontal stress (σh), and in low permittivity minerals - due to high volume fraction and larger size. The simulation approach is a powerful way to link the macro-scale characterization and heating to micro-mechanisms of rock failure. Also this work provides mineral classification and criteria to define a priori evaluation of the effectiveness of microwave treatment of shales and other mineral aggregates. | 10.1016/j.ijrmms.2020.104520 | English | Australia | Journal Article | International Journal of Rock Mechanics and Mining Sciences | 136 | 104520 | ||
| A102 | 2021 | Microwave-assisted damage and fracturing of hard rocks and its implications for effective mineral resources recovery | Xu, Tao; Yuan, Yang; Heap, Michael J.; Zhou, Guang-Lei; Perera, M.S.A.; Ranjith, P.G. | https://linkinghub.elsevier.com/retrieve/pii/S0892687520304830 | basalt | microwave radiation; damage evolution; inhomogeneity; rock fracturing; numerical model | Microwave radiation can be used to pre-damage hard rock to reduce the cost of drilling and excavation typically required in tunneling, mining, and deep Earth energy recovery. A 3D damage-based, electromagnetic-thermomechanical coupled model to simulate damage and fracturing of rock under microwave radiation is proposed in this manuscript. The model is first validated against experimental test and then used to simulate the damage and fracturing of rock under microwave radiation at various microwave power levels and radiation times. The simulations show that the distribution of temperature in the rock sample is extremely non-uniform, resulting in high thermal gradients that can damage and/or fracture the rock sample. Higher power levels and longer durations impart more damage. The simulations also show, under the same microwave radiation conditions, that the resultant sample temperature, and therefore damage, is higher in samples with high ratios of compressive to tensile strength. A good agreement between the modeling and experimental results suggests that the model can be used to assist in the management and optimization of mineral mining, oil and gas recovery, and deep Earth energy recovery. | 10.1016/j.mineng.2020.106663 | English | Australia, China, France | Journal Article | Minerals Engineering | 160 | 106663 | ||
| A103 | 2024 | Enhancing rock breakage efficiency by microwave fracturing: A study on antenna selection | Ma, Zhongjun; Zheng, Yanlong; Li, Jianchun; Zhao, Xiaobao; Zhao, Jian | https://linkinghub.elsevier.com/retrieve/pii/S036054422303270X | equipment evaluation, granite, diorite, diabase | microwave heating; rock fracturing; antenna selection; dielectric heating | Microwave fracturing of rocks prior to mechanical breakage has the potential to significantly enhance rock breakage efficiency while reducing the wear of cutters/bits of mechanical excavators. However, rocks in nature require a vastly different microwave power intensity to be fractured, and they tend to fail in varying patterns under different power intensities. At present, there is no established suggest method for selecting the most suitable microwave antenna to fracture a specific rock in the field. In this study, we compared the technical characteristics of the four open-ended waveguide-based antennas: namely, the horn antenna, the standard waveguide antenna, the converging waveguide antenna, and the dielectric-loaded converging waveguide antenna. Using a 6 kW microwave source and these antennas, we treated four types of hard rocks. We investigated the impact of antenna type on rock fracturing and found that depending on the rock type and antenna used, rocks were typically fractured or weakened in the pattern of cracking, spalling, melting, or a combination thereof. Based on our observations, we have, for the first time, proposed a method for selecting the optimal antenna to fracture rocks with varying microwave fracturability indexes. This paves the way for the commercialization of microwave-assisted mechanical rock breakage. | 10.1016/j.energy.2023.129876 | English | Australia, China | Journal Article | Energy | 288 | 129876 | ||
| A104 | 2021 | Study on Microwave Heating Order and Electromagnetic Characteristics of Copper and Gold Ores | Lin, Feng; Feng, Xia-Ting; Lu, Gao-Ming; Su, Xiang-Xin; Li, Shi-Ping; Zhang, Jiu-yu | https://link.springer.com/10.1007/s00603-021-02376-4 | copper ore, gold ore | microwave heating; grinding; electromagnetic characteristics; shielding effect; reflection | Microwave heating and grinding experiments were conducted on samples of Hongtoushan copper ore and Dandong gold ore with different particle sizes and forms. The differences between the heating effects observed were then investigated using the electromagnetic characteristics of the bulk and powdered ore samples. The results show that the bulk copper ore experiences a high shielding effect as the microwaves are strongly reflected. The dielectric constant and reflection from a powdered sample are significantly weaker. Microwaves of frequency 2.45 GHz produce an insignificant heating and grinding effect in a cylindrical sample of Hongtoushan copper ore; the heating and grinding effect using a particulate sample is significantly better. In contrast, the heating and grinding effect obtained using a cylindrical sample of Dandong gold ore is better than that obtained using a particulate sample. The reasonable use of microwave heating to process ore is also discussed. Hongtoushan copper ore is suitable for microwave treatment after fine crushing. Dandong gold ore is suitable for microwave treatment before fine crushing. In the latter case, the application of microwaves could be moved forward to the mining process stage before carrying out the other procedures further downstream. | 10.1007/s00603-021-02376-4 | English | China | Journal Article | Rock Mechanics and Rock Engineering | 54 | 5 | 2129-2143 | |
| A105 | 2023 | Effects of particle size and morphology on microwave cracking characteristics and cracking mechanism of three Fe-containing ores | Lin, Feng; Feng, Xia-Ting; Li, Shi-Ping; Zhang, Jiu-Yu; Su, Xiang-Xin; Tong, Tian-Yang | https://link.springer.com/10.1007/s40948-023-00626-z | copper ore, gold ore | particle size; morphology; cracking characteristics; arcing; heating effect | Abstract Microwave irradiation is a potential technology for use in rock fracturing. It is of great significance for the application of microwave technology in metal mines to understand the microwave cracking characteristics of ores and the mechanism of microwave action of ores. Taking Hongtoushan copper ore, Sishanling iron ore, and Dandong gold ore as research objects, the microwave cracking characteristics of ores with different morphologies (bulk/particle samples) and particle sizes were investigated. The microwave action mechanism of ores was revealed based on dielectric properties and arc characteristics. The results show that the change in morphology of the ore affects the microwave cracking characteristics thereof. The failure of iron ore and gold ore is characterized by the generation of cracks and the crack direction is related to the ore morphology. The bulk copper ore is not damaged after microwave irradiation, but the damage to particles of copper ore is characterized by scorching or scorching and melting accompanied by cracks. The more power applied, the larger the particles, and the stronger the arcing. Compared with the type and morphology of ore, particle size has little effect on dielectric properties. The microwave action mechanism of bulk copper ore (smooth surface) is a reflection effect and that of bulk copper ore (rough surface) is a discharge effect. The microwave mechanism of action on particulate copper ore is the combined action of discharge and heating effects, which leads to fracture. The microwave mechanism of action on iron ore and gold ore is mainly one of heating. The research results provide guidance for the development of microwave ore-cracking equipment and the selection of the optimal heating sequence. | 10.1007/s40948-023-00626-z | English | China | Journal Article | Geomechanics and Geophysics for Geo-Energy and Geo-Resources | 9 | 1 | 100 | |
| A106 | 2018 | The effect of microwave radiation on grinding kinetics by selection function and breakage function - A case study of low-grade siliceous manganese ores | Heshami, Monireh; Ahmadi, Rahman; Rahimi, Esmaeil | https://doi.org/10.22104/jpst.2018.2992.1129 | manganese silicate ore | microwave treatment; work index; grindability; specific rate of breakage; siliceous manganese ore | In this study, the effect of microwave radiation on grindability and grinding kinetics were investigated. Microwave treatment was performed using an oven with 1100 W power and 2.45 GHz frequency. In order to study the breakage mechanism the grindability from the standard Bond ball mill work index (BBMWI) test was used with the selection function and breakage function as grinding parameters for treated and untreated samples. Based on the results of grindability, the work index (Wi) of a standard Bond ball mill after 4 min of microwave radiation decreased from 12.46 kWh/t to 6.45 kWh/t. Selection function results showed that the specific rate of breakage (Si) value for the size fraction -3350+2360 μm increased to 8.42% after microwave treatment. Cumulative breakage function results showed that microwave-treated products were coarser in comparison with untreated products. This phenomenon is more significant in coarse fractions, where the effect of microwave treatment is more obvious. | 10.22104/jpst.2018.2992.1129 | English | Iran | Journal Article | Journal of Particle Science & Technology | 4 | 1 | 39-47 | |
| A108 | 2021 | Multiphysics study of microwave irradiation effects on rock breakage system | Teimoori, Khashayar; Cooper, Richard | https://linkinghub.elsevier.com/retrieve/pii/S1365160920309527 | basalt | microwave irradiation; rock heating and preconditioning; microwave-assisted rock breakage; Maxwell's theory; single-mode microwave; distance from microwave antenna | The development of a model to describe the Electromagnetic-Thermal-Mechanical (ETM) multiphysics interaction in rocks requires careful consideration of the heating mechanism when microwave irradiation is applied. Since the rock breakage process by microwave energy depends on different microwave operating parameters, such as power level, exposure time, and distance from microwave antenna, a fully coupled numerical modeling approach is necessary to evaluate the corresponding effects, i.e. temperature changes, initiation of mechanical stresses, formation of micro/macro cracks, and disintegration/separation mechanism caused by thermal strains among rock particles from the coupling of ETM multiphysics interaction. To gain a better understanding of the rock breakage system due to microwave irradiation, this paper develops and analyzes numerical simulations of rock-microwave interactions using the finite element method. Several numerical models are conducted, and their results are tested and compared with data obtained from the experiments on basalt samples as part of the validation process. The models and experiments consider different microwave parameters, such as distance from microwave antenna, power level, and exposure time. The models are solved for electrical and magnetic fields, temperature distribution and maximum principal stress. The numerical results suggest that microwave energy has potential application for rock breakage and, therefore, continuous excavation. | 10.1016/j.ijrmms.2020.104586 | English | Canada | Journal Article | International Journal of Rock Mechanics and Mining Sciences | 140 | 104586 | ||
| A109 | 2020 | Rising characteristics of internal and external temperatures of rock specimens under different microwave irradiation modes | Gao, F.; Shao, Y.; Xiong, X.; Zhou, K.; Cao, S. | https://www.cgejournal.com/en/article/doi/10.11779/CJGE202004007?viewType=HTML | granite | microwave; rock breakage; irradiation method; temperature; power | Microwave-assisted mechanical rock breaking is an important means to achieve non-blasting continuous mining of hard rock. The microwave irradiation is of important theoretical and practical significances for studying the temperature response and failure mechanism of rock. For the granite samples subjected to microwave heating, the unilateral and double-sided heating tests with different power and time as well as the P-wave velocity tests before and after heating of the samples are carried out. The results show that the reverse power of the samples decreases with time as a whole, and the degree of decrease increases with the increase of power. The internal temperature of the samples is higher than the surface temperature, and the change has obvious phase characteristics, and there is an "inflection point" in the temperature rising phase, and the surface temperature gradually decreases from the center to the edge in the radial direction. Microwave heating causes thermal stress inside the samples and generation and propagation of cracks, reducing the P-wave velocity. Heating the samples with a single, single-sided, high-power and short-time microwave irradiation method can increase the temperature of the samples more significantly. | 10.11779/CJGE202004007 | Chinese | China | Journal Article | Chinese Journal of Geotechnical Engineering | 42 | 4 | 650-657 | |
| A110 | 2010 | Comminution behaviour of microwave heated two sulphide copper ores | Kaya, Erol | https://www.researchgate.net/publication/228582101_Comminution_behaviour_of_microwave_heated_two_sulphide_copper_ores | copper ore | microwave irradiation;comminution; copper ore | The effect of microwave irradiation on the comminution of two sulphide copper ores with different mineralogy were investigated to enhance the milling processes. Each ore was subjected to microwave radiation for varying time periods to determine their heating profiles. Changes in breakage characteristics with the microwave exposure time were quantified by sieving breakage, standard Bond work index grindability and single particle drop weight comminution tests. The results of the sieving breakage tests with the untreated and microwaved samples indicated significant improvements in the size reduction due to microwave energy induced macro fracturing. Differing ore mineralogy has been shown to affect the effectiveness of microwave assisted size reduction. The results of the standard Bond work index grindability tests performed with both the microwave treated copper ores, on the other hand, suggested no significant improvements in grindability. The single particle fracture experiments performed with an Ultrafast Load Cell (UFLC) indicated similar results of no significant improvements in the fracture energies of the microwave treated ore samples. | N/A | English | Turkey | Journal Article | Indian Journal of Chemical Technology | 17 | 455-461 | ||
| A111 | 2008 | Study of the processes of destruction of the kimberlite rock by the microwave field | Didenko et al. | |||||||||||||
| A112 | 2020 | Textural and Mineralogical Controls on Microwave-Induced Cracking in Granites | Nicco, Marion; Holley, Elizabeth A.; Hartlieb, Philipp; Pfaff, Katharina | https://link.springer.com/10.1007/s00603-020-02189-x | Microwave irradiation has been considered as a potential method for weakening rock in mining and civil engineering applications, and numerous studies have demonstrated the strength-reducing effects. SEM-based automated mineralogy provides new opportunities to examine the mineralogical controls on microwave-induced cracking. This study employed a combined approach of optical microscopy and automated mineralogical analysis of scanning electron microscopy to investigate the roles of mineralogy and texture in microwave-induced cracking of granitic rocks. Most rocks on Earth, such as granite, are composed of relatively weak microwave absorbing minerals, compared to those tested in prior investigations on ores. This study examined three types of natural granite specimens, selected for their varying proportions of weak microwave absorbers (albite, amphibole, biotite, orthoclase, and quartz), and their contrasting textures (perthitic, granophyric and oikocrystic) and grain sizes (fine and coarse grained). Microwave irradiation experiments at 3.2 kW and 2.45 GHz led to the generation of macroscopically and microscopically visible cracks and lower P-wave velocities after irradiation. The optical investigations revealed that coarse-grained (1–5 mm) granites developed extensive networks of narrow cracks; whereas, fine-grained (<1 mm) granites of similar composition developed few cracks which were comparatively wider. Quantitative assessment of the spatial relationships between these cracks and the host minerals showed that intragranular cracks developed along cleavage planes of albite and amphibole, potentially in response to thermal expansion of brittle grains. Intergranular cracking occurred adjacent to thermally conductive or highly expansive grains such as quartz and biotite. In these specimens, cracking appears to be driven by contrasts among the chemical, mineralogical, thermal and microwave properties of the constituent minerals, and strong absorbers are not essential. The limited dataset from this study suggests that granitoid rocks may be potential targets for industrial applications of microwave irradiation. | 10.1007/s00603-020-02189-x | English | Journal Article | Rock Mechanics and Rock Engineering | 53 | 10 | 4745-4765 | ||||
| A113 | 2023 | Effect of strong dielectric substances on the damage characteristics of rocks exposed to microwave radiation: Insight from experiments and mechanisms | Gao, Feng; He, Yindong; Xiong, Xin; Zhou, Keping; Yang, Chun | https://journals.sagepub.com/doi/10.1177/10567895231171410 | It has been demonstrated that microwave pretreatment can weaken rocks, reduce tool wear, and improve mechanical rock breaking efficiency. The dielectric properties of rock minerals are a major factor affecting the ability of rocks to absorb microwaves, so it is important to conduct experimental research on rock modification to improve the microwave absorption capacity of rocks. The concept of “microwave-assisted absorbing reagents” has been proposed to increase the microwave absorption capacity of rocks. Sandstone specimens are first pretreated with strong dielectric substances before being exposed to microwave radiation to increase their microwave absorption capacity, then they are exposed to microwave fields and finally conducted to uniaxial compression tests. Enhancement in microwave absorption capacity of sandstone specimens is showed by P-wave velocity, nuclear magnetic resonance, and mechanical tests before and after microwave treatment. The results showed that barium titanate suspension and water are both effective microwave-assisted absorbing agents. The specimens treated with barium titanate suspension exhibited better microwave absorption capacity; in 5 kW microwave power irradiation, its p-wave velocity falls by 14.04%, porosity rises by 25.43%, and uniaxial compressive strength falls by 24.98%. Additionally, the failure form of sandstone specimens changes from brittle to plastic once it has fully absorbed microwave energy. | 10.1177/10567895231171410 | English | Journal Article | International Journal of Damage Mechanics | 32 | 6 | 849-871 | ||||
| A114 | 2021 | Effect of microwave treatment on thermal properties and structural degradation of red sandstone in rock excavation | Yao, Junhui; Tao, Ming; Zhao, Rui; Hashemi, Sam S.; Wang, Yiqing | https://linkinghub.elsevier.com/retrieve/pii/S0892687520305501 | Weakening rocks using microwave irradiation has been a major topic in research for the past 50 years. However, the thermal effect of microwaves on rocks is mostly studied with a multi-mode metal cavity, in which rocks absorb microwaves reflected from all directions, and this method cannot represent how the microwave pretreatment affects the rock mass in the rock excavation process. To simulate microwave treatment before an excavation, we wrapped a sample of red sandstone in a copper foil to avoid microwave overheating and the thermal properties and structural deterioration of the sample were investigated. Collected temperature data showed that pore water not only elevated the heating rate significantly but also it related to the temperature distribution within the rock sample. With the continuous removal of moisture during the heating process, the temperature distribution changed from exponential to linear equation. Besides, increasing the microwave power was beneficial to improve the heating rate and energy concentration on the rock fragmentation. Combining the results from nuclear magnetic resonance (NMR) and scanning electron microscopy (SEM), it was found that the porosity of macropores (T2 greater than 100 ms) and mesopores (10 ms＜T2＜100 ms) increased after microwave treatment, and change in porosity led to forming transgranular fracture and increasing the number of intergranular fracture. Furthermore, intragranular fractures decreased with microwave propagation, which indicated that the rock damage was a result of the development of intragranular fractures. | 10.1016/j.mineng.2020.106730 | English | Journal Article | Minerals Engineering | 162 | 106730 | |||||
| A115 | 2020 | Analysis of microwave thermal stress fracture characteristics and size effect of sandstone under microwave heating | Gao et al. | https://www.mdpi.com/1996-1073/13/14/3614 | ||||||||||||
| A116 | 2020 | Microwave fracturing of water-bearing sandstones: Heating characteristics and bursting | Zhao, Q.H.; Zhao, X.B.; Zheng, Y.L.; Li, J.C.; He, L.; Zou, C.J. | https://linkinghub.elsevier.com/retrieve/pii/S1365160920308637 | Microwave treatment has been considered as a promising rock breakage method. The weakening mechanism of vaporizing expansion of pore water in sandstone under microwave irradiation was studied in this paper. The effect of water in the heating process was studied by comparing the heating characteristics of dry and saturated sandstones, which was further explained by the mercury intrusion porosimetry tests. Moreover, the influencing factors including rock strength, permeability, saturation degree and microwave power on rock bursting were investigated by comparing the bursting time of water-bearing sandstone samples under microwave irradiation. The results show that water plays a more important role in the heating process of sandstones with higher porosity and lower microwave sensitivity. The heating curves of saturated sandstones can be divided into 3 stages according to the heating rate, which is related to the interaction of water heating and steam escape during microwave irradiation. In addition, it is found that the favorable conditions of water-bearing sandstone bursting under microwave irradiation are low rock strength, low permeability, high saturation degree and high microwave power. This law can be explained by the interaction of rock properties and the generation, increase, diffusion, and escape of steam in rock. | 10.1016/j.ijrmms.2020.104495 | English | Journal Article | International Journal of Rock Mechanics and Mining Sciences | 136 | 104495 | |||||
| A117 | 2022 | Natural factors related to the differential heating of aggregates exposed to microwaves | Trigos, Laura; Escavy, José Ignacio; Gallego, Juan; Gulisano, Federico | https://linkinghub.elsevier.com/retrieve/pii/S0950061821033900 | The heating produced by microwaves has been demonstrated to be effective in materials such as aggregates, although notable differences in heating have been observed between different types of aggregates. The geological factors of each material are responsible for these differences in heating due to compositional elements such as the mineralogy and chemistry of the material and physical characteristics such as crystal size and apparent density. The study of each of these characteristics could unravel the factors determining differential heating in aggregates, which would be relevant for different applications in the mining industry (heating, drying, and comminution) and in civil engineering in self-healing (microcrack repair) or winter road maintenance (surface de-icing). | 10.1016/j.conbuildmat.2021.125654 | English | Journal Article | Construction and Building Materials | 314 | 125654 | |||||
| A118 | 2021 | Thermo-Mechanical Response of Layered Rocks upon Single-Mode microwave treatments | Roshankhah et al. | https://onepetro.org/armaigs/proceedings-abstract/IGS21/IGS21/ARMA-IGS-21-133/473091 | ||||||||||||
| A119 | 2023 | Acoustic emission characteristics and damage evolution of basalt by microwave irradiation | Yang, Jinqiang; Wang, Chaolin; Zhao, Yu; Bi, Jing | https://www.nature.com/articles/s41598-023-30220-y | Abstract The microwave-assisted rock breaking technology has been proven to be feasible, and has received considerable attention in the field of civil and mining engineering. A copper foil was used to wrap basalt to simulate rock excavation of practical application scenario in this paper. To this end, a multi-mode cavity with an operating frequency of 2.45 GHz was used to conduct microwave irradiation experiments on basalts with different irradiation times and different power. The thermal properties, AE characteristics, and damage evolution process of basalt were studied. The results show that the high heat generated by microwave leads to the development of cracks in the upper part of basalt. The higher the power level, the higher the degree of crack propagation in the sample, the lower the basalt strength, and the more active the AE activity. The fluctuation rule of the b value indicates that the basalt is dominated by small-scale microfractures before failure. High power levels or long irradiation time lead to more microwave-induced cracks participating in the failure process during loading. Compared with unheated basalt, microwave-heating basalt detects the characteristics of the precursor of failure in advance. The AE source location and the nephogram of the maximum principal stress of microwave-treated basalt reflected that the fracture path begins in the upper part of the rock. In addition, the combination of high power level and short irradiation time can achieve the purpose of energy saving. | 10.1038/s41598-023-30220-y | English | Journal Article | Scientific Reports | 13 | 1 | 6006 | ||||
| A120 | 2022 | Quasi-Static and Dynamic Tensile Behavior of Water-Bearing Sandstone Subjected to Microwave Irradiation | Wang, Pin; Yin, Tubing; Li, Xibing; Konietzky, Heinz | https://www.mdpi.com/2227-7390/11/1/203 | Microwave irradiation on rocks before excavation is an effective method to reduce equipment wear and energy consumption during mechanical cutting. Rock mass excavation is usually carried out in a water-rich environment and exposed to dynamic loads, thus understanding the coupled effects of water content and loading rate on the mechanical behavior of rocks under microwave radiation is essential. In this study, sandstone samples with five levels of water content (from oven-dried to water-saturated) were exposed to microwave irradiation at a power of 700 W for 10 min. Brazilian disc tests were conducted on sandstone samples after microwave radiation under both quasi-static and dynamic loading conditions. Test results revealed that, with the increase of the initial water content, the microwave heating capacity of the rock is significantly improved. The surface temperature of the saturated samples is approximately 1.38 times higher than that of the dry ones. Moreover, weight, P-wave velocity, quasi-static and dynamic tensile strength of the rock decrease, while porosity and damage factor exhibit a similar growth law. Before microwave irradiation, the average value of the P-wave velocity and the quasi-static tensile strength of sandstone were about 2521.3 m·s−1 and 4.65 MPa. However, after microwave treatment, when the initial water content was 2%, 3%, 4% and 5.4%, the P-wave velocity decreased by 6.1%, 9.8%, 16.4% and 30.2%, while that quasi-static tensile strength reduced by 9.2%, 16.7%, 30.6% and 48.9%, respectively. For watersaturated samples under microwave irradiation, the porosity increases from 13.02% to 18.12% (showing an increase of 39.2%), and the damage value rises to 0.51. In addition, the dynamic tensile strength shows a significant loading rate dependence, and as the initial water content increases, also the dynamic increase factor (DIF) increases. At a given loading rate, the energy dissipation decreases with the increase of the initial water content, which indicates that the presence of water cause more significant damage to the rock when subjected to microwave radiation. Scanning electron microscopy (SEM) results indicate that the internal damage of the rock after microwave radiation is dominated by intergranular cracks, and crack density increases with increasing initial water content of the samples. The underlying damage mechanisms of microwave radiation on water-bearing sandstone were interpreted with the theory of pore water pressure and structural thermal stresses. | 10.3390/math11010203 | English | Journal Article | Mathematics | 11 | 1 | 203 | ||||
| A121 | 2018 | Strength Characteristics of Sedimentary Rock in Daegu-Gyungbuk Area Followed by Saturation and Crack Initiation | Park, Sung-Sik; Kim, Seong-Heon; Bae, Do-Han | https://doi.org/10.7843/KGS.2018.34.12.29 | Shale and mudstone in Daegu-Gyungbuk area have low strength and resistance to weathering compared to other rocks. Therefore, it is necessary to evaluate their strength depending on the degree of saturation and crack development. In this study, shales and mudstones were collected from several construction sites in Daegu-Gyungbuk area. Their basic material properties such as porosity, SEM, chemical component, and durability were tested. A porosity (absorptivity) of mudstone was 31% (25%), which was 6 (8) times higher than that of shale. Some mudstone was easily disintegrated with water and it consisted of highly-active clay mineral such as smectite type. These rocks were prepared by small cube specimens for unconfined compression test. An unconfined compressive strength of dry rock was compared with saturated one. Microwave oven was operated step by step to stimulate void water within a saturated rock, which resulted into high temperature and micro crack initiation within rocks. A strength of microwaved rocks was compared with operation time and crack initiation. As a result, the average unconfined compressive strength of dry and saturated shale was 62 and 33 MPa, respectively. The strength of mudstone for each condition was 11 and 4 MPa. When a rock became saturated, its strength decreased by 47% and 64% for shale and mudstone at average. In addition to saturation, a rock was in the microwave for 15 secs, its strength decreased into 49% for shale and 52% for mudstone. When a microwave oven operated up to 20 sec, a rock was crushed into several pieces and its temperature was approximately 200 degrees. | 10.7843/KGS.2018.34.12.29 | Korean | Journal Article | Journal of the Korean Geotechnical Society | 34 | 12 | 29-42 | ||||
| A122 | 2023 | Microwave-assisted breakage of basalt: A viewpoint on analyzing the thermal and mechanical behavior of rock | Liang, Cun-Guang; Guo, Ze-Shi; Yue, Xiu; Li, Hui; Ma, Peng-Cheng | https://linkinghub.elsevier.com/retrieve/pii/S0360544223006199 | Microwave-assisted breakage of rock has gained widespread popularity in the field of mining and geotechnical engineering. However, the breakage mechanism of rock is not clearly explained due to the involvement of complex multiphysics coupling issues. To study the thermal and mechanical behavior of basalt rock under the microwave irradiation, a coupled electromagnetic-thermal-mechanical mathematical model was established to analyze the heating process and explain the breakage mechanism. The results showed that in the energy conversion stage of the electric field, an inhomogeneous electric field distribution was observed in the cavity and basalt rock, which further resulted in the generation of a temperature gradient in the sample due to the dielectric losses of rock. This phenomenon can be demonstrated in the coupled electromagnetic-thermal model. The simulation results indicated that internal compression and external tension are the main causes of the fracture or blast of basalt rock. The experimental failure position of basalt was in line with the generation of the maximum thermal stress and strain in the simulation. The experimental and simulated results demonstrated synergistic stress and strain damage in the breakage process. The outcomes of this study can provide some scientific guidelines for the application of microwave-assisted breakage of rock. | 10.1016/j.energy.2023.127225 | English | Journal Article | Energy | 273 | 127225 | |||||
| A123 | 2021 | Heating process and damage evolution of microwave absorption and transparency materials under microwave irradiation | Wei, Wei; Shao, Zhushan; Chen, Wenwen; Qiao, Rujia; Yuan, Yuan; Cheng, Junxi | https://link.springer.com/10.1007/s40948-021-00284-z | 10.1007/s40948-021-00284-z | English | Journal Article | Geomechanics and Geophysics for Geo-Energy and Geo-Resources | 7 | 3 | 86 | |||||
| A124 | 2023 | Interaction of dry and water-saturated uranium ore with microwave and enhanced extraction of uranium | Liu, Chao; Liu, Hongwei; Long, Jie; Liao, Bingyou; Wang, Xuegang; Sun, Zhanxue; Guo, Yadan; Zheng, Zhihong | https://linkinghub.elsevier.com/retrieve/pii/S0892687523000614 | Uranium encapsulated in gangue minerals is difficult to leach. How to improve the permeability of uranium ore is a key issue to promote uranium leaching. Microwave treatment can effectively weaken gangue inclusions of uranium ore. However, microwave dielectric properties and the characteristics of microwave induced microcracks have not sufficiently been investigated. Resonant cavity perturbation technology and various pore structure characterization methods are used to analyze interaction of uranium ore with microwave. Uranium ore has high dielectric properties at 150–200 ◦C, which is conducive to induce more microcracks. The role of microwave is mainly to induce a significant increase in macropores (>6.2 μm) volume, which increases by 213.89 % for water-saturated uranium ore. Compared with dry uranium ore, pores in water-saturated uranium ore are better developed. The microwave treatment of uranium ore enhances uranium extraction with both chemical and bioleaching. | 10.1016/j.mineng.2023.108047 | English | Journal Article | Minerals Engineering | 196 | 108047 | |||||
| A125 | 2018 | Rock Fracturing by Low Power Microwave Treatment – Observations, Mechanisms and Applications | Zhao, Jian; Zheng, Yanlong; Zhang, Qianbing; Zhao, Xiaobao | https://onepetro.org/ISRMARMS/proceedings-abstract/ARMS1018/ARMS1018/ISRM-ARMS10-2018-258/43435?redirectedFrom=PDF | The three most predominant methods for hard rock excavation and fragmentation are the use of explosives, mechanical impact/cutting and hydraulic fracturing. However, those methods have inherent drawbacks, such as non-applicability or poor performance in extremely hard and abrasive rocks. Novel rock fracturing and fragmentation methods are in need to either work individually or in combined forms to break rocks. Research shows that some rock forming minerals and water can be heated up rapidly by microwave, to induce microcracks and fractures in rocks. Microwave therefore can be regarded as a promising technology of hard rock fracturing and fragmentation, with the potential of energy and cost efficiency. This keynote first provides a brief review of the research on microwave effects on rock fracturing, followed by descriptions of experimental studies of crack formation in different rocks treated by a low power industrial microwave. Possible fracturing mechanisms by microwave treatment are discussed, and the applications of microwave treatment assisting rock excavation coupled with mechanical means are outlined at the end of this keynote. | English | Journal Article | |||||||||
| A126 | 2021 | The effects of pilot-scale microwave pretreatment on the cyanidation of a canadian gold ore | Olmsted, A; Forster, J.; Tian, X.; Boucher, D.; Bobicki, E.R.; Pickles, C.A. | https://www.researchgate.net/publication/365446970_The_Effects_of_Pilot-scale_Microwave_Pretreatment_on_the_Cyanidation_of_a_Canadian_Gold_Ore | gold sulphide ore | BET; comminution; energy; leaching; microwaves pilot plant | English | |||||||||
| A127 | 2022 | Microwave heating behavior of ores and its application to high-power microwave assisted comminution and ore sorting | Forster, J.; Olmsted, A.; Tian, X.; Boucher, D.; Goldbaum, M.; Pickles, C.A.; Bobicki; E.R. | https://www.ceecthefuture.org/resources/microwave-heating-behaviour-of-ores-and-its-application-to-high-power-microwave-assisted-comminution-and-ore-sorting | microwaves; heating rate; mineral processing; comminution; liberation; sorting | English | ||||||||||
| A128 | 2023 | Microwave pre-conditioning of granite and concrete and the implications on their geotechnical parameters | Lehmann, Gabriel; Mayr, Martin; Käsling, Heiko; Thuro, Kurosch | https://linkinghub.elsevier.com/retrieve/pii/S136516092200260X | Microwave pre-conditioning is considered to be the most promising complementary hard rock cutting method, with a strong potential to improve the advance rate and profitability of future mechanized tunnel boring and mining equipment. This technique is based on selective heating and differential volumetric expansion of minerals causing micro- and macrofracturing in rock. Over 700 samples consisting of granite and three different strength grades of concrete were irradiated and underwent a comprehensive geotechnical testing program. Besides longitudinal wave velocity, porosity, specific heat capacity, density, and temperature difference, additional geotechnical parameters are influenced by material-specific heating intervals: Unconfined compressive strength (UCS), Brazilian tensile strength (BTS), Point load index (PLI), CERCHAR abrasivity index (CAI), the LCPC abrasivity coefficient (LAK) and its breakability coefficient (LBK). Comparisons of thin sections of irradiated and non-irradiated materials show microscopic structural changes. A slight reduction of the UCS was observed after longer irradiation intervals for granite and concrete, while the weakening effect on the BTS and PLI is more pronounced. Rock strength was reduced by up to 48% for granite and 40–48% for concrete, which potentially leads to a substantial increase in penetration rate of a tunnel boring machine and reduced wear. Furthermore, we found a linear correlation between granite strength, sample temperature, and specific energy, resulting in a reduction of the PLI by 0.12% K 1. The tested concrete types showed strength reduction ratios between 0.21 and 0.28% K 1. By calculating efficiencies of the deployed energy, we showed that pre-conditioning with microwaves can be an effective and efficient tool to artificially reduce the strength of rocks in order to increase the advance rate of tunnel boring and mining machines. | 10.1016/j.ijrmms.2022.105294 | English | Journal Article | International Journal of Rock Mechanics and Mining Sciences | 164 | 105294 | |||||
| A129 | 2017 | Towards large scale microwave treatment of ores: Part 1 – Basis of design, construction and commissioning | Buttress, A.J.; Katrib, J.; Jones, D.A.; Batchelor, A.R.; Craig, D.A.; Royal, T.A.; Dodds, C.; Kingman, S.W. | https://linkinghub.elsevier.com/retrieve/pii/S089268751730081X | porphyry copper ore | microwave; ore; copper; pilot scale; fracture; beneficiation | Despite over thirty years of work, microwave pre-treatment processes for beneficiation of ores have not progressed much further than laboratory testing. In this paper we present a scaleable pilot-scale system for the microwave treatment of ores capable of operating at throughputs of up to 150tph. This has been achieved by confining the electric field produced from two 100kW generators operating at 896MHz in a gravity fed vertical flow system using circular choking structures yielding power densities of at least 6x108 W/m3 in the heated mineral phases. Measured S11 scattering parameters for a quartzite ore (-3.69±0.4dB) in the as-built applicator correlated well with the simulation (-3.25dB), thereby validating our design approach. We then show that by fully integrating the applicator with a materials handling system based on the concept of mass flow, we achieve a reliable, continuous process. The system was used to treat a range of porphyry copper ores. | 10.1016/j.mineng.2017.03.006 | English | UK | Journal Article | Minerals Engineering | 109 | 169-183 | ||
| A130 | 2017 | Towards large scale microwave treatment of ores: Part 2 – Metallurgical testing | Batchelor, A.R.; Buttress, A.J.; Jones, D.A.; Katrib, J.; Way, D.; Chenje, T.; Stoll, D.; Dodds, C.; Kingman, S.W. | https://linkinghub.elsevier.com/retrieve/pii/S0892687517301322 | porphyry copper ore | microwave; ore; copper; pilot scale; comminution; liberation | A pilot scale microwave treatment system capable of treating 10-150t/h of material at 10-200kW was designed, constructed and commissioned in order to understand the engineering challenges of microwave-induced fracture of ores at scale and generate large metallurgical test samples of material treated at approximately 0.33kWh/t. It was demonstrated that exposing more of the ore to a region of high power density by improving treatment homogeneity with two single mode applicators in series yielded equivalent or better metallurgical performance with up to half the power and one third the energy requirement of that used with a single applicator. Comminution testing indicated that A*b values may be reduced by up to 7-14% and that the Bond Ball Mill Work Index may be reduced by up to 3-9% depending on the ore type under investigation. Liberation analysis of the microwave-treated ore indicated that equivalent liberation may be achievable for a grind size approximately 40-70µm coarser than untreated ore, which is in agreement with laboratory scale investigations reported in the literature at similar or higher doses. Flow sheet simulations further indicated that reduced ore competency following microwave treatment could potentially yield up to a 9% reduction in specific comminution energy (ECS) at a nominal plant grind of P80 190µm, or up to 24% reduction at a grind of P80 290µm, for a microwave energy input of 0.7-1.3kWh/t. Throughput could also be increased by up to approximately 30% depending on grind size, ore type and equipment constraints. To date, approximately 900t of material has been processed through the pilot plant, approximately 300t of which was under microwave power. Metallurgical testing has demonstrated that comminution and liberation benefits are achievable at doses lower than that previously reported in the literature, which allow high throughputs to be sustained with low installed power requirements providing a pathway to further scale-up of microwave treatment of ores. | 10.1016/j.mineng.2017.05.003 | English | UK | Journal Article | Minerals Engineering | 111 | 5-24 | ||
| A131 | 2024 | Development of high-power microwave mechanical integrated continuous mining device | Feng, Xia-Ting; Lin, Feng; Zhang, Jiuyu; Yang, Chengxiang; Ao, Yuntan; Tong, Tianyang | https://linkinghub.elsevier.com/retrieve/pii/S1674775523002615 | This article introduces a high-power microwave mechanical integrated continuous mining device, which can achieve synchronous cutting of hard rocks by microwave and machinery. The device includes a cutting system, a rotary translation system, a loading system, a high-power microwave system, and a control and monitoring system. The technology of “master-slave follow-up” disc cutter alternating side cutting of rock was proposed, which could improve the effectiveness of rock breaking. The integrated structure of a microwave-cut system was then proposed, and synchronous motion of the microwave-cut system and adjustment of the loading system could be realized. The automatic adjustment technology of the microwave working distance was developed to dynamically control the optimal microwave working distance. The basic functions of the equipment were verified by tests. By comparing the two types of disk cutters, it is found that the master-slave follow-up disk cutter can improve significantly the dust removal effect and rock breaking efficiency in rock breaking process versus the conventional large disc cutter. Cutting tests of slate with or without microwave were conducted using a master-slave follow-up disk cutter. The results show that the cutting patterns of slates change from intermittent chunks (without microwave irradiation) to persistent debris (with microwave irradiation), and the cutting speed is significantly improved (170%). The development of the device provides a scientific basis for changing the conventional mining technology of metal mines and realizing the mechanical continuous mining in hard metal mines. | 10.1016/j.jrmge.2023.10.001 | English | Journal Article | Journal of Rock Mechanics and Geotechnical Engineering | 16 | 9 | 3365-3377 | ||||
| A132 | 2023 | An open-end high-power microwave-induced fracturing system for hard rock | Feng, Xia-Ting; Zhang, Jiuyu; Lin, Feng; Yang, Chengxiang; Li, Shiping; Tong, Tianyang; Su, Xiangxin | https://linkinghub.elsevier.com/retrieve/pii/S1674775523002494 | Microwave pre-treatment is considered as a promising technique for alleviating cutter wear. This paper introduces a high-power microwave-induced fracturing system for hard rock. The test system consists of a high-power microwave subsystem (100 kW), a true triaxial testing machine, a dynamic monitoring subsystem, and an electromagnetic shielding subsystem. It can realize rapid microwave-induced fracturing, intelligent tuning of impedance, dynamic feedback under strong microwave fields, and active control of microwave parameters by addressing the following issues: the instability and insecurity of the system, the discharge breakdown between coaxial lines during high-power microwave output, and a lack of feedback of rock-microwave response. In this study, microwave-induced surface and borehole fracturing tests under true triaxial stress were carried out. Experimental comparisons imply that high-power microwave irradiation can reduce the fracturing time of hard rock and that the fracture range (160 mm) of a 915-MHz microwave source is about three times that of 2.45 GHz. After microwave-induced borehole fracturing, many tensile cracks occur on the rock surface and in the borehole: the maximum reduction of the P-wave velocity is 12.8%. The test results show that a high-power microwave source of 915 MHz is more conducive to assisting mechanical rock breaking and destressing. The system can promote the development of microwave-assisted rock breaking equipment. | 10.1016/j.jrmge.2023.09.002 | English | Journal Article | Journal of Rock Mechanics and Geotechnical Engineering | 15 | 12 | 3163-3172 | ||||
| A133 | 2005 | Techno-economic considerations in the commercial microwave processing of mineral ores | Bradshaw et al. | https://www.tandfonline.com/doi/abs/10.1080/08327823.2005.11688544 | English | |||||||||||
| A134 | 2021 | Microscopic mechanisms of microwave irradiation thawing frozen soil and potential application in excavation of frozen ground | Jia, Hailiang; Wang, Ting; Chen, Weihang; Ding, Shun; Luo, Tao; Sun, Qiang | https://linkinghub.elsevier.com/retrieve/pii/S0165232X2100029X | Engineering activities are becoming increasingly frequent in seasonally frozen and permafrost regions. Artificially thawing frozen soil before excavation may significantly increase the efficiency of excavation and reduce cost. Microwave irradiation can thaw frozen soil very rapidly, but has not yet been widely used in the field. One important reason is that the mechanisms of thawing and softening of frozen soil by microwave irradiation are not fully understood yet, therefore, the practicability and efficiency of this method cannot be well evaluated. In this study, microwave irradiation tests of frozen soils with five moisture contents were conducted and changes in their temperature, unfrozen water content and strength were measured. The results showed the following: (1) Microwave irradiation heating thawed frozen soil with a temperature of 14.4 ◦C completely within 60 s. The interior and surface of frozen soil samples melted simultaneously. (2) Conduction heating required 8400 s to melt frozen soil with the same temperature, which is 140 times longer than microwave irradiation. (3) Strength of the frozen soil decreased rapidly during microwave irradiation. Combined with the results of nuclear magnetic resonance (NMR) tests, it was found that the fundamental cause of the rapid melting of frozen soil is that a certain amount of unfrozen water exists between ice and soil grains. Accordingly, the following microscopic mechanisms of microwave irradiation thawing frozen soil are revealed. Unfrozen water absorbs microwaves and its molecular thermal motion increases along with its temperature. Then heat is transferred to ice and soil grains and frozen soil is thawed further. Based on a careful discussion on the efficiency and penetration depth of microwave-induced thawing, it was suggested that microwave heating is a promising artificial thawing technology in excavation of frozen ground. | 10.1016/j.coldregions.2021.103248 | English | Journal Article | Cold Regions Science and Technology | 184 | 103248 | |||||
| A135 | 2012 | Effect of load variability on matching during continuous microwave treatment of crushed mineral ores | Bradshaw, S.M.; Marchand, R. | https://www.saimm.co.za/Journal/v112n01p023.pdf | English | |||||||||||
| A136 | 2021 | Experimental investigation on the effects of microwave irradiation on kimberlite and granite rocks | Deyab, Samir M.; Rafezi, Hamed; Hassani, Ferri; Kermani, Mehrdad; Sasmito, Agus P. | https://linkinghub.elsevier.com/retrieve/pii/S1674775520301311 | This study is a part of an overall research project on the effects of microwave (MW) irradiation on rocks for assisted rock breaking systems as well as mineral processing at McGill University. For the first time, this paper highlights a comprehensive investigation on the effects of microwave irradiation on Canadian kimberlites. Potential contribution to the continuous rock excavation and rock weakening effect prior to implementation of mechanical techniques was explored. Two different kimberlite rocks, i.e. volcaniclastic kimberlite (VK) and hypabyssal kimberlite (HK), and granite samples were studied. Some important physical properties of the rock samples were measured including rock quality designation (RQD), specific gravity, porosity, and specific heat capacity. Rock samples were treated for various exposure times using a multi-mode MW unit at different power levels ranging from 2 kW to 15 kW. The effect of MW irradiation on rock samples was investigated. The results indicate that the mechanical properties including unconfined compressive strength (UCS) and Brazilian tensile strength (BTS) were significantly dropped as a result of MW irradiation. Finally, the effect on rock abrasivity using the Cerchar abrasivity index (CAI) has also been discussed. | 10.1016/j.jrmge.2020.09.001 | English | Journal Article | Journal of Rock Mechanics and Geotechnical Engineering | 13 | 2 | 267-274 | ||||
| A137 | 2020 | The Effect of Microwave Irradiation On The Mechanical Properties of Kimberlite And Limestone | Deyab, Samir M; Rafezi, Hamed; Hassani, Ferri; Sasmito, Agus P; Kermani, Mehrdad | https://sujes.selcuk.edu.tr/sujes/article/view/514 | In underground excavation, rock fragmentation can be achieved by blasting with explosive materials or using continuous excavation machinery. The significant challenges with the explosives include noise, vibration, pollution, and potential issues such as damage to nearby structures. A less disruptive method for breaking rocks is using machines such as tunnel boring machine and road header those have the capability of continuous operation and are suitable for autonomous mining. In hard rock applications, the excavation machinery is associated with high equipment wear rates, low penetration rates and consequently high operating costs. This paper investigates the work being undertaken at McGill University on the effect of microwave (MW) irradiation on hard rocks to facilitate continuous mining and improve the production rate while reducing costs. Tuffistic Kimberlite (TK) and limestone rocks were studied in this research. Physical properties of untreated samples were measured, and the rock samples were treated for various exposure times in a multi-mode MW unit at power levels ranging from 2 to 10 kW. The results indicate that MW irradiation reduced the strength of TK and limestone rocks. It was concluded that Brazilian Tensile Strength (BTS) and Uniaxial Compressive Strength (UCS) of samples decayed proportionally with exposure time and power level. | English | Journal Article | 2020 | ||||||||
| A138 | 2022 | Microwave impacts on more sustainable kimberlite processing | Rasyid et al. | https://link.springer.com/chapter/10.1007/978-3-031-17425-4_102 | English | |||||||||||
| A139 | 2023 | Towards microwave-assisted comminution of a volcaniclastic kimberlite: permittivities, heating behaviour, and grindability | Forster et al. | https://link.springer.com/chapter/10.1007/978-3-031-38141-6_115 | English | |||||||||||
| A140 | 1989 | Rock Excavation with Microwaves - A literature review | Santamarina, J.C. | https://www.semanticscholar.org/paper/Rock-Excavation-with-Microwaves%3A-A-Literature-Santamarina/0397da27524ce9be80c2b33d4bc91492ae044bff | English | |||||||||||
| A141 | 2013 | Evaluating the effects of radio-frequency treatment on rock samples: implications for rock comminution purposes | Swart, A.J. | https://www.sciencedirect.com/science/article/abs/pii/S0301751613000367 | English | |||||||||||
| A142 | 1995 | Improved Grindability of Taconite Ores by Microwave Heating | Walkiewicz, John W; Lindroth, David P; Clark, Andrea E; Babbitt, Bruce; Graham, Rhea Lydia | https://pubs.nbmg.unr.edu/Improved-Grindability-of-Taloni-p/ri9559.htm | English | Journal Article | ||||||||||
| A143 | 2015 | Characterising and quantifying microwave induced damage in coarse sphalerite ore particles | Charikinya, E.; Bradshaw, S.; Becker, M. | https://linkinghub.elsevier.com/retrieve/pii/S0892687515300443 | sphalerite ore | microwaves; sphalerite; X-ray tomography; mineralogy; cracks; heap leaching; particles | Microwave induced cracks have the potential to enhance metal recovery from coarse sphalerite particles in heap leaching operations by creating new crack surface areas for lixiviant. The characteristics and quantity of microwave induced cracks and how these cracks subsequently affect heap leaching recovery has not yet been investigated. This study characterised and quantified microwave induced crack damage by applying X-ray computed tomography (XCT) and Quantitative Evaluation of Minerals by Scanning Electron Microscopy (QEMSCAN) analysis. Sphalerite ore particles representing small ( 5 + 4.75) mm, medium ( 16 + 9.5) mm, and large ( 25 + 19) mm HPGR and cone crushed products were microwave treated at specific microwave heating energies of between 1 and 3 kW h/t. Image segmentation, thresholding and spatial registration techniques were used to study crack patterns in the XCT 3D images. The results showed the presence of microwave induced cracks within the cone and HPGR microwave treated particles. The cracks consist of both interphase trans-granular and grain boundary cracks. Both XCT and QEMSCAN analysis results showed that microwave treatment resulted in a significant increase of over 500% in crack volume for both modes of prior comminution at all particle sizes. | 10.1016/j.mineng.2015.07.020 | English | South Africa | Journal Article | Minerals Engineering | 82 | 14-24 | ||
| A144 | 2019 | Influence of microwave treatment on surface roughness, hydrophobicity, and chemical composition of galena | Barani et al. | https://jme.shahroodut.ac.ir/article_1478_16895325a3147610676492b6f4b4d040.pdf | ||||||||||||
| A145 | 2004 | Impact of microwave irradiation on the processing of a sulfide ore | Orumwense, A. O.; Negeri, T. | http://link.springer.com/10.1007/BF03403302 | Microwave pretreatment is one of the emerging technologies that have been reported as having potential economic benefits for the processing of amenable ores. The application of microwave pretreatment to the processing of refractory and finely disseminated ores is of great interest because the technology can potentially reduce high comminution costs and improve mineral liberation. To determine the influence of heating rate on mineral transformation, ground product size distribution and mineral liberation, sized ore samples were subjected to microwave irradiation at power levels varying from 1 to 5 kW over exposure times of between one and six minutes. The microwave-irradiated samples were ground and subsequently floated. A comparison was made with non-microwave-treated samples. Zinc flotation grade and all metal recoveries show a strong dependence on the microwave absorption characteristics ofthe mineral components ofthe ore in the following decreasing order: sphalerite, galena and, lastly, chalcopyrite. | 10.1007/BF03403302 | English | Journal Article | Mining, Metallurgy & Exploration | 21 | 1 | 44-51 | ||||
| A146 | 2004 | Effect of microwave pretreatment on the liberation characteristics of a massive sulfide ore | Orumwense, O. A.; Negeri, T.; Lastra, R. | http://link.springer.com/10.1007/BF03403307 | The influence of microwave radiation on the liberation of the valuable minerals in a massive sulfide ore is presented. In general, sphalerite shows the highest degree of liberation with a maximum value of 84%. Sphalerite is followed by galena with 73% liberation and chalcopyrite with 63% liberation. Afine feed size and a high microwave power are the two common requirements for the liberation of the valuable metalbearing minerals in the are. Some of the valuable base-metal minerals show slightly different degrees of sensitivity to microwave irradiation. Therefore, process efficiency and economics should be considered in deciding the applicable level ofheating. Chalcopyrite and galena, which are readily affected by microwave radiation, show a tendency to generate high amounts oflocked particles, due presumably to randomfracture, partial (non-uniform) particle transformation and irregular particle shape. | 10.1007/BF03403307 | English | Journal Article | Mining, Metallurgy & Exploration | 21 | 2 | 77-85 | ||||
| A147 | 2023 | Application of dense media separation data for studying the mineral liberation of kimberlite treated by microwave irradiation | Aslam, A; Rasyid, M.A.; Rafiei, A.; Sasmito, A.P.; Hassani, F. | https://www.researchgate.net/publication/373485435_Application_of_Dense_Media_Separation_Data_for_Studying_the_Mineral_Liberation_of_Kimberlite_Treated_by_Microwave_Irradiations | kimberlite ore | mineral liberation; size and density; microwave irradiation | Microwave treatment on ores has shown improvements in comminution and separation of valuable minerals due to differential dielectric heating phenomenon which results in intergranular crack generation Traditional methods of analyzing mineral liberation by using Scanning Electron Microscopy (SEM) and statistical methods can be expensive. This study aims to introduce a practical approach of studying mineral liberation based on density and product size fraction to evaluate the impacts of MW treatment on kimberlite samples. Batches of 500g of kimberlite samples were treated in single mode MW cavity design at power of 15 kW with different exposure times and then crushed in a single roller crusher. The crushed product was first separated based on density by densiometric testing and then screened into different size fractions. The results of MW treated samples showed improvement in mineral liberation as compared to fresh/untreated samples. | English | Canada | Conference Proceeding | World Mining Congress 2023 | |||||
| A148 | 2024 | Analysis of Pore Characterization and Energy Evolution of Granite by Microwave Radiation | Zhou, Keping; Zhang, Yifan; Yang, Chun; Yang, Niange; Pan, Zheng | https://www.mdpi.com/2504-3110/8/3/161 | To study the dynamic response of granite to different levels of microwave power, an intelligent microwave rock-breaking instrument is used to irradiate different power from three directions. The servo universal testing machine is used to carry out a uniaxial compression test on the granite after microwave damage to analyze the strength damage characteristics and the degree of pore damage. Pore fractal characteristics are analyzed based on nuclear magnetic resonance to establish the microwave damage degradation model. In parallel, the energy evolution process of granite under the influence of various power levels is analyzed using the theory of energy dissipation. Simultaneously, based on the energy dissipation theory, we analyze the energy evolution process of granite under the action of different powers. The results show that with higher microwave power, the peak strength and modulus of elasticity show a linear decreasing law. The degree of fragmentation is more obvious, showing the damage characteristics with two big ends and little in the middle. The higher the power, the greater the porosity and the more sensitive the micropore becomes to microwaves. Additionally, the damage degradation model established to evaluate the microwave damage of the rock showed that it was feasible. The higher the power, the lower the total energy, elastic energy, and dissipation energy, and the granite is gradually transformed from elastic deformation to plastic deformation. The elastic energy ratio decreases, the dissipation energy ratio increases, and the degree of damage becomes more and more serious. This study provides theoretical support for exploring the mechanical behavior and mechanism of microwave-assisted rock breaking and is of great practical significance. | 10.3390/fractalfract8030161 | English | Journal Article | Fractal and Fractional | 8 | 3 | 161 | ||||
| A149 | 2024 | Investigating the Efficiency of Microwave Treatment in Mine-to-Mill Operations: An Energy-Based Analysis | Ahmadihosseini, Adel; Aslam, Azlan; Hassani, Ferri; Sasmito, Agus | https://www.energy-proceedings.org/?p=11072 | basalt; kimberlite | microwave treatment; mine-to-mill operations; energy efficiency; sustainable mining | Mining is one of the most energy-intensive industries, accounting for almost 10 percent of worldwide energy consumption. This study investigates microwave treatment as a rock pre-conditioning method to improve energy efficiency in mine-to-mill operations. A novel energy-based data analysis is used to evaluate the application of the method, considering the input microwave energy and its corresponding effect on the mining processes. The results show that microwave treatment provides advantageous outcomes such as reducing the strength of rocks, specific crushing energy, field penetration index, and increasing cutter life cycle. The energy-based analysis emphasizes the significance of optimizing microwave power and exposure time as major design criteria. The results show that applying microwave energy can influence multiple mine-to-mill operations simultaneously, which exponentially improves the efficiency of the method. This understanding showcases the potential of microwave treatment in field applications, leading to more energy efficient and sustainable mining. | 10.46855/energy-proceedings-11072 | English | Canada | Conference Proceeding | 15th International Conference on Applied Energy (ICAE2023), Dec. 3-7, 2023, Doha, Qatar | ||||
| A150 | 1978 | 100 kW, 915 MHz CW Magnetron for Industrial Heating Application | Shibata, C.; Akioka, T.; Tamai, H. | http://www.tandfonline.com/doi/full/10.1080/16070658.1978.11689076 | 10.1080/16070658.1978.11689076 | English | Journal Article | Journal of Microwave Power | 13 | 1 | 59-64 | |||||
| A151 | 2023 | The Impact of Microwave Treatment on the Andesite Rock Mechanical Properties | Heriyadi, Bambang; Nata, Refky Adi; Tanjung, Ardhymanto Am; Fadhilah | https://iopscience.iop.org/article/10.1088/1742-6596/2582/1/012023 | Alternate rock-breaking techniques to drilling and blasting could include using microwaves to break up rock masses. Drilling for blasting has a significant issue with the cost of drill bit replacement in a short time (weekly). The microwave-breaking technology could be a solution, but research is continuing. This research clarifies the proposed methods through a case study of PT. ATC is an andesite quarry that employs the drill-and-blast technique to break rock. This experiment replicates the previous study's conclusion that rock strength decreases following microwave treatment on two rock strength tests involving the Point Load Index (PLI) and Schmidt Hammer (SH). The dynamic test (PUNDIT) result indicates that the p-wave velocity of microwaved samples is greater than that of non-microwaved samples (NMW). As a consequence of evaporation and mineral transformation within the rock, the density of the rock decreases, and the porosity increases. | 10.1088/1742-6596/2582/1/012023 | English | Journal Article | Journal of Physics: Conference Series | 2.582 | 1 | 12023 | ||||
| A152 | 2023 | MICROWAVE HEATING IMPACTS ON BREAKAGE PHENOMENA OF KIMBERLITE ROCK IN CRUSHER | Rasyid, M A; Aslam, A; Rafiei, A; Sasmito, A P; Hassani, F | https://www.researchgate.net/publication/373485438_Microwave_Heating_Impacts_on_Ore_Breakage_Phenomena_of_Kimberlite_Rock_in_Crusher | Microwave irradiation is capable to generate macrocracks and microcracks between mineral boundaries due to different dielectric properties providing some reported benefits such as reduction in crushability and grindability as well as improvement of mineral liberation and recovery. However, the practical observation on the ore particle breakage physical phenomena in a continuous crushing mechanism has not been studied. In traditional comminution practices, mechanical energies (impact, compression, and attrition) are transferred to rock particles to induce breakage unselectively (random). The inherent natural cracks (macrocracks) are readily “consumed” in early comminution stages and as particles go smaller, lesser macro cracks present. Preferential breakage around mineral boundaries is favored over random breakage because it will not only improve mineral liberation, but it will also benefit the comminution energy efficiency. In this study, magnetite-bearing kimberlite rock were microwaved in a single mode cavity at varied power and exposure time, before crushed in a single-roll crusher. Thermal profiles of microwave-treated samples have shown tendency of bigger particles to be more readily heated in shorter exposure time. Therefore, macrocracks are potentially more concentrated on larger particles than smaller particles. In a typical single roll crushing mechanism, larger particles experience more breakage events than smaller particle since the discharge gap between the roll and the plate will classify the progenies of broken particles. With microwave irradiation, the breakage function of larger particles may have been altered, thus affecting the overall breakage phenomena. This hypothesis is in alignment with the experimental observation where power draw dynamics were measured to capture this breakage events alteration. Power draw dynamics also indicates preferential breakage are more apparent after microwave treatment. The highly impacted sample has achieved crushing rate improved by 24% as compared to untreated sample. Microwave-treated ores have reduction on maximum instantaneous power draw at the beginning of crushing sequence, followed by shorter high-resistance period, decline sharper over crushing time, and results in higher breakage rate. | English | Conference Proceeding | |||||||||
| A153 | 2023 | Application of instantaneous power draw analysis to investigate the impact of microwave heating on kimberlite ore crushing | Rasyid, M.A.; Aslam, A.; Rafiei, A.; Hassani, F.; Sasmito, A.P. | https://linkinghub.elsevier.com/retrieve/pii/S0306261923012643 | Traditional crushing methods rely on a limited number of existing natural cracks as the source of crack propagation to break ore particles. Microwave-assisted crushing, on the other hand, facilitates the crushing process by inducing intergranular and transgranular cracks in ore particles. This not only reduces the energy consumption of the crusher but also improves the production rate of the process. In this study, microwave-assisted crushing of kimberlite ore is investigated ingeniously by examining the change in power draw trends to understand better the roles of larger cracks and smaller cracks induced by microwave treatment. An innovative calculation method is proposed to enable continuous monitoring of power draw instead of average power consumption. This method establishes a quantitative standard for exploring ore crushing capacity and the mechanisms of rock samples. From this study, the cumulative specific crushing energy and crushing time reduction in microwave-treated samples can be attributed to three distinct mechanisms. Firstly, the preferential generation of comparatively bigger cracks on large particles improves the breakage rate within the accumulating zone. Secondly, the generation of sufficient comparatively smaller cracks on large particles contributes to a lower peak net power amplitude. Lastly, the well-distributed generation of cracks across all particle sizes results in a shorter declining zone and an overall improvement in crushing time. The most significant reduction in both crushing energy and crushing rate is observed with the high microwave energy input. However, even at lower microwave energy inputs, substantial reductions in specific crushing energy and crushing time can still be achieved. This study demonstrates that the proposed method can be applied to other comminution systems, whether with or without microwave assistance. | 10.1016/j.apenergy.2023.121900 | English | Journal Article | Applied Energy | 352 | 121900 | |||||
| A154 | 2012 | The Effect of Microwave Treatment on Dry Grinding Kinetics of Iron Ore | Javad Koleini, S. M.; Barani, K.; Rezaei, B. | http://www.tandfonline.com/doi/abs/10.1080/08827508.2011.562947 | grinding; iron ores; microwave processing | The effect of microwave treatment on the grinding kinetics of an iron ore was assessed using mono-sized materials of 2.360 þ 2.0 mm, 1.400 þ 1.180 mm, 1.0 þ 0.850 mm, and 0.355 þ 0.300 mm as feed. Microwave-treated samples were kept in a multimode microwave oven with 1100 W input power. The grinding tests were conducted using a laboratory ball mill under identical conditions to allow a comparative analysis of the results. The specific rates of breakage (Si) and cumulative breakage distribution function (Bi,j) values, as grinding breakage parameters, were determined for those size fractions of untreated and microwave-treated feeds. It was determined that breakage of iron ore followed a first-order behavior for fine feed sizes and deviated from first order for coarse feed size. The specific rate of breakage parameters of untreated iron ore was compared with microwave-treated iron ore under the same experimental conditions and it was found that microwave-treated materials break faster than untreated in terms of the Si and A values. Breakage parameters showed that treated materials produce more coarse material than untreated material in terms of the c value of Bi,j. | 10.1080/08827508.2011.562947 | English | Journal Article | Mineral Processing and Extractive Metallurgy Review | 33 | 3 | 159-169 | |||
| A155 | 2024 | The Comminution of Chert Gravel by Microwave Irradiation for Reuse Optimization of Quarry Areas | Tzibulsky, Mark; Frid, Vladimir | https://www.preprints.org/manuscript/202312.0004/v1 | microwave irradiation; rock comminution; quartz response; chert gravel; reuse of quarry area | Chert rock is a by-product of sand quarrying (about 40% in the geological section). All attempts to use ordinary technologies for aggregate production from chert have been economically unsuccessful, resulting in significant chert "waste" accumulation covering vast quarry areas. This paper presents the study results of the effect of microwave irradiation on the mechanical properties of chert gravel, which is mineralogically relatively homogenous and consists of fine quartz grains. The results show that an increase in irradiation time decreases the strength of chert gravel (by a factor of 4-6 for the 2.5 min of irradiation), while the quenching changes the fractional content of the samples after the crushing test, decreasing the Gravel-to-Sand ratio. | https://doi.org/10.3390/resources13050063 | English | Journal Article | |||||||
| A156 | 2024 | Comparative study on grinding kinetics behavior of vanadium-titanium magnetite ore before and after microwave pretreatment | Wang, Junpeng; Jiang, Tao | https://www.metallurgical-research.org/10.1051/metal/2024009 | vanadium-titanium magnetite; microwave pretreatment; micro-cracks; grinding kinetics; grinding speed | Vanadium-titanium magnetite underwent closed circuit crushing before and after microwave pretreatment. Subsequently, batch grinding tests were conducted on the crushed products, with varying grinding times. Ultimately, the m-order grinding kinetics model of the ore was established both before and after microwave pretreatment. The results show that microwave pretreatment causes a significant increase in the number of micro-cracks on the ore’s surface. Moreover, the specific surface area and pore volume of the ore increase by 17.29% and 40.98% respectively. These changes result in a reduction in the mechanical properties of the ore. During the grinding tests, the number of micro-cracks is found to be the primary factor influencing the grinding speed in the initial stage. However, as the grinding progresses, the grinding probability becomes the main factor affecting the grinding speed. The coarse particle size of the microwave-treated ore exhibits a significantly higher grinding speed than the untreated ore. Conversely, the grinding speed of fine particle size ore change slightly. The application of microwave-assisted grinding for vanadium-titanium magnetite proves advantageous in improving the particle size composition of the grinding product. Consequently, this can lead to enhanced separation efficiency and concentrate quality. | 10.1051/metal/2024009 | English | Journal Article | Metallurgical Research & Technology | 121 | 2 | 211 | |||
| A157 | 2024 | An applicator for high-power rock comminution using microwave technology in the megawatt range | Alekajbaf, Yasin; Dancila, Dragos | https://www.cambridge.org/core/product/identifier/S1759078724000308/type/journal_article | granite rock | comminution; hard rock; high-power microwave; microwave applicator; microwave energy; mining industry; rock breakage | The mining industry is heavily dependent on energy-intensive processes, such as rock breakage, which leads to significant operational costs. This paper explores microwave-assisted rock breakage as an innovative method to enhance the efficiency of comminution within the mining industry. It introduces a system that employs a Klystron microwave power source with a maximum output of 7.5 MW, using a TM010 single-mode cavity at 3 GHz, to channel energy inside a specially designed rock cavity. The paper emphasizes the importance of designing an efficient microwave cavity for this system, focusing on the cavity’s design and simulation. Through both simulated results (using HFSS software) and experimental observations, the study reveals the promising application of microwave technology in the field of mining. The simulated frequency response of the designed cavity (S11) is −22 dB, it demonstrates significant potential for reducing both energy consumption and associated costs. Additionally, the designed cavity is fabricated from aluminum and filled with polyether ether ketone material. The measured frequency response (S11) of the cavity at 3 GHz is −17 dB. | 10.1017/S1759078724000308 | English | Sweden | Journal Article | International Journal of Microwave and Wireless Technologies | 1-6 | |||
| A158 | 2024 | Heating and Water Transport Behavior of Sandstones Under Microwave Irradiation | Zhao, Qinhua; Zheng, Yanlong; Li, Jianchun; Che, Ping; Zhao, Xiaobao | https://link.springer.com/10.1007/s00603-024-03814-9 | microwave treatment; water-bearing sandstones; water transport behavior; burst | Microwave treatment has become a promising method to improve the efficiency of mechanical excavators in hard rocks. This paper conducted microwave irradiation tests on three water-bearing sandstones and analyzed the heating and water-escaping process by real-time temperature and mass measurement. Meanwhile, nuclear magnetic resonance tests were performed to investigate the water transport behavior inside the samples under microwave irradiation. The results show that the thermal behaviors are jointly governed by the water content, permeability and microwave power used. As the sample temperature increase, the contained water would firstly transport from the drying front to the surface driven by the temperature gradient. Subsequently, water began to escape from the sample with a rate determined by the permeability of the sandstone. At this stage, energy dissipation brought by water escaping would slow down the initial heating rate. Hence, the thermal cracking of the sandstones under microwave irradiation can hardly be enhanced by the existence of pore water in spite of its superior dielectric properties. Nevertheless, the vapor pressure could be large enough to burst the sample when water was heated to a high temperature. | 10.1007/s00603-024-03814-9 | English | Journal Article | Rock Mechanics and Rock Engineering | 57 | 7 | 4755-4770 | |||
| A159 | 2024 | Rockburst prevention by microwave destressing: a numerical investigation | Yang, Chun; Zhou, Keping; Zhang, Quan; He, Manchao; Gao, Feng; Xiong, Xin; Pan, Zheng; Topa, Ameen | https://link.springer.com/10.1007/s40948-024-00749-x | N/A | Abstract Rockbursts are a complex phenomenon characterized by a violent ejection of rock fragments from the free face of deep underground mines. Due to the sudden, disruptive, and complex nature of these events, accurate predictions of rockbursts are difficult. Therefore, geotechnical intervention is imperative to prevent the occurrence of a rockburst. The scenarios of microwave destressing is introduced here as an application method to potentially prevent their occurrence. To understand the influences of microwave destressing, such as microwave exposure duration, spatial layout, and geometric parameters of the microwave preconditioned zone (MPZ), on the occurrence of a rockburst, numerical simulation was conducted based on an impact-induced rockburst model. The feasibility of microwave destressing technology was validated numerically. This paper also provides guidance for the utilization of microwave destressing in practice. Discontinuous MPZ is suitable for a known blasting source with a fixed position, and continuous MPZ can be applied for a working condition with multiple blasting sources with variable positions. A closer distance of MPZ from the free face results in a better microwave destressing effect. However, the closer distance of MPZ from the free face also introduces more negative influences on the static stability of surrounding rock. | 10.1007/s40948-024-00749-x | English | Journal Article | Geomechanics and Geophysics for Geo-Energy and Geo-Resources | 10 | 1 | 38 | |||
| A160 | 2019 | Localized microwave-heating (LMH) of basalt-Lava, dusty-plasma, and ball-lightning ejection by a miniature volcano | Jerby, E.; Shoshani, Y. | https://www.nature.com/articles/s41598-019-49049-5 | N/A | English | ||||||||||
| A161 | 2021 | Rock excavation efficiency improvement by microwave treatment | Andraș, Andrei; Andraș, Iosif; Danciu, Ciprian | https://ojs.uni-miskolc.hu/index.php/multi/article/view/895 | limestone; marble | microwaves; excavation; rock; microwave assisted rock destruction | The paper deals with an overview of the state of art in using microwaves for assist hard rock cutting with mechanical means. The information provided consist on actual findings of researches previously performed in this field, from the literature review, which represents the start elements in the recently started MIWACUT project in the frame of ERAMIN-2 programme, financed jointly by EU and national research agency (UEFISCDI). | 10.35925/j.multi.2021.5.45 | English | Romania | Journal Article | Multidiszciplináris tudományok | 11 | 5 | 438-449 | |
| A162 | 2024 | The Law and Mechanism of the Effect of Surface Roughness on Microwave-Assisted Rock Breaking | Chen, Fangfang; Li, Guoqing; Zhang, Zhiqiang; Wu, Zhanqiang | https://www.mdpi.com/2076-3417/14/1/207 | basalt | microwave irradiation; surface roughness; crack propogation; thermal stress; thermal conduction | In physical engineering, a rock surface, whether naturally or artificially formed, is rough. When irradiating rocks, microwaves produce reflections and diffractions on the surface of rough rocks, which significantly affect the absorption of microwave energy by rocks, thus influencing the result of microwave irradiation. In order to explore the influence of rough rock surfaces on the effect of microwave-assisted rock breaking, microwave irradiation tests were carried out on basalt samples with different values of roughness to test the temperature and P-wave velocity of the samples before and after microwave irradiation. Numerical test methods were used to systematically study the influence of rough rock surfaces on microwave irradiation. The results show that, under the same microwave irradiation conditions, the effect of microwave irradiation on rough surface basalt is more significant than that of flat surface basalt. The surface temperature distribution range of flat surface specimens is narrow, the surface temperature range of rough surface specimens is wider and more inhomogeneous, and the maximum surface temperatures of rough surface specimens are much higher than those of flat surface specimens. After irradiation, new macroscopic cracks were generated on the surface of the samples, and the crack propagation of the rough surface samples was more obvious. The decrease in P-wave velocity before and after the irradiation of flat surface samples is small, and that of rough surface samples is larger. The main factors affecting the effect of microwave irradiation on the rough surface are the refraction and reflection of electromagnetic waves, heat conduction, and stress concentration on the surface. | 10.3390/app14010207 | English | China | Journal Article | Applied Sciences | 14 | 1 | 207 | |
| A163 | 2024 | Experimental study on rock breaking using a microwave-assisted tunnel boring machine cutter | Ning, Bo; Liu, Fengzhou; Liu, Hao; Xia, YiMin | https://link.springer.com/10.1007/s10064-024-03632-x | tunnerl boring machine; microwave assistance; disc cutter; extremely hard rock; full-scale rock breaking experiment | Tunnel boring machines (TBMs), excavation tools for tunnel construction, often struggle to penetrate extremely hard rock formations. This study proposes an innovative solution to enhance the construction efficiency of TBMs in such environments: a microwave-assisted TBM cutter. In our experiments, we irradiated basalt samples with 3 kW microwaves for varying durations. We conducted a full-scale rock-breaking experiment using the multifunctional rock-breaking platform at Central South University, China. We then compared the cutting force, cutting coefficient, and specific energy consumption of the cutter at different processing times. Our results indicate that microwave pretreatment can effectively reduce both the cutting force and specific energy consumption of rock. Furthermore, under certain cutting force conditions, the quantity of rock broken can be significantly increased with extended microwave irradiation. However, we found a critical threshold for the processing time of 3 kW microwave-assisted rock breaking. Beyond this threshold, the specific energy consumption of rock breaking is not significantly reduced. For a microwave processing time of 16 min, the optimal ratio of cutter spacing to penetration (s/p) is 16.7. The findings of this study offer valuable insights and guidance for TBM construction operations in extremely hard-rock environments. | 10.1007/s10064-024-03632-x | English | Journal Article | Bulletin of Engineering Geology and the Environment | 83 | 4 | 114 | |||
| A164 | 2021 | Thermally Assisted Grinding of Cassiterite Associated with Pollimetallic Ore: A Comparison between Microwave and Conventional Furnaces | He, Chunlin; Zhao, Jian; Su, Xiujuan; Ma, Shaojian; Fujita, Toyohisa; Wei, Yuezhou; Yang, Jinlin; Wei, Zongwu | https://www.mdpi.com/2075-163X/11/7/768 | cassiterite; microwave heating; sulfide ore; grinding | We investigated the influence of microwave and conventional heating pretreatments on the grinding of cassiterite associated with pollimetallic ore. The minerals that exhibited a stronger microwave absorption ability crushed first, which is the main difference between the microwave and the traditional heating pretreatments. The distribution of Fe, Pb, Zn, and Sn increased in the fine size range (−0.425 mm). The Fe and Pb grades in the size ranges of −3.2 + 2 mm and −2 + 1 mm after the microwave pretreatment (6 kW, 1 min) were lower than those of the traditional heating (12 kW, 400 ◦C, 20 min), indicating that the microwave selective heating was beneficial for pyrite and jamesonite. The grade and distribution of Sn decreased significantly in the size ranges of −3.2 + 2 mm and −2 + 1 mm and increased in the size ranges of −0.425 + 0.15 mm and −0.15 + 0.074 mm. Microwave heating treatment promoted the grinding of sulfide ore and reduced the cassiterite overgrinding. | 10.3390/min11070768 | English | Journal Article | Minerals | 11 | 7 | 768 | |||
| A165 | 2024 | Microwave Treatment of Minerals and Ores: Heating Behaviors, Applications, and Future Directions | Chen, Jin; Li, Xinpei; Gao, Lei; Guo, Shenghui; He, Fei | https://www.mdpi.com/2075-163X/14/3/219 | N/A | microwave; mineral; applications; future directions | The application of microwave technology in mineral metallurgy is a transformative approach to ore processing that offers new ideas about the current progressive depletion of resources and the environmental impact of mineral processing. This review delves into the principles, applications, and future directions of microwave treatment in mineral and ore processing. Microwave technology, characterized by its unique advantages such as rapid and uniform heating, selective heating, and energy efficiency, stands in contrast to traditional heating methods. It directly interacts with materials at the molecular level, enabling volumetric heating. The review encompasses a wide range of applications, including ore pre-treatment, drying, mineral processing, hydrometallurgy, smelting, and reduction. It highlights the role of microwave treatment in enhancing metal recovery, reducing energy consumption, and improving processing speeds. Future research directions are identified, focusing on enhanced equipment design, process optimization, integration with conventional methods, and technological innovations. The comprehensive overview assists researchers, engineers, and decision-makers in understanding the potential of microwave technology in mineral metallurgy, emphasizing its contribution to innovation and sustainability in the sector. | 10.3390/min14030219 | English | China | Journal Article | Minerals | 14 | 3 | 219 | |
| A166 | 2023 | Predicting strength loss of igneous rocks treated with microwave energy | Kahraman, Sair; Canpolat, A Niyazi; Fener, Mustafa | https://onepetro.org/isrmcongress/proceedings-abstract/CONGRESS23/All-CONGRESS23/ISRM-15CONGRESS-2023-395/540180?redirectedFrom=PDF | granite; siyenite; gabbro | igneous rocks; microwave treatment; strength loss; regression analysis | This paper investigates the predictability of the strength loss of igneous rocks treated with microwave energy. First microwave treatment tests were performed at 6 kW power for the duration of 120s on the core samples of nine different igneous rocks such as granite, syenite and gabbro. Then uniaxial compressive strength (UCS) tests were carried out on the hot specimens. Mineralogical analysis, density and porosity tests were also performed on the samples. The data were evaluated using multiple regression analysis and an estimation equation with very high correlation coefficient was derived for the strength loss. The equation includes UCS, maximum surface temperature, quartz plus feldspar content and porosity values. The statistical test showed that the equation was valid. It was concluded that the derived equation could be used for the estimation of the strength loss of igneous rocks treated with microwave energy. | English | Turkey | Conference Proceeding | ||||||
| A167 | 2022 | Effects of microwave radiation on dynamic compressive properties of basalt | Yin, Tu-bing; Jin, Fei-yan; Li, Qiang; Li, Xi-bing | https://linkinghub.elsevier.com/retrieve/pii/S1003632622660278 | basalt | microwave radiation; nuclear magnetic resonance (NMR); dynamic compressive properties; thermal damage | The dynamic mechanical properties of basalt affected by microwave were investigated by performing dynamic compressive tests using the SHPB system. Meanwhile, the thermal damage of the treated basalt was characterized by ultrasonic non-destructive testing and nuclear magnetic resonance technology. The results show that with the increase of microwave power and exposure time, the P-wave velocity, dynamic compressive strength and elastic modulus decrease continuously, and the dynamic failure mode tends to be a more complex fracturing. The increase in microwave power and exposure time can enhance the temperature difference and transfer coefficient among minerals, hence intensifying the rock damage induced by thermal shock. | 10.1016/S1003-6326(22)66027-8 | English | China | Journal Article | Transactions of Nonferrous Metals Society of China | 32 | 10 | 3388-3403 | |
| A168 | 2023 | Effect of moisture on microwave ignition of bituminous coal | Yao, Junhui; Chen, Hui; Guo, Chenxiang; Liu, Kai | https://dx.plos.org/10.1371/journal.pone.0283434 | bitumionous coal | N/A | The interaction between water and microwave is of vital importance to reveal the microwave ignition mechanism of water-bearing coal. This study used two group of bituminous coal after drying and water saturation treatment, for experimental testing and contrastive analysis. During the experiment, permeability of coal samples was obtained based on nuclear magnetic resonance(NMR) test, then different power of microwaves were applied to coal samples, and the occurrence of hot spots within coal samples was regarded as a sign of microwave ignition. Microwave ignition of water-saturated coal is mainly affected by microwave power and coal permeability. The pore water in low permeability coal is conducive to microwave ignition, while the pore water in high permeability coal will prolong the ignition time. There is a permeability threshold, above which the average ignition time of water-saturated coal samples is longer than that of dry coal samples, but below which the opposite is true. These insights can be used to evaluate the safety of microwave technology when applied to coal engineering. | 10.1371/journal.pone.0283434 | English | China | Journal Article | PLOS ONE | 18 | 4 | e0283434 | |
| A169 | 2023 | Numerical and experimental analyses of rock failure mechanisms due to microwave treatment | Ahmed, Haitham M.; Ahmadihosseini, Adel; Hassani, Ferri; Hefni, Mohammed A.; Ahmed, HussinA.M.; Saleem, Hussein A.; Moustafa, Essam B.; Sasmito, Agus P. | https://linkinghub.elsevier.com/retrieve/pii/S1674775523000835 | Rhyolite rocks | microwave treatment; numerical modeling; failure mechanism; energy efficiency; rock pre-conditioning | Despite the extensive studies conducted on the effectiveness of microwave treatment as a novel rock preconditioning method, there is yet to find reliable data on the rock failure mechanisms due to microwave heating. In addition, there is no significant discussion on the energy efficiency of the method as one of the important factors among the mining and geotechnical engineers in the industry. This study presents a novel experimental method to evaluate two main rock failure mechanisms due to microwave treatment without applying any mechanical forces, i.e. distributed and concentrated heating. The result shows that the existence of a small and concentrated fraction of a strong microwave absorbing mineral will change the failure mechanism from the distributed heating to the concentrated heating, which can increase the weakening over microwave efficiency (WOME) by more than 10 folds. This observation is further investigated using the developed coupled numerical model. It is shown that at the same input energy, the existence of microwave absorbing minerals can cause major heat concentration inside the rock and increase the maximum temperature by up to three times. | 10.1016/j.jrmge.2023.02.016 | English | Canada | Journal Article | Journal of Rock Mechanics and Geotechnical Engineering | 15 | 10 | 2483-2495 | |
| A170 | 2020 | Analysis of microwave treated rocks by discontinue deformation analysis method | Xu, T; He, L | https://onepetro.org/ISRMEUROCK/proceedings-abstract/EUROCK20/All-EUROCK20/ISRM-EUROCK-2020-023/447337 | granite | microwave; DDA; thermal coupling; voronoi; cohesive fracture model | This paper aims to simulate heterogeneous rock under microwave heating treatment and study the effect of microwave irradiation on the rock with the discontinuous deformation analysis (DDA) method. A coupled thermo-mechanical discontinuous model for simulating the rock cracking process induced by microwave irradiation is programmed in the framework of the DDA method combined with the Voronoi tessellation net generate algorithm and cohesive fracture model. Finally, the influence of the shape of microwave power input and the fracture growth process is discussed. The improved cohesive crack model can show the fracture types better. It is found that the initial failure is the shear failure on the boundary of sensitive minerals, followed by tensile failure at the corner of minerals when the shear strength is low. Generally, this study has improved the application of the simulation for microwave-assisted rock breaking, and give us a better understanding of microwave heating treatment of rock. | English | China | Journal Article | ||||||
| A171 | 1982 | Rock Breaking by Microwave Radiation | Okamoto et al. | N/A | granite; slate; sandstone; pumice-tuff | N/A | English | Japan | Conference Proceeding | IV Congress International Association of Engineering Geology | 4 | 43-52 | ||||
| A172 | 1971 | Experiment of rock breaking by micro-wave | Misawa, S.; Takahashi, A; Kishimoto, T.; Naito, K. | N/A | granite; rhyolite; basalt; mudstone; concrete blocks | N/A | N/A | English | Japan | Journal Article | Railway Technical Research Institute | 12 | 4 | 187-191 | ||
| A173 | 2022 | Studying the fracture characteristics of fractured rock mass after microwave irradiation | Yuan, Shihao; Sun, Qiang; Bai, Guogang; Chen, Zupeng; Ge, Zhenlong | https://link.springer.com/10.1007/s12665-022-10491-w | gabbro | microwave irradiation | This study explored the influence of X-shaped joint cracks and microwave irradiation on the failure characteristics of gabbro. Gabbro samples with joint angles of 15°, 30°, 45°, 60°, and 75° were subjected to microwave irradiation treatment for three, seven, or eleven minutes at 0.89, 1.47, or 1.89 kW. This study analysed the sample quality, chromaticity, and temperature changes before and after microwave irradiation, and analysed the failure characteristics and failure modes under pressure. The main research results are as follows. First, the surface temperature of gabbro increased linearly with irradiation time and the mass-loss rate increased with increasing microwave irradiation time and power. Furthermore, the colour coordinate of the sample was also altered by microwave irradiation; the red-green component a* changed from green to red while the yellow-blue component b* changed from blue to yellow. Second, the compressive strength of the sample increased with increasing conjugate joint angle α and decreased with increasing microwave power. Third, under compression, the jointed gabbro sample showed four failure modes. Increasing joint angle caused the failure mode of gabbro to change from Mode I, IV (15°) → Mode I, II (30°, 45°) → Mode I, II, III (60°) → Mode III (75°). | 10.1007/s12665-022-10491-w | English | China | Journal Article | Environmental Earth Sciences | 81 | 14 | 361 | |
| A174 | 2022 | Laboratory Microwave (C-Band) Response of Compressive Stress With Partially Saturated Sandstone | Mao, Wenfei; Wu, Lixin; Liu, Shanjun; Xu, Zhongyin; Huang, Jianwei; Gao, Xiang | https://ieeexplore.ieee.org/document/9881578/ | red sandstone | remote sensing rock mechanics; microwave radiation; pore water; radiative transfer theory; effective dielectric constant | Many studies have confirmed that the microwave radiation of rock materials will change with compressive stress and pore water. However, how the presence of pore water in rock volume influences the stress-induced change in microwave radiation (∆𝑻𝑩) is not clear. In this study, both the air-dry and humid (partially saturated) sandstone specimens were loaded compressively and the C-band (6.9 GHz) microwave radiometer was used to investigate the change of 𝑻𝑩 and the differences of ∆𝑻𝑩. The experimental results illustrated that the presence of pore water in sandstone promotes significantly the relationship between the positive ∆𝑻𝑩 and the applied compressive load. On the basis of radiative transfer theory and effective dielectric constant model of multiple-phase media, we found that the ∆𝑻𝑩 of sandstone mainly results from the compressive stress distributing on mineral grains, which is able to reduce the dielectric constant of minerals and lead to the increase of microwave radiation. For dry sandstone, the distribution of compressive stress on minerals is mainly controlled by grain contact. While for humid sandstone, the pore water plays an important role in applying uniform pressure on grain surface and reducing the dielectric constant of grains, thus the effective dielectric constant of rock volume is sensitive to the applied loads on partially saturated specimen. This study is important for understanding the positive 𝑻𝑩 anomalies prior to large tectonic earthquakes in condition of ground surface rock partially saturated, and is valuable to uncover potential 𝑻𝑩 anomaly related with seismic activities. | 10.1109/TGRS.2022.3204002 | English | China | Journal Article | IEEE Transactions on Geoscience and Remote Sensing | 60 | |||
| A175 | 2022 | Effect of microwave treatment on the thermal properties and dynamic splitting behavior of red sandstone | Yang, Chun; Hassani, Ferri; Zhou, Keping; Xiong, Xin; Wang, Famin; Shao, Yan | https://cdnsciencepub.com/doi/10.1139/cgj-2021-0313 | red sandstone | microwave treatment; dynamic splitting behavior; infrared temperature; rock fracturing; dynamic nominal tensile strength | Microwave energy is a promising application in future rock breakage operations in the civil, mining, processing and space industries. Rock engineering projects frequently experience mechanical vibration and blasting impacts. Thus, understanding the dynamic fracturing behavior of microwave-treated rock is essential for its future application in microwave-assisted mechanical rock breakage. A customized industrial microwave system with a multimode resonant cavity was used to heat red sandstone at different microwave power levels (up to 4 kW) for a constant exposure time (4 min). The rock surface temperature distribution after microwave treatment was measured by an infrared camera. Dynamic splitting tests were conducted using a split Hopkinson pressure bar (SHPB) system in combination with a high-speed camera. Experimental results indicate that the rock dynamic splitting strength is negatively related to the microwave power, and the maximum reduction is 47.8%. Microwave treatment induced an obvious nonuniform temperature distribution and C-shaped surface cracks on disc specimens. During the dynamic splitting test, the crack induced by dynamic loading always initiates from the crack tip induced by microwave irradiation and then propagates along the loading diameter. The distribution of the inner high-temperature zone in the disc specimen is symmetric along the horizontal centerline of the disc specimen. | 10.1139/cgj-2021-0313 | English | China | Journal Article | Canadian Geotechnical Journal | 59 | 7 | 1231-1242 | |
| A176 | 2021 | Effect of microwave pretreatment on grindability of lead-zinc ore | Yu, Qing; Ding, Dexin; Chen, Wenguang; Hu, Nan; Wu, Lingling; Zhang, Qiucai; Liu, Yulong; Zhang, Zhijun; Li, Feng; Xue, Xilong; Li, Zhaopeng; He, Guicheng | https://www.hindawi.com/journals/geofluids/2021/4418684/ | lead-zinc ore | N/A | The influence of microwave pretreatment on grindability of lead-zinc ore was studied through comparison analysis on the changes of particle size distribution, percentage of below 0.074 mm, energy consumption, and other indexes of grinding products before and after microwave pretreatment in the ball milling process. The results showed that the grindability of lead-zinc ore was improved obviously by microwave pretreatment. The particle size distribution curve of the grinding products was obviously higher than that of the samples without microwave irradiation. The yield of size fraction below 0.074 mm was also improved in a certain degree. Pulsed microwave irradiation was more effective than continuous microwave irradiation when other microwave parameters were consistent. The comprehensive energy consumption of lead-zinc ore pretreated by different microwave parameters was lower than that without microwave irradiation under the same grinding fineness. The total energy consumption was down by 30.1% when irradiated for 15 s at 7 kW power, and it was lower than that without microwave irradiated. The results showed that pulsed microwave pretreatment was more effective in reducing the comprehensive energy consumption of grinding process for lead-zinc ore. And water quenching after microwave irradiation can improve the grindability and reduce the energy consumption of grinding for lead-zinc ore. | 10.1155/2021/4418684 | English | China | Journal Article | Geofluids | 2.021 | |||
| A177 | 2021 | The effect of microwave pretreatment on impact crushing of lead-zinc ore | Liu, Yulong; Ding, Dexin; Chen, Wenguang; Hu, Nan; Wu, Lingling; Hu, Lin; Zhang, Qiucai; Zhang, Zhijun; Li, Feng; Xue, Xilong; Li, Zhaopeng; He, Guicheng; Yu, Qing | https://www.metallurgical-research.org/10.1051/metal/2021055 | lead-zinc ore | lead-zinc ore; drop weight test; microwave pretreatment; water quenching; crushing characteristic | The relationship between energy input and particle size of ore samples after crushing and effect of microwave pretreatment on impact crushing of lead-zinc ore were studied by drop weight impact test. The results showed that the lead-zinc ore became softer and had higher degree of crushing after microwave pretreatment. Compared with continuous microwave pretreatment, pulsed microwave pretreatment could improve the drop weight impact crushing efficiency of lead-zinc ore. When the specific comminution energy were 5 kW h/t, 10 kW h/t respectively, the crushing characteristic parameters t10 were 60.42% and 67.46% respectively by continuous microwave. But the values of t10 were increased to 68.64% and 75.88% respectively after pulsed microwave radiation under same microwave power and time. In addition, water quenching could more promote the impact crushing efficiency of lead-zinc ore after microwave irradiation. | 10.1051/metal/2021055 | English | China | Journal Article | Metallurgical Research & Technology | 118 | 5 | 501 | |
| A178 | 2023 | Heat transfer analysis of microwave irradiation in rock grain minerals | Ahmadihosseini, Adel; Sasmito, Agus P; Hassani, Ferri | https://www.ihtcdigitallibrary.com/conferences/ihtc17,5f2e244a33e3313f,25f6bc1a79173bf1.html | basalt | microwave treatment; numerical model; energy efficiency; heat absorbing minerals | Over the past decade, researchers have investigated rock strength reduction due to microwave irradiation for the potential application in the mining and minerals industries to provide more efficient mine-to-mill practices. Minerals react differently facing microwave energy. They can intensely absorb microwave energy and heat up or be transparent to the wave, leading to various thermal expansions and stresses throughout the rocks. The thermal stresses create micro-cracks, resulting in rock strength reduction. Due to the complex nature of the method, the interactions between the electromagnetic waves, thermal responses, and micro-cracks generation are not well understood. In this study, a fully coupled numerical model is developed and validated against an experimental benchmark conducted in the Geomechanics Laboratory of McGill University with less than 10% error. This model provides insight into heat and energy transfer characteristics during microwave irradiation to improve the energy efficiency of mechanical excavation in different rock types and patterns. For that purpose, the importance of temperature-dependent rock properties is investigated, and it is shown that employing constant material properties in high microwave energy dosages leads to unrealistic conclusions. Furthermore, the existence of microwave-absorbing minerals within the rock is introduced as a significant parameter influencing the efficiency of the microwave treatment method. The results show that microwave-absorbing minerals can create substantial heat concentration during the irradiation, which can increase the microwave treatment efficiency significantly. | 10.1615/IHTC17.100-30 | English | Canada | Conference Proceeding | International Heat Transfer Conference, IHTC-17 | 0 | |||
| A179 | 2023 | Preparation for Megawatt-range Trials at 3 GHz: A Preliminary Study of Rocks Comminution with Very High Pulsed Microwave Power | Alekajbaf, Y; Dancila, D | https://www.cambridge.org/core/journals/international-journal-of-microwave-and-wireless-technologies/article/an-applicator-for-highpower-rock-comminution-using-microwave-technology-in-the-megawatt-range/A9F06DBC9C703503F88DCDDE64A31528 | N/A | This abstract presents an optimized microwave assisted rock breakage system using a 7.5 megawatts microwave power source at 3 GHz. To provide an efficient electromagnetic field inside the rock samples a TM010 single mode cavity is designed and fabricated at 3 GHz. The designed cavity is measured and its frequency response (S11) at 3GHz is -17dB. | https://doi.org/10.1017/S1759078724000308 | English | Sweden | Conference Proceeding | SMWD 2023, KTH Royal Institute of Technology, Stockholm, 23rd – 25th May 2023 | |||||
| A180 | 2022 | Effects of microwave heating on mechanical properties and energy evolution mechanism of granite under conventional triaxial compression | Yang et al. | http://journal.multiphysics.org/index.php/IJM/article/view/16-4-407 | granite | N/A | To explore the influences of microwave irradiation on the mechanical response mechanism of rock under different confining pressures, granite specimens were subjected to different microwave heating paths, then conventional triaxial compression experiments were conducted. The experimental results show that: 1) As microwave irradiation power and time increase, the density and P-wave velocity of the specimen show a downward trend and the higher the power, the faster the decline; 2) The sensitivity of specimen strength to confining pressure and microwave (power and time) is ranked thus (in descending order): confining pressure, microwave power, then irradiation time. Under a low confining pressure, the strength value of the specimen exhibits a decreased trend with the increase of irradiation time, but with the increase of confining pressure, the change of the strength of the specimen tended to be consistent; 3) The strain energy evolution of the specimen is similar, it is mainly manifested in energy accumulation before the peak, and energy dissipation and release thereafter. Under the influence of microwave radiation, the evolution of dissipation ratio shows a significant microwave effect, but the microwave effect becomes weaker with the increase of confining pressure. Therefore, when using microwave rock-breaking techniques, combined with necessary pressure-relief technique, microwave irradiation can produce the best rock-breaking effect. | 10.21152/1750-9548.16.4.407 | English | China | Journal Article | The International Journal of Multiphysics | 16 | 4 | 1-18 | |
| A181 | 2021 | Workability and mechanical properties of microwave heating for recovering high quality aggregate from concrete | Wei, Wei; Shao, Zhushan; Qiao, Rujia; Chen, Wenwen; Zhang, Pengju; Cheng, Junxi | https://linkinghub.elsevier.com/retrieve/pii/S0950061820342409 | concrete mortar-aggregate specimens | microwave; concrete recycling; microstructure; chemical content; energy consumption; practical application | Microwave assisted concrete recycling is highlighted by a large number of research groups all over the world due to its potential for significant process benefit. In this paper, systematic experiments are established to investigate the heating process of mortar-aggregate under microwave irradiation. Four different aggregate types are selected that widely used as aggregates in concrete to represent different kinds of aggregates. The temperature field of both mortar and aggregate under different heating time and microwave power input are obtained. The crack formation, propagation and material damage during the heating process are graphically presented. XRD tests and SEM analysis are carried out to clarify the chemical content and microstructure variation around the aggregate-mortar interface before and after microwave heating. The mechanical properties of recycled concrete are evaluated through the UCS tests. Energy consumptions are tested during the heating process. The applications of microwave recovering aggregates from standard concretes are conducted based on the results obtained in the simplified concrete. The research proves that microwave irradiation could weaken the bonding between mortar and aggregate effectively, which provide a contribution and reference for the further application of microwaveassisted aggregates recycling. | 10.1016/j.conbuildmat.2020.122237 | English | China | Journal Article | Construction and Building Materials | 276 | 122237 | ||
| A182 | 2019 | Microwave strengthens decomposition of mixed rare earth concentrate: microwave absorption characteristics | Huang, Y.; Zhang T.; Dou, Z.; Lv, G.; Han, G; Peng, W. | https://www.sciencedirect.com/science/article/pii/S1002072118303454 | mixed rare earth concentrate | microwave processing; microwave absorption characteristics; dielectric constant; loss tangent; mixed rare earth concentrate | The potential application of microwave heating technology for processing the mixed rare earth concentrate was systematically investigated by analyzing the microwave absorption characteristics in this study. The complex permittivity was measured through resonant cavity perturbation method. The variations of permittivity, the loss factor, loss tangent and the penetration depth with the increasing temperature were investigated numerically. The results indicate that the permittivity increases as the temperature increases, and temperature has a pivotal effect on it. The mixed concentrate is high loss material at the temperature range from 600 to 800 °C according to theoretical analyses of loss tangent and penetration depth. The results of phase transition analysis prove that the variation of microwave absorption characteristics of mixed concentrate is caused by the changes of crystal and lattice structures. The reflectivity, loss factor and penetration depth of the mixed concentrate were also calculated, and the results indicate that processing the mixed concentrate by microwave heating is of high feasibility and industrial potential. | https://doi.org/10.1016/j.jre.2018.08.010 | English | China | Journal Article | Journal of Rare Earths | 37 | 541-546 | ||
| A183 | 2022 | Improvement of the grindability of vanadium-bearing shale and the direct vanadium leaching efficiency of grinded product via microwave pretreatment with particle size classification | Yuan, Yizhong; Zhang, Yimin | https://linkinghub.elsevier.com/retrieve/pii/S0927775722007348 | vanadium-bearing shale | vanadium-bearing shale; microwave; grindability; leaching efficiency; classification of particle size; simulations | The total wet extraction technology without roasting will be the mainstream in the field of vanadium extraction from shale under China's strict carbon emission policy. Reducing energy consumption of grinding and improving leaching efficiency are the main directions of efforts. In this study, microwave pretreatment (MT) was used to improve the grindability of vanadiumbearing shale (VBS) and leaching efficiency. Sieving out the particles above 1.5 mm for MT under 2500 W for 4 min and then combining with 0-1.5 mm untreated particles for grinding increases the breakage rate of VBS by 209.0% with a 36.64% reduction in energy consumption. The particles passing 1.5 mm are prone to soft melt due to the hot pot caused by intensification of electromagnetic fields at the junctions of the adjacent particles. This negative effect can be avoided by pre-screening before MT. MT with particle size classification can obtain a 14.2% increasement of vanadium leaching efficiency of grinded products. Simulations and microscopic morphology analyses indicates the temperature gradient between minerals with different dielectric loss properties causes thermal stress with the maximum value at the junction of minerals. It promotes the dissociation of vanadium-bearing minerals and other absorbing minerals, providing more active reaction interfaces for vanadium leaching. | 10.1016/j.colsurfa.2022.128979 | English | China | Journal Article | Colloids and Surfaces A: Physicochemical and Engineering Aspects | 647 | 128979 | ||
| A184 | 2023 | Assessing the Size Effect on Microwave Fracturing of Diorite Using a Dielectric-Loaded Converging Waveguide Antenna | Ma, Zhongjun; Zheng, Yanlong; Gao, Mingzhong; Li, Jianchun | https://link.springer.com/10.1007/s00603-023-03357-5 | diorite | size effect; microwave fracturing of rocks; fracturing behavior; representative elementary volume (REV); crack desnity; arrangement of microwave radiation point | Microwave fracturing and assisted mechanical breakage of rocks has been demonstrated to be efficient and cost-effective, holding great potential in rock excavation. However, the size effect on the fracturing process using open-ended microwave antennas has not been well studied or understood. To address this issue, a dielectric-loaded converging antenna is used to heat and fracture diorite specimens of different dimensions. The study investigates the effect of specimen plane size and thickness, as well as microwave energy, on the crack characteristics. The results show that as specimen plane size increases, fracturing becomes more localized with shorter and narrower cracks. Conversely, specimen thickness is negatively correlated with crack characteristics on the microwave-treated surface. The study also defines and examines the representative elementary volume (REV) of microwave fracturing using the antenna. Regression models are developed and validated to predict crack characteristics such as number, density, total length, and maximum width. The paper concludes by discussing the arrangement of microwave radiations on rock masses with different joint spacings using the antenna. | 10.1007/s00603-023-03357-5 | English | China | Journal Article | Rock Mechanics and Rock Engineering | 56 | 8 | 5677-5691 | |
| A185 | 2022 | Effect of joints on microwave fracturing of the Bukit Timah granite using an open-ended antenna | Ma, Z.; Zheng, Y.; He, L.; Li, J. | https://onlinelibrary.wiley.com/doi/full/10.1002/dug2.12024 | Bukit Timah granite | Bukit Timah granite; crack propagation; joints; microwave treatment; open-emded antenna | Microwave fracturing of rocks before mechanical breakage could improve the performance of mechanical excavators and reduce environmental impacts. Previous research focused on the microwave fracturing of intact rock blocks. By using an open-ended antenna, this paper investigates the effect of pre-existing joints on the microwave fracturing of the Singapore Bukit Timah granite blocks. The results show that the specimens are weakened in the manners of cracking, spalling, melting, or a combination of them. The crack number and the total crack length produced by microwave treatment of jointed rock blocks are slightly smaller than those in the intact rock blocks. The interaction between joints and microwave-induced cracks can be summarized into the following four patterns: (1) microwave-induced cracks become arrested so that the crack propagation is terminated; (2) microwave-induced cracks penetrate the joints and continue to propagate; (3) microwave-induced cracks become deflected along the joints; and (4) microwave-induced cracks propagate forward following the joints. The smaller the approach angle between the microwave-induced crack and the pre-existing joint is, the more microwave-induced cracks tend to be arrested at the joint. Increasing the approach angle between the microwave-induced crack and the joint can increase the chance of microwave-induced crack penetrating the joint. The results also show that the smaller the distance is between the microwave radiation point and the joint, the easier it is for microwave-induced cracks to penetrate the joints; otherwise, the microwave-induced crack is more likely to be arrested at the pre-existing joint. | https://doi.org/10.1002/dug2.12024 | English | China | Journal Article | Deep Underground Science and Engineering | 1-10 | |||
| A186 | 2022 | Microwave-assisted hard rock breakage by impact hammers: heating, fracturing and mechanical breakage | Ma, Zhongjun; Zheng, Yanlong; Zhao, Xiaobao; Li, Jianchun | https://link.springer.com/10.1007/s10064-022-02808-7 | biotite diorite | microwave fracturing; hard rock breakage; thermal damage; impact hammer | Microwave fracturing has a great potential in assisting the breakage of hard rocks using impact hammers by inducing artificial cracks and downgrading the rock mass quality. In this article, the techno-economy of microwave-assisted impact hammer breakage of hard rocks was investigated. Microwave heating tests of 50-cm cubic biotite diorite blocks were carried out, followed by temperature measurement, ultrasonic velocity tests, Schmidt hammer rebound tests and rock breakage tests. The fracturing characteristics, the interaction between the radiation locations and the rock breaking by impact hammer were comprehensively investigated. The results show that the microwave system is efficient in fracturing the diorite. Cracks generated by the subsequent radiation tend to develop toward the centre of, or the cracks generated by, the previous radiation. Cracks produced by the previous radiations can be widened and extended by a following radiation. The maximum length and width of crack increase with the increase of the microwave power and heating time. Rock breakage tests demonstrate that microwave treatment greatly weakens the specimens and improves the efficiency of rock breaking by impact hammer. It is technologically feasible and economically viable to conduct microwave-assisted rock breakage by impact hammers. | 10.1007/s10064-022-02808-7 | English | China | Journal Article | Bulletin of Engineering Geology and the Environment | 81 | 8 | 308 | |
| A187 | 2021 | Design and performance of an open-ended converging microwave antenna in fracturing biotite diorite at low microwave power levels | Ma, Z. J.; Zheng, Y. L.; Li, X. Z.; Zhao, X. B.; He, L.; Zhao, Q. H.; He, J. L.; Li, J. C. | https://link.springer.com/10.1007/s40948-021-00291-0 | biotite diorite | microwave rock fracturing; converging waveguide antenna; thermal damage; crack pattern; P-wave velocity; Schmidt hammer; breakage tests | The converging waveguide antennas have great potential in fracturing rocks at relatively low microwave power outputs and short exposure times comparing to the standard waveguide and horn antennas. This article presents the design process of a converging waveguide antenna considering the maximum temperature, the volume characteristics of the high temperature zone and the effective working distance. It is decided that the waveguide with an aperture height of 30 mm is the optimal design. The antenna was then manufactured and used for surface radiation tests on a biotite diorite at low power levels. Non-destructive tests including temperature measurement, crack pattern characterisation, ultrasonic velocity tests, Schmidt hammer rebound tests and rock breakage tests using pneumatic and hydraulic hammers were performed to quantify the thermal damage and the weakening effect. The tests results show the converging waveguide antenna is efficient in fracturing the biotite diorite. The cracks are in the radial pattern. The maximum P-wave velocity and rebound number reductions on the radiation face are 22.7% and 22.6% for the specimens heated at 6 kW for 4 min, and the maximum P-wave velocity reduction is 54% in the lateral direction. Rock breakage tests on microwave specimens using impact hammers demonstrated that microwave treatment substantially improves the mechanical rock breakage efficiency. | 10.1007/s40948-021-00291-0 | English | China | Journal Article | Geomechanics and Geophysics for Geo-Energy and Geo-Resources | 7 | 0 | ||
| A188 | 2021 | Improvement of uranium bioleaching from uranium embedded in granite using microwave pretreatment | Wang, Xuegang; Liao, Bingyou; Nie, Shiyong; Liu, Chao; Sun, Zhanxue; Ke, Pingchao; Wang, Jian; Guo, Yadan | https://link.springer.com/10.1007/s10967-021-07833-6 | uranium ore | uranium ore; bioleaching; improvement; microwave pretreatment | We evaluated the effect of uranium bioleaching and mechanism by microwave pretreatment on uranium embedded in granite. The maximum uranium bioleaching ratio reached 93.1% after an ore sample was pretreated with microwave at 10 kW for 10 min, which was approximately 20% higher than untreated. After microwave pretreatment, the generation of micro-cracks can provide more adsorption sites for bacteria and promote contact between uranium-bearing minerals and leaching solution, a portion of the strongly bound uranium in the uranium ore was transformed into weakly bound uranium, and insoluble U(IV) into soluble U(VI), further improving uranium leaching ratio. | 10.1007/s10967-021-07833-6 | English | China | Journal Article | Journal of Radioanalytical and Nuclear Chemistry | 329 | 2 | 913-922 | |
| A189 | 2020 | Methods of Ore Pretreatment for Comminution Energy Reduction | Adewuyi, Sefiu O.; Ahmed, Hussin A. M.; Ahmed, Haitham M. A. | https://www.mdpi.com/2075-163X/10/5/423 | Multiple | mining operation; ore milling; ore grinding; rock; liberation | The comminution of ores consumes a high portion of energy. Therefore, different pretreatment methods of ores prior to their comminution are considered to reduce this energy. However, the results of pretreatment methods and their technological development are scattered in literature. Hence, this paper aims at collating the different ore pretreatment methods with their applications and results from published articles, conference proceedings, and verified reports. It was found that pretreatment methods include thermal (via oven, microwave, or radiofrequency), chemical additive, electric, magnetic, ultrasonic, and bio-milling. Results showed that the chemical pretreatment method has been used at an industrial scale since 1930, mainly in cement production. The microwave pretreatment results showed positive improvements at pilot scale mining applications in 2017. The results of ore pretreatment using electric and ultrasonic methods showed up to 24% and 66% improvement in energy consumption, respectively. The former and the latter have been piloted for gold and carbonate ore, respectively. Findings also showed that magnetic, radiofrequency, and bio-milling methods have not led to significant reductions in comminution energy. Based on energy reduction, safety, costs, stage of application, and downstream benefits, microwave and electrical pretreatment methods may be focused for applications in the mining industry. | 10.3390/min10050423 | English | Saudi Arabia | Journal Article | Minerals | 10 | 5 | 423 | |
| A190 | 2023 | Study of the Influence of Microwave Irradiation on Hard Rock Formation Property Alteration through nondestructive/destructive tests and drilling/coring operations | Abugharara, A; Mafazy, A.; Butt, S. | https://asmedigitalcollection.asme.org/OMAE/proceedings-abstract/OMAE2023/86915/V009T11A051/1167414 | drilling rate of penetration; microwave irradiation; destructive and non-destructive tests | Enhancing the Drilling Rate of Penetration (D-ROP) is a target for lowering the ultimate cost in reaching hydrocarbon reservoirs, evaluating reservoir formation, and extracting minerals and reducing rock crushing consumed energy through mining operations. It has been reported that ROP can be positively influenced depending on optimization of several factors such as drilling parameters alteration and rock fragmentation process. In this research, D-ROP is evaluated by altering the status of the formations being drilled by the use of Microwave Irradiation (MI) while all other applied parameters are kept constant. Unlike published works, this research collectively investigates the influence of MI on D-ROP of hard formation providing confirmation on rock property alteration through non-destructive tests including ultrasonic wave velocities measurement and destructive tests including Indirect Tensile Strength (ITS). Results show gradual alteration in rock properties as per MI exposure time including a reduction in Pwave and S-wave velocity, a decrease in Young’s Modulus of elasticity (E) as well as Poisson’s ratio (v). Results also show formation fractures occur when exposed to MI, which lead to a decrease in the rock strength and ultimately lead to the increase of D-ROP | https://doi.org/10.1115/OMAE2023-105113 | English | Canada | Conference Proceeding | Proceedings of the ASME 2023 42nd International Conference on Ocean, Offshore and Arctic Engineering OMAE2023 | |||||
| A191 | 2008 | Spilling type installation for thermal fracture of rocks by microwave power of 5 kW | N/A | Russian | Russia | |||||||||||
| A192 | 2021 | Grinding Behaviour of Microwave-Irradiated Mining Waste | Adewuyi, Sefiu O.; Ahmed, Hussin A. M. | https://www.mdpi.com/1996-1073/14/13/3991 | comminution; grindability; work index; energy; minerals; cement | The combined microwave-assisted sorting and microwave-assisted comminution of minerals has been proposed to reduce the huge grinding energy consumption in mineral processing. However, gangue minerals would be discarded after the sorting process despite the microwave energy absorbed during their treatment. Therefore, this paper investigates the effect of microwave pretreatment on the Bond work index (BWI) of quartz and calcite samples, as they represent the dominant gangues in many ores and are key inputs in the cement industry, which requires intensive grinding. The samples were characterized using a scanning electron microscope coupled with energy dispersive X-ray (SEM-EDX), and Fourier transform infrared (FTIR) and X-ray diffraction (XRD) methods. The BWIs of the two samples were determined before and after the microwave treatment (2.45 GHz, 1.7 kW) at 2, 4 and 6 minutes. SEM image analyses of the untreated and microwavetreated samples were performed using ImageJ software. The results showed that after 4 minutes of radiation treatment, the BWI of the studied quartz was reduced by 13.83%, while that of the calcite increased by 15.59%. The results of the SEM image analysis indicated that the quartz developed more cracks than the calcite under the same microwave treatment conditions. Based on these findings, microwave pretreatment is suitable to reduce the grinding energy of the studied quartz, but offers no energy-saving benefit to the studied calcite. | 10.3390/en14133991 | English | Saudi Arabia | Journal Article | Energies | 14 | 13 | 3991 | ||
| A193 | 2019 | Effect of microwave treatment on rock properties | Adewuyi, Sefiu Olakunle | 10th Students Scientific Forum, King Abdulaziz University | microwave treatment; work index; grindability; particle size; comminution | On preparing rocks for certain industrial applications, crushed rocks usually go through different pretreatment stages that may have an effect on their physical properties. This paper investigates the impact of microwave exposure on physical properties of coral (soft rock) and granodiorite (hard rock). The monitored physical properties of the two rock types were specific gravity, whiteness and grindability. The tested rock samples were treated for different time intervals in a commercial microwave (frequency = 2.45 GHz). For grindability follow up, Particle size distributions were performed before and after microwave treatment of the tested rocks. The percentage of grindability improvement was evaluated on the bases of Bond Work Index. Results showed that for both tested rock types, whiteness increases with increasing treatment up to 120 – 150 s. at treatment times higher than 150s no noticeable changes in rocks whiteness can be seen. On the other hand, the specific gravity of soft rock decreases by 1.43% after microwave treatment while that of hard rock is not affected. Also, due to treatment both rock types show an improvement of their grindability. Hard rock depicted a 31.32 % decrease in its work index corresponding to 22.20 % in that of soft rock. This was more emphasized using the Gates-Gaudin-Schuhmann size distribution model. Its results indicate that treated hard rock responds higher than soft rock. | English | Saudi Arabia | Poster | 10th Students Scientific Forum, King Abdulaziz University | ||||||
| A194 | 2017 | Pre-treatment of rocks prior to comminution – A critical review of present practices | Somani, A; Nandi, T. K.; Pal, S. K.; Majumder, A. K. | https://linkinghub.elsevier.com/retrieve/pii/S2095268617300599 | It has been an established fact that comminution processes, crushing and grinding, are most energy intensive processes which account for more than half of the total energy consumed in mineral industries. Various alternative pre-treatment methods have been tried by experts around the globe. Although these methods yielded positive results in terms of reduction in energy consumption in crushing and particularly, in grinding operations at laboratory scale, their industrial application still remains an unresolved issue and challenge. Present review paper describes each one of these methods along with outcome of earlier studies and issues that need to be addressed through further rigorous experimental investigation. It also suggests the direction in which future studies can be carried out to meet the primary objective of making comminution processes more energy efficient than today they are. | 10.1016/j.ijmst.2017.01.013 | English | India | Journal Article | International Journal of Mining Science and Technology | 27 | 2 | 339-348 | |||
| A195 | 2015 | Technological Feasibility and Cultural Acceptability Study of Solar Power Systems for Microwave Assisted Sandstone Artisanal Mining | Agwa-Ejon, J.F.; Mulaba-Bafubiandi, A.F.; Pretorius, J.H | http://ieeexplore.ieee.org/document/7273130/ | N/A | N/A | This paper investigates the technical feasibility of microwave assisted artisanal mining in the production of Sandstone from QwaQwa in South Africa. It further discusses the cultural acceptability by the rural community of the synergetic application of the emerging technology (microwave energy) and the renewable resource (solar). Sandstone in QwaQwa, Free State is artisanally mined using chisels and hammers. This form of mining is extensively laborious and is normally accompanied by numerous casualties . The paper demonstrates the existence and the possible utilization of alternative methods including emerging technologies which are more productive, efficient, effective and sustainable. The solar energy systems are used to trigger the microwave magnetron which results into high energy microwave dosage. The dosage causes differential or selective heating on the rocks which culminate into rock breaking along the interfacial grain boundaries between the different constituting minerals. The data used in the analysis was collected by administering questionnaires to the artisanal mining community in QwaQwa and from observations made on site as well as desktop information obtained from secondary sources. The paper contributes to knowledge by drawing on the solar energy systems to generate the dosage required to trigger the microwave magnetron used to facilitate a more efficient and economical artisanal mining of sandstones. In conclusion the paper recommends to policy makers the application of microwave energy in mineral artisanal mining and processing instead of the manual chisel and hammer currently being utilized country wide. It then gives a detail analysis of the technical, scheduling and economic analysis of the sandstone artisanal mining in QwaQwa. | 10.1109/PICMET.2015.7273130 | English | South Africa | Conference Proceeding | 2015 Portland International Conference on Management of Engineering and Technology (PICMET) | 0 | - | 2095-2102 | 0 |
| A196 | 2022 | Computational study of microwave heating for rock fragmentation | Ahmadihosseini, A; Shadi, A.; Rabiei, M; Samea, P; Hassani, F; Sasmito, A.P. | https://linkinghub.elsevier.com/retrieve/pii/S1290072922002794 | basalt | microwave treatment; numerical modelling; parametric study; electromagnetic-thermal-flow-radiation analysis; rock fragmentation | Microwave heating can be useful in mining, tunneling and mineral processing by reducing the strength of rocks and ores. Understanding the multiphysics interaction between electric and magnetic waves on rocks due to microwave irradiation is of utmost importance in optimizing energy absorption (heating) and maximizing microcracks generation. In this study, a coupled lectromagnetic-thermal-flow-radiation model comprising of conservation of mass, momentum, energy and Maxwell equations is derived, developed and solved using the finite element method. The model is validated against an experimental benchmark in terms of the overall heat absorption as well as the local temperature distributions over a range of operating parameters, i.e. distance from the antenna, microwave power and exposure time. Results show that the real and imaginary part of the dielectric permittivity of the rocks significantly affect the temperature distribution and intensity of the energy absorption, respectively. The energy absorption is also affected by the distance of the rocks from the antenna. Furthermore, at higher microwave energy dosages, the natural convective flow starts to develop and the effect of thermal radiation becomes more prominent, which adversely affects the energy absorption in the rock sample by more than 20% in some cases. | 10.1016/j.ijthermalsci.2022.107746 | English | Canada | Journal Article | International Journal of Thermal Sciences | 181 | 107.746 | ||
| A197 | 2024 | Numerical and experimental evaluation of microwave treatment of rocks for application in mining excavation | Ahmadihosseini, A. | https://escholarship.mcgill.ca/concern/theses/hh63t2578 | Efficiently breaking hard rocks remains a persistent challenge in mining and geotechnical engineering. Traditional explosive-based methods such as blasting, while effective in some cases, bring about a host of issues including but not limited to low productivity rate, noise pollution, dust, vibration, mine collapse, and safety hazards. Consequently, the mining sector seeks to transition from non-continuous explosive-based techniques to continuous mining approaches. However, continuous mining methods suffer from drawbacks such as the short life span of the cutting blades, especially when dealing with hard rocks. Rock pre-conditioning has emerged as a promising solution to address the challenges and facilitate the shift towards continuous mining. Among the various pre-conditioning methods, microwave treatment has achieved significant attention over the past decade. This research endeavours to assess the efficacy of microwave treatment as a rock pre-conditioning method through a combination of experimental and numerical analyses for field applications and introduce potential ways for its improvement. A comprehensive series of experiments, including microwave treatment, calorimetric measurements, thermal imaging, and rock mechanical testing, are conducted using a novel energy efficiency-based approach. Additionally, a fully coupled numerical model is developed to simulate heat transfer and energy absorption behaviours in rocks during microwave treatment and is validated against experiments conducted in this study. The developed numerical model is leveraged to enhance the energy efficiency of microwave treatment experiments. Through the integration of an energy efficiency-focused perspective, this research offers new insights into the potential application of microwave treatment for rock pre-conditioning in field settings. Moreover, the developed numerical model contributes to a deeper understanding of the mechanisms underlying microwave treatment and aids in achieving superior energy efficiency in experimental and potential field outcomes. | English | Canada | PhD Thesis | N/A | |||||||
| A198 | 2017 | Fracturing Mechanisms in Granite when Exposed to Different Modes of Microwave Irradiation | Akbari, B. | https://pure.unileoben.ac.at/en/publications/fracturing-mechanisms-in-granite-when-exposed-to-different-modes- | granite | drilling and blasting; rock breakage; microwave treatments; thermal fracturing; granite rocks; cracks | Drilling and blasting is one of the most convenient and commonly used methods to break rocks in mining and civil applications. Due to numerous environmental, safety and productivity issues, the industry and contractors are looking for an alternative rock breaking system. Heating of rocks and minerals with the help of microwave treatments has therefore been the topic of many laboratory investigations and field tests since last decades. | English | Austria | Thesis | N/A | |||||
| A199 | 2010 | Bonded Particle Modelling of Microwave Induced Damage in Ore Particles | Ali, A.Y.; Bradshaw, S.M. | https://linkinghub.elsevier.com/retrieve/pii/S0892687510001524 | calcite and galena | discrete element modelling; liberation | Microwave heating of mineral ores offers a mechanism to induce fractures around grain boundaries due to the different rates of microwave power dissipation and the differences in thermal expansion coefficient among various minerals in the ore particles. As a consequence, this has the potential to reduce the energy required in subsequent grinding and to enhance liberation of valuable minerals. In this paper, numerical simulation using a bonded-particle model was undertaken to provide a better understanding of the mechanism of microwave-induced micro-fracture and to predict the effect of microwave power delivery and ore texture on microwave treatment of ores. Computational simulations of microwave heating and thermal damage have been carried out on two-phase conceptual ores. It was shown that the extent of damage and the crack pattern in an ore sample for the same microwave energy input depend strongly on the applied power density and the microwave absorbent phase grain size. It is possible both to reduce the energy input and to localize the microwave-induced damage around the grain boundaries by operating at high power density. It was also shown that high power pulsed equipment would be more efficient than continuous wave equipment for treating fine-grained ores. | 10.1016/j.mineng.2010.05.019 | English | South Africa | Journal Article | Minerals Engineering | 23 | 10 | 780-790 | |
| A200 | 2011 | Confined particle bed breakage of microwave treated and untreated ores | Ali, A.Y.; Bradshaw, S.M. | https://linkinghub.elsevier.com/retrieve/pii/S0892687511003104 | calcite and galena | comminution; discrete element modelling; liberaiton | The effect of microwave treatment on the processing of mineral ores was investigated through simulations of microwave heating, thermal damage and confined particle bed breakage test on bonded-particle models. The simulations were undertaken on two-phase mineral ore consisting of a microwave-absorbing mineral in a non-absorbing matrix. The microwave heating was simulated by dissipating a volumetric heat source in the absorbent phase. The progeny size distribution and degree of liberation for the untreated and microwave treated ores after breakage tests were determined by undertaking image analysis of the model outputs. It was shown that microwave treatment at high power density considerably changed the progeny size distribution and enhanced the degree of liberation in confined particle bed breakage tests. It was also found that crushing velocity has a significant effect on both progeny size distribution and liberation, particularly for the ore treated at high power density. | 10.1016/j.mineng.2011.08.020 | English | South Africa | Journal Article | Minerals Engineering | 24 | 14 | 1625-1630 | |
| A201 | 2023 | Multiphysics Simulations of Microwave Induced Damage Applied to Rock Samples of Varying Strength and Absorptivity | Allen, J. B.; Patel, R. R.; Taylor, O.-D. S. | https://asmedigitalcollection.asme.org/materialstechnology/article/145/3/031005/1159790/Multiphysics-Simulations-of-Microwave-Induced | basalt; granite; sandstone | microwave radiation; thermally induced stress; damage; numerical modelling | Abstract In this work, we show the development of a numerical model to investigate the 3D interactions between microwave radiation and basalt, granite, and sandstone rock samples. In particular, we assign sample heterogeneity based on the Weibull statistical distribution, and invoke a damage model for elemental tensile and compressive stresses based on the maximum tensile stress and the Mohr–Coulomb theories, respectively. Model implementation is facilitated by the use of comsol for use in coupling the electromagnetic, thermal, and solid displacement relations. Various parametric studies are conducted related to variable input power and waveguide port alignment, with model validation conducted with respect to damage resulting from a uniaxial compression test. The results indicate that relatively high induced temperatures will promote damage potential, but its impact must be placed within the context of the sample strength to quantify the true potential damage evolution of a given rock mass. As observed herein, a mechanically weaker rock may be prone to mechanical damage; however, it may also possess a relatively large relative permittivity, enabling it to absorb the least amount of microwave radiation thus yielding comparatively low overall damage profiles compared to a more mechanically competent rock mass. | 10.1115/1.4056996 | English | USA | Journal Article | Journal of Engineering Materials and Technology | 145 | 3 | 31005 | |
| A202 | 2024 | Multiphysics simulations of uniaxial compression applied to various rock samples subject to microwave pretreatment | Allen, Jeff; Patel, Reena; Mondragon, Tomas; Taylor, Oliver | https://www.emerald.com/insight/content/doi/10.1108/MMMS-09-2023-0312/full/html | basalt; granite; sandstone | microwave radiation; thermally induced stress; damage; numerical modelling | Purpose – Among the various applications involving the use of microwave energy, its growing utility within the mining industry is particularly noteworthy. Conventional grinding processes are often overburdened by energy inefficiencies that are directly related to machine wear, pollution and rising project costs. In this work, we numerically investigate the effects of microwave pretreatment through a series of compression tests as a means to help mitigate these energy inefficiencies. | 10.1108/MMMS-09-2023-0312 | English | USA | Journal Article | Multidiscipline Modeling in Materials and Structures | 20 | 3 | 510-525 | |
| A203 | 2012 | The Effects of Microwave Treatment on the Froth Flotation of Rare Earth Elements | Allen, Kaleb; Waters, Kristian; Jordens, Adam | https://www.mcgill.ca/engineering/files/engineering/sure-2012-minmat-allen.pdf | Thor Lake Ore | N/A | N/A | N/A | English | Canada | Poster | N/A | 0 | N/A | N/A | |
| A204 | 2012 | Effects of Microwave and Conventional Drying Methods on Grinding Characteristics of AfsinElbistan Lignite | Altiner, M.; Yildirim, M; Vapur, H. | https://www.researchgate.net/publication/273631962_Effects_of_Microwave_and_Conventional_Drying_Methods_on_Grinding_Characteristics_of_Afsin-Elbistan_Lignite | lignite (brown coal) | N/A | This study includes effects of reducing moisture content on grindability characteristics of Afsin-Elbistan lignite using conventional and microwave drying methods. Drying rates obtained in the conventional drying method were lower 4-10 times than that of the microwave drying method. Hardgrove Grindability Index (HGI) and ball mill grinding tests were done in order to determine the grinding properties of the samples. The highest HGI value of the sample dried at 105o C for 240 minutes in the conventional method reached to 71.83, which corresponds to 187% increase in the average HGI value of original sample. Whereas, the highest HGI value obtained in the microwave drying method was 52.24 at 0.90 kW for 20 minutes. In the end, although the HGI value obtained from the conventional method was higher than the microwave method, the better grindability result was obtained in the microwave method in shorter periods. | English | Turkey | Conference Proceeding | Proceedings of XIIIth International Mineral Processing Symposium – Bodrum-Turkey | 0 | N/A | N/A | 0 | |
| A205 | 2024 | The effect of microwave irradiation and shock cooling on rock properties- A review | Alwaar, A.; Abugharara, A.; Zhang, Y.; Butt, S. | https://sebhau.edu.ly/journal/index.php/sucp/article/view/3424 | drilling engineering; microwave irradiation; mining excavation; rate of penetration; rock properties | Understanding rock properties and rock behavior under varying conditions is essential for predicting and managing rock behavior across different engineering applications. This study focuses on how rock properties respond to temperature variations, specifically through Microwave Irradiation (MI) and Shock Cooling (SC), and the implications of these changes for civil engineering, oil and gas drilling, and mining. In civil engineering, such knowledge is vital for designing stable and durable foundations. In drilling and excavation, altering rock properties to weaken rocks can enhance drilling efficiency, increase the Drilling Rate of Penetration (ROP), and reduce operational costs. The objective of this review is to consolidate research findings on the impact of MI and SC on rock properties, such as mechanical strength and mineral composition. By assessing these studies, the review aims to identify the potential benefits of using MI and SC to improve drilling performance, extend the lifespan of drill bits, and minimize drilling expenses. The review also explores the mechanisms through which these temperature-induced treatments create micro-fractures that facilitate easier drilling. In conclusion, the compiled research demonstrates that both MI and SC can significantly alter rock properties, offering practical applications in drilling and excavation. These techniques can effectively reduce rock strength, leading to improved ROP and cost savings in drilling operations. The insights provided by this review could guide future developments in engineering practices, particularly in enhancing the efficiency and sustainability of drilling activities. | 10.51984/SUCP.V3I2.3424 | English | Canada; Libya | Conference Proceeding | SEBHA UNIVERSITY CONFERENCE PROCEEDINGS | 3 | 2 | |||
| A206 | 2005 | Improved grindability and gold liberation by microwave pretreatment of a free-milling gold ore | Amankwah, R.K.; Khan, A.U.; Pickles, C.A.; Yen, W.T. | https://journals.sagepub.com/doi/full/10.1179/037195505X28447 | free-milling gold ore | Free-milling gold ore, microwave pretreatment, grindability, gold liberation | The gravity concentration of gold is very efficient if the metal is fully liberated and the particle size of the gold is relatively coarse. Liberation is usually achieved by comminution, but due to the association of the gold with the other minerals in the ore, overgrinding occurs in conventional comminution circuits and slime generation leads to inefficient recovery. The liberation of minerals can be improved by adding grinding aids, which modify the mechanical properties of the ore and allow breakage at lower stress levels. In this research, microwave pretreatment was used to augment the grinding of a free-milling gold ore containing quartz, silicates and iron oxides. Under microwave irradiation, selective heating of the different mineral components resulted in thermal stresses that caused cracking. These intergranular and transgranular fractures were confirmed by scanning electron microscopy. After microwave processing, the grindability of the ore was improved and the crushing strength and the Bond Work Index were reduced by 31·2% and 18·5%, respectively. In addition to the enhanced grindability, gold was released from the matrix of the host minerals at a coarser size, resulting in a significant increase in free gold recovery by gravity concentration. For a gold ore with a head grade of 6·4 g t–1, the gold recovery improved from about 28% to 40% after microwave pretreatment. | 10.1179/037195505X28447 | English | Canada | Journal Article | Mineral Processing and Extractive Metallurgy | 114 | 1 | 30-36 | |
| A207 | 2011 | Microwave Assisted Breakage of Metallic Sulfide Bearing Ore | Andriese, Matthew D.; Hwang, Jiann‐Yang; Bell, Wayne; Peng, Zhiwei; Upadhyaya, Anish; Borkar, Shivanand A. | https://onlinelibrary.wiley.com/doi/10.1002/9781118062081.ch45; https://www.onemine.org/documents/microwave-assisted-breakage-of-metallic-sulfide-bearing-ore | refractory sulphide ore body | sulfide ore; microwave energy; Curie temperature; Bond work index | A refractory ore body located in Michigan’s Upper Peninsula contains high concentrations of nickel and copper chiefly occurring in the minerals pyrrhotite, chalcopyrite, and pentlandite. Refractory ore bodies are difficult to treat by conventional mineral processing methods so microwave pre-treatment of the ore is employed to increase metallic-particle/host rock liberation by making use the differential thermal expansion properties of the mineral phases that absorb microwave energy. The Curie temperature measurement of metallic-bearing particles is in agreement with the known value for pyrrhotite occurring at 325°C. A nickel-rich iron sulfide mineral is found to be in occurrence and also appears to be magnetic under BSE imaging. It is shown the ore particles heat rapidly when exposed to microwave radiation for short durations of time mainly due to the high concentration of ferromagnetic mineral phases. Rapid heating causes thermal expansion of constituent mineral phases that produce cracks within ore particles. SEM imaging shows fracture occurring along grain boundaries and throughout host rock matrix. Ball milling experiments show an increased grindability of the ore resulting in a decrease in work index values. | English | USA | Conference Proceeding | 2nd International Symposium on High‐Temperature Metallurgical Processing | 379-386 | ||||
| A208 | 2023 | Microwave impacts on fine waste in kimberlite processing | Aslam, Azlan; Rasyid, Muhammad A; Rafiei, Arash; Sasmito, Agus; Hassani, Ferri; Aslam, Azlan; Rasyid, Muhammad A; Rafiei, Arash; Sasmito, Agus; Hassani, Ferri | https://www.researchgate.net/publication/373485415_Microwave_Impacts_on_Fine_Wastes_in_Kimberlite_Processing | kimberlite ore | N/A | Processing of the diamond from kimberlite results in 99.9% waste. 80% of waste is fine-processed kimberlite (size < 1 mm), which requires high cost and amount of water for management. Microwave heating of rock samples has the potential of better mineral liberation and can produce coarser product resulting in the reduction of fine waste particles. | English | Canada | Poster | CIM Convention | |||||
| A209 | 2018 | New Excavation Technologies for Underground Construction: Linear Cutting Machine Tests on Microwave-Irradiated Granodiorite | Arora, S.; Kaunda, R. B. | https://rosap.ntl.bts.gov/view/dot/40073 | granodiorite | N/A | The objective of this project is to measure the specific energy requirements for representative hard rock which has been weakened by microwave irradiation. Granodiorite rock blocks were collected from Boulder, Colorado and prepared at a local quarry. Three of the rock blocks were placed inside a commercial microwave and heated for 30 seconds, 100 seconds and 200 seconds. The four blocks were cast in concrete inside a fabricated metallic box and allowed to cure at the Earth Mechanics Institute (EMI) at Colorado School of Mines. Large scale linear cutting tests were conducted on the four blocks using a single disc cutter. During each linear cutting pass, displacements, horizontal and vertical cutting forces were measured by a computer monitoring system connected to the large scale linear cutting machine. The specific energies required during each cut were then calculated, compiled and analyzed. Further cutting tests are recommended to improve the statistical significance of the findings and to quantify the actual specific energy reductions after microwave preconditioning. | English | USA | Report | N/A | |||||
| A210 | 2024 | Investigating the Effect of Microwave Pretreatment on Bastnasite Grinding for Comminution Energy Reduction and Rare Earth Recovery | Asgari, K; Huang, Q.; Honaker, R.; Sabolsky, E. | https://www.mdpi.com/2227-9717/12/11/2468 | bastnaesite ore | bastnaesite ore; fine grinding; microwave; Box–Behnken design; energy reduction | This study explored the impact of microwave pretreatment on the grinding efficiency of bastnaesite ore using a stirred mill. Bastnaesite ore was prepared using a staged crushing and sieving process, followed by microwave pretreatment in a specially designed microwave furnace system. Representative samples of the crushed ore underwent stirred mill grinding, with power draw measurements recorded and adjusted to reflect only the specific energy input required for grinding. Particle size distribution was analyzed periodically using laser particle size analysis. In addition, a Box–Behnken design was used to statistically assess the effects of various parameters on the results, ensuring a robust analysis of the factors influencing energy consumption and particle size reduction. The findings reveal that microwave pretreatment significantly influenced specific energy and product P80, with SEM analyses showing increased microcracking and porosity and XRD analyses suggesting possible mineralogical alterations. This enhancement was also proved via statistical tools and analyses such as Design Expert software Ver. 13 and ANOVA. In summary, the research concludes with the following critical points: (1) Microwave pretreatment was found to reduce the energy consumption required for bastnaesite grinding by 27%. (2) Following pretreatment, bastnaesite achieved a 25% finer product size under identical grinding conditions. (3) Structural and compositional changes in bastnaesite after grinding were confirmed through scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis. (4) Based on these analyses, potential mechanisms for the observed energy savings and product size reductions have been suggested. Additionally, we have enhanced the Abstract to better highlight the methods used in the study. This investigation not only advances our understanding of microwave-assisted comminution but also opens avenues for future research on optimizing and implementing this technique in large-scale mining operations. | https://doi.org/10.3390/pr12112468 | English | USA | Journal Article | Processes | 12 | 11 | N/A | 2.468 |
| A211 | 2018 | Iron Ore Concentrate Particle Size Controlling Through Application of Microwave at the HPGR Feed | Athayde, M.; Bagatini, M. C. | https://link.springer.com/article/10.1007/s42461-018-0013-y | iron ore concentrate | HPGR; microwave; moisture; pelletizing | Nowadays, the HPGR (high-pressure grinding rolls) is an intermediate step between filtering and balling in the most modern iron ore pelletizing operation. The operation debottlenecks filtering process and reduces pressure over the typical milling process to control particle size to the balling. The present study evaluated aspects of microwave application to the iron ore concentrate fed to HPGR in a bench scale unit. Iron ore concentrate was irradiated varying the microwave exposure time and grinding efficiency was evaluated. The moisture influence in the HPGR efficiency was also assessed. The pellet feed blaine surface area (BSA) improved by 300 cm2/g and % < 325# fraction by 3%. Scanning electron microscope (SEM) images show the formation of micro-cracks onto the particle surface induced by microwave; the effect observed helped improve the milling process performance, in addition to the moisture reduction observed due to the temperature increase. | https://doi.org/10.1007/s42461-018-0013-y | English | Brazil | Journal Article | Mining, Metallurgy & Exploration | 36 | N/A | 353-362 | |
| A212 | 2023 | Enhancing the Recycling of Steelmaking by-products by Applying an Innovative Microwave Energy | Omran, M.; Fabritius, T.; Wolfelschneider, S.; Schmid, H.; Hauselmann, M.; Gronen, L.; Morillon, A.; Pietruck, R.; Adolphy, D. | https://zenodo.org/records/10159426 | basic oxygen furnace slag | microwave treatment, magnetic properties, dielectric properties, intergranular cracks, steelmaking wastes. | N/A | English | Finland | Conference Proceeding | AMPERE 2023 | 39-40 | ||||
| A213 | 2021 | Variations in fracture toughness of SCB granite influenced by microwave heating | Bai, Guogang; Sun, Qiang; Jia, Hailiang; Ge, Zhenglong; Li, Pengfei | https://linkinghub.elsevier.com/retrieve/pii/S0013794421004665 | SCB granite | granite; microwave time; surface temperature; fracture toughness; destruction time | This technical description introduces a microwave-assisted mechanical rock breaking technology. After SCB granite is subjected to microwave action, the surface temperature of the rock rises. Due to the obvious difference in absorption of internal minerals, cracks on the rock surface began to appear and spread. The fracture toughness of SCB granite decreased significantly, with a decrease of about 35%, and the time required for fracture failure was shortened. Facts have proved that compared with other auxiliary rock breaking methods (such as heat conduction methods), microwave-assisted mechanical rock breaking is a convenient and efficient technology, which can improve the efficiency of underground rock breaking and has a wide range of application prospects. | 10.1016/j.engfracmech.2021.108048 | English | China | Journal Article | Engineering Fracture Mechanics | 258 | 108.048 | ||
| A214 | 2024 | Micro-mechanical Properties of Main Rock-Forming Minerals in Granite Under Microwave Irradiation | Bai, Yanbo; Gao, Mingzhong; Xie, Jing; Yang, Bengao; Tang, Ruifeng; Zhang, Yang | https://link.springer.com/10.1007/s00603-024-03982-8 | granite | microwave irradiation; granite; rock-forming minerals; nanoindentation; micro-mechanical parameters | Currently, the large-scale crushing technology for high-strength hard rock is struggling to meet the increasing construction demand for deep underground engineering. Although microwave-coupled mechanical rock breaking is safe, clean, and efficient, the weakening mechanism of the mechanical properties of microwave-treated hard rock is unclear, especially for quantitative description in mineralogical terms. Thus, the variation laws of micro-mechanical properties and surface morphology of samples in different parts of ten major granite-forming minerals were systematically studied after being irradiated with 2 kW microwaves for 3 min. Results show that minerals can be classified into three categories based on their micromechanical properties: high-hardness (H > 11 GPa, quartz and amphibole) and medium-hardness minerals (6 < H < 11 GPa, feldspar minerals) with good elasticity (EER ≥ 0.59) and brittleness (H/Kc ≥ 1.65), and low-hardness minerals (< 6 GPa, muscovite, phengite and chlorite) with excellent plasticity (EER ≤ 0.46) and ductility (H/Kc ≤ 0.96), excluding diopside. After microwave irradiation, chlorite, altered plagioclase, and amphibole were categorized as microwave-sensitive minerals (heating rates above 2.5 °C/s). Among them, amphibole decreased its mechanical parameters by up to 32.7%, while chlorite and altered plagioclase were enhanced. The heating rates of the other minerals are lower than 2 °C/s, and the surface deterioration is not obvious. Peculiarly, the change rates of mechanical parameters of muscovite and phengite are up to 42.3%, which are clearly distinguished from the lower mechanical parameters change rates of other minerals. Clearly, minerals’ microwave sensitivity cannot determine the variation rule of their mechanical properties. Differences in indentation morphology depend mainly on minerals' fracture toughness, elasticity, and brittleness parameters. This study reveals the weakening mechanism of the mechanical behavior in granite after microwave irradiation mineralogically, and offers reliable basic data for cross-scale modeling of granite. | 10.1007/s00603-024-03982-8 | English | China | Journal Article | Rock Mechanics and Rock Engineering | ||||
| A215 | 2003 | Taking the grind out of grinding | Bansal, R. | https://ieeexplore.ieee.org/document/1237474 | N/A | N/A | Existing uses of RF/microwave heating involve soft targets. This article focuses on current research being carried out in the United Kingdom and South Africa, where microwave energy is being applied to "soften up" rocks for the purpose of mineral extraction. | English | USA | Magazine Article | IEEE Microwave Magazine | 4 | 3 | |||
| A216 | 2021 | Microwave Pretreatment on Copper Sulfide Ore: Comparison of Ball Mill Grinding and Bed Breakage Mechanism | Barani, Kianoush; Azadi, M. R.; Moradpouri, Farzad | https://link.springer.com/10.1007/s42461-021-00458-z | copper sulfide ore | microwave treatment; bed breakage; ball milling; particle shape; liberation; flotation | The aim of this paper is to assess the effect of microwave treatment on copper sulfide ore for ball milling and bed breakage. Liberation analysis of ground products in eight size fractions showed that microwave pretreatment liberated more chalcopyrite particles from the bed breakage product than the ball mill product. In bed breakage, microwave pretreatment caused a 2% increase in chalcopyrite liberation on average. Microwave pretreatment produces more elongated particles in ball milling and more rounded particles in bed breakage, respectively. Microwave pretreatment produces coarser chalcopyrite particles with a wide range of sizes. This effect is more significant in bed breakage compared with ball milling. Micro-flotation test results showed that in ball milling, treated and untreated materials have similar metallurgical performance and there is a little difference (1%) between the average Cu recovery values. However, in bed breakage, the average recovery for the treated materials is about 5% higher than the untreated materials. | 10.1007/s42461-021-00458-z | English | Iran | Journal Article | Mining, Metallurgy & Exploration | 38 | 5 | 2209-2216 | |
| A217 | 2004 | Theory and Applications of Microwave Energy in Communition | Batar, T. | https://www.scientific.net/KEM.264-268.1399 | N/A | microwave; heating; comminution; grindability | Thermal expansion of the selectively heated minerals offers the potential to further liberate the ore minerals from the gangue at larger particle sizes [1]. Cleaner liberation of the ore mineral at a larger particle size would reduce the grinding energy requirements as well as improve the concentrate grade and metal recovery after beneficiation. Microwaves used in comminution, including crushing and grinding processes, have the potential to reduce the required energy. The applications of microwave to mineral processing include drying of coal, recovery of gold from low grade ores and tailings, extraction of rare earth elements, the retorting of soil shale end smelting of metals. Energy consumed in comminution can be as high as 50-70% of the total process energy [2, 3 & 4]. If full-scale application of microwave technology can be accomplished, the addition and operation of a microwave could be an easy and efficient retrograde to reduce the mill power requirements by 25%. In this paper, it is shown that microwave energy is capable of inducing thermal stress cracking to decrease the energy requirements of grinding and leading to possible new applications for mining and ceramics industries. | 10.4028/www.scientific.net/KEM.264-268.1399 | English | Turkey | Journal Article | Key Engineering Materials | 264 | 1399-1402 | ||
| A218 | 2013 | Effects of microwave pre-heating on grindability and liberalization degree of chromite ores | Bayat, O; Altıner, M; Altınçelep, Z; Kaymakoğlu, B | https://www.researchgate.net/publication/281614427_Effects_of_microwave_pre-heating_on_grindability_and_liberalization_degree_of_chromite_ores | chromite | In this study, the influence of microwave pretreatment on the grindability and liberalization degree of the chromites ore was investigated. The samples were crushed and sized into three fractions as (-12+4.75 mm), (-4.75+2 mm) and (-2 mm). Approximately 300 grams of each sized sample were heated in a lab scale microwave oven. During the microwave heating process, the samples were exposed to radiation at the three different powers (360, 600 and 900 W) and the radiation times were determined as 5, 10, 20 and 30 minutes, respectively. The treated samples and the ones untreated with microwave heating were grinded in the laboratory rod mill and particle size distributions were determined before and after milling. The results obtained from all grinding experiments were compared with the feed sample. It was observed that fineness of the feed sample (-12+4.75 mm) treated with the microwave heating was increased comparing the ones untreated with microwave heating. | English | Turkey | Journal Article | Proceedings of the XV Balkan Mineral Processing Congress | ||||||
| A219 | 2019 | On the Possibility of Creating a Technology of Explosive Destruction of a Rocks-Dielectrics by directed electromagnetic flow of concentrated microwave energy | Blinov et al. | http://jre.cplire.ru/jre/feb19/4/text.pdf | destruction of hard rocks – dielectrics; destroying and disaggregation of hard rock mass; high power microwave field; focused microwave power; “explosive” effect of a destroying | Many different electrical and dielectrical characteristics of hard rock materials (as granites, sandstones, e t. c.) are presented here. The microwave region of electromagnetic wavelengths (1,0 ÷ 20 cm) was in the spotlight, because the main goal of authors was the maximum effective influence on these materials by this electromagnetic field to achieve a maximal destroying in available power level 50 kW. Different methods and arrangements are proposed here to concentrate and inject microwave power in massive hard rocks. To avoid an unwanted microwave breakdown in high electromagnetic power level, mechanical power addition from two or more sources of lower electromagnetic power, is proposed and confirmed experimentally. Also, a microwave power transport through a plasma channel by surface wave is proposed and accompanied by necessary calculations. Experimental equipment, having a microwave power 50 kW, is described. It has a metallic ellipsoidal reflector, which reflects microwave power from quasi-point source, located in neighbor focus of ellipsoid, into another focus. In this focus, probing the massive hard rocks, very high power concentration is achieved; it causes a destruction and disaggregation of the material. The main new approval of this work is the existing of some “explosive” mechanism of destroying, which is very intensive and occurs when some phase transformation happens in the material under the influence of intensive microwave field, and in the same time some active temporal change of the field occurs. The result can exceed the expected many times. All conclusions, however, are now qualitative in nature and demand the careful experimental check and study. In the final part of the work authors propose their opinion about prospects of method and compare it with other known methods. Their conclusions are very optimistic and encouraging. | Russian | Russia | Journal Article | Journal of Radio Electronics | 2 | 1684-1719 | ||||
| A220 | 2024 | Impact of high-power microwave treatment on comminution and downstream processing of kimberlite ores | Borhan Mehr, R.; Pickles, C.A.; Danoczi, J,; McCubbing, M.; Forster, J.; Tian, X. | https://ikcabstracts.com/index.php/ikc/article/download/4060/4060/4046 | kimberlite | N/A | N/A | English | Canada | Conference Proceeding | 12th International Kimberlite Conference | 0 | ||||
| A221 | 2024 | Influence of high-power microwave treatment on comminution and subsequent downstream processing with characterization studies of kimberlites | Borhan Mehr, R.; Pickles, C.A.; Forster, J.; Tian, X.; Danoczi, J. | https://link.springer.com/chapter/10.1007/978-3-031-67398-6_285#DOI | kimberlite | comminution; DMS; energy; HPGR; kimberlite; liberation; microwave; permittivities; pilot-scale; settling | Prior research has shown that microwave treatment diminishes the competency of kimberlites. However, there is a lack of information regarding the downstream processing of microwave-treated kimberlites. In this study, the microwave treatment of kimberlites at both the bench-scale and the pilot-scale was investigated. First, a comprehensive study of the kimberlite characteristics was conducted, including mineralogy, thermogravimetric analysis, and permittivities. Second, bench-scale microwave treatments were performed to investigate the heating behaviours of the kimberlites and their amenability to microwave treatment. Third, pilot-scale microwave studies were conducted to weaken the kimberlite by inducing microfractures along the grain boundaries. This weakened kimberlite requires less comminution energy, which could potentially lead to a reduction in diamond breakage and damage. Fourth, comparative comminution studies were performed on both the as-received (reference) and the pilot-scale microwave (PMW) treated samples, utilizing jaw and cone crushers followed by high-pressure grinding rolls (HPGR). These results demonstrated that the microwave-treated samples consumed less energy and generated fewer ultrafine particles (1 mm) were separated into both the concentrate (sinks) and the tails (floats) via dense media separation (DMS) with both fractions being subjected to liberation analysis. Sixth, the fine particles (<1 mm) were utilized in the settling studies. Finally, some conclusions and key findings are presented as well as recommendations for further research. | English | Canada | Conference Proceeding | Proceedings of the 63rd Conference of Metallurgists | 1763-1774 | ||||
| A222 | 2016 | Microwave installation for mineral raw materials | Brienkov, A.S.; Morozov, A.O.; Morozov, O.A.; Prokopenko, A.V.; Trebuk, V.P. | https://ieeexplore.ieee.org/document/7878979 | minerals; raw materials; microwave devices; research and development | Research and development of microwave installation for high-intensity thermal treatment of the mineral raw materials on 50 kW at 915 MHz have been done. The possibility of using the working chamber of the waveguide transmission type for the creation of efficient microwave installations, high power was shown. Device for sacrifices and movement of minerals in microwave working chamber was developed. The system of automation based on the industrial controller allowing to completely automate technological processing was created. Tested works of microwave installations for processing of mineral raw materials at a high microwave power level in the experimental workshop the mining and processing enterprise were carried out. The technological scheme of mineral raw material processing is developed. | 10.1109/APEDE.2016.7878979 | Russian | Russia | Conference Proceeding | 2016 International Conference on Actual Problems of Electron Devices Engineering (APEDE) | |||||
| A223 | 2015 | Microwave processing of cement and concrete materials – towards an industrial reality? | Buttress, A.; Jones, A.; Kingman, S. | http://dx.doi.org/10.1016/j.cemconres.2014.11.002 | cement; concrete | microwave processing; clinker; cement; hydration; radioactive waste | Each year a substantial body of literature is published on the use of microwave to process cement and concrete materials. Yet to date, very few if any have lead the realisation of a commercial scale industrial system and is the context under which this review has been undertaken. The state-of the–art is evaluated for opportunities, and the key barriers to the development of new microwave-based processing techniques to enhance production, processing and recycling of cement and concrete materials. Applications reviewed include pyro-processing of cement clinker; accelerated curing, non-destructive testing and evaluation (NDT&E), and end-of-life processing including radionuclide decontamination. | English | UK | Journal Article | Cement and Concrete Research | 68 | 112-123 | |||
| A224 | 2009 | Quantifying damage around grain boundaries in microwave treated ores | Ali, A.Y.; Bradshaw, S.M. | https://linkinghub.elsevier.com/retrieve/pii/S0255270109001664 | 10% galena/90% calcite (by volume) | microwave; thermal stress; ore; damage | Thermally induced damage due to microwave heating of mineral ore particles was simulated numerically using a continuum approach. Particles were represented as dispersions of microwave-absorbing grains in a non-absorbing matrix. As the aim of microwave treatment of ores is liberation of the absorbing grains from the matrix rather than bulk damage to the particle, damage was quantified by comparing the tensile stress in the zones surrounding the absorbing grains with the tensile strength of the matrix. Through comparison of two different ores it was shown that the most energy-efficient method of maximising grain boundary damage is by increasing the microwave power density and decreasing the treatment time. The amount of damage incurred at a specific power density and energy input was dependent on the ore mineralogy and its texture. More grain boundary damage was induced in coarser textured ores for the same energy input and damage was maximised for ores with microwave-absorbing grains with a large thermal expansion coefficient. | 10.1016/j.cep.2009.09.001 | English | South Africa | Journal Article | Chemical Engineering and Processing: Process Intensification | 48 | 11-12 | 1566-1573 | |
| A225 | 2018 | Selective Liberation of High-Phosphorous Oolitic Hematite Assisted by Microwave Processing and Acid Leaching | Cai, Xianyan; Qian, Gongming; Zhang, Bo; Chen, Qiushi; Hu, Chenqiang | https://www.mdpi.com/2075-163X/8/6/245 | oolitic hematite ore | oolitic hematite; microwave; acid leaching; selective liberation; dephosphorization | The release of valuable minerals from the associated gangues is called liberation. Good liberation is essential to the subsequent separation stage. Selective liberation is advantageous to improve the degree of liberation. Oolitic hematite is one of the typical refractory iron ores in China, and its resources are abundant. However, owing to its fine dissemination and complex mineralogical texture, the conventional grinding processes are inefficient in improving the selective liberation of oolitic hematite. In this study, microwave processing and acid leaching were used to assist the liberation of oolitic hematite. The assisted liberation of the oolitic hematite mechanisms of microwave processing and acid leaching were studied by using scanning electron microscope (SEM), X-ray diffraction (XRD), BET specific surface area detection method (BET) and the transflective microscope method. The results indicated that microwave processing can reduce the mechanical strength of oolitic hematite and improve the liberation of hematite, and acid leaching can improve the microwave-assisted liberation efficiency and reduce the content of phosphorus in the grinding product. Compared to direct grinding, the liberation of hematite increased by 54.80% in the grinding product, and especially, the fractions of −0.038-mm and 0.05–0.074 mm increased significantly; however, there was no obvious change in other grain sizes, and the dephosphorization ratio reached 47.20% after microwave processing and acid leaching. After the two stages, the iron grade and recovery of the magnetic separation product increased by 14.26% and 34.62%, respectively, and the dephosphorization ratio reached 88.59%. It is demonstrated that microwave processing and acid leaching comprise an efficient method to improve the liberation of hematite and the dephosphorization ratio of oolitic hematite. The two-stage treatment can achieve selective liberation of oolitic hematite, which is beneficial to the following magnetic separation. | 10.3390/min8060245 | English | China | Journal Article | Minerals | 8 | 6 | 245 | |
| A226 | 2001 | The Use of The Three point bend test to quantify the effects of thermal pre-treatment on rock strength | Campbell, P.; Vorster, W.; Merchant, A.J.; Rowson, N.A. | https://www.sciencedirect.com/science/article/pii/S0892687501000929 | carbonatite ore core; granite core | comminution; mineral processing | A significant problem of thermal pre-treatment methods is that of assessing the influence of these methods on the ore strength. Single practice breakage tests may be used to determine the effect of thermal pre-treatment on intrinsic strength parameters of the material as opposed to bulk parameters. In order to test the validity and sensitivity of a new method, the Three-point bend test, experiments were conducted on a heterogenous carbonatite ore and a homogenous shap granite which were thermally pre-treated. The test successfully detected the sharp strength decrease (up to 87%) due to quartz phase inversion within the granite as well as reductions of up to 80% in the carbonatite due to the thermal pre-treatment. Results correspond well to those of the Berry and Bruce method. Overall the Three point bend test is sensitive enough to detect changes in rock strength whilst being a much simpler method than conventional grinding tests. | https://doi.org/10.1016/S0892-6875(01)00092-9 | English | United Kingdom | Technical Note | Minerals Engineering | 14 | 8 | 901-904 | 0 |
| A227 | 2020 | Investigating the Effects of Microwave Treatment on the Strength of Igneous Rocks | Canpolat, Ahmet Ni̇Yazi̇ | granite; syenite; gabbro | magmatic rocks; microwave treatment; microwave heating; uniaxial compressive strength; Brazilian tensile strength | Rock drilling and cutting technology has developed rapidly in the last century. However, there are problems in drilling and cutting very hard rocks such as low penetration rate and high wear rate of cutting tools. In order to increase the advance rate and reduce wear during drilling or cutting of very hard rocks, recent studies on some innovative methods such as microwave assisted rock breakage has been drawing attention. Studies on the effects of microwave exposure on the mechanical properties of igneous rocks are new and limited. Therefore, there are many gaps to be investigated in this area. In this thesis, the effects of microwave treatment were investigated on the strength of igneous rocks. In this study, microwave energy up to 6 kW was applied to 9 different magmatic rocks such as; 6 granite, 2 syenite and 1 gabbro. First, thin sections of each rock used in the experiments were prepared and the mineral contents and percentages were determined. Then, the uniaxial compressive strength (UCS) and the Brazilian tensile strength (BTS), density, porosity, and ultrasonic wave velocity tests were carried out. After that, more than 600 samples were exposed to microwave energy. The microwave treatment was applied at 1 kW, 2 kW, and 6 kW powers for the durations ranging from 60 s to 420 s. The surface temperature of each specimen was measured with an infrared gun before the microwave irradiation and immediately after removing the sample from the oven. The evaluation of the results show that the rock strength decreases generally with increasing microwave power and exposure duration. The strength losses and the heating degrees are different for each tested rock type illuminated by microwave power because of the different the mineral content. crackings and meltings were observed on some samples depending on the applied microwave power, the exposure duration, and the mineral content. The UCS and the BTS values of granites decreased usually after 200°C and 100°C, respectively. The significant losses in the strength of syenite and gabbro samples were generally observed below 100°C due to their metallic mineral contents or high amount of microwave absorber minerals. Concluding remark is that microwave treatment affects strongly the strength of igneous rocks depending on the applied power, the exposure time, and mineralogy. | Turkish | Turkey | Thesis | 0 | N/A | 0 | ||||
| A228 | 2015 | Assessing Tensile Strength of Unconventional Tight Rocks Using Microwaving | Chen, Jin-Hong; Georgi, Daniel; Liu, Hui-Hai; Jilin, Zhang; Eppler, Gary | http://www.onepetro.org/doi/10.2118/178590-MS | sandstone; shale plugs; clay disks | N/A | Rock tensile strength is a critical parameter needed to design and model hydraulic fracturing (or crack initiation and propagation) in oil and gas reservoirs, especially in tight organic-rich shale. Conventional methods for measuring rock tensile strength are either time consuming (direct tensile strength method) or unreliable (indirect method), and require precision “machined” samples and heavy mechanical instruments. We propose a new technique that is simple and rapid for measuring the tensile strength of rocks with low permeability using microwave heating. Our method is developed based on the fact that when the temperature of water in a confined space, e.g., within a tight rock, increases, water cannot freely expand and consequently the pressure within water-filed pores quickly elevates to the point where it exceeds the rock’s tensile strength such that the rock breaks. Microwave heating can rapidly increase the temperature of water in the rock sample due to the relatively large dielectric loss of innate water. This method works well for rocks with low permeability where pressure leak off during the rapid heating is negligible. This paper presents both the theory and results of our initial laboratory tests for the microwaving heating method. The test results demonstrate that microwaving cracks and sometimes pulverizes shales and tight sandstones with water content. When the sample is pulverized, likely 100% of the light hydrocarbons will be released. Hence, the proposed method also may provide insight into total recoverable light hydrocarbons per kilogram. We believe that microwave (or electromagnetic wave (EM)) heating approach, for some tight reservoirs, has the potential to be further developed to provide a practical waterless fracturing technology. | 10.2118/178590-MS | English | USA | conferencePaper | Unconventional Resources Technology Conference | 0 | |||
| A230 | 2023 | Effect of Waveguide Aperture and Distance on Microwave Treatment Performance in Rock Excavation | Chen, Fangfang; Wu, Zhanqiang; Zhang, Zhiqiang | https://www.mdpi.com/1424-8220/23/4/1929 | microwave-assisted rock breaking; waveguide aperture; irradiation distance; waveguide aperture; rock temperature; rock damage | Rock burst is a common hazard during tunnel excavation in high-stress and hard rock strata. Microwave-assisted breaking has a great potential application in hard rock tunnel excavation, reducing the possibility of rock burst, and how to reasonably make the application on the TBM cutterhead is one of the critical issues. The waveguide aperture and distance between the rock face and waveguide have serious effects on its performance. In this paper, based on the arrangement of the microwave waveguide of the TBM cutterhead and the actual excavation situation, considering the reflection of microwave energy by the metal cutterhead and the scattering state of electromagnetic waves at the rock surface irradiation, a 2D model of rock irradiated by microwaves is established. The effects of waveguide aperture and distance on microwave irradiation performance of rock are studied, considering three different waveguide types: convergent waveguide, rectangular waveguide, and horn waveguide. The results show that the maximum temperature is located on the rock irradiation surface, rather than inside the rock. The rock temperature decreases in a cosine pattern with irradiation distance, rather than in linearity, which is consistent with the characteristics of electromagnetic wave propagation. The interval of irradiation distance where the rock temperature local maximum value appears is 1/4 of the electromagnetic wavelength, corresponding to the crest and trough of the electromagnetic wave. The rock temperature at the wave trough distance is lower than that of the wave crest distance, but the high-temperature zone is wider. In the range of 50~200 mm waveguide apertures, the rock temperature and damage decrease with the increase in waveguide aperture when irradiated at the crest distance, while the valley distance is opposite. A convergent waveguide and short irradiation distance enhance the energy focusing performance, so the temperature rise characteristics and rock damage are more concentrated. A large-waveguideaperture horn waveguide and long irradiation distance form a wide range of high-temperature zones and rock damages. | 10.3390/s23041929 | English | China | Journal Article | Sensors | 23 | 4 | 1929 | ||
| A231 | 2014 | Using Microwave Heating to Completely Recycle Concrete | Choi, Heesup; Lim, Myungkwan; Choi, Hyeonggil; Kitagaki, Ryoma; Noguchi, Takafumi | http://www.scirp.org/journal/doi.aspx?DOI=10.4236/jep.2014.57060 | concrete | recycling; surface modification; interfacial transition zone; pozzolanic reaction; microwave; recovery | The aim of this study was to develop a technique for the complete recycling of concrete based on microwave heating of surface modification coarse aggregate (SMCA) with only inorganic materials such as cement and pozzolanic materials (silica fume, fly ash). The mechanical properties of SMCA, which was produced using original coarse aggregate (OCA) and inorganic admixtures, as well as its separation from the cement matrix and recovery performance were quantitatively assessed. The experimental results showed that micro structural reinforcement of the interfacial transition zone, which is a weak part of concrete, by coating the surface of the OCA with cement and admixtures such as pozzolanic materials can help suppress the occurrence of micro-cracks and improve the mechanical performance of the OCA. Microwave heating was observed to cause micro-cracking and hydrate decomposition. Increasing the void volume and weakening the hydrated cement paste led to the effective recovery of recycled coarse aggregate. | 10.4236/jep.2014.57060 | English | Japan | Journal Article | Journal of Environmental Protection | 5 | 7 | 583-596 | |
| A232 | 2017 | Microwave Pretreatment for Thiourea Leaching for Gold Concentrate | Choi, Nag-Choul; Kim, Bong-Ju; Cho, Kanghee; Lee, Soonjae; Park, Cheon-Young | https://www.mdpi.com/2075-4701/7/10/404 | gold concentrate | microwave; pyrite; thiourea leaching; gold | In this research, we studied the use of microwave pretreatment to enhance the efficiency of Au leaching from gold concentrate. The gold concentrate was pretreated using microwaves with different irradiation time. The sample temperature was increased up to 950 ◦C by the microwave irradiation. A scanning electron microscope-energy dispersive spectrometer showed the evolution of microcracks and the reduction of sulfur on the mineral surface. X-ray diffraction data also showed the mineral phase shift from pyrite to hematite or pyrrhotite. A leaching test was conducted for the microwave-treated and untreated gold concentrates using thiourea. Although the thiourea leaching recovered 80% of Au from the untreated concentrate, from the treated concentration, the Au could be recovered completely. Au leaching efficiency increased as the microwave irradiation time increased, as well as with a higher composition of thiourea. | 10.3390/met7100404 | English | Korea | Journal Article | Metals | 7 | 10 | 404 | |
| A233 | 2022 | Microwave assisted grinding process of Metallurigcal coke | Arango, L. C. | N/A | Grinding is the most energy-intensive stage in the mineral processing plant reaching up 70% of comminution operations energy and around 30% of total mining energy. In this project, the influence of microwave assisted grinding process of metallurgical coke is studied. Firstly, the Bond work index was evaluated as a performance variable to select the better microwave-grinding conditions at different irradiation times (0, 5, 10, 20, and 30 s). A reduction in the Bond work index of 23 % was observed at 20 s of irradiation. The metallurgical coke-microwave interaction effects were evidenced employing analytical techniques. Increase in the surface area, defects, vacancies, edges, and crystalline borders, as well as fracture face and pore collapse in the metallurgical coke grain were found. Secondly, six different particle size distribution (Gates-Gaudin-Schuhmann (GGS), Rosin-Rammler (RR), Lognormal, Normal, Gamma, and Swebrec) models were compared under different metallurgical coke grinding conditions. Adjusted R2, Akaike information criterion (AIC), and the root mean of square error (RMSE) were employed as comparison criteria. Three ball sizes (2.54, 3.00, 4.00 cm) and nine different grinding times (0, 0.5, 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 10 min) were evaluated. Swebrec and RR presented superior comparison criteria with the higher goodness of fit and the lower AIC and RMSE, containing the minimum variance values among data. The worst model fitting was GGS, according to the poorest comparison criteria and a wider results variation. Finally, the grinding kinetics behavior of metallurgical coke was assessed based on the population balance model. The specific rate of breakage (Sj) and breakage distribution function (Bij) as kinetic model parameters were defined using 20 s of microwave exposure time and grinding media of 2.54 cm. The parameter determination was carried out directly by a mono-size experimental method (-2000+1400 _m (10x14), -1180+850 _m (16x20), -800+600 _m (20x30), -425+280 _m (40x50)) and a numerical back-calculation method using the Reid solution. It was found that under the same grinding scenery, microwave implementation modifies metallurgical coke breakage parameters regarding the untreated process. The first-order law can be applied at evaluated conditions with a coefficient of determination larger than 0.95. The specific rate of breakage increases with microwave exposure time. The 10x14, 16x20, 20x30, 40x50 fractions break material 11.66%, 9.95%, 10.53%, 17.01% faster than untreated samples. The Bij after microwave irradiation presented breakage as fracture mechanism whereas untreated Bij evidence breakage, chipping, and abrasion. Therefore, this work enhances the metallurgical coke grinding kinetics and the breakage behavior to improve combustion and steelmaking processes.operations energy and around 30% of total mining energy. In this project, the influence of microwave assisted grinding process of metallurgical coke is studied. Firstly, the Bond work index was evaluated as a performance variable to select the better microwave-grinding conditions at different irradiation times (0, 5, 10, 20, and 30 s). A reduction in the Bond work index of 23 % was observed at 20 s of irradiation. The metallurgical coke-microwave interaction effects were evidenced employing analytical techniques. Increase in the surface area, defects, vacancies, edges, and crystalline borders, as well as fracture face and pore collapse in the metallurgical coke grain were found. Secondly, six different particle size distribution (Gates-Gaudin-Schuhmann (GGS), Rosin-Rammler (RR), Lognormal, Normal, Gamma, and Swebrec) models were compared under different metallurgical coke grinding conditions. Adjusted R2, Akaike information criterion (AIC), and the root mean of square error (RMSE) were employed as comparison criteria. Three ball sizes (2.54, 3.00, 4.00 cm) and nine different grinding times (0, 0.5, 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 10 min) were evaluated. Swebrec and RR presented superior comparison criteria with the higher goodness of fit and the lower AIC and RMSE, containing the minimum variance values among data. The worst model fitting was GGS, according to the poorest comparison criteria and a wider results variation. Finally, the grinding kinetics behavior of metallurgical coke was assessed based on the population balance model. The specific rate of breakage (Sj) and breakage distribution function (Bij) as kinetic model parameters were defined using 20 s of microwave exposure time and grinding media of 2.54 cm. The parameter determination was carried out directly by a mono-size experimental method (-2000+1400 m (10x14), -1180+850 m (16x20), -800+600 m (20x30), -425+280 m (40x50)) and a numerical back-calculation method using the Reid solution. It was found that under the same grinding scenery, microwave implementation modifies metallurgical coke breakage parameters regarding the untreated process. The first-order law can be applied at evaluated conditions with a coefficient of determination larger than 0.95. The specific rate of breakage increases with microwave exposure time. The 10x14, 16x20, 20x30, 40x50 fractions break material 11.66%, 9.95%, 10.53%, 17.01% faster than untreated samples. The Bij after microwave irradiation presented breakage as fracture mechanism whereas untreated Bij evidence breakage, chipping, and abrasion. Therefore, this work enhances the metallurgical coke grinding kinetics and the breakage behavior to improve combustion and steelmaking processes. | English | Colombia | Thesis | ||||||||
| A234 | 2018 | Surface characterization of microwave-treated chalcopyrite | Da Silva, G.R.; Espiritu, E.R.L.; Mohammadi-Jam, S.; Waters, K.E. | https://linkinghub.elsevier.com/retrieve/pii/S0927775718305958 | chalcopyrite | chalcopyrite; microwave treatment; zeta potential; microflotation; IGC; XPS; FTIR | The application of microwave radiation as an assisted grinding technique has shown great potential to improve comminution. Besides fracturing, the treatment also leads to phase transformations at the grain boundaries of the minerals, changing their surface properties and affecting downstream processes, such as flotation. Therefore, the study of the effects of microwave treatment on a mineral’s surface properties is important for the industrial application of microwave assisted grinding. In this work, the surface properties of untreated and microwavetreated chalcopyrite were investigated by XRD, XPS, ATR-FTIR, SEM, BET/BJH, IGC, ELS (zeta potential) and microflotation. While short exposure times were found to favor the formation of copper polysulphides (CuxFeySn) at the mineral surface, longer treatments converted CuFeS2 into iron oxides/ hydroxides/oxyhydroxides and sulfate at the surface and, enriched CuxFeySn underneath the oxidation layer. A shift in the zeta potential curves to less negative values was observed after treatment, reaching an IEP around pH 4.5. The collectorless floatability of chalcopyrite initially improved after exposure as its surface energy decreased. However, the samples’ surface became energetically more active after longer treatment times, and the flotation recovery decreased. Microwave treatment also increased the mineral’s specific surface area (SSA) and porosity; and changed the pore size distribution. | 10.1016/j.colsurfa.2018.06.078 | English | Canada | Journal Article | Colloids and Surfaces A: Physicochemical and Engineering Aspects | 555 | 407-417 | ||
| A235 | 2012 | The Effect of Microwave Energy on Grindability of a Turkish High-Ash Coal | Delibalta, M S; Toraman, O Y | http://cscanada.net/index.php/est/article/view/2565 | high-ash coal | microwave energy; low rank coal; crushability; grindability; impact strength index (ISI) | In the present study, the effect of microwave energy on grindability of high-ash (46.39%) and sulphur (3.99%) Turkish coal has been investigated. Coal samples (-9.52+3.18 mm) was treated by microwave at a frequency of 2.45 GHz with different power levels (0.48-0.64-0.80 kW) and residence times (30-150s.). In order to determine the crushing/grinding resistance of low ranked lignite coal samples treated by microwave oven, the Impact Strength Index (ISI) test was applied for each treated and untreated sample and compared with each other. Experimental results have shown that significant increases in grindability were achieved when the coal samples were exposed to microwave radiation. The ISI of samples decreased up to 96%. | 10.3968/j.est.1923847920120302.293 | English | Turkey | Journal Article | Energy Science and Technology | 3 | 2 | 46-49 | |
| A236 | 2017 | Effect of microwave energy on the comminution and flotation of colemanite ore | Demir, İsmail; Güngören, Can; Özkan, Şafak Gökhan | https://dergipark.org.tr/en/pub/boron/issue/31236/294967 | colemanite ore | microwave; comminution; flotation; colemanite; boron minerals | Microwaves create internal friction in the material body and hence thermal stress and internal pressure. This situation can generate fractures according to the material features. Therefore, microwaves can be used in various mineral processing processes owing to this effect. In this study, the effect of microwave energy on the comminution, and flotation of a colemanite ore, which is an important boron mineral, was investigated. As a result, a positive effect of microwave energy on the comminution of coarser particles was determined while no significant effect was observed on the comminution of finer particles. The colemanite ore as supplied has 32.21% B2O3 grade. The samples were sieved to +0.250, -0.250+0.038 mm, and -0.038 mm particle size fractions separately before the flotation experiments. The grades of these samples were 44%, 40%, and 21% B2O3, respectively. The samples coarser than 0.25 mm particle size were not subjected to flotation because of their high grades. In the flotation experiments of the particles at -0,250+0,38 mm particle size, a concentrate with 44.76% B2O3 grade was recovered with 55.05% recovery by conventional flotation. On the other hand, a concentrate with 42.99% B2O3 grade was recovered with 59.69% recovery in the flotation of microwave treated samples. In addition, in the flotation of the particles at -0,038 mm particle size, a concentrate with 37.91% B2O3 grade was recovered with 24.79% recovery by conventional flotation. On the other hand, a concentrate with 37.21% B2O3 grade was recovered with 31.17% recovery in the flotation of microwave treated samples. | Turkish | Turkey | Journal Article | Boron | 2 | 2 | 75-81 | ||
| A237 | 2023 | Investigating Microwave Treatment of Rocks Based on Fracture Mechanics Analysis in Mode I Fracture Toughness Test | Deyab, Samir M.; Ahmadihosseini, Adel; Rafezi, Hamed; Hassani, Ferri; Sasmito, Agus P. | https://link.springer.com/10.1007/s00603-023-03327-x | basaltic rocks | numerical simulations; Mode I fracture toughness; microwave treatment; failure mechanisms; energy efficiency | During the past decade, numerous research has been conducted to evaluate the effectiveness of microwave treatment in improving rock fragmentation. While these studies focused on investigating the effect of microwave treatment on rock parameters, the current research approaches the problem from another perspective by studying the applicability of mode I fracture toughness parameters to evaluate the effectiveness of the microwave treatment as a rock pre-conditioning method based on energy analysis. Different rock sizes are investigated, and it is shown that for the basalt rock used in this study, the minimum required diameter for the fracture toughness experiments is 70 mm. In a novel approach, a finite element based numerical model is employed to maximize the energy absorption of the sample in the cavity. It is shown that optimizing the location of the rock sample in the cavity can increase the heat over microwave efficiency (HOME) and weakening over microwave energy (WOME) by more than 40% and 30%, respectively. Furthermore, it is concluded that although increasing the exposure time results in more KIC value reduction, it decreases the WOME value by more than 50% in some cases. Finally, the applicability of fracture toughness experiments in evaluating the effectiveness of microwave treatment is discussed in detail. | 10.1007/s00603-023-03327-x | English | Canada | Journal Article | Rock Mechanics and Rock Engineering | 56 | 7 | 5275-5291 | |
| A238 | 2020 | CANMICRO: SCALING UP MICROWAVE TECHNOLOGY FOR THE MINING INDUSTRY | Bobicki, E.R.; Boucher, D.; Forster, J.; Gillis, A.; Holcroft, G.;Fragomeni, D.; Whiteman, E. C. Pickles, A. Olmsted | https://www.researchgate.net/publication/365444138_CANMICRO_SCALING_UP_MICROWAVE_TECHNOLOGY_FOR_THE_MINING_INDUSTRY | gold sulphide, copper-nickel sulphide | microwaves; permittivity; comminution; ore sorting; scale-up; flotation; leaching; gravity separation | After 30 years of investigation, scale-up remains a key impediment to commercial adoption of microwave technology in mining. The CanMicro combination of scalable microwave-assisted comminution and sorting has the potential to achieve maximum benefits with minimum energy input. The treatment selectively heats value minerals, resulting in micro-fracturing along grain boundaries, thereby reducing ore competency and increasing mineral liberation after grinding. It also generates a thermal signature that will be used to sort ore particles so that only those that contain value minerals are subjected to fine grinding. It is anticipated that comminution energy can be reduced by up to two-thirds using CanMicro technology, which will employ a high-powered (150 kW) multi-mode microwave system that can scale-up to throughputs >1000 tph. The impact of the CanMicro prototype on varying ore types will be evaluated on downstream processes and a technoeconomic assessment of commercial-scale feasibility will be performed. The CanMicro project team is a multi-disciplinary consortium of industry professionals, academics, and researchers brought together by the Canada Mining Innovation Council (CMIC). This paper provides come background on microwave technology, outlines the project plan, discusses the potential energy savings and downstream benefits resulting from CanMicro treatment, and provides an update on progress to date. | English | Canada | Conference Proceeding | 52nd Annual Canadian Mineral Processors Operators Conference | 131-144 | ||||
| A239 | 2024 | Coupled Electromagnetic-Thermal-Mechanical modeling on the damage mechanism of coaxial microwave heating granite | Duan, Zhibo; Yang, Jun; Zhao, Zhihong; Zeng, Shu; Yan, Zhenguo; Ma, Shaokun | https://linkinghub.elsevier.com/retrieve/pii/S0266352X24004051 | granite | coaxial microwaves; granite breakage; electromagnetic-thermal-mechanical coupling; damage mechanism; super-long gravity heat pipe | Microwave radiation is pioneered for weakening and cracking rock in the fields of tunneling and mining engineering. However, there has been limited research on the application of microwave heating for geothermal energy extraction, and the precise damage mechanism remains poorly understood. To address this gap, a fully coupled electromagnetic-thermal–mechanical model, incorporating damage variables, was established and then verified by lab tests. Simulation results of coaxial microwave heating granite show that the damage mechanism is different from that of conventional rectangular waveguide heating. Coaxial microwave heating leads to the formation of two distinct hot spots in the granite. The differential tensile stress between the interior and exterior of the borehole contributes to the damage in the upper hot spot, while the interior compressive and exterior tensile stress state induces damage in the lower hot spot. Consequently, the deformation pattern of granite assumes a vase shape, with the damaged area exhibiting a canopy shape. When the initial crack trend is 135◦, the crack connectivity efficiency is maximized to 61 % at 1.5 kW microwave power and 2.45 GHz frequency. These findings offer valuable theoretical insights for the potential application of microwave-assisted super-long gravity heat pipes in geothermal extraction. | 10.1016/j.compgeo.2024.106469 | English | China | Journal Article | Computers and Geotechnics | 172 | 106469 | ||
| A240 | 2024 | Effectiveness analysis of ultra high frequency treatment of pyrite-bearing ore | Vinnikov V. A., Zemlianskii G. S. | https://giab-online.ru/en/catalog/issledovanie-effektivnosti-vozdeystviya-svch-poley-na-piritosode | pyrite-bearing ore | processing; pyrite-bearing ore; UHF treatment effectiveness; stabilization temperature; structural changes; ore softening; rock relaxation; energy efficiency | This article describes the study into effectiveness of ultra high frequency (UHF) exposure of metal-bearing ore for its softening. The review of the domestic and foreign research on this topic is implemented: the reasons of high interest in development and application of energy-efficient technologies are explained; the basic notions, potential and relevancy of UHF energy application in mineral processing are revealed; the retrospective data on the amount of annual research in the field of UHF effects on rocks are presented; the main achievements and science gaps are described. The patterns of change in the UHF treatment effectiveness as function of percentage and size of pyrite grains are experimentally found as a case-study of quartz–pyrite ore samples. In particular, it is determined that the content of pyrite has a higher influence on the UHF treatment efficiency than the coarseness of pyrite grains, and the rate of temperature growth is higher and the “temperature stabilization” period arrives earlier in the samples with the higher pyrite content. Furthermore, beyond the zone of “temperature stabilization” in the samples with the higher content of pyrite, the temperature grows more intensively, which may imply a sharp rise in the density of the crystal lattice in such samples in their further heating. | 10.25018/0236_1493_2024_4_0_22 | Russian | Russia | Journal Article | MIAB. Mining Inf. Anal. Bull. | 4 | 22-32 | ||
| B001 | 2018 | Microwave Treatment of Ultramafic Nickel Ores: Heating Behavior, Mineralogy, and Comminution Effects | Bobicki, Erin R.; Liu, Qingxia; Xu, Zhenghe | https://www.mdpi.com/2075-163X/8/11/524 | ultramafic nickel ore | mineral processing; microwave; permittivity; ultramafic ores; comminution; mineralogy | Ultramafic nickel ores are difficult to process because they contain serpentine, an anisotropic mineral with a nonspherical morphology and multiple pH-dependent surface charges. Dehydroxylation of serpentine in ultramafic nickel ores by microwave treatment is proposed to improve the processability of these ores. Upon heating, serpentine is converted to olivine, an isotropic mineral that is benign in mineral processing circuits. The microwave heating of two ultramafic nickel ores is explored in this paper, as well as effects on mineralogy and grindability. The first ore was sourced from the Okanogan nickel deposit in Washington State, USA, while the second ore was obtained from the Vale-owned Pipe deposit located in the Thomson Nickel Belt in Manitoba, Canada. The ultramafic nickel ores were found to heat well upon exposure to microwave radiation and the heating behaviors were a function of the imaginary permittivities. The temperatures achieved during microwave treatment were sufficient to dehydroxylate serpentine, and the serpentine content in ultramafic nickel ores was reduced by 63–84%. The grindability of ore with consistent texture (OK ore) improved dramatically with microwave treatment, whereas the grindability of ore with inconsistent texture (Pipe ore) was found to decrease. Pentlandite liberation and specific surface area improved for both ores with microwave treatment. Ultimately, microwave pretreatment did not decrease the energy required for grinding under the conditions studied. However, energy savings may be realized when overall process improvements are considered (e.g., grinding, rheology, flotation, material handling, dewatering and tailings treatment). | 10.3390/min8110524 | English | Canada | Journal Article | Minerals | 8 | 11 | 524 | |
| B002 | 2022 | Study on the Difference of Microwave Irradiation Effect Caused by the Particle Size Distribution of Rock Minerals | Botian, Xue | http://www.sciencepublishinggroup.com/journal/paperinfo?journalid=229&doi=10.11648/j.ajce.20221001.13 | In the process of microwave-assisted rock breaking, there are many factors that affect the rock breaking effect, among which the particle size distribution of minerals has an important influence. In this paper, the samples composed of common minerals calcite and pyrite in rocks were used as the research object, and six kinds of mineral particle size ratio schemes were set up. By using COMSOL multi-physical field coupling analysis platform, a binary medium analysis model was established to study the distribution characteristics and evolution law of electromagnetic field, temperature field, stress field and plastic zone of the model after microwave irradiation. The results showed that the mineral particle size ratio had no significant effect on the size and distribution of electromagnetic field, while the central temperature of the sample increased with the increase of particle size ratio; with the extention of irradiation time, the larger the particle size ratio, the greater the first principal stress of the model, and the tensile zone appeared in pyrite; The larger the particle size ratio, the earlier the initiation time of plastic zone, the larger the area of plastic zone, and the more obvious the difference of morphological characteristics of plastic zone. When the size of minerals in the rock was uniform, the weakening effect of microwave irradiation on the rock was better. | 10.11648/j.ajce.20221001.13 | English | Journal Article | American Journal of Civil Engineering | 10 | 1 | 23 | ||||
| B004 | 2007 | Crack Generation in Blast Furnace Slag Bearing High Titanium by Microwave Cyclic Heating | Chen, Yan; Ishizuka, Etsuko; Yoshikawa, Noboru; Taniguchi, Shoji | https://www.jstage.jst.go.jp/article/isijinternational/47/2/47_2_193/_article | microwave; cyclic heating; blast furnace slag; high titanium content; microstructure; crack; compressive strength; selective heating | In order to facilitate grinding a blast furnace (BF) slag bearing high TiO2 (Ti-BF slag) for extracting CaTiO3 (TiO2 containing phase) from it, microwave (MW) cyclic heating was attempted to induce cracks. In this study, MW heating behavior of Ti-BF slag, general BF slag and sintered perovskite (CaTiO3) body were examined. Under the same heating conditions, Ti-BF slag was heated better than the general BF slag. And the sintered perovskite powder compact was heated best among them. Considering the measured large permittivity of Ti-BF slag, the perovskite phases in the Ti-BF slag are responsible for heating of the whole slag.Cracks were induced in the Ti-BF slag by cyclic irradiation of MW. They extended and opened as an increase of the cycle number. In order to examine the effect of the induced cracks on the strength of Ti-BF slags, compression test of the specimens was performed after the treatment. It was demonstrated that MW treatment caused reduction in the compressive strength, such that the strength decreased about 35% after 10 cycles of heating for 5 min.It was also shown that while the treatment with longer heating time caused a smaller decrease in the compressive strength, increasing of cyclic number decreased the strength more effectively. | 10.2355/isijinternational.47.193 | ISIJ International | 47 | 2 | 193 | |||||
| B005 | 2018 | The effects of microwave irradiation on the floatability of chalcopyrite, pentlandite and pyrrhotite | Da Silva, G.R.; Waters, K.E. | https://linkinghub.elsevier.com/retrieve/pii/S0921883118303339 | 10.1016/j.apt.2018.07.025 | English | Journal Article | Advanced Powder Technology | 29 | 12 | 3049-3061 | |||||
| B006 | 2017 | Analysis of the Microwave Heating Effect in the Comminution Efficiency of Iron Ore Particles | Da Silval, Leonardo Martins; Nascimento, M.; Mota, I.O.; Oliveira, E.M.; Castro, J.A. | https://www.scientific.net/MSF.899.383 | Heating iron ore fine particles using microwave energy has been effective due to the different interactions between minerals and gangue in the magnetic field generated by the microwave. In this way, this paper proposes to use microwave energy to heat the particles of iron ore to promote micro cracks and fissures, which would facilitate the comminution and pulverization process to produce pellet feed. It was analyzed different conditions of heating and cooling in the comminution step. By using techniques of scanning electron microscopy (SEM) and image analysis it was possible to assess and quantify the micro cracks and subsequent analysis of the energy and size fragmentation in the comminution step of ultrafine particles. | 10.4028/www.scientific.net/MSF.899.383 | English | Journal Article | Materials Science Forum | 899 | 383-388 | |||||
| B007 | 2020 | Apparatus and a Method for Treatment of Mined Material with Electromagnetic Radiation | Dimitrakis et al. | https://patents.google.com/patent/US10597750B2/en | ||||||||||||
| B011 | 2000 | Effect of Microwave Radiation on Ilmenite Flotation | Fan, X.; Kelly, R.M.; Rowson, N.A. | http://www.tandfonline.com/doi/full/10.1179/cmq.2000.39.3.247 | The studies indicate that microwave radiation pretreatment is an effective method to modify ilmenite surface properties and improve ilmenite flotability. After exposure to microwave radiation for a short time, ilmenite recovery was increased by about 20%. | 10.1179/cmq.2000.39.3.247 | English | Journal Article | Canadian Metallurgical Quarterly | 39 | 3 | 247-254 | ||||
| B012 | 2000 | Fundamental Investigation of Microwave Pretreatment on the Flotation of Massive Ilmenite Ores | Fan, X.; Rowson, N. A. | https://onlinelibrary.wiley.com/doi/10.1002/apj.5500080111 | Abstract Microwave energy was used as a novel method to modify massive ilmenite surface properties and improve ilmenite flotation. Studies concentrated on an investigation into the effect of microwave radiation pre‐treatment on the flotation behaviour of a massive ilmenite ore sample from Norway. Experimental programmes were carried out in both Hallimond‐tube and Denver‐cell flotation devices. The experimental results indicate that the flotability of massive ilmenite was greatly improved after microwave‐induced thermal pretreatment. In comparison with conventional flotation, at the same optimised flotation conditions, massive ilmenite subjected to microwave heat treatments floated well in both the roughing and cleaning stages. Ilmenite recoveries were greatly increased over non‐treated samples. The major factors affecting ilmenite microwave‐pretreatment flotation are microwave power level and irradiation time. The investigation into the surface zeta potential indicates that microwave irradiation enhanced the adsorption of oleate ions in the Helmholtz layer of the ilmenite particles and resulted in ilmenite surface charge being more negative. Improved ilmenite flotation recovery was observed after microwave pretreatment. | 10.1002/apj.5500080111 | English | Journal Article | Developments in Chemical Engineering and Mineral Processing | 8 | 45293 | 167-182 | ||||
| B013 | 2002 | Surface Modification and Column Flotation of a Massive Ilmenite Ore | Fan, X.; Rowson, N.A. | http://www.tandfonline.com/doi/full/10.1179/cmq.2002.41.2.133 | 10.1179/cmq.2002.41.2.133 | English | Journal Article | Canadian Metallurgical Quarterly | 41 | 2 | 133-142 | |||||
| B015 | 2014 | The Development of the Microwave Assisted Rock Breaking Device | Feng, Guang Tong; Wang, Zong Gang; Wei, Zhen | https://www.scientific.net/AMR.900.627 | Microwave crag broken is a thermal assisted rock breaking method which could melt rocks. Microwave assisted rock breaking method will not bring new impact, wear and tear, instead, the microwave pretreatment on the rock reduces the difficulty of breaking rock and prolongs the service life of the drill bit. This microwave generator accumulates the microwave near the hot spot to soften and melt the rock through generating and transmitting the microwave. And we had experimented with the microwave generator to penetrate the wood, and weaken the strength of the rock. And the experiment proved the scheme of the microwave assisted rock breaking through microwave near field energy and the thermal runaway effect is feasible. | 10.4028/www.scientific.net/AMR.900.627 | English | Journal Article | Advanced Materials Research | 900 | 627-630 | |||||
| B016 | 2022 | The Influence of the Rotary Speed of a Microwave Applicator on Hard-Rock Fracturing Effect | Feng, Xia-ting; Li, Shi-ping; Yang, Cheng-xiang; Lin, Feng; Tong, Tian-yang; Su, Xiang-xin; Zhang, Jiu-yu | https://link.springer.com/10.1007/s00603-022-02956-y | Microwave-induced hard rock fracturing technology has potential application prospects in tunnel boring machine (TBM) hard tunnel excavation. It is of great significance to research the hard rock cracking induced by rotary microwave applicator irradiation to promote the application of microwave–TBM coupling. Based on a rotary open microwave irradiation hard rock fracturing true triaxial test system independently developed by Northeastern University, Chifeng basalt is taken as the research object. The crack propagation characteristics of hard rock irradiated by a microwave applicator at different rotation speeds under the conditions of no stress and true triaxial stress are studied, and the fracturing mechanism of hard rock irradiated by rotary microwave applicator is revealed. The results show that the temperature in the same area of hard rock rises in a “step shape” under rotary microwave applicator irradiation. The faster the microwave applicator rotation speed is, the shorter the intermittent irradiation time of the same area of hard rock, the quicker the temperature rise is, and the earlier the hard rock cracking time is first detected. The degree of crack propagation and the decrease in compressional wave velocity are positively correlated with the microwave applicator rotation speed. In the process of rotary microwave applicator irradiation, the cracks in the irradiated hard rock surface develop and expand from the high principal strain region at the boundary to the central region of the irradiated surface. Under the condition of no stress, tensile failure in hard rock is induced by rotary microwave applicator irradiation. Under the condition of true triaxial stress, tensile failure induced by rotary microwave applicator irradiation mainly occurs in hard rock, although shear failure occurs at the same time. This makes the crack development in the irradiated hard rock surface denser and the crack network more complex. This research provides a new perspective for microwave–TBM coupled tunneling in hard rock tunnel engineering. | 10.1007/s00603-022-02956-y | English | Journal Article | Rock Mechanics and Rock Engineering | 55 | 11 | 6963-6979 | ||||
| B017 | 2021 | A novel true triaxial test system for microwave-induced fracturing of hard rocks | Feng, Xia-Ting; Zhang, Jiuyu; Yang, Chengxiang; Tian, Jun; Lin, Feng; Li, Shiping; Su, Xiangxin | https://linkinghub.elsevier.com/retrieve/pii/S1674775521000494 | This study introduces a test system for microwave-induced fracturing of hard rocks under true triaxial stress. The test system comprises a true triaxial stress loading system, an open-ended microwaveinduced fracturing system, a data acquisition system, an acoustic emission (AE) monitoring system, and an auxiliary specimen loading system. Microwave-induced surface and borehole fracturing tests under true triaxial stress were fulfilled for the first time, which overcomes the problem of microwave leakage in the coupling loading of true triaxial stress and microwave. By developing the dynamic monitoring system, the thermal response and fracture evolution were obtained during microwave irradiation. The monitoring system includes the infrared thermometry technique for monitoring rock surface temperature, the distributed optic fiber sensing technique for monitoring temperature in borehole in rock, the AE technique and two-dimensional digital speckle correlation technique for monitoring the evolution of thermal damage and the rock fracturing process. To validate the advantages of the test system and investigate the characteristics of microwave-induced fracturing of hard rocks, the study demonstrates the experimental methods and results for microwave-induced surface and borehole fracturing under true triaxial stress. The results show that thermal cracking presented intermittent characteristics (calm eactiveecalm) during microwave-induced surface and borehole fracturing of basalt. In addition, true triaxial stress can inhibit the development and distribution of thermal cracks during microwave-induced surface fracturing. When microwave-induced borehole fracturing occurs, it promotes the distribution of thermal cracks in rock, but inhibits the width of cracks. The results also prove the reliability of the test system. | 10.1016/j.jrmge.2021.03.008 | English | Journal Article | Journal of Rock Mechanics and Geotechnical Engineering | 13 | 5 | 961-971 | ||||
| B019 | 2021 | The quantification of entropy for multicomponent systems: Application to microwave-assisted comminution | Fernandes, I.B.; Rudolph, M.; Hassanzadeh, A.; Bachmann, K.; Meskers, C.; Peuker, U.; Reuter, M.A. | https://linkinghub.elsevier.com/retrieve/pii/S0892687521002454 | The second law of thermodynamics, through exergy analysis, is commonly applied to quantify process inefficiencies in metallurgical reactors, however, it has not yet been used to understand physical processes and changes in particle-based systems. Correlating the state of mixing of particle texture and homogeneous liquid mixtures is of importance. This paper applies the exergy analysis and excess entropy method to two sets of experiments highlighting the differential breakage as microwave pre-treatment is applied to a gold-copper ore. Grinding kinetic properties were measured following the top-size fraction method and calculated using the population balance model. The approach combines the mixing entropy on the system level (streams) and the entropy for multicomponent particle systems, using automated mineralogy data to quantify the effects of intergrowth and improvements in grinding performance. This is a first step towards understanding mineral processing not only in terms of energy conservation (first law of thermodynamics) but also in terms of the quality of energy available at multicomponent systems (second law of thermodynamics). When applied to comminution processes, this methodology enables us to understand the change in particle composition (its degree of liberation) as well as changes in particle size, being an important measure of process efficiency and selectivity. | 10.1016/j.mineng.2021.107016 | English | Journal Article | Minerals Engineering | 170 | 107016 | |||||
| B020 | 2016 | Understanding selectivity in radio frequency and microwave sorting of porphyry copper ores | Ferrari-John, R.S.; Batchelor, A.R.; Katrib, J.; Dodds, C.; Kingman, S.W. | https://linkinghub.elsevier.com/retrieve/pii/S030175161630165X | 10.1016/j.minpro.2016.08.011 | English | Journal Article | International Journal of Mineral Processing | 155 | 64-73 | ||||||
| B021 | 1973 | Microwave heating in concrete analysis | Figg, J. | https://onlinelibrary.wiley.com/doi/10.1002/jctb.2720240306 | Abstract Microwave heating has been shown to be a valuable method for weakening concrete prior to the separation of aggregate in the analysis of hardened concrete. Quantitative determinations were made of the strength reductions of concrete samples after microwave radiation using a 5 kW laboratory microwave generator and a 1.5 kW (later 2.5 kW) microwave oven. Aggregate separation was much easier after heating for 5 and 20 to 30 min respectively. The modulus of elasticity correlated best with subjective assessments of the ease of aggregate removal. Thirty minutes irradiation in the microwave oven reduced the modulus of elasticity to one fifth of its original value, compressive strength was reduced to 80% of the unheated value and the tensile strength to 55 to 65%. Tests with ‘miniature’ concrete showed that the reduction in impact strength was similar to the compressive strength. Conducting aggregate does not preclude the use of microwave heating although large metallic inclusions (reinforcement) should be avoided. Irradiated concretes containing an appreciable proportion of clay may yield increased amounts of soluble silica during subsequent chemical analysis. Comparison with conventional heating shows that microwave heating can produce the same strength reductions in about half the time, but the cohesiveness of the material is affected more markedly by microwave irradiation. Appendices give notes on the use of microwave heating in the analysis of concrete and some observations on the behaviour of different types of concrete heated during routine investigations. | 10.1002/jctb.2720240306 | English | Journal Article | Journal of Applied Chemistry and Biotechnology | 24 | 3 | 143-155 | ||||
| B022 | 1998 | Electromagnetic properties of dry and water saturated basalt rock, 1-110 GHz | Frasch, L.L.; McLean, S.J.; Olsen, R.G. | http://ieeexplore.ieee.org/document/673669/ | This paper reports on the measured electromagnetic properties of dry and water saturated basalt rock over a frequency range of 1–110 GHz. Tests were conducted in standard waveguides below 12 GHz and with free-space systems above 12 GHz. The basalt used in this investigation was found to be nonmagnetic. Measured relative permittivities for the dry basalt varied from approximately (8.19,-0.71) at 1.12 GHz to (6.80,0.49) at 110 GHz. The porosity of the basalt was determined to be roughly 10%. Properties of water saturated basalt were also measured at several frequencies and compared to theoretical predictions based on a simple Maxwell-Garnett mixing theory. Finally, the potential of using microwave tomography on basalt rock was examined based on the resulting properties. | 10.1109/36.673669 | English | Journal Article | IEEE Transactions on Geoscience and Remote Sensing | 36 | 3 | 754-766 | ||||
| B023 | 2022 | The mechanism of microwave rock breaking and its potential application to rock-breaking technology in drilling | Gao, Ming-Zhong; Yang, Ben-Gao; Xie, Jing; Ye, Si-Qi; Liu, Jun-Jun; Liu, Yi-Ting; Tang, Rui-Feng; Hao, Hai-Chun; Wang, Xuan; Wen, Xiang-Yue; Zhou, Xue-Min | https://linkinghub.elsevier.com/retrieve/pii/S1995822622000024 | The exploration and development of oil and gas resources have shifted from shallow to deep and ultradeep. The difficulty of rock breaking has also increased, introducing new challenges to traditional rock-breaking technology. Hence, there is an urgent need to develop new rock-breaking technologies to improve the development efficiency of deep oil and gas resources. Therefore, this study focused on the new microwave rock-breaking technology and conducted experimental and numerical simulation research on typical deep, hard rock granite. The research results showed that granite in the microwave field exhibited high-temperature melting and fracture, and the highest temperature could reach 550 ºC. Under the irradiation of circulating microwaves, a minimum irradiation time threshold of 3 min was needed to cause irreversible damage to the rock. The numerical simulation results showed that the interaction of thermal stress and in situ stress would cause the inside of the rock stratum to separate into a disturbed deterioration area, disturbed unloading area and initial stress area. These results are expected to provide the necessary technical guidance and theoretical support for the research and development of high-efficiency rockbreaking drilling for deep hard rock. | 10.1016/j.petsci.2021.12.031 | English | Journal Article | Petroleum Science | 19 | 3 | 1110-1124 | ||||
| B024 | 2024 | Thermal fracturing of anthracite under low-energy microwave irradiation: An experimental study | Gao, Yirui; Zhao, Yixin; Gao, Sen; Sun, Zhuang; Wang, Xiaoliang; Wang, Hao | https://linkinghub.elsevier.com/retrieve/pii/S1365160924001503 | Microwave-assisted coalbed methane (CBM) development is a very promising technology for engineering applications. The mechanism of the macro and micro thermal fracture of coal must be further discussed because of the thermal inhomogeneity of microwave caused by the heterogeneity and structural complexity of coal. In this study, the temperature, weight and P-wave velocity of anthracite were tested under low-energy microwave irradiation. The characteristics of fracture initiation, extension, and connectivity in coal after microwave irradiation were extracted from macroscopic and microscopic observations. Then the mechanisms of microwave thermal fracturing in anthracite were analyzed. The results showed that the temperature of anthracite under lowenergy microwave irradiation varies asynchronously. The temperature distributions with high and low temperature partitions exhibit obvious bedding effects. The coal mass loss varies in stages with microwave irradiation time, first increasing slowly and then increasing dramatically above 500 ◦C. The P-wave velocity presents a decreasing trend with the increase of input microwave energy. Coal generates a complex fracture network at the micro and macro scales, with fractures expanding outwards in a divergent pattern. The nonuniformity of the temperature distribution promotes fracture development. It is related to the asynchronous heating caused by the mineral composition, water content, pore fracture structure, and electromagnetic field in coal. It is of great significance to improve the thermal fracturing efficiency by using the nonuniformity of microwave heat in the application of microwave-assisted CBM development. | 10.1016/j.ijrmms.2024.105785 | English | Journal Article | International Journal of Rock Mechanics and Mining Sciences | 179 | 105785 | |||||
| B025 | 2021 | Acoustic emission characteristics of gabbro after microwave heating | Ge, Zhenlong; Sun, Qiang | https://linkinghub.elsevier.com/retrieve/pii/S1365160921000058 | In recent years, microwave mechanical rock breaking—an energy-saving technology with environmental benefits and high efficiency—is increasingly being used to improve the rock-breaking efficiency of geothermal well drilling. Herein, we studied the evolution of different types of cracks in gabbro under uniaxial loading using the acoustic emission (AE) technique. The results show that, after microwave heating, the number of microcracks in gabbro increases and AE becomes more and more active. During the loading process, AE characteristics can be divided into three typical periods: the peak period, silent period, and active period, which are closely related to the deformation process of the rock. When the heating power exceeds 3.3 kW, the proportion of shear cracks increases with increases in irradiation energy. With an increase in stress level, the proportion of tensile cracks increases, but near failure, shear fracture is still dominant. Under the same irradiation energy, the combination of high heating power and low heating time is more conducive to rock failure. Further, when the heating power is greater than 3.3 kW, the damage to rock is more obvious. The test results provide a theoretical and experimental basis for determining the optimal microwave irradiation conditions to improve rock-breaking efficiency in geothermal development. | 10.1016/j.ijrmms.2021.104616 | English | Journal Article | International Journal of Rock Mechanics and Mining Sciences | 138 | 104616 | |||||
| B026 | 2024 | The effect of microwave’s location in a comminution circuit on improving grindability of a porphyry copper deposit | Gholami, Hamed; Rezai, Bahram; Hassanzadeh, Ahmad; Mehdilo, Akbar; Jabbari, Majid Behjat | https://www.tandfonline.com/doi/full/10.1080/15567036.2020.1753859 | The present work initially studies the impact of a laboratory microwave (MW)’s location (before and after a jaw crusher) on grindability of a copper ore. Additionally, the role of MW’s radiation time (15–150 sec) and grinding time (13, 15 and 17 min) on the produced particle size distribution (PSD), mineral liberation degree (LD) and energy consumption are investigated. relative work index (RWI), standard Bond work index (Wi), and grindability index (GI) together with the breakage and selection functions were utilized to assess the grinding efficiency and its kinetics of the untreated and MWpretreated (at a constant power of 0.9 kW) samples. Bond work indices were obtained 13.70, 13.04 and 10.86 kWh/t for the untreated, MW-treated uncrushed and MW-treated crushed samples, respectively. Besides, the results confirmed that the microwave pretreatment was comparatively effective at the shortest grinding time (13 min). Furthermore, locating the microwave after the crushing stage indicated substantial improvements in the sample’s grindability and its kinetics rate. The product size (P80) of the MW-treated crushed sample (13 min, 0.9 kW, 150 sec) showed enhancements of 27% and 17% in comparison with the un-microwaved and MWtreated uncrushed samples. Finally, the comparative GIs acquired in the entire spectrum of the particle range were reasonably higher if the microwave was located after the jaw crusher, particularly for the coarse fraction sizes. | 10.1080/15567036.2020.1753859 | English | Journal Article | Energy Sources, Part A: Recovery, Utilization, and Environmental Effects | 46 | 1 | 7323-7342 | ||||
| B027 | 2021 | Effect of microwave pretreatment on grinding and flotation kinetics of copper complex ore | Gholami, Hamed; Rezai, Bahram; Hassanzadeh, Ahmad; Mehdilo, Akbar; Yarahmadi, Mohammadreza | https://link.springer.com/10.1007/s12613-020-2106-0 | The present study initially investigates the kinetics of microwave-assisted grinding and flotation in a porphyry copper deposit. Kinetic tests were conducted on untreated and microwave-irradiated samples by varying the exposure time from 15 to 150 s. Optical microscopy, energy-dispersive X-ray spectroscopy, and scanning electron microscopy were conducted to determine the mineral liberation and particle surface properties, and to perform mineralogical analyses. Results showed that the ore breakage rate constant monotonically increased by increasing the exposure time, particularly for the coarsest fraction size (400 µm) due to the creation of thermal stress fractures alongside grain boundaries. Excessive irradiation time (>60 s) led to the creation of oxidized and porous surfaces along with a dramatic change in particle morphologies that result in a substantial reduction of chalcopyrite and pyrite flotation rate constants and ultimate recoveries. We concluded that MW-pretreated copper ore was ground faster than the untreated variety, but the two types have slightly similar floatabilities. | 10.1007/s12613-020-2106-0 | English | Journal Article | International Journal of Minerals, Metallurgy and Materials | 28 | 12 | 1887-1897 | ||||
| B028 | 2020 | Effect of microwave system location on floatability of chalcopyrite and pyrite in a copper ore processing circuit | Gholami, Hamed; Rezai, Bahram; Mehdilo, Akbar; Hassanzadeh, Ahmad; Yarahmadi, Mohammadreza | http://www.journalssystem.com/ppmp/Effect-of-microwave-system-location-on-floatability-of-chalcopyrite-and-pyrite-in,118799,0,2.html | The present work aims at investigating the effect of microwave local positions (i.e. before crushing (BC), after crushing (AC) and after milling (AM)) on microwave-assisted flotation of chalcopyrite and pyrite in a porphyry copper complex deposit. Individual given samples for each state were pre-treated with a variable power microwave at a power level of 90 to 900W for 15, 30, and 60s. Furthermore, froth floatation experiments were carried out using a laboratory mechanical Denver flotation cell on both microwave-treated and untreated samples. Particle surface properties were characterized by a scanning electron microscopy (SEM) and an energy-dispersive X-ray spectroscopy (EDX) analysis. The results showed that the chalcopyrite and pyrite floatabilities increased monotonically by rising the exposure time and power level for the uncrushed preconditioned samples (BC) due to the enhancement of mineral liberation degrees together with the formation of sulphide species and polysulphides on the mineral surfaces. However, flotation results of treated samples for the crushed one (AC) revealed an optimum range. Formation of intensive oxide layers on the mineral surfaces of milled samples (AM) led to a substantial reduction in their recoveries by increasing the microwave’s power level and the sample’s exposure time. The results obtained from mineral’s floatabilities in recleaner stage showed that the microwave-assisted sample at 900W for 30s at BC state favourably provided 5% higher S.E.’s than that of the untreated sample. Finally, it was concluded that the microwave pretreatment of samples induced the best floatability responses if it located before the crusher. | 10.37190/ppmp/118799 | English | Journal Article | Physicochemical Problems of Mineral Processing | 56 | 3 | 432-448 | ||||
| B029 | 2024 | Effect of Water on Granite Deterioration Under Microwave Radiation Based on Real-Time AE Monitoring | Gu, Chao; Geng, Jishi; Sun, Qiang; Zhang, Yuliang; Hu, Jianjun | https://link.springer.com/10.1007/s00603-024-04144-6 | Microwave-assisted rock-breaking is highly promising in the process of hard rock tunnel excavation due to its safety and high efficiency. Water plays a pivotal role in the microwave heating process, significantly impacting the effectiveness of microwave-assisted rock fragmentation. Nevertheless, there is a lack of comprehensive research on the influence of water in the process of microwave heating of rocks. This study investigated the influence of water on the response characteristics of granite under microwave irradiation by analyzing the changes in the real-time acoustic emission (AE) signals, porosity, wave velocity, and uniaxial compressive strength of samples with different levels of water saturation. The experimental results revealed the real-time AE characteristics of rock samples were categorized into three periods: a quiet period, a violent period, and an attenuation period. The maximum temperature in the quiet period was about 150 ℃, resulting in the proliferation of mineral crystal defects under the action of water, and the intensity of AE counts was positively correlated with water saturation. Simultaneously, the degree of thermal damage to porosity, wave velocity, and uniaxial compressive strength also increased with increasing water saturation. During the violent and attenuation periods, the activity of AE signals increased, yet remained largely unaffected by the the water saturation level. Moreover, the presence of water facilitated the transition of rock samples from elastic to ductile behavior under microwave irradiation. This investigation holds significant importance for the practical application and advancement of water utilization in microwave-assisted rock fragmentation technology. | 10.1007/s00603-024-04144-6 | English | Journal Article | Rock Mechanics and Rock Engineering | |||||||
| B030 | 2024 | Acoustic emission real-time monitoring and analysis of microwave thermal damage of granite | Gu, Chao; Sun, Qiang; Geng, Jishi; Zhang, Yuliang; Jia, Hailiang | https://link.springer.com/10.1007/s12665-024-11745-5 | Microwave rock fracturing has a wide range of application prospect in deep resource development due to its advantages of high efficiency and energy saving, and the study of damage in the fracturing process is of great importance in guiding the safety and high efficiency of rock fracturing. However, damage characterisation during microwave rock fracturing has not been sufficiently investigated. Therefore, studying the characteristics of crack propagation and evolution during microwave heating is of great significance. This paper investigates the crack evolution characteristics and failure mechanism of granite under microwave irradiation by collecting the real-time acoustic emission signals during heating using the self-developed microwave hot rock damage real-time dynamic monitoring system. The results indicate similar change characteristics of the real-time acoustic emission counts, energy, and RA/AF values of rock samples with corresponding stages after 900 s of microwave power irradiation at 0.3 kW, 0.6 kW, and 0.9 kW under the same temperature range and the most active acoustic emission range is 200–310 °C. The degree of thermal damage to rock samples and the power show a positive correlation under similar temperature ranges. The characteristics of real-time RA/AF values reflect the tensile failure of granite during microwave heating, accounting for more than 65%. However, the shear crack ratio increases with irradiation time or power, with the highest ratio of 33.3%. In addition, the real-time acoustic emission curve in the microwave heating process reaches the acoustic emission active point at 200 °C, which is far less than 300 °C and 350 °C of the traditional conduction heating method, with 1/2th and 1/15th of the heating time of the traditional conduction heating method, indicating the superiority of microwave rock breaking. | 10.1007/s12665-024-11745-5 | English | Journal Article | Environmental Earth Sciences | 83 | 15 | 443 | ||||
| B031 | 1996 | Microwave Processing and Grindability | Gungor & Atalay | |||||||||||||
| B032 | 1973 | Driving of workings by a cutter-loader with electrothermal rock breaking | Gushchin, V. V.; Rzhevskii, V. V.; Kuznetsov, V. V.; Protasov, Yu. I.; Yurchenko, N. N. | http://link.springer.com/10.1007/BF02501780 | 10.1007/BF02501780 | English | Journal Article | Soviet Mining Science | 9 | 6 | 618-622 | |||||
| B033 | 2017 | Simulation on Development of Micro Cracks of Galena by microwave | Hao et al | https://www.researchgate.net/publication/318663014_Simulation_on_Development_of_Micro_Cracks_of_Galena_Ore_by_Microwave_Irradiation | ||||||||||||
| B036 | 1999 | Microwave energy for mineral treatment processes: a brief review | Haque, Kazi E. | https://www.sciencedirect.com/science/article/abs/pii/S0301751699000095 | This review is a brief account of R&D results generated from microwave-assisted mineral treatments tests. The R&D results demonstrate that microwave energy has potential in mineral treatment and metal recovery operations such as heating, drying, carbothermic reduction of oxide minerals, leaching, roasting/smelting, pretreatment of refractory gold ore and concentrate, spent carbon regeneration and waste management. However, challenges remain to be overcome through a fundamental understanding of microwave interaction with minerals, innovations, R&D investigations and advanced engineering, especially in designing efficient applicator, processes and process control devices. | 10.1016/s0301-7516(99)00009-5 | International Journal of Mineral Processing | 57 | 1 | 45315 | ||||||
| B037 | 2012 | Damage of basalt induced by microwave irradiation | Hartlieb, P.; Leindl, M.; Kuchar, F.; Antretter, T.; Moser, P. | https://linkinghub.elsevier.com/retrieve/pii/S0892687512000271 | In this work microwave irradiation on cylindrical samples of basaltic rock is investigated by laboratory experiments and compared with results from numerical models. Due to the temperature gradient in the samples induced by the microwave irradiation a significant damage indicated by a reduction of the sound velocity and finally the formation of cracks occurs. Applying a microwave power of 3.2 kW leads to a surface temperature of 250 °C and to 400 °C in the centre of a cylindrical sample after 60 s of irradiation. Temperature rise goes along with the formation of both axial and radial cracks. Cracks are not bound to the mineralogical composition but their development is governed by macroscopic temperature gradients and the geometry of the sample. A thermal and a thermomechanical finite element model are formulated and used to calculate temperature distributions and induced thermal stresses. The results indicate that tensile stresses exceed tensile strength leading to cracks as observed experimentally. | 10.1016/j.mineng.2012.01.011 | English | Journal Article | Minerals Engineering | 31 | 82-89 | |||||
| B038 | 2016 | Thermo-physical properties of selected hard rocks and their relation to microwave-assisted comminution | Hartlieb, P.; Toifl, M.; Kuchar, F.; Meisels, R.; Antretter, T. | https://linkinghub.elsevier.com/retrieve/pii/S0892687515301278 | This paper deals with experimental studies regarding the thermo-physical properties of granite, sandstone and basalt in the temperature range of 25–1000 °C. It is shown how phase transitions (e.g. a-b quartz phase transition) influence the texture and stability of these rock types. The results of these measurements and analyses are linked to microwave irradiation tests at 17.5 kW power. The measurements demonstrate the strong variation of effects depending on the parameter rock/mineralogy showing possible applications in a mineral processing environment. | 10.1016/j.mineng.2015.11.008 | English | Journal Article | Minerals Engineering | 91 | 34-41 | |||||
| B039 | 2016 | The influence of microwave irradiation on rocks for microwave-assisted underground excavation | Hassani, Ferri; Nekoovaght, Pejman M.; Gharib, Nima | https://linkinghub.elsevier.com/retrieve/pii/S1674775515001341 | Demand is growing for explosive-free rock breakage systems for civil and mining engineering, and space industry applications. This paper highlights the work being undertaken in the Geomechanics Laboratory of McGill University to make a real application of microwave-assisted mechanical rock breakage to fullface tunneling machines and drilling. Comprehensive laboratory tests investigated the effect of microwave radiation on temperature profiles and strength reduction in hard rocks (norite, granite, and basalt) for a range of exposure times and microwave power levels. The heating rate on the surface of the rock specimens linearly decreased with distance between the sample and the microwave antenna, regardless of microwave power level and exposure time. Tensile and uniaxial compressive strengths were reduced with increasing exposure time and power level. Scanning electron micrographs (SEMs) highlighted fracture development in treated basalt. It was concluded that the microwave power level has a strong positive influence on the amount of heat damage induced to the rock surface. Numerical simulations of electric field intensity and wave propagation conducted with COMSOL MultiphysicsÒ software generated temperature profiles that were in close agreement with experimental results. | 10.1016/j.jrmge.2015.10.004 | English | Journal Article | Journal of Rock Mechanics and Geotechnical Engineering | 8 | 1 | 45306 | ||||
| B040 | 2020 | A REVIEW OF EXPLOSIVE-FREE ROCK BREAKAGE (EFRB) TECHNOLOGIES IN MINING INDUSTRY | Hassani, Ferri; Rafezi, Hamed; Deyab, Samir M | https://www.researchgate.net/publication/365318996_A_REVIEW_OF_EXPLOSIVE-FREE_ROCK_BREAKAGE_EFRB_TECHNOLOGIES_IN_MINING_INDUSTRY | There are strategic drivers within the mining industry which are making explosive-free rock breakage approaches an option that is being reconsidered for the excavation of rock masses. A comprehensive review of the performance and related aspects of explosivefree rock breaking (EFRB) technologies is necessary to assess and demonstrate their applicability in the mining industry, particularly in continuous operations and autonomous mining. Additionally, it would facilitate a clear path of research and development. A comprehensive review of rock breakage technologies and expert projects would also provide sufficient understanding from available information and expert opinions of the advantages, limitations, and broad performance specifications of existing and promising EFRB methods for open pit and underground mining applications. The main EFRB technologies include mechanical cutting, microwave, laser, fluid, thermal and electrical applications. Finally, the application of microwave irradiation of rocks has been conducted successfully in the laboratory as a high potential concept. The approach can be expanded to full-scale field implementation as a pre-conditioning tool to facilitate the mechanical breakdown of rock in a continuous fashion as well as possible destressing of rock under high stress. A reduction in mechanical strength of rocks as a result of microwave irradiation could improve the performance of rock excavation equipment such as a tunnel boring machine. This will be increasing the rate of penetration and reducing operation time. | English | Journal Article | 2020 | ||||||||
| B041 | 2004 | EFFECT OF MICROWAVE-PRECONDITIONING ON THE GRINDABILITY AND FLOATABILITY OF COPPER- NICKEL ORE | Hermas, Ahmed N | https://xueshu.baidu.com/usercenter/paper/show?paperid=1e2f0tn0197m0pn02m0s0ew0ey162213&svcp_stk=1_txKiuzZ-EcOQxBas0RqG-i7cpfgFlsOkphk67BHHEZqRuCIvI6zDrTBouw8sh8QdRx5qHwN-T9kh0bf_rm70aQqc2OXQOvLcjR-SxGtW0rOFJhg4zsTwP54blCDHs01FFyEFAWESwh_8PsSGXggUlY0mlbfnuCLuIQRAn4zxzFM6C2CK3FcEqiw6uwOp-CH3CsuddVsS2tJDUsQB95yUuP_B2f6qsx_Y0cdQPFH4bDs%3D | English | Journal Article | ||||||||||
| B042 | 2020 | SELECTIVE HEAT ORE TREATMENT: SHAKING UP THE ECONOMICS OF MINERAL RECOVERY | Holmes, T; Craig, D; Batchelor, A R; Dodds, C; Kingman, S W; Legault, E; Whetton, M | https://www.researchgate.net/publication/355710161_Selective_Heat_Ore_Treatment_Shaking_Up_The_Economics_of_Mineral_Recovery | Crushing and grinding rocks uses significant energy. Up to 50% of the total energy used in mineral processing can be just for particle size reduction. As ore bodies age and grades decline, increasingly higher energy input is required for comminution, which increases costs and the carbon footprint of these operations. A step change in energy reduction is required to meet the future demand of these processes. | English | Journal Article | |||||||||
| B044 | 2018 | Property Changes of Formation Rocks under Electromagnetic Heating: An Experimental Study | Hu, Lanxiao; Li, Huazhou; Babadagli, Tayfun | https://onepetro.org/SPETTCE/proceedings/18TTCE/2-18TTCE/Port%20of%20Spain,%20Trinidad%20and%20Tobago/215476 | Electromagnetic (EM) heating has been proposed to recover heavy oil due to its great environmental friendliness. Previous studies focused on investigating the feasibility and enhancing the oil recovery of such non-aqueous method. However, the effect of EM heating on the variations of formation rock properties is still elusive. Detailed experiments/measurements are required to understand the effect of EM heating on changing the petrophysical properties of formation rocks. | 10.2118/191238-MS | English | conferencePaper | Day 2 Tue, June 26, 2018 | D021S015R003 | ||||||
| B045 | 2023 | Research on the Harmless Treatment of Weak Muddy Intercalation in Red-Bedded Soft Rock via Microwave Energy | Hu, Qijun; Gu, Yucheng; Liu, Zhicheng; Zeng, Junsen; Zhang, Wenjin; He, Leping; Li, Muyao | https://www.mdpi.com/2075-163X/13/10/1327 | The WMI (weak muddy intercalation) is a typical weak structural surface in the red-bedded rock mass; ensuring slope stability by increasing the strength of the WMIs helps reduce project costs and carbon emissions. With the advantages of energy saving, high efficiency, and green, microwave technology has attracted scholars’ attention to geotechnical material property improvement. However, the mineral composition of the WMIs is complex and variable, and the applicability of microwave technology needs further evaluation. In this paper, the effects of microwave temperature and clay mineral types and content on the physical and mechanical properties of the WMIs were evaluated. The results show that microwave heating can substantially improve the uniaxial compressive strength of the WMIs, regardless of the types and content of clay minerals. Dehydration, dehydroxylation of clay minerals, and local melting of albite occurring in the specimens under microwave heating enhanced the strength of the soil particles and the interparticle joints. The strength increase ratios of the WMI specimens increased with the temperature increase. With the increase in clay mineral content, the strength increase ratio of kaolinite WMIs and illite WMIs decreased, while the strength increase ratios of montmorillonite WMIs increased. The present multiple regression analysis methods are used to establish the strength prediction models of the WMI microwave-reinforced specimens, which can guide the engineering application. | 10.3390/min13101327 | English | Journal Article | Minerals | 13 | 10 | 1327 | ||||
| B046 | 2022 | Mineralogical properties of ludwigite and the effects of microwave radiation on its particle characteristics and mineral liberation properties | Huang, Weijun; Jiang, Tao; Liu, Yajing; Guo, Tonglai | https://www.tandfonline.com/doi/full/10.1080/08327823.2022.2066770 | To effectively separate the valuable minerals in ludwigite, this study investigated the mineralogy of ore, particle-size distribution and mineral liberation characteristics. Most of the magnetite was intergrown with ascharite and serpentine. Nearly half of the serpentine existed in a dense, massive body. Most of the ascharite was encased in magnetite, and a small amount was embedded in the serpentine phase. After the microwave radiation, some intergranular and through cracks were formed to improve mineral liberation during the grinding process. The mass fractions for the þ75 lm range decreased from 43.16 wt% for untreated samples to 24.31 wt% for treated samples with a microwave power of 3 kW for 40 s. By contrast, the mass fractions of particles in the 75 lm range increased from 56.84 wt% for untreated samples to 75.69 wt% for treated samples. D50 decreased from 53.54 mm for the untreated sample to 21.58 mm for the treated sample. The liberation degrees after the treated samples clearly improved and increased by 26.64% for magnetite, 18.92% for ascharite and 14.10% for serpentine. | 10.1080/08327823.2022.2066770 | English | Journal Article | Journal of Microwave Power and Electromagnetic Energy | 56 | 2 | 124-142 | ||||
| B047 | 2024 | Study on Microwave-Assisted Grinding and Dissociation Characteristics of Bayan Obo Ore | Huang, Weijun; Liu, Yajing; Jiang, Tao; Hou, Shaochun | https://link.springer.com/10.1007/s11837-024-06851-5 | 10.1007/s11837-024-06851-5 | English | Journal Article | JOM | 76 | 11 | 6741-6750 | |||||
| B052 | 2014 | Influence of microwave irradiation on ilmenite flotation behavior in the presence of different gangue minerals | Irannajad, Mehdi; Mehdilo, Akbar; Salmani Nuri, Omid | https://linkinghub.elsevier.com/retrieve/pii/S1383586614003414 | As a pretreatment method, microwave irradiation was applied to modify ilmenite surface properties and to improve its flotation behavior in the presence of different gangue minerals including olivine, pyroxene, tremolite, clinochlore and quartz. The flotation experiments were carried out in both micro (Hallimondtube) and laboratory (flotation cell) scales. The microflotation experiments showed that the ilmenite surface irradiation converts Fe2+–Fe3+ ions, characterized by XPS analysis, improving the floatability. This is due to the increase of oleate adsorption and the formation of more insoluble ferric iron oleate as evidenced by FTIR analysis and zeta potential measurements. In addition, this pretreatment decreases the consumption of flotation reagents. The microwave irradiation does not have a significant effect on surface properties and floatability of quartz. In laboratory scale flotation experiments, when quartz is the main gangue mineral, the TiO2 grade and recovery of flotation concentrate improved from 27.1% to 28.3% and 85.3% to 92.7%, respectively by using microwave irradiation. In the presence of tremolite and clinochlore containing almost 12.4% Fe, the microwave irradiation improved the TiO2 grade and recovery from 21.3% to 22.1% and 71% to 82.5%, respectively. In the case of olivine and pyroxene with 30.1% Fe, the recovery of TiO2 increases from 66.9% to 69.1%. In the flotation of the ore sample containing 24.5% Fe, the microwave irradiation improves the recovery of TiO2 in the ilmenite concentrate from 65.4% to 76.2%. In a general result, in the flotation of ilmenite from different gangue minerals, the separation efficiency and selectivity index have a negative correlation with the iron content of gangue minerals. | 10.1016/j.seppur.2014.05.046 | English | Journal Article | Separation and Purification Technology | 132 | 401-412 | |||||
| B053 | 2022 | MICROWAVE ACTED MICRO GRINDING OF ŞIRNAK ASPHALTITE SLIME, LIGNITE SLIME | İsmail Tosun, Yıldırım; Chichek, Fethullah | https://euroasiajournal.org/index.php/ejas/article/view/241 | In terms of the advanced technological developments in energy production the low quality coals need the most feasible technologies. it is possible to produce coal-derived products from low quality coals. On the contrary of environmental concerns of low quality coal burning, coal preparation, grinding and washing of various type of low quality coals need feasible evaluation. The grinding systems are needed in today's modern technology. In this fine grinding study, Hardgrove and Bond grindability tests are practiced over Şırnak shale, Şırnak asphaltites and bottom ash. Grinding tests ere carried out to certain weight samples conditioned in microwave oven at the fine size values in the product. The duration period are changed after grinding for 60 and 90 minutes. Şırnak asphaltite and Şırnak shale were dry milled in two different horizontal and vertical roller mills in different micro-grinders and the fineness values of 20 μm and 45 μm are determined and compared. The unit energy consumption for different types of clinker production in industrial mills has been calculated and presented comparatively. The differences in the grindability of raw materials and the amount of energy consumed in cement production were determined by experimental and industrial tests. The easiest to grind is Şırnak asphaltite and shale, while the most difficult to grind is marl. As a result of the HGI and Bond tests, they are the decisive tests in industrial-scale grinding of cement. Since materials that are easy to grind are evaluated, it has been observed in this study that clinkers with additives produced using claystone are more advantageous. Micronized grinding of soft limestone instead of marly limestone has proven to be easy. The particle size functions in the micro pulp are defined in the vertical ball mill. In the production of additive Portland cement, micronized grinding of oak charcoal and fly ash with microwave requires less energy and can be grinded more easily. | 10.38065/euroasiaorg.926 | English | Journal Article | Euroasia Journal of Mathematics, Engineering, Natural & Medical Sciences | 9 | 20 | 38-45 | ||||
| B054 | 2014 | IVSON FERREIRA DOS ANJOS - TESE PPGEE 2014 | ||||||||||||||
| B056 | 2020 | Effects of microwave irradiation on impact comminution and energy absorption of magnetite ore | Jiawang, Hao; Qingwen, Li; Lan, Qiao; Naifu, Deng | https://iopscience.iop.org/article/10.1088/1755-1315/570/5/052003 | The severe mechanical wear and high-energy consumption in the comminution process of high hardness iron ore have always restricted the efficient and economic development of an enterprise. On the basis of the basic principle that microwave irradiation can induce rock damage, the magnetic ore specimens were subjected to microwave heating treatment with different heating paths and cooling paths; the uniaxial impact comminution test was conducted by the drop hammer impact equipment. This study analyzed the effect of the heating and cooling paths on the crack propagation process, dynamic mechanical strength, and energy consumption of magnetite ore. The results show that microwave irradiation causes obvious microwave-induced cracks in ore, and in the subsequent impact cracking process, the new cracks gradually penetrate the microwave-induced cracks and form the macroscopic fracture surface. With the increase of irradiation power and time, the ore dynamic strength decreased, and the absorption energy increased. Therefore, increasing the total output energy of microwave can effectively alleviate the mechanical wear and enhance the comminution effect of ores. Among the factors that affect the mechanical properties and absorption energy of ore, power has a higher priority than time. With the increase in the heat exchange rate between the ore and the external environment, the ore comminution becomes more intense, leading to the best comminution effect of ores. The research results have an important reference for the practical application of microwave irradiation technology in hard rock comminution. | 10.1088/1755-1315/570/5/052003 | English | Journal Article | IOP Conference Series: Earth and Environmental Science | 570 | 5 | 52003 | ||||
| B057 | 2019 | MW heating of rock particles and their cross-dependencies | Jokovic, Vladimir; Antonio, Christian; Morrison, Robert | https://linkinghub.elsevier.com/retrieve/pii/S0892687519302341 | Microwave heating inside a cavity is not uniform and depends on various factors such as: cavity geometry, properties of treated material and frequency. In most applications of microwave (MW) heating there is only a small variation in the nature of the feed. However, this is not the case for the MW/Infra-Red (IR) ore sorting. As microwaves are electromagnetic waves, the microwave field around a given ore particle is influenced by its dielectric and magnetic properties and the modified field should also influence the heating of neighbouring particles. While influence is reciprocal it is clear that particles with high dielectric properties will dominate field effects. Understanding of this process is important in the particle-by-particle ore sorting process where the accept/reject decision is based on the temperature of the ore particle. | 10.1016/j.mineng.2019.105834 | English | Journal Article | Minerals Engineering | 141 | 105834 | |||||
| B058 | 2005 | Understanding microwave assisted breakage | Jones, D.A.; Kingman, S.W.; Whittles, D.N.; Lowndes, I.S. | https://linkinghub.elsevier.com/retrieve/pii/S0892687504002730 | A finite difference quasi-static thermo-mechanical 2-D model of a theoretical 2-phase mineral is constructed. The aim is to simulate the thermal stresses generated and subsequent thermal damage when a rock particle is exposed to high electric field strength microwave energy. The influences of power density and grain size are assessed for a theoretical 2 mm by 2 mm sample of calcite host rock deemed transparent to microwave energy, containing a strongly absorbent circular pyrite phase of varying diameter. The simulations have predicted the extent of microwave heating, thermal conduction and expansion, strain softening and thermally induced fracturing. The stress regime is analysed and it is concluded that fractures are likely to occur around the grain boundary between absorbent and transparent species. This suggests that liberation of valuable minerals can be improved and that a reduction in comminution energy is possible after microwave treatment. The effect of size on peak temperatures is analysed, and it is shown why microwave treatment is less efficient at lower particle sizes for a fixed applied power density. | 10.1016/j.mineng.2004.10.011 | English | Journal Article | Minerals Engineering | 18 | 7 | 659-669 | ||||
| B059 | 2007 | The influence of microwave energy delivery method on strength reduction in ore samples | Jones, D.A.; Kingman, S.W.; Whittles, D.N.; Lowndes, I.S. | https://linkinghub.elsevier.com/retrieve/pii/S025527010600170X | Recent work has shown for the first time that high electric field strength microwave energy can facilitate comminution of ores, at energy inputs considered economically viable. However, due to difficulties in measuring stress formation inside a solid being exposed to microwave energy, the accuracy of a suggested thermal stress weakening mechanism has not been quantified. It is thought that microwave induced differential thermal expansion of certain mineral phases is sufficient to cause stresses that exceed the strength of the material. This study simulated this proposed weakening mechanism using a quasi-static thermo-mechanical 2D model of a simplified pyrite/calcite system formulated in commercial finite difference numerical modelling software. The effects of microwave power density and exposure time on simulated uniaxial compressive strength are quantified. Power densities expected in both continuous wave and pulsed microwave applications are examined, and the work concludes that pulsed treatment is more effective for weakening rocks. The paper makes recommendations as to the future operating requirements of microwave equipment for the most effective weakening at economic energy inputs. | 10.1016/j.cep.2006.06.009 | English | Journal Article | Chemical Engineering and Processing: Process Intensification | 46 | 4 | 291-299 | ||||
| B060 | 2022 | Effects of high-power microwave irradiation on tar-rich coal for realising in situ pyrolysis, fragmentation, and low-carbon utilisation of tar-rich coal | Ju, Yang; Zhu, Yan; Zhang, Yuwei; Zhou, Hongwei; Peng, Suping; Ge, Shirong | https://linkinghub.elsevier.com/retrieve/pii/S1365160922001319 | Tar-rich coal was directly combusted during power generation, resulting in a huge waste of precious oil resources and a large amount of carbon emissions. The idea of intelligent unmanned mining machine (IUMM) for in-situ fluidised mining and conversion of tar-rich coal was proposed to solve the problems of traditional mining and utilisation methods, realise efficient utilisation of tar-rich coal, and achieve net-zero CO2 emission. A key technology of IUMM is the pyrolysis and fragmentation of tar-rich coal by high-power microwave irradiation. In this study, we carried out experiments on the strength and microstructural changes of tar-rich coal under different microwave irradiation conditions using the high-power microwave irradiation testing system to explore the effects of microwave irradiation on tar-rich coal and provide a reference for the design of IUMM. The X-ray computed tomography was employed to observe and characterize the initiation, growth, connection, and spatial distribution of internal fractures of tar-rich coal under different microwave irradiation conditions. The quantitative relationship between the strength characteristics of tar-rich coal and microwave irradiation conditions was established. The results show that under a fixed microwave power or irradiation time, the overflow rate of coal gas and tar is linearly positively correlated with microwave energy E, and both the uniaxial compressive strength and brittleness of tar-rich coal have piecewise linear negative correlation with E. With the increase of E, the internal fractures grow and connect more, which are synchronised with the decrease of the uniaxial compressive strength and elastic modulus of the tar-rich coal. With equal E input, high-power microwave has a more significant effect on strength weakening, fracturing, and fragmentation of tar-rich coal. Our findings can be used for the subsequent implementation of in-situ pyrolysis and fragmentation technology of IUMM for realising the insitu conversion, high-efficiency utilisation, and low carbon emissions of tar-rich coal. | 10.1016/j.ijrmms.2022.105165 | English | Journal Article | International Journal of Rock Mechanics and Mining Sciences | 157 | 105165 | |||||
| B061 | 2013 | EXPERIMENTAL RESEARCH ON REDUCTION OF GRANITE STRENGTH INDUCED BY MICROWAVE IRRADIATION | Dai, J. | https://onemine.org/documents/experimental-research-on-reduction-of-granite-strength-induced-by-microwave-irradiation | granite | Based upon research findings from several countries, the combination of microwave and mechanical means to break hard rock holds promise for the future. To achieve this goal, it is essential to understand the laws governing strength reduction of hard rock, such as granite, induced by microwave irradiation. Two aspects to consider are: 1) laws associated with the tensile strength of hard rock after microwave irradiation and 2) the sensitivity of different types of rock strengths to microwave energy. In this study, granite with a range of tensile strengths was exposed to microwaves for various time periods to compare the response of rocks with different strength values exposed to the same microwave irradiation. In addition, a method based on hotspots is presented to explain the mechanism by which granite strength is reduced by microwave irradiation. | English | Journal Article | ||||||||
| B062 | 2020 | Evaluating the surface temperatures and the strength of igneous rocks treated by microwave | Kahraman, S; Canpolat, A N; Fener, M | https://onepetro.org/ISRMEUROCK/proceedings-abstract/EUROCK20/EUROCK20/ISRM-EUROCK-2020-079/447287?redirectedFrom=PDF | The mechanical excavation of rocks has been increasing in rock engineering projects. However, the cutting rate is low and the wear of cutting tools is high during the excavation of hard and abrasive rocks. There are some preliminary studies on the microwave assisted hard rock cutting. The objective of these studies is to decrease the rock strength by microwave energy before cutting, and therefore to increase cutting rate and decrease cutter wear. | English | Journal Article | |||||||||
| B063 | 2024 | Investigating the changes in the strength of carbonate rocks exposed to microwave energy | Kahraman, Sair; Ozbek, Muhammed; Rostami, Masoud; Fener, Mustafa; Andras, Andrei; Popescu, Florin Dumitru | https://link.springer.com/10.1007/s12517-024-12058-4 | Microwave treatment is one of the research topics to solve cutting problems of hard rocks such as low cutting rate and high tool wear. Microwave irradiation creates fractures in the rock body and decreases its strength. Numerous studies have been conducted to ascertain how microwaves affect the strength of rocks. Ten carbonate rocks are examined in this paper to see how microwaving affects their strength. First, unconfined compression and tensile strength tests were conducted on unirradiated dry and saturated core specimens. Following that, the two tests were performed again on samples that had been exposed to radiation for varying amounts of time—between 2 and 6 min—at a microwave power of 6 kW. The results showed that the uniaxial compressive strength loss due to microwave irradiation was between 9.0 and 90.0% and 7.3 and 92.0% for the dry and saturated samples, respectively. Tensile strength loss was between 15.6 and 62.7% and 23.2 and 63.1% for the dry and saturated samples, respectively. The efficiency of treating carbonate rocks with microwaves is significantly impacted by density, porosity, and impurities. Multiple regression equations were derived to estimate the strength losses. Concluding remark is that the strength reductions due to microwaves are significant for carbonate rocks. | 10.1007/s12517-024-12058-4 | English | Journal Article | Arabian Journal of Geosciences | 17 | 9 | 255 | ||||
| B064 | 2022 | The effect of mineralogy on the microwave assisted cutting of igneous rocks | Kahraman, Sair; Sarbangholi, Faraz S.; Balci, Cemal; Fener, Mustafa; Karpuz, Ceyhun; Comakli, Ramazan; Unver, Bahtiyar; Ozcelik, Yilmaz | https://link.springer.com/10.1007/s10064-021-02561-3 | Hard rocks can be excavated difficultly by some mechanical miners such as roadheaders. Tunnel boring machines (TBMs) can excavate hard rocks, but the cost is high due to low advance rate and high tool wear. The difficulties in hard rock excavation can be overcome by exposing hard rocks to microwave energy while cutting. This study investigates influence of mineralogy on the microwave assisted cutting of igneous rocks. The normal and cutting forces were measured during the cutting tests, and the specific energy values were calculated. The optimum specific energy (SEopt.) values reduce quite steadily with the increasing microwave power. The SEopt. of some tested crystalline rocks first increases at the low power (3 kW) and then decreases at the high power (6 kW). The losses in the SEopt. range from 22.5 to 38.7% at the power of 6 kW. The equations were also developed for the estimation of the SEopt. loss. Concluding remark is that the same rock types may be affected differently by microwave energy because of the different mineral types and percentages, and thus they behave diversely under cutting tests. The derived equations will be useful for the prediction of the SEopt. loss due to the microwave treatment. | 10.1007/s10064-021-02561-3 | English | Journal Article | Bulletin of Engineering Geology and the Environment | 81 | 1 | 62 | ||||
| B065 | 2024 | The effect of microwave treatment on the abrasivity of igneous rocks | Kahraman, Sair; Saygin, Egemen; Fener, Mustafa | https://link.springer.com/10.1007/s12517-023-11830-2 | Excessive tool wear is an important problem during the mechanical excavation of hard and abrasive rocks. However, there is no concrete solution for this problem yet. The microwave-assisted cutting of hard and abrasive rocks may be a solution. This study investigates the effect of microwave treatment on the Cerchar abrasivity index (CAI) of nine different igneous rocks such as granite, syenite, and gabbro. First, the mineral contents and percentages of each rock was determined. Then, microwave treatment was applied on the specimens broken in the indirect tensile strength test for 180 s at the microwave powers of 2 kW and 6 kW. The evaluation of the test results shows that the surface temperatures of the specimens increase with increasing microwave power. The surface temperatures of the specimens including metallic minerals or the mineral having metallic ions reach very high values. The CAI values of the specimens decrease with increasing microwave power. The CAI losses increase generally with increasing surface temperature and microwave power depending on mineral contents. | 10.1007/s12517-023-11830-2 | English | Journal Article | Arabian Journal of Geosciences | 17 | 1 | 21 | ||||
| B066 | 2022 | Investigation of Cerium Reduction Efficiency by Grinding with Microwave Irradiation in Mechanochemical Processing | Kato, Tatsuya; Iwamoto, Motonori; Tokoro, Chiharu | https://www.mdpi.com/2075-163X/12/2/189 | This study evaluated the efficiency of cerium reduction by grinding with microwave irradiation in mechanochemical processing. Grinding experiments with microwave irradiation were conducted using an agitating mixer. Since the structure of the ground samples was amorphous and the cerium concentration was much lower than those of other elements, the valence change and structural change of cerium after grinding with microwave irradiation were investigated using X-ray absorption fine structure (XAFS) analysis in the cerium K-edge. The X-ray absorption near-edge structure (XANES) analysis revealed that a portion of tetravalent cerium was reduced to trivalent cerium by grinding with microwave irradiation. In addition, it was confirmed by extended X-ray absorption fine structure (EXAFS) analysis that oxygen vacancies were produced as a result of the cerium reduction reaction. To evaluate the efficiency of cerium reduction efficiency, the percentage reduction by grinding with microwave irradiation was compared to that by planetary ball milling and microwave irradiation. As a result, it was revealed that the efficiency of cerium reduction via grinding with microwave irradiation was higher than that via microwave irradiation and the same as that via planetary ball milling. Moreover, a larger amount of tetravalent cerium could be reduced to trivalent cerium by grinding with microwave irradiation than when using planetary ball milling and microwave irradiation. | 10.3390/min12020189 | English | Journal Article | Minerals | 12 | 2 | 189 | ||||
| B067 | 2010 | Effect of Microwave Radiation on the Floatation of Copper Sulfide Ores | Kaya, Erol | https://asianpubs.org/index.php/ajchem/article/download/12075/12056 | The objective of this study is to evaluate the floatation behaviour of microwave pre-treated 2 sulfide copper ores containing different mineralogy. Each ore was subjected to microwave radiation for varying time periods before grinding and subsequent floatation testing. The changes in floatation recoveries and grades with the microwave exposure time were quantified by batch type laboratory tests. The results of the floatation tests indicated essentially the same recoveries at low temperatures for both the microwave treated copper ores compared to untreated samples. On the other hand, the results showed that high microwave radiation temperatures were detrimental to floatation recovery for both the copper ores due possibly to microwave energy induced oxidation of minerals at relatively high temperatures. The existence of significant oxidized areas on high-grade chalcopyrite particles were shown when heated with microwaves. Differing ore mineralogy has been shown to affect the floatability of the ores treated with microwaves. | English | Journal Article | |||||||||
| B068 | 2016 | Rock Crushing Using Microwave Pre-Treatment | Kim, Seunghee; Carlos Santamarina, J. | http://ascelibrary.org/doi/10.1061/9780784480151.071 | Crushing and grinding are primary contributors to a high energy demand in the mining industry, yet, both are surprisingly inefficient processes, often with efficiencies as low as 1%. We analyze size reductions during crushing and grinding operations and explore the potential of multiplying internal weaknesses in rock materials by non-mechanical means. In particular, when rock blocks (wet or even dry if polycrystalline) are exposed to microwaves, internal cracks can develop along grain boundaries via differential thermal expansion between grains and volumetric thermal expansion of water in pores. Brazilian tests conducted on granite and cement mortar specimens show that the tensile strength decreases proportional to the duration of microwave treatment. Thermal changes, excessive fluid pressure buildup and induced stresses are analyzed in the context of hydro-thermomechanically coupled processes. Results confirm that both differential thermal expansion of mineral grains and volumetric thermal expansion of water can generate cracks upon microwave exposure. Optimal conditions are suggested to lower the combined consumption of electric and mechanical energy. | 10.1061/9780784480151.071 | English | conferencePaper | Geo-Chicago 2016 | 720-729 | ||||||
| B070 | 2000 | The effect of microwave radiation on the processing of Palabora copper ore | Kingman, S W; Vorster, W; Rowson, N A | http://saimm.s1029.sureserver.com/Journal/v100n03p197.pdf | English | Journal Article | ||||||||||
| B071 | 2006 | Recent developments in microwave processing of minerals | Kingman, S. W. | https://journals.sagepub.com/doi/full/10.1179/174328006X79472 | The demand for minerals and metals is increasing. However, it is well established that the impact of mining and subsequent processing operations must be reduced to meet future sustainability requirements. One way in which mining operations may reduce their impact is through the use of emerging science and technology. One such area which has shown particular promise over a period of several years is the use of microwave heating technologies to improve the efficiency of various mineral processing unit operations including: leaching, refractory gold ore treatment, grindability and liberation and coal grinding. Each of the above areas is reviewed and the main reasons that have either ensured or hindered development to a pilot or industrial scale are discussed. Opportunities for the future development of microwave technologies for the minerals industry are discussed and the review concludes by identifying a series of research challenges that must be met before scale up to an industrial level can be considered. | 10.1179/174328006X79472 | English | Journal Article | International Materials Reviews | 51 | 1 | 45303 | ||||
| B072 | 2004 | Recent developments in microwave-assisted comminution | Kingman, S.W.; Jackson, K.; Cumbane, A.; Bradshaw, S.M.; Rowson, N.A.; Greenwood, R. | https://linkinghub.elsevier.com/retrieve/pii/S0301751603001753 | The influence of high electric field strength microwave energy on copper carbonatite ore has been elucidated. It has been shown that very short exposures times can lead to significant reductions in ore strength as determined by point load tests. Comparative drop weight tests were carried out to determine any potential change in required comminution energy for microwave-treated material. It was shown that reductions in required comminution energy of over 30% could be achieved for microwave energy inputs of less than 1 kW h t 1. Comparative specific rate of breakage grinding studies showed that significant increases in grindability could also be achieved after short microwave exposure times, changes being related to particle size. QEM*SEM liberation studies showed that the amount of locked and middling copper sulphides was reduced from 69.2% to 31.8% in the + 500 Am size fraction. Conclusions are made regarding the potential future development of this technology. | 10.1016/j.minpro.2003.09.006 | English | Journal Article | International Journal of Mineral Processing | 74 | 45295 | 71-83 | ||||
| B073 | 1998 | Microwave treatment of minerals-a review | Kingman, S.W.; Rowson, N.A. | https://www.sciencedirect.com/science/article/abs/pii/S0892687598000946 | This paper presents a review of the advances in the microwave treatment of minerals from the early stages of development to possibilities for future utilisation. Many different applications are considered, including fundamental heating rate studies, microwave assisted grinding, possible exploitation in the area of extractive metallurgy and also microwave treatment of coal. Conclusions are presented regarding the need for further fundamental and pilot scale data. Further indications of the potential for the commercial exploitation of microwaves within the mineral processing and extractive metallurgical industries have been included. | 10.1016/s0892-6875(98)00094-6 | Minerals Engineering | 11 | 11 | 1081-1087 | ||||||
| B074 | 2000 | The influence of mineralogy on microwave assisted grinding | Kingman, S.W.; Vorster, W.; Rowson, N.A. | https://linkinghub.elsevier.com/retrieve/pii/S0892687500000108 | The influence o f mineralogy on microwave assisted grinding is elucidated. Detailed mineralogical analysis of various commercially exploited ores was carried out and the textural relationships between the individual mineral phases established. Microwave heating profiles were determined for each constituent mineral. Each ore was then subjected to microwave radiation for varying time periods, and change in work index with microwave exposure time quantified. It is suggested that increases in grindability of ores after microwave treatment are related to the specific mineral species present, particle size of the specific mineral and also the degree of dissemination. Conclusions are made regarding the economic implementation of this technology. © 2000 Elsevier Science Ltd. All rights reserved. | 10.1016/S0892-6875(00)00010-8 | English | Journal Article | Minerals Engineering | 13 | 3 | 313-327 | ||||
| B076 | 2019 | A Numerical Study of the Effects of Microwave Pre-Treatment on Value Liberation from a Zinc Ore | Koch, Pierre-Henri; Charikinya, Edson | https://ltu.diva-portal.org/smash/record.jsf?pid=diva2%3A1287818&dswid=-8033 | The extraction of mineral values from ore requires liberation followed by separation steps. Liberation is achieved by size reduction operations which are energy inefficient processes typically dominating the energy consumption in a mineral concentrator. As the grade of ore reserves declines, future viability of mineral operations will be determined by energy costs of comminution. | English | Journal Article | |||||||||
| B077 | 2021 | Investigation of Source Rock Heating and Structural Changes in the Electromagnetic Fields Using Experimental and Mathematical Modeling | Kovaleva, Liana; Zinnatullin, Rasul; Musin, Airat; Kireev, Victor; Karamov, Tagir; Spasennykh, Mikhail | https://www.mdpi.com/2075-163X/11/9/991 | The paper presents the results of an experimental study of heating and the structural resultant changes of source rocks under the influence of the electromagnetic field in the microwave and radio-frequency ranges. The samples from the Bazhenov Formation (West Siberia, Russia) and the Domanic Formation (Ural, Russia) have been tested. It is shown that samples from these formations demonstrate very different heating rates at the same electromagnetic field parameters and the their heating rate depends on the type of the electromagnetic field (radio-frequency or microwave) applied. The temperature of the Bazhenov Formation samples reaches 300 ◦C within one hundred seconds of the microwave treatment but it slowly rises to 200 ◦C after twelve minutes of the radio-frequency influence. The samples of the carbonate Domanic Formation heat up more slowly in the microwave field (within two hundred seconds) and to lower temperatures in the radio-frequency (150 ◦C) than the Bazhenov Formation samples. The study of the structure of the samples before and after experiments on the electromagnetic treatment shows fracture formation during the heating process. Numerical simulations of heating dynamics of source rock samples have been based on a simple mathematical model of the electromagnetic influence and main features of heating for different types of source rock have been revealed. The opportunities for application of electromagnetic heating for oil source rock recovery are discussed. | 10.3390/min11090991 | English | Journal Article | Minerals | 11 | 9 | 991 | ||||
| B078 | 2006 | Microwave Energy Aided Mineral Comminution | Kumar, Ashish; Kamath, Bala P; Ramarao, V V; Mohanty, D B | https://eprints.nmlindia.org/6266/1/398-404.PDF | Mineral liberation during beneficiation is essentially through comminution. However, the fact that the major slice (up to 50 percent) in the pie for total energy requirements during beneficiation is occupied by comminution, dictates us to look into various possibilities to render comminution more energy-efficient. | English | Journal Article | |||||||||
| B079 | 2010 | Iron ore grindability improvement by microwave pre-treatment | Kumar, P.; Sahoo, B.K.; De, S.; Kar, D.D.; Chakraborty, S.; Meikap, B.C. | https://linkinghub.elsevier.com/retrieve/pii/S1226086X10001899 | The influence of microwave pre-treatment on grindability of iron ore (Orissa, India) was investigated by grindability tests. SEM analysis characterized the micro-fractures in microwave treated sample. This may be due to the thermal stress cracking resulted from microwave energy pre-treatment. XRD analysis showed the crystalline content of the sample. It was found that the microwave treated iron ore has peak more than that of untreated ore, i.e. the crystallinity increased with the microwave exposure time. The calculation of HGGI indicated increase in the ease of grinding or decrease in grindability index of the microwave treated ore. Grindability test showed that the microwave treated iron ore grinds much more rapidly initially than the untreated ore. The results showed that the breakage function of both microwave untreated and treated iron ore is dependent of the particle size. The grindability increased significantly as a result of microwave pre-treatment with the specific rate of breakage (Si) increasing by an average of 50%. It was concluded that microwave assisted grinding produced good results particularly for grinding characteristics. | 10.1016/j.jiec.2010.05.008 | English | Journal Article | Journal of Industrial and Engineering Chemistry | 16 | 5 | 805-812 | ||||
| B087 | 2024 | Mechanical properties and damage constitutive relationship of microwave irradiation of granite under uniaxial compression | Li, Diyuan; Lyu, Xinxin; Zhou, Aohui; Ru, Wenkai; Su, Xiaoli | https://www.tandfonline.com/doi/full/10.1080/01495739.2024.2409176 | Microwaves have great potential to increase the efficiency of hard rock breakage during mechanical excavation in engineering. This study conducted uniaxial compression tests on granite specimens after microwave irradiation at 4.85 kW. The results demonstrated a linear decrease in uniaxial compressive strength and elastic modulus correlating with increasing irradiation durations. Acoustic emission data indicated increased normalized crack closure stress and decreased normalized crack initiation and damage stress, suggesting complex crack propagation and evolution patterns under microwave influence. 3D Digital Image Correlation revealed that as heating time increased, the macrocrack leading to specimen failure shifted from being load-dominated to involving both load and microwave-induced thermal cracks. A simple four-parameter damage constitutive model for granite (a1, r1, a2, and r2) effectively described the damage evolution under the coupling effect of microwave and uniaxial load. The model accurately characterized the complete stress–strain curves, including both microcrack compaction and post-peak stages, revealing that initial damage escalates with longer heating, though the progression rate decreases. | 10.1080/01495739.2024.2409176 | English | Journal Article | Journal of Thermal Stresses | 45311 | ||||||
| B088 | 2019 | Fully-coupled simulations of thermally-induced cracking in pegmatite due to microwave irradiation | Li, Jielin; Kaunda, Rennie B.; Arora, Shrey; Hartlieb, Philipp; Nelson, Priscilla P. | https://linkinghub.elsevier.com/retrieve/pii/S1674775518302312 | Fully-coupled thermo-mechanical simulations are implemented in COMSOL Multiphysics to investigate micro-scale stress-strain variability in pegmatite specimens subjected to thermal loading using microwaves. Thermally-induced compressive and tensile stresses increase as the microwave irradiation duration increases. The dielectric constant, coefficient of expansion, and type and size of mineralogical boundary have significant impacts on the responses of the rock to microwave irradiation. The maximum principal stress of the chlorite is the smallest, indicating that the chlorite experiences the most damage under microwave irradiation, followed by the quartz. The maximum principal stress values of plagioclase and orthoclase are larger, indicating that they are likely to incur the least damage. Where quartz or chlorite is dominant, the resulting von Mises stresses are consistently higher after 120 s of microwave irradiation. The rate of generation of von Mises stresses increases most rapidly along the interface between quartz and plagioclase, and the interface between quartz and orthoclase, followed by the interface between quartz and chlorite, and finally the interface between plagioclase and orthoclase. The presented modeling approach provides a practical method to investigate stress-strain relationships within mineralogical boundaries inside a rock thin section. | 10.1016/j.jrmge.2018.12.007 | English | Journal Article | Journal of Rock Mechanics and Geotechnical Engineering | 11 | 2 | 242-250 | ||||
| B089 | 2024 | Experimental Study on Differential Thermal Response and Pore-Fracture Structure Evolution Characteristics of Coals under Microwave Irradiation: A Case Study of Five Different Rank Coals | Li, Jin; Zhang, Junjian; Xiao, Qianlong; Liu, Bianyu; Lin, Wei; Li, Wu | https://pubs.acs.org/doi/10.1021/acs.energyfuels.4c01228 | Microwave irradiation (MI) is a leading-edge technology for increasing the permeability and production of coalbed methane (CBM) reservoirs. To study the characteristics of thermal response, pore-fracture structure and seepage behavior of coals under MI, a microwave heating device was operated to irradiate five different rank coal samples for 2 and 4 min. The variation of chemical structure has been explored using Fourier transform infrared spectroscopy (FTIR). The variation of pore fracture has been studied via low-field nuclear magnetic resonance (LF-NMR) and micro-computed tomography (μ-CT). Additionally, the pore distribution heterogeneity has been analyzed by multifractal dimension, an equivalent pore-fracture network model has been established by μ-CT, and the modification benefit of coal pore-fracture structure under MI has been revealed by simulation of absolute permeability. The results showed that the temperature of the coal samples reached 220−440 °C under MI for 4 min. The chemical structure of the coal samples did not change significantly. The Ptotal, Pfree, connectivity, and Df increased, while the proportion of adsorption pores, Pbound, and T2c decreased under MI. The permeability significantly increased under MI, based on the single-phase water fluid flow simulation. The modification of coal pore fracture under MI was controlled by the physical and chemical structures of coal. The more developed the pore fracture, the better the modification effect under MI. The chemical structure of low-rank coal was more disordered, compared to high-rank coal, and the higher the thermal stress value generated under MI, the stronger the degree of pore-fracture damage. This study might provide some details for increasing fractures and permeability in coal reservoirs and increasing CBM production. | 10.1021/acs.energyfuels.4c01228 | English | Journal Article | Energy & Fuels | 38 | 11 | 9497-9514 | ||||
| B090 | 2022 | Fracture behaviour of microwave-heated granite under indentation: Experimental and numerical investigation | Li, Qiang; Cheng, Bo; Li, Xibing; Yin, Tubing; Huang, Linqi | https://linkinghub.elsevier.com/retrieve/pii/S0013794422002739 | Microwave-assisted rock breakage is a promising solution for drilling and crushing hard-rock formations. The fundamental mechanical and thermophysical properties of microwave-treated granite were obtained, and the factors affecting the fracture behaviour under indentation were investigated using experimental and numerical methods. The results show that the uniaxial compressive strength, tensile strength, brittleness index, thermal conductivity, and thermal diffusivity of microwave-heated granite are negatively correlated with temperature, whereas the specific heat capacity of treated granite is positively correlated with temperature. The fracture process of microwave-heated granite under indentation can be divided into three stages: elastic deformation, fluctuating penetration, and post-peak. The indentation damage zone near the indenter consists mainly of tensile cracks. Meanwhile, regression analysis shows that the peak indentation force, penetration depth, and consumed energy of the microwave-heated sample are linearly correlated with the brittleness index. In addition, microwave treatment can weaken the inhibitory effect of a high confining stress on the damage zone and is conducive to reducing the indentation force and penetration depth of rock fragmentation. The specific energy is more sensitive to temperature under high confining stress conditions, and the relationship between the specific energy, temperature, and confining stress can be described by a 2D poly function. | 10.1016/j.engfracmech.2022.108535 | English | Journal Article | Engineering Fracture Mechanics | 269 | 108535 | |||||
| B091 | 2021 | Effect of microwave heating on fracture behavior of granite: An experimental investigation | Li, Qiang; Li, Xibing; Yin, Tubing | https://linkinghub.elsevier.com/retrieve/pii/S0013794421002046 | Hard rock breaking is a great challenge for deep drilling and mining engineering, and the microwave-assisted rock breaking technique offers a promising solution. However, the lack of knowledge of the effects of microwave irradiation on hard rocks limits the further development of this technology. Laboratory tests have been conducted to investigate the variations of fracture properties of granite subjected to microwave heating. The semi-circular bend (SCB) specimens were prepared, and mode I fracture tests were conducted on the microwave treated granite specimens. The acoustic emission (AE) events was recorded and the strain field was calculated by the digital image correlation (DIC) technique. The test results demonstrated that the temperature of the sample surface increased linearly as the increasing heating time, and increasing microwave power contributes to enhancing the heating rate. According to the results of scanning electron microscope (SEM), intergranular cracks were the main form of cracks, and the transgranular cracks usually appeared in samples with high microwave power or longer heating time. The generation of micro-cracks can be attributed to the high temperature and the thermal shock. With the increasing heating time, the fracture toughness decreased exponentially, the AE active period prolonged, and the fractal dimension of the fracture surfaces (FSD) continuous increased. Compared to an untreated sample, the maximum principal strain and fracture process zone (FPZ) size of the microwave heated sample were larger at the same loading level, which indicated the enhancement of ductility. According to the experimental results, the relationships between FPZ size, fracture toughness and FSD were empirically regressed. Understanding the effects of microwave heating on the fracture properties is of significant to improve hard rock breaking efficiency. | 10.1016/j.engfracmech.2021.107758 | English | Journal Article | Engineering Fracture Mechanics | 250 | 107758 | |||||
| B092 | 2024 | Experimental study of microwave heating on mechanical properties of fly ash-based cementitious materials | Li, Tan; Yue, Zihan; Li, Jingkai; Li, Qinghai; Li, Yanhui; Chen, Guangbo | https://linkinghub.elsevier.com/retrieve/pii/S2352710224000214 | The mechanical properties of fly ash-based cementitious materials significantly impact the quality of backfilling in coal mine goafs. This paper first conducts experiments on the material proportion of fly ash-based cementitious materials to study the influence characteristics of water-cement ratio and fly ash activator on the mechanical properties of fly ash-based cementitious materials. Based on this, microwave heating experiments are conducted to study the effect characteristics of different microwave heating conditions on the mechanical properties of cementitious materials. When the activator content is 10 g and the mass ratio of ash and cement is 6: 4, the strength of the cementitious material reaches 9.21 MPa after curing for 7 days, which meets the requirements of coal mine filling. When the microwave power is 3 kW and the heating time is 3min, the uniaxial compressive strength is the highest. The increase rate of the strength with the microwave heating power of 3 kW and the heating time of 3min is the largest. The increase rate of the strength of the cementing material with the curing time of 1 d, 3 d and 7 d is 43.13%, 47.68% and 38.44%, respectively. A reasonable microwave heating path is beneficial to increase the strength of cementitious material. The unreasonable microwave heating paths will expand the internal structure of cementitious materials and reduce the strength. The research content of this paper can provide help for microwave heating technology in coal mine backfill application of fly ash-based cementing material and has essential significance for coal mine environmental protection. | 10.1016/j.jobe.2024.108454 | English | Journal Article | Journal of Building Engineering | 83 | 108454 | |||||
| B093 | 2022 | Quantification of thermal damage and dynamic tensile behaviors of hard rock under microwave irradiation: an experimental investigation | Li, Xibing; Wu, Yangchun; Li, Qiang; Yin, Tubing; Huang, Linqi | https://link.springer.com/10.1007/s10064-022-02954-y | Microwave-assisted hard rock breakage is a potential solution for exploitation of deeper resources. A series of ultrasonic nondestructive tests and NMR tests were conducted to quantitatively characterize the thermal damage of granite. The effects of temperature, microwave power, and loading rate on the dynamic tensile behaviors of granite were investigated by the SHPB tests. Results indicate that, when the temperature is higher than 400 °C, the ultrasonic velocity of microwave-treated granite samples significantly decreases, and the dynamic elastic modulus is more sensitive to temperature than microwave power. The microwave heating promotes the simplification of pore structure of granite, which manifests as the conversion of the pore size distribution from bimodal to trimodal and the decreases of fractal dimension of macropores. The dynamic tensile strength increases as the increasing loading rate and decreases as the increasing temperature and power. Under dynamic tensile stress, the microwave treatments weaken the brittleness of granite and the dependence of the dynamic tensile strength on the loading rate. The investigation of rock damage and dynamic tensile strength in this study provides guidance for optimizing microwave-assisted rock breakage technology. | 10.1007/s10064-022-02954-y | English | Journal Article | Bulletin of Engineering Geology and the Environment | 81 | 11 | 461 | ||||
| B094 | 2020 | Effect of microwave irradiation on dynamic mode-Ι fracture parameters of Barre granite | Li, Xing; Wang, Shuai; Xu, Ying; Yao, Wei; Xia, Kaiwen; Lu, Gaoming | https://linkinghub.elsevier.com/retrieve/pii/S0013794419310550 | 10.1016/j.engfracmech.2019.106748 | English | Journal Article | Engineering Fracture Mechanics | 224 | 106748 | ||||||
| B096 | 2016 | Analysis on the growth of different shapes of mineral microcracks in microwave field | Like, Qin; Jun, Dai | https://www.fracturae.com/index.php/fis/article/view/1756 | Microwave heating-assisted ore grinding and crushing can effectively increase the dissociation energy of minerals and decrease energy consumption. Microcrack growth and distribution characteristics inside different shapes of ore particles, which are composed of galena and calcite under microwave irradiation, were analyzed using discrete element method to explore the effects of mineral shapes on microwave-assisted dissociation. Growth laws on the total number of microcracks, numbers of microcracks in galena and calcite, and boundary damage rate against irradiation time under high power and low power were studied. Research results demonstrated that mineral shape mainly affects the quantity of microcracks inside ores but does not their growth law. | 10.3221/IGF-ESIS.37.45 | English | Journal Article | Frattura ed Integrità Strutturale | 10 | 37 | 342-351 | ||||
| B098 | 2025 | A high-power microwave continuous cracking system for hard ores | Lin, Feng; Li, Shiping; Tong, Tianyang; Ao, Yuntan; Liu, Yuxi | https://www.sciencedirect.com/science/article/pii/S2090447925001819#f0025 | English | Journal Article | ||||||||||
| B099 | 2012 | Investigation of microwave-assisted concrete recycling using single-particle testing | Lippiatt, Nicholas; Bourgeois, Florent | https://linkinghub.elsevier.com/retrieve/pii/S0892687511003645 | Microwave heating stands as a strong candidate for selective liberation of multiphase materials like concrete. It takes advantage of the differences in thermal, dielectric and mechanical properties of each of the components to create stress gradients that can lead to grain boundary fracture and embrittlement. | 10.1016/j.mineng.2011.09.017 | English | Journal Article | Minerals Engineering | 31 | 71-81 | |||||
| B107 | 2013 | The Effect of Temperature on Dielectric Permitivity and Microwave Absorption Properties of Anthracite in Microwave Field | Liu, Chenhui; Zhang, Libo; Peng, Jinhui; Liu, Bingguo; Xia, Hongâ€ying; Chen, Hua; Huang, Kaâ€ma | https://onlinelibrary.wiley.com/doi/10.1002/9781118659045.ch46?msockid=2df15d11050e60b5226c4a17049461ac | This chapter contains sections titled: Introduction Experimental Results and Discussion Conclusions Acknowledgements Introduction Experimental Results and Discussion Conclusions Acknowledgements | 10.1002/9781118659045.ch46 | Characterization of Minerals, Metals, and Materials 2013 | 397-406 | ||||||||
| B108 | 2012 | The Effect of Temperature on Complex Permittivity and Microwave Absorption Properties of an Ilmenite Concentrate at 2450MHz | Liu, Chenhui; Zhang, Libo; Peng, Jinhui; Liu, Bingguo; Xia, Hongâ€ying; Li, Wei | https://onlinelibrary.wiley.com/doi/abs/10.1002/9781118364833.ch69?msockid=2df15d11050e60b5226c4a17049461ac | This chapter contains sections titled: Introduction Experimental Results and Discussion Conclusions Acknowledgements Introduction Experimental Results and Discussion Conclusions Acknowledgements | 10.1002/9781118364833.ch69 | T.T. Chen Honorary Symposium on Hydrometallurgy, Electrometallurgy and Materials Characterization | 741-750 | ||||||||
| B109 | 2022 | Coal and Gangue Active Identification Method Using Microwave Irradiation-Infrared Detection | Liu, Chuang; Mitri, Hani S.; Li, Huamin | https://www.mdpi.com/2075-163X/12/8/951 | In the process of the longwall top coal caving method, automatic distinction between coal and gangue at the working face is one of the most critical factors for the success of the operation. An active coal and gangue identification method using microwave irradiation combined with infrared detection is proposed in this paper. Coal and gangue are irradiated with microwave to actively enhance the external differences between them, and then the quantitative data of the difference are quickly collected by a noncontact infrared thermal imager, to perform identification of coal and gangue. Using theoretical analysis and laboratory experiments, the physical and chemical properties of coal and gangue are analyzed in order to reveal the thermal sensitivity of coal and gangue to microwave irradiation. The influences of the coal and gangue particle size, microwave irradiation time and microwave frequency on the thermal sensitivity to microwave irradiation are investigated. The experimental results show that the average temperature rise in coal is approximately 1.5 times that in gangue material under the same microwave irradiation conditions. This supports the feasibility of this identification method, and provides theoretical and experimental bases for achieving rapid and accurate identification of coal and gangue in top coal caving operations. | 10.3390/min12080951 | English | Journal Article | Minerals | 12 | 8 | 951 | ||||
| B110 | 2014 | Exploration of microwave-assisted breakage of rocks: The effect of size, shape, and internal discontinuity of rock on microwave distribution | Liu, Fan | https://escholarship.mcgill.ca/downloads/d791sk22g.pdf | English | Canada | Masters Thesis | |||||||||
| B111 | 2022 | Mechanistic Study of a Microwave Field-Controlled Static Crushing Agent for Efficient Rock Breaking | Liu, Huabin; Li, Wentao; Guan, Weiming; Zhao, Hongchao; Junhui, Yao; Yingyuan, Wen | https://pubs.acs.org/doi/10.1021/acsomega.2c03598 | The long reaction time and uncontrollable reaction process of the swelling agent in the process of rock breaking by static crushing agent lead to unsatisfactory efficiency and effect of rock breaking. This paper uses physical experiments to compare and analyze the changes in temperature and pressure of the hydration reaction under different microwave conditions; utilizes microscopic analysis of the hydration reaction products under each condition, combined with numerical calculations to elucidate the mechanism of the effect of microwave field on the hydration reaction of the expansion agent; and proposes a microwave fieldcontrolled static crushing agent rock-breaking method. The study reached the following main conclusions: (1) microwave heating is better than conventional heating in terms of heating rate, peak temperature, and peak pressure; (2) using static crushing agent rock breaking is preferable to use a low-power microwave field to control the reaction process, and to ensure that the initial temperature is not higher than the local water boiling point; (3) microwave heating to promote the reaction mechanism lies in its deep heating of the system, faster heating rate, and higher energy utilization, and is more conducive to hydration expansion reaction; (4) selective heating of microwaves can enhance the hydration reaction of calcium oxide and inhibit the production of hydrated tricalcium silicate, making the reaction more complete, while microwave heating will also improve the microstructure of hydration products. | 10.1021/acsomega.2c03598 | English | Journal Article | ACS Omega | 7 | 33 | 29344-29355 | ||||
| B112 | 2022 | Investigation of microwave-induced cracking behavior of shale matrix by a novel phase-field method | Liu, Jia; Xue, Yi; Zhang, Qi; Shi, Fang; Wang, Huimin; Liang, Xin; Wang, Songhe | https://linkinghub.elsevier.com/retrieve/pii/S0013794422003927 | 10.1016/j.engfracmech.2022.108665 | English | Journal Article | Engineering Fracture Mechanics | 271 | 108665 | ||||||
| B113 | 2022 | Microwave heating uniformity, road performance and internal void characteristics of steel slag asphalt mixtures | Liu, Jianan; Wang, Zhenjun; Li, Meng; Wang, Xiaofeng; Wang, Zehui; Zhang, Tonghuan | https://linkinghub.elsevier.com/retrieve/pii/S0950061822028112 | Steel slag (SS) has good microwave absorption and microwave heating potential. Firstly, SS was classified by the difference of microwave capacity, and high heat source (HHS) steel slag was selected to partially replace limestone to prepare steel slag asphalt mixture (SSAM) in this work. The morphology and elements of SS were analyzed by microcosmic tests. Then the surface temperature and thermal transfer process of SSAM were studied. In addition, the road performance of SSAM under different microwave cycles was evaluated. Finally, the influence of microwave heating on the air voids structures of SSAM was analyzed by X-ray computed tomography (CT). The results show that the surface temperature of SSAM prepared by HHS steel slag is not significantly reduced, and the uniformity of microwave heating is greatly improved. The metallic elements in SS are the reasons for enhancing the microwave absorption performance of SSAM. After microwave cycling, the road performance of the mixture continues to decline; CT scan results show that microwave heating can reduce the micro voids in SSAM but increase the ratio of large voids and extra-large voids, which causes the decrease of durability. Overall, this work contributes to improving the durability and sustainability of asphalt pavements under microwave irradiation. | 10.1016/j.conbuildmat.2022.129155 | English | Journal Article | Construction and Building Materials | 353 | 129155 | |||||
| B114 | 2024 | Stress-induced Strong Microwave Radiation of Rock: The Recent Experimental Results | Liu, Wenfang; Liu, Shanjun; Wei, Lianhuan; Han, Xin; Zhu, Ankui; Cui, Huashuo | https://ieeexplore.ieee.org/document/10720132/ | Microwave brightness temperature (TB) anomalies preceding strong earthquakes have been frequently observed by satellite microwave remote sensing. To reveal the physical mechanism of the pre-earthquake TB anomalies, rock mechanics experiments have been conducted through microwave radiation observation at low stress levels, and only weak microwave radiation has been detected, which is insufficient to detect by satellite microwave sensors. This is inconsistent with the strong pre-earthquake TB anomalies monitored by satellite microwave remote sensing. In this study, a microwave observation experiment of rock under tiered cyclic loading with a gradually increasing cyclic stress was conducted, to investigate the TB variation throughout the elastic deformation and failure process. The experimental results illustrate that the TB and stress continuously maintain a positive correlation, with a linear correlation coefficient greater than 0.90. A stronger TB variation of 3.07 K than the previous experimental results is observed at a high stress change of 96 MPa, which is quantitatively in the same order as the TB anomalies detected by satellite microwave remote sensing. And with the stress increases, the TB variation decreases shortly preceding rock failure due to the formation of fractures, which is in agreement with the short-term weakening of preearthquake TB anomalies. The outcome of this study promotes the understanding of pre-earthquake TB anomalies detected by satellite microwave remote sensing. | 10.1109/TGRS.2024.3481892 | English | Journal Article | IEEE Transactions on Geoscience and Remote Sensing | 45292 | ||||||
| B115 | 2015 | Stuy on Microwave-Assisted Grinding of Low-Grade Ludwigite | Liu, Ya Jing; Jiang, Tao; Deng, Zhi; Xue, Xiang Xin; Duan, Pei Ning | https://www.scientific.net/MSF.814.214#:~:text=By%20the%20microwave%20heating%20temperature,which%20would%20not%20affect%20the | The low-grade ludwigite is one of the complex and refractory ores. Based on the high energy consumption and inefficient in the grinding process and according to the microwave-assisted grinding principle, this paper studied the microwave absorption property of ludwigite and researched the effect of microwave heating on the grinding efficiency of it. The non-microwaved and microwaved samples were characterized with regard to the chemical components, mineral compositions, macroscopic structure and microstructure, grinding efficiency by methods of the chemical analysis, X-ray diffraction (XRD), scanning electron microscopy (SEM) and grain size analysis, etc. The results indicated that ludwigite, with good microwave absorption property, was suitable for microwave processing. The grindability of microwaved ludwigite was related to the microwave power and microwave heating temperature. By the microwave heating temperature attained 500~650°C, many macro-cracks and micro-cracks were produced by thermal stress between different mineral interfaces, which resulted in the decrease of strength of ludwigite and easy levigation, but the mineral compositions had no obviously changed, which would not affect the subsequent magnetic separation. It was concluded that short, high-power treatments were most effective but over-exposure of the sample led to reductions in efficiency. Under the same conditions, the grinding efficiency of ludwigite was improved 24.54% higher than untreated ore, which significantly improved the grinding efficiency and reduced energy consumption. | 10.4028/www.scientific.net/msf.814.214 | Materials Science Forum | 814 | 214-219 | |||||||
| B116 | 2017 | Influence of microwave treatment on mechanical behaviour of compact basalts under different confining pressures | Lu et al. | https://www.sciencedirect.com/science/article/pii/S1674775519307243 | ||||||||||||
| B117 | 2019 | Experimental Investigation on the Effects of Microwave Treatment on Basalt Heating, Mechanical Strength, and Fragmentation | Lu et al. | https://link.springer.com/article/10.1007/s00603-019-1743-y | ||||||||||||
| B119 | 2016 | Review of theoretical and experimental studies on mechanical rock fragmentation using microwave-assisted approach | Lu, G.; Li, Y.; Hassani, F. | https://www.cgejournal.com/en/article/doi/10.11779/CJGE201608018 | ||||||||||||
| B121 | 2023 | Influences of Microwave Irradiation on the Physicomechanical Properties and Cerchar Abrasivity Index of Rocks | Lu, Gaoming; Ding, Cong; Hong, Kairong; Zhou, Jianjun; Liu, Haining; Yan, Changbin | https://www.hindawi.com/journals/geofluids/2023/3889083/ | The research is aimed at exploring the influences of microwave irradiation on the physicomechanical properties and Cerchar abrasivity index (CAI) of rocks. For this purpose, basalt collected in Chifeng (the Inner Mongolia Autonomous Region, China) was taken as research objects to carry out microwave irradiation tests for different durations in a multimode cavity. By using the MTS815 mechanical testing machine and the abrasion servo tester of rocks, mechanical tests and Cerchar abrasion tests were conducted before and after microwave irradiation. Changes in the mass, volume, surface fractures, surface temperature, ultrasonic wave velocity, uniaxial compressive strength (UCS), and CAI of the basalt samples before and after microwave irradiation were analyzed. Results show that the surface temperature of basalt samples linearly increases with the duration of microwave irradiation. The volume and fracture coalescence of the rock samples both increase with the prolonging duration of microwave irradiation. The mass, ultrasonic wave velocity, UCS, and CAI of the basalt samples all decrease with the increase in the duration of microwave irradiation. The reduction of the physicomechanical properties and CAI of rocks indicates that microwave irradiation can reduce the wear of rock-breaking tool and thus improve the efficiency of rock breaking. | 10.1155/2023/3889083 | English | Journal Article | Geofluids | 2.023 | 45301 | |||||
| B122 | 2019 | Experimental Investigation on the Effects of Microwave Treatment on Basalt Heating, Mechanical Strength, and Fragmentation | Lu, Gao-Ming; Feng, Xia-Ting; Li, Yuan-Hui; Hassani, Ferri; Zhang, Xiwei | http://link.springer.com/10.1007/s00603-019-1743-y | Microwave energy can be used to assist mechanical rock breakage for civil and mining engineering operations. To assess the industrial applicability of this technology, microwave heating of basalt specimens in a multi-mode cavity (a microwave chamber) at different power levels was followed by conventional mechanical strength and fragmentation effect tests in the laboratory. X-ray diffraction and scanning electron microscopy/energy-dispersive X-ray spectroscopy were used to determine the mineral composition and distribution of the basalt, to aid interpretation of crack propagation patterns and the associated strength reduction mechanism. These analyses demonstrated that cracks mainly occurred around olivine grains, primarily as intergranular cracks between olivine and plagioclase grains and intragranular cracks within olivine grains. Strength reduction during microwave fracturing of basalt is driven by heat from enstatite (a microwave-sensitive mineral) and volumetric expansion of olivine (a thermally expansive mineral). Uniaxial compressive, Brazilian tensile, and point load strengths all decreased with increasing microwave irradiation time at rates that were positively related to the power level. For a given power level, mechanical strength reduction can be estimated from linear relationships with irradiation time. On the other hand, a power function best described burst time (the irradiation time at which the specimen burst into fragments) vs. power level (for a given specimen size) and burst time vs. specimen size (for a given power level) relationships. Microwave-induced hard rock fracturing can be an integral part of new methods for rock breakage and tunnel excavation. | 10.1007/s00603-019-1743-y | English | Journal Article | Rock Mechanics and Rock Engineering | 52 | 8 | 2535-2549 | ||||
| B123 | 2020 | Influence of microwave treatment on mechanical behaviour of compact basalts under different confining pressures | Lu, Gaoming; Feng, Xiating; Li, Yuanhui; Zhang, Xiwei | https://linkinghub.elsevier.com/retrieve/pii/S1674775519307243 | The realisation of microwave-induced fracturing of hard rocks has potential significance for microwaveassisted mechanical rock fracturing and stress release in deep rock masses. In this context, compact basalts were treated by microwave heating in a multi-mode cavity at a frequency of 2450 MHz, and then, we investigated the mechanical behaviour of basalt samples after microwave treatment under uniaxial compression and conventional triaxial compression (CTC) tests. After microwave exposure, cracks appeared on the surface and inside of the rock sample, and the temperature of the sample’s surface was unevenly distributed. The results show that the conventional triaxial compressive strength (CTCS) of basalt samples decreased linearly with microwave exposure time, and the higher the confining pressure, the smaller the reduction in the strength of basalt samples after microwave treatment. Under uniaxial compression, microwave exposure greatly affected the axial deformation, suggesting that deformation resistance of the samples gradually decreases with increasing microwave exposure time. Under triaxial compression, some microcracks induced by microwave exposure closed due to the effect of confining pressure, resulting in the confining pressure inhibiting any rightward shift of the axial deformation curve. Furthermore, under uniaxial compression, the elastic modulus and Poisson’s ratio of basalts also decreased in a quasi-linear manner with elapsed microwave exposure time. Under triaxial compression, microwave exposure has slight influence on elastic modulus and Poisson’s ratio. After microwave treatment, the changes in rock strength and deformation mainly result from changes in between the mineral structures. Confining pressure results in the closure of microcracks produced by microwave exposure, so that effects of microwave treatment on strength and deformation decrease, thus reducing the influence on elastic constants. The cohesion decreases with increasing microwave exposure time and shows an approximately linear decrease over time. In the basalt samples, new microcracks in various directions generated by microwave exposure can increase the discreteness of test results, while the discreteness of test results caused by microcracks gradually reduces with increasing confining pressure. Ó 2019 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/ licenses/by-nc-nd/4.0/). | 10.1016/j.jrmge.2019.06.009 | English | Journal Article | Journal of Rock Mechanics and Geotechnical Engineering | 12 | 2 | 213-222 | ||||
| B124 | 2020 | The influence of minerals on the mechanism of microwave-induced fracturing of rocks | Lu, Gaoming; Zhou, Jianjun; Li, Yuanhui; Zhang, Xiwei; Gao, Wenyuan | https://linkinghub.elsevier.com/retrieve/pii/S0926985119308213 | 10.1016/j.jappgeo.2020.104123 | English | Journal Article | Journal of Applied Geophysics | 180 | 104123 | ||||||
| B125 | 2018 | The thermal damaging process of diorite under microwave irradiation | Lu, Xirui; Yuan, Chen; Junsen, Zeng; Qijun, Hu; Dadong, Shao; Haibin, Zhang; Xirui, Lu | https://www.fracturae.com/index.php/fis/article/view/2214 | 10.3221/IGF-ESIS.47.06 | English | Journal Article | Frattura ed Integrità Strutturale | 13 | 47 | 65-73 | |||||
| B126 | 2020 | Effects of microwave pre-treatment on the flotation of ilmenite and titanaugite | Luo, Liping; Wu, Houqin; Yang, Jie; Tang, Zhen; Shu, Kaiqian; Xu, Yanbo; Yan, Weipin; Xu, Longhua | https://linkinghub.elsevier.com/retrieve/pii/S0892687520302727 | The selective separation of titanium-containing minerals is industrially important. Microwave irradiation pretreatment can be used to modify the surface properties of minerals to promote selective flotation. However, the effects of MW treatment on titanium-containing minerals is not well understood. Therefore, in this study, we investigated the effects of microwave treatment on the flotation behaviour of ilmenite and titanaugite in a mixture of these minerals. The effects of this pre-treatment method were investigated by various techniques, including flotation tests, scanning electron microscopy (SEM), inductively coupled plasma-optical emission spectrometry (ICP-OES), zeta potential measurements, X-ray photoelectron spectroscopy (XPS), and Fouriertransform infrared (FTIR) spectroscopy. The flotation tests results reveal that, under the optimum microwave conditions (800 W, 450 s), microwave irradiation has a remarkable effect on the flotation of ilmenite but no significant effect on the floatability of titanaugite at pH 6.0. The results of the SEM and ICP-OES analyses indicate that microwave irradiation promotes the dissolution of Ca2+ and Mg2+ ions from the titanaugite surface, whereas the dissolution of these ions from ilmenite is limited. Further, the zeta potential of the microwave-irradiated ilmenite shifted toward negative values, and the isoelectric point shifted from pH 4.9 to pH ~1.9. In addition, the XPS results reveal that microwave irradiation facilitates the conversion of Fe2+ to Fe3+ on the mineral surfaces. The FTIR spectra and zeta potential values indicate that microwave irradiation can enhance the chemical adsorption of oleate ions on the surface of the ilmenite. After microwave irradiation, the effects of both the dissolution of Ca2+ and Mg2+ ions and the oxidation of Fe2+ to Fe3+, the floatability of ilmenite was significantly improved, whereas that of titanaugite was not changed significantly. | 10.1016/j.mineng.2020.106452 | English | Journal Article | Minerals Engineering | 155 | 106452 | |||||
| B127 | 2022 | Three-dimensional mesostructure model of coupled electromagnetic and heat transfer for microwave heating on steel slag asphalt mixtures | Luo, Wei; Huang, Siyang; Liu, Yuhong; Peng, Hui; Ye, Yong | https://linkinghub.elsevier.com/retrieve/pii/S0950061822009151 | Steel slag as a special type of aggregate in asphalt mixture owns excellent potential for microwave heating. To gain high heating performance, the determinant of the optimal content of steel slag in asphalt mixture becomes a key problem. This paper develops a numerical model of the mesostructure of the three-phase asphalt mixture (aggregate, steel slag, and asphalt mortar) with coupled electromagnetic field and heat transfer process. Firstly, the model generates spherical aggregates by the random placement method based on the given grading. Then, the limestone aggregate particles are replaced by steel slag with the same volume. Finally, microwave heating analysis of asphalt mixtures with different steel slag contents is performed by FEM. The comparison between our numerical simulations and the reported experimental data demonstrates that the proposed model is reliable and effective. This research can characterize well the heat transfer among components of asphalt mixture during microwave heating and show the details of the inner temperature distribution. The results also indicate that the microwave heating performance of asphalt mixture enhances with the increase of steel slag content. However, excessive steel slag content can lead to overheating in most areas of the asphalt mixture, and the temperature distribution is more uniform and suitable when steel slag replaces coarse aggregate (4.75 – 9.5 mm) with an equal volume about 60 %. | 10.1016/j.conbuildmat.2022.127235 | English | Journal Article | Construction and Building Materials | 330 | 127235 | |||||
| B130 | 2022 | Effect of joints on microwave fracturing of the Bukit Timah granite using an open‐ended antenna | Ma, Zhongjun; Zheng, Yanlong; He, Lei; Li, Jianchun | https://onlinelibrary.wiley.com/doi/10.1002/dug2.12024 | Microwave fracturing of rocks before mechanical breakage could improve the performance of mechanical excavators and reduce environmental impacts. Previous research focused on the microwave fracturing of intact rock blocks. By using an open‐ended antenna, this paper investigates the effect of pre‐existing joints on the microwave fracturing of the Singapore Bukit Timah granite blocks. The results show that the specimens are weakened in the manners of cracking, spalling, melting, or a combination of them. The crack number and the total crack length produced by microwave treatment of jointed rock blocks are slightly smaller than those in the intact rock blocks. The interaction between joints and microwave‐induced cracks can be summarized into the following four patterns: (1) microwave‐induced cracks become arrested so that the crack propagation is terminated; (2) microwave‐induced cracks penetrate the joints and continue to propagate; (3) microwave‐induced cracks become deflected along the joints; and (4) microwave‐induced cracks propagate forward following the joints. The smaller the approach angle between the microwave‐induced crack and the preexisting joint is, the more microwave‐induced cracks tend to be arrested at the joint. Increasing the approach angle between the microwave‐induced crack and the joint can increase the chance of microwave‐induced crack penetrating the joint. The results also show that the smaller the distance is between the microwave radiation point and the joint, the easier it is for microwave‐induced cracks to penetrate the joints; otherwise, the microwave‐induced crack is more likely to be arrested at the pre‐existing joint. | 10.1002/dug2.12024 | English | Journal Article | Deep Underground Science and Engineering | 1 | 2 | 138-147 | ||||
| B131 | 2021 | Thermal stresses and temperature distribution of granite under microwave treatment | Ma, Zhongjun; Zheng, Yanlong; Sun, Tingwen; Li, Jianchun | https://iopscience.iop.org/article/10.1088/1755-1315/861/3/032094 | Efficient breakage of high strength rocks is a challenging task where conventional drilling and blasting methods are not preferred or allowed, for example, rock excavation in long tunnels at a great depth and urban environment sensitive to noise and vibration. Microwave treatment is an efficient and environmentally friendly method, which is considered to be one of the most promising ways to increase the performance of mechanical excavators, such as roadheaders and impact hammers. However, the mechanisms of microwave fracturing of granitic rocks have not been well investigated. In this study, Chinese granite was used as the research material. Its mineral composition and grain size were first characterized using petrographic thin section observation. Cubic granite samples were then heated in a single-mode industrial microwave. The temperature was captured using a high resolution infrared thermal camera. Then a realistic 3-D rock model with the same mineralogical properties was established using Voronoi tessellation. The multi-physics numerical model was calibrated using data from microwave heating tests. The effect of microwave power intensity, heating time, and mineral grain size on the temporal and spatial temperature distribution, and thermal stresses in the granite matrix was investigated in a comprehensive manner. The temperature gradients and thermal stresses were calculated. The maximum temperature gradient and the maximum tensile stress appeared at the interface between quartz and biotite. As either power level or heating time increased, the thermal gradient and the maximum tensile stress increased, and with same microwave energy output, greater temperature gradient and thermal stress could be generated during microwave heating at higher power levels for shorter durations. Moreover, the greater the grain size, the bigger the maximum tensile stress. The finding of the paper contributes the understanding of the mechanisms of microwave fracturing of rocks. | 10.1088/1755-1315/861/3/032094 | English | Journal Article | IOP Conference Series: Earth and Environmental Science | 861 | 3 | 32094 | ||||
| B132 | 2022 | A Dielectric-Loaded Converging Waveguide Antenna for Microwave Fracturing of Hard Rocks | Ma, Zhongjun; Zheng, Yanlong; Zhao, Xiaobao; Li, Jianchun; Zhao, Jian | https://ieeexplore.ieee.org/document/9670676/ | Microwave fracturing has a great potential in assisting excavators in breaking hard and abrasive rocks. The key to utilizing this technology is to design an antenna that is capable of fracturing low loss rocks at relative low power levels in a short duration. This article presents the design of a dielectric-loaded converging waveguide antenna (DLCWA) composed of a pyramid-shaped alumina infilling and a converging waveguide. The design of the DLCWA is optimized based on the maximum temperature, the high temperature volume and the effective working distance. To validate the design, a prototype antenna is manufactured and used for microwave heating and fracturing tests. The numerical simulations and experimental tests demonstrate that the designed DLCWA has unparalleled advantages at the radiation distance of 0-30 mm over the WR430 waveguide and a 30 mm unloaded converging waveguide antenna. With improved performance in power focusing and directivity, the proposed DLCWA is by far the most suitable antenna for microwave fracturing of low loss hard rocks. | 10.1109/TAP.2021.3138425 | English | Journal Article | IEEE Transactions on Antennas and Propagation | 70 | 6 | 4243-4249 | ||||
| B133 | 2020 | Absorbance and transformation of SHF electromagnetic waves in quartz-containing heterogenic materials | Makhmudov, Kh F | https://iopscience.iop.org/article/10.1088/1742-6596/1697/1/012182 | A study of the mechanism of uptake and conversion of microwave energy into heat energy is presented. The term ”SHF – trigger”, which activates at the atomic, electronic, and molecular scales, is introduced for the mechanism of micro cracking, destruction, and crashing of quartz-containing rocks. It has been found that the uptake and conversion of microwave energy into heat energy begins there were some criteria of the sample instability in energy consummation are satisfied. This mechanism of the energy conversion with the heating effect differs from other modes of heating by its efficiency; accordingly, a special criterion is required. The loss tangent of a dielectric, such as mineral or heterogeneous rock, could serve as a measured parameter. This parameter is attributed to slowly establishing modes of relaxation, which manifest themselves in the presence of polar molecules, complicated anion radicals, chemically bounded water, solid/liquid interfaces, borders of dielectrics and conductors. In addition, a new mechanism of conversion of microwave energy into heat energy in points of contact between water-saturated pores in model specimens was suggested. | 10.1088/1742-6596/1697/1/012182 | English | Journal Article | Journal of Physics: Conference Series | 1.697 | 1 | 12182 | ||||
| B134 | 2006 | An Experimental Study of Microwave Emissions from Compression Failure of Rocks | Maki, Ken-ichiro; Takano, Tadashi; Soma, Eriko; Ishii, Kentaro; Yoshida, Shingo; Nakatani, Masao | https://www.jstage.jst.go.jp/article/zisin1948/58/4/58_4_375/_article/-char/ja/ | Electromagnetic emissions observed in a series of rock fracture tests are described. Four kinds of rocks, basalt, gabbro, granite and quartzite were pressed by uniaxial compression to fracture, for all of which many signals were detected at two microwave bands (2 GHz and 300 MHz). These detected signals consist of intermittent pulses of a short duration. Comparing the microwave records and the observation with a high-speed digital video camera, we found that the pulse signals were generated after the decrease of the axial load, and even after the macroscopic fracture (deformation) was completed. This differs from the occurrence of lower frequency emissions (0.3-300 kHz) monitored as well, which became active and was strongest during the load decrease. The occurrence of signals at the two microwave bands did not always coincide, but a signal at 300 MHz often followed a signal at 2 GHz with a short interval of 50-100 ns. An additional detector at 22 GHz picked up emissions only for quartzite, which occurred exclusively during the decrease of axial load. | 10.4294/zisin1948.58.4_375 | ja | Journal Article | Zisin (Journal of the Seismological Society of Japan. 2nd ser.) | 58 | 4 | 375-384 | ||||
| B136 | 2019 | Microwave Emission of Rock Change with Compressive Stress: Experiments and Physics | Mao, Wenfei; Wu, Lixin; Liu, Shanjun; Qi, Yuan | https://ieeexplore.ieee.org/document/9021879/ | The stress-induced additional microwave emission of rock is of great importance and potentialities for studying geo-hazards and monitoring thermal anomalies in seismic prone zones with satellite remote sensing. Many laboratory experiments have illustrated obvious variation of microwave emission in process of rock loading to fracturing, but the underlying mechanism is not clear. By using a C-band microwave radiometer (6.9 GHz) and an open end resonant probe, the variations of microwave brightness temperature (MBT) and microwave dielectric property of rock specimens being axially compressively loaded are experimentally investigated, respectively. The experimental results show 1) the MBT of rock specimen increase obviously with increasing loads at elastic deformation stage; 2) the dielectric constants of rock specimens decreases by 0.03 ∼ 0.05 with increasing compressive stress, of which the induced variations of MBT is basically consistent with the results from MBT observations. Therefore the alteration of rock microwave dielectric permittivity at elastic deformation stage is presented to be the basic mechanism of rock microwave emissivity change, and thus lead to the variation of rock MBT. This study provides an electromagnetic base for analyzing stress-induced rock microwave emission and for monitoring crust stress filed alteration process (such as in process of tectonic earthquake preparation) using satellite microwave remote sensing data. | 10.1109/PIERS-Fall48861.2019.9021879 | English | conferencePaper | 2019 Photonics & Electromagnetics Research Symposium - Fall (PIERS - Fall) | 1811-1818 | ||||||
| B137 | 2020 | Impact of Compressive Stress on Microwave Dielectric Properties of Feldspar Specimen | Mao, Wenfei; Wu, Lixin; Qi, Yuan | https://ieeexplore.ieee.org/document/8886361/ | As one of the most important electrical properties, the dielectric permittivity of minerals and rocks has been studied with respect to its influencing factors, such as texture, density, moisture, frequency, pressure, etc., and has aroused great interest in geophysics, mineralogy, petrology, and microwave remote sensing. However, the studies on the effect of stress on the dielectric property of rock are limited to lower frequencies, and the related mechanism is not yet clear. Considering the limitations of traditional testing methods and the complexities of compositions and structures of rock specimens, in this article, we choose the minerals of the feldspar group as specimens to investigate the impact of compressive stress on their dielectric property at a higher frequency range from 2 to 18.3 GHz. For this purpose, an open coaxial resonator probe is applied to measuring the alteration of the dielectric permittivity of the feldspar specimen in the process of increasing compressive stress using a specially designed loading device. The dielectric constants of the feldspar specimen at all of the five high-frequency points demonstrate obviously decreasing trends with increasing compressive stress. The particular discovery is that the ionic and electronic polarizations are much sensitive to the increasing compressive stress in the microwave frequency band, where the minerals behave like ionic crystals. This article implies that the variation of the microwave dielectric permittivity of rock mass under altering crustal stress due to tectonic plate movements and engineering disturbances is an important factor to be considered in applying radar investigation and microwave remote sensing for mineral exploration, geological exploration, and geo-hazard perception. | 10.1109/TGRS.2019.2946155 | English | Journal Article | IEEE Transactions on Geoscience and Remote Sensing | 58 | 2 | 1398-1408 | ||||
| B138 | 2021 | Temperature-Induced Explosive Behaviour and Thermo-Chemical Damage on Pyrite-Bearing Limestones: Causes and Mechanisms | Martínez-Ibáñez, V.; Benavente, D.; Hidalgo Signes, C.; Tomás, R.; Garrido, M. E. | http://link.springer.com/10.1007/s00603-020-02278-x | In this investigation, two different varieties of ‘Prada’ limestones were studied: a dark grey texture, bearing quartz, clay minerals, organic matter and pyrites, and a light grey texture with little or no presence of such components. We have observed two effects of different intensity when heating the dark texture from 400 °C: (1) the explosion of certain samples and (2) greater thermal damage than in the light grey texture. Chemical and mineralogical composition, texture, microstructure, and physical properties (i.e. colour, open porosity, P and S-wave velocity) have been evaluated at temperatures of 105, 300, 400, and 500 °C in order to identify differences between textures. The violence of the explosive events was clear and cannot be confounded with ordinary splitting and cracking on thermally treated rocks: exploded samples underwent a total loss of integrity, displacing and overturning the surrounding samples, and embedding fragments in the walls of the furnace, whose impacts were clearly heard in the laboratory. Thermogravimetric results allowed the identification of a process of oxidation of pyrites releasing SO2 from 400 °C. This process jointly with the presence of microfissures in the dark texture, would cause a dramatic increase in pore pressure, leading to a rapid growth and coalescence of microcracks that leads to a process of catastrophic decay in rock integrity. In addition to the explosive events, average ultrasound velocities and open porosity showed a greater variation in the dark grey texture from 400 °C. That result also points towards a significant contribution of oxidation of pyrites on the thermo-chemical damage of the rock, among other factors such as the pre-existence of microfissures and the thermal expansion coefficient mismatch between minerals. Implications in underground infrastructure and mining engineering works are critical, as the explosive potential of pyrite-bearing limestones bears risk for mass fracturing and dramatic strength decay from 400 °C. Moreover, SO2 released has harmful effects on health of people and the potential to form acid compounds that corrode materials, shortening their durability and increasing maintenance costs. | 10.1007/s00603-020-02278-x | English | Journal Article | Rock Mechanics and Rock Engineering | 54 | 1 | 219-234 | ||||
| B140 | 2015 | Microwave propagation and absorption and its thermo-mechanical consequences in heterogeneous rocks | Meisels, R.; Toifl, M.; Hartlieb, P.; Kuchar, F.; Antretter, T. | https://linkinghub.elsevier.com/retrieve/pii/S0301751615000046 | 10.1016/j.minpro.2015.01.003 | English | Journal Article | International Journal of Mineral Processing | 135 | 40-51 | ||||||
| B141 | 2017 | Effect of Microwave Pretreatment on Grinding of Iron Ore | Mendoza, A. López; Gómez, J.A. Delgadillo | https://asianpubs.org/index.php/ajchem/article/view/29_5_9 | The effect of microwave radiation on grinding of an iron ore was investigated. Significant reductions in Bond work index are demonstrated for microwave treated samples. These reductions are sensitive to the power applied in relation to the exposure time of the mineral to microwaves. The best result was obtained with an exposure time of 3 min, achieving a reduction of 41 % in Bond work index. The grinding kinetics shows that there is a significant effect on the production of fines for the treated sample, since for each grinding time tested, the distribution of passing cumulative size was higher respect to the sample non-treated, particularly for short times. The results obtained indicated important improvements in the size reduction, due to microwave energy, produced microfractures intergranular and transgranular level, caused by differential heating and subsequent thermal expansion between mineral phases absorbing and transparent to microwave radiation. These changes are supported by analytical studies of X-ray diffraction and scanning electron microscopy. It was confirmed that microwave pre-treatment has a significant positive effect on the efficiency of the energy applied to the grinding of iron ore studied. | 10.14233/ajchem.2017.20365 | English | Journal Article | Asian Journal of Chemistry | 29 | 5 | 983-988 | ||||
| B144 | 2024 | Microwave Thermal Treatment for the Recovery of Re in Copper and Molybdenum Concentrates | Bazan, V; Maratta, A.; Villafane, G.; Pacheco, P.; Brandaleze, E. | https://www.eurekaselect.com/article/140596 | ||||||||||||
| B145 | 2017 | The effect of microwave radiation on the flotation of chalcocite | Mirshekari, B.; Koleini, S.M.; Shahbazi, B. | https://www.researchgate.net/publication/313718262_The_effect_of_microwave_radiation_on_the_flotation_of_chalcocite | ||||||||||||
| B146 | 2012 | Microwave-assisted rock breaking modelling and application | Monchusi, B | https://researchspace.csir.co.za/items/be43b025-e387-44a4-8bde-93943fa90cd2 | English | Journal Article | ||||||||||
| B147 | 2009 | An investigation on the influence of microwave energy on basic mechanical properties of hard rocks | Motlagh, Pejman Nekoovaght | https://spectrum.library.concordia.ca/id/eprint/976521/ | English | Journal Article | ||||||||||
| B148 | 2005 | Effects of Microwave Energy Treatment on Value Liberation from Zn and Co-Cu Ores | Mulaba, Antoine F; Lewis, John M L | https://www.researchgate.net/publication/311899809_EFFECTS_OF_MICROWAVE_ENERGY_TREATEMENT_ON_VALUE_LIBERATION_FROM_Zn_AND_Co-Cu_ORES | In the irradiation of ore particles by microwave energy preferential absorption of this energy occurs in minerals having specific dielectric properties (Bradshaw, 1999). This leads to a selective heating of the various components of within the ore particle matrix. The result is a differential thermal expansion of such components and the resulting induced stresses become ideally concentrated at mineral grain boundaries (Kingman et al., 2000). Dependent upon the relative composition of absorbent, opaque and reflective components this may lead to enhancement of the inter-granular fracture of the ore particles in the initial comminution process (Fandrich et al., 1997). The potential is thus a greater proportion of free mineral grain within the fractured ore particle that may lead to improvement in subsequent mineral separation processes. As the composition of the ore dictates the result of such a treatment (Kingman et al., 2000) it is essential to evaluate the response of each ore sample on an individual basis. This paper reports on results obtained from two ore samples: the one being the zinc ore from the Black Mountain mine (South Africa) and the other a pre-concentrated sample of handpicked cobalt–copper mixed oxide ore from the Gecamines (DRC). The equipment and methods used to simulate the comminution of the samples and evaluate the level of the value liberation will be described along with the results obtained. Using King (1975), Kanellopoulous and Ball (1975), and Gungor and Atalay (1998), a comparison between the behaviour upon microwave irradiation of sulphide and mixed oxide ores leads to conclude that while the technique (i.e. microwave irradiation) is appropriate to the zinc sulphide ore, it does not seem to lead to exceptional results for the oxide. | English | Journal Article | |||||||||
| B149 | MW Impact on Mineral Liberation by using DMS | |||||||||||||||
| B150 | 2015 | The Behaviour of Rocks When Exposed to Microwave Radiation | Nekoovaght, P; Gharib, N; Hassani, F | https://onemine.org/documents/the-behavior-of-rocks-when-exposed-to-microwave-radiation | Novel rock breakage techniques are becoming more viable and attractive to industry. Microwave energy, as a thermal energy capable of inducing micro cracks through differential heating (therefore expansion) is a technology gaining considerable attention in mineral processing and ore comminution applications. Recently, the use of microwave radiation has been evaluated as a possible avenue for terrestrial and extra-terrestrial drilling applications as well as full face tunneling or rock breaking machines. As part of an overall research on use of microwave in rock breaking systems, the influence of microwave energy on the mechanical properties of common hard rock types as basalt has been investigated. The results revealed that microwave energy irradiation imposes micro and macro cracks to the surface of the rock being irradiated. In explosive free tunneling applications using TBM, jointed and cracked surface of rock eases the cutting process and increases penetration rate. The experimental setups have been simulated with the help of a multi-physics numerical modeling and the results have been compared with practical experiment. The wave propagation of microwave has been simulated and the distances where the power intensity is higher are identified. Experimental and simulation results underlined the potential impact of the use of microwave energy in underground or surface excavation applications such as mining and tunneling. This will also contribute economically when mine-to-mill operation is fully considered to improve the efficiency of rock crusher stages. | English | Journal Article | |||||||||
| B151 | 2018 | Methods for Characterizing Cracks Induced in Rock | Nicco, Marion; Holley, Elizabeth A.; Hartlieb, Philipp; Kaunda, Rennie; Nelson, Priscilla P. | http://link.springer.com/10.1007/s00603-018-1445-x | A detailed understanding of how induced cracks form and propagate in rock is important in many fields, particularly in mining where size reduction of material is a major cost. This contribution provides a comprehensive review of previously published methods for characterizing rock cracks. The existing methods generate one of the two types of data: crack-related changes in bulk rock properties or the nature of the actual cracks, such as aperture, location, morphology and mineralogical boundaries. However, no single technique provides both types of information. Using a suite of granodiorite specimens which were cracked under microwave irradiation, this contribution illustrates how multiple nondestructive and destructive techniques can be integrated to provide both types of data on cracks induced in rock. Rock property changes were quantified using P-wave velocity measurements and uniaxial compressive strength tests. The cracks were characterized qualitatively and quantitatively using a combined approach of micro-computed tomography, optical microscopy and automated mineralogical analysis of scanning electron microscopy images. The resulting dataset provides information on the mechanical and mineralogical effects of the cracking. The microwave irradiation led to a significant reduction in rock strength, caused by networks of intergranular and intragranular cracks in granodiorite, disproportionately associated with biotite. Based on the strengths and limitations of each method as illustrated by the granodiorite results, recommended protocols are provided for evaluating cracks in four different types of studies: (1) quick assessments of damage; (2) geotechnical investigations; (3) mineralogical investigations and (4) comprehensive evaluations of the effects of cracking, requiring data on mechanical properties and the characteristics of the cracks. | 10.1007/s00603-018-1445-x | English | Journal Article | Rock Mechanics and Rock Engineering | 51 | 7 | 2075-2093 | ||||
| B152 | 2014 | Deep Geothermal Drilling Using Millimeter Wave Technology (Final Technical Research Report) | Oglesby, Kenneth; Woskov, Paul; Einstein, Herbert; Livesay, Bill | http://www.osti.gov/servlets/purl/1169951/ | Conventional drilling methods are very mature, but still have difficulty drilling through very deep, very hard and hot rocks for geothermal, nuclear waste entombment and oil and gas applications. This project demonstrated the capabilities of utilizing only high energy beams to drill such rocks, commonly called ‘Direct Energy Drilling’, which has been the dream of industry since the invention of the laser in the 1960s. A new region of the electromagnetic spectrum, millimeter wave (MMW) wavelengths at 30-300 giga-hertz (GHz) frequency was used to accomplish this feat. | English | report | DE--EE0005504Final, 1169951 | ||||||||
| B154 | 2016 | EFFECT OF MICROWAVE TREATMENT ON THE GRINDABILIY OF GALENA-SPHALERITE ORES | Ola-Omole, O O; Adewuyi, B O; Potgieter, J H; Borode, J O | http://www.ijlret.com/Papers/Vol-2-issue-2/version-2/20-B2016084.pdf | This work studied the effect of microwave treatment on the grindabiliy of galena-sphalerite ores using iron ore of known work index as the reference ore. The sulphide ore was divided into four portions, three portions were microwaved for 30, 60 and 90 seconds respectively while the fourth portion was used for the controlled experiment. The samples were treated at 750W in 2.45GHz microwave oven. All samples including iron ore were crushed in a jaw crusher and milled in a ball mill. 300g of 600µm samples were weighed for sieve analysis as feed for the reference ore. The work index of the sulphide ore has reduced from 11.22kwhr/sht to 9.38 Kwhr/sht, 8.19kwhr/sht, 7.35kwhr/sht after microwave treatment for 30, 60 and 90 seconds respectively. This means that there had been reduction in energy expended in pulverizing. Anka ore can saved up to 15.4%, 27.0% and 34.3% after 30, 60 and 90seconds treatment respectively when comminuted. | English | Journal Article | |||||||||
| B155 | 2021 | The Effects of high-power microwaves on comminution and downstream processing | Olmsted, Adam Edward | https://queensu.scholaris.ca/items/4f89d159-2809-45d2-bff3-c2ed81b89cf0 | gold sulphide ore; copper-nickel sulphide ore | microwave; BET; comminution; leaching; pilot plant; roasting | The incentive for this research was to assess the potential of microwave treatment to fracture ores and improve surface area to reduce comminution energy consumption and improve downstream recovery. Pilot-scale microwave treatment was performed on two ores: a gold ore and a copper-nickel sulphide ore. Three microwave tests were done for each ore: batch tests at low-power (BB) and high-power (BP), and a continuous belt test at high-power (CP). Treatment variables investigated were heating time, microwave power and particle size. Treated ore was then used to assess the impacts on comminution (ore competency and liberation). Additionally, impacts on leaching (gold ore) and roasting (sulphide ore) were studied. Surface area measurements showed improvements for each gold ore treatment; between a 2.5% and 21% increase in m2/g. The sulphide ore reported marginal increases to surface area, although the CP test showed a 7% improvement. While the differential heating improved surface area, comminution energy consumption was unchanged apart from the CP test, which reported a 19% decrease in SAG work index, WSDT. The treatments did not weaken the ore enough to reduce the energy consumption, but still promoted grinding that enhanced surface area. Liberation analysis confirmed this, showing increases to value sulphide liberation, particularly for the high-power tests. Cyanidation showed that enhanced surface area improved the gold recovery. Improvements to gold recovery were proportional to the surface area increases reported. After 6 hours, a 26% increase in gold recovery was reported for the BP test; a 16% increase was reported for the CP test. This confirmed that continuous high-power microwave treatment can improve gold recovery by creating rapid thermal stresses. No significant trend was found between fracture and cyanide consumption. Roasting of the sulphide ore showed no trend with surface area. A lower sulphur content after microwave heating occurred due to oxidation of the sample, prior to entering the roaster. This degree of oxidation from the treatment was proportional to higher heating rates, and showed that the roast of the BP sample was adversely affected. For an industry process with shorter residence times, oxidation from microwave treatment would be less impactful. | English | Canada | Masters Thesis | ||||||
| B156 | 2015 | Thermally assisted liberation of high phosphorus oolitic iron ore: A comparison between microwave and conventional furnaces | Omran, Mamdouh; Fabritius, Timo; Mattila, Riku | https://www.sciencedirect.com/science/article/abs/pii/S003259101400789X | This paper aims to investigate the effects of microwave, and conventional heating pretreatment on the liberation of iron bearing minerals from high phosphorus oolitic iron ore, specifically iron ore from the Aswan region of Egypt. These effects were analyzed by examining intergranular fractures generated between the oolitic/matrix and in the oolitic layers. Grindability and energy consumption were also measured after both microwave and conventional heating pretreatments.Scanning electron microscope (SEM) photomicrographs indicated that intergranular fractures are formed between the gangues (fluoroapatite and chamosite) and hematite after microwave treatment (resulting in improved liberation of the iron ore) while only a small number of micro-cracks were observed between the oolitic/matrix and in the oolitic layers after conventional heating of iron ore. Grindability tests indicated that microwave treated iron ore could be more easily ground compared with iron ore treated in a conventional furnace. This improved grindability is attributable to the large amount of intergranular fractures which are formed on the oolitic iron ore after treatment with microwave radiation. Energy consumption measurements also revealed that microwave treatment consumes much smaller quantities of energy compared with conventional heating ovens. | 10.1016/j.powtec.2014.08.073 | Powder Technology | 269 | 45487 | |||||||
| B158 | 2009 | Effect of Microwave Radiation on Coal Flotation | Özbayoğlu, G.; Depci, T.; Ataman, N. | http://www.tandfonline.com/doi/abs/10.1080/15567030701531337 | Most low-rank coals are high in moisture and acid functional groups, therefore showing poor floatability. Drying, which removes the water molecules trapped in the pores and adsorbed at the surface of coal, decreases the hydrophilic character and improves the floatability. Microwave heating, whose simplest application is drying, was applied at 0.9 kW power level for 60 sec exposure time in the experiments to decrease the moisture content of coal in order to enhance the hydrophobicity. The flotation tests of microwave-treated coal by using heptanol and octanol lead to a higher flotation yield and ash removal than original coal. | 10.1080/15567030701531337 | English | Journal Article | Energy Sources, Part A: Recovery, Utilization, and Environmental Effects | 31 | 6 | 492-499 | ||||
| B159 | 2022 | Experimental study on microbial desulphurization of sulfide ores and self-heating simulation of ore heaps under ultrasonic and microwave | Pan, Wei; Yang, Lingrong; Jin, Huimin; Yi, Ruge; Liao, Zhigang | https://linkinghub.elsevier.com/retrieve/pii/S0957582022005638 | The objective of this study was to improve the efficiency of microbial desulphurization of sulfide ore by pretreatment with ultrasonic and microwave techniques. Different combinations of ultrasound and microwave were used to pretreat the sulfide ore and compare the microbial desulphurization effect of the treated ore and the raw ore. The experimental results show that ultrasonic and microwave can effectively improve the efficiency of bacterial desulphurization, whereas the pretreatment method of ultrasonic followed by microwave has the best enhancement effect on bacterial desulphurization of sulfide ores. The best experimental combination for microbial desulphurization is ultrasonic power of 300 W, ultrasonic action time of 50 mins and microwave power of 500 W, microwave action time of 20 s. In subsequent self-heating simulations of sulfide ore heaps, the optimal ultrasonic and microwave combination was used to pretreat the ores and the two-dimensional temperature field of the heaps was reconstructed. The results further show that the microbial desulphurization efficiency is increased when the sulfide ore is pretreated with ultrasonic followed by microwave. The purpose of inhibiting the self-heating reaction and preventing spontaneous combustion of sulfide ore was achieved. | 10.1016/j.psep.2022.06.033 | English | Journal Article | Process Safety and Environmental Protection | 164 | 435-448 | |||||
| B161 | 2022 | Effect of moisture on concrete damage and aggregate recycling under microwave irradiation | Pengju, Zhang; Wei, Wei; Zhushan, Shao; Rujia, Qiao | https://linkinghub.elsevier.com/retrieve/pii/S2352710221015990 | Microwave-assisted concrete aggregate recycling is a novel green technology, which causes less pollution and generates low energy during heating. This study aimed to explore the influence of moisture content on the heating process of concrete as well as its strength under microwave irradiation. Interfacial debonding of aggregate and mortar after the microwave irradiation was analyzed. Through a uniaxial compression experiment, the compressive strength of test blocks with different moisture contents is gained after microwave irradiation. The changes of microstructure are obtained using Scanning Electron Microscopy analysis. The results demonstrated that microwave power and moisture content were two important factors affected the concrete breaking. When the moisture content of the test block is relatively high, the concrete will break with a short irradiation time and low temperature under a high microwave power input. The aggregate–mortar interface separation was evident, and intact aggregates with low mortar adhesion could be picked out from the crushed concrete. In this study, we provided a reference for further development of microwave-assisted concrete recycling technology. | 10.1016/j.jobe.2021.103741 | English | Journal Article | Journal of Building Engineering | 46 | 103741 | |||||
| B162 | 1977 | The possibilities of using UHF Electromagnetic Fields to Improve Ore Concentrates | Petrov et al. | |||||||||||||
| B163 | Poiski novykh metodov razrusheniya krepkikh gornykh porod | |||||||||||||||
| B164 | 2022 | Numerical Modelling of Microwave Heating Assisted Rock Fracture | Pressacco, Martina; Kangas, Jari J. J.; Saksala, Timo | https://link.springer.com/10.1007/s00603-021-02685-8 | This paper presents a numerical study on the effects of microwave irradiation on the mechanical properties of hard rock. More specifically, the weakening effect of microwave heating induced damage on the uniaxial compressive and tensile strength of granite-like rock is numerically evaluated. Rock fracture is modelled by means of a damage-viscoplasticity model with separate damage variables for tensile and compressive failure types. We develop a global solution strategy where the electromagnetic problem is solved first separately in COMSOL multiphysics software, and then provided into a staggered implicit solution method for the thermo-mechanical problem. The thermal and mechanical parts of the problem are considered as uncoupled due to the dominance of the microwave-induced heat source. The model performance is tested in 2D finite element simulations of heterogeneous numerical rock specimens subjected first to heating in a microwave oven and then to uniaxial compression and tension tests. According to the results, the compressive and tensile strength of rock can be significantly reduced by microwave heating pretreatment. | 10.1007/s00603-021-02685-8 | English | Journal Article | Rock Mechanics and Rock Engineering | 55 | 2 | 481-503 | ||||
| B165 | 2023 | Comparative Numerical Study on the Weakening Effects of Microwave Irradiation and Surface Flux Heating Pretreatments in Comminution of Granite | Pressacco, Martina; Kangas, Jari; Saksala, Timo | https://www.mdpi.com/2076-3263/13/5/132 | Thermal pretreatments of rock, such as conventional heating and microwave irradiation, have received considerable attention recently as a viable method of improving the energy efficiency of mining processes that involve rock fracturing. This study presents a numerical analysis of the effects of thermal shock and microwave heating on the mechanical properties of hard, granite-like rock. More specifically, the aim is to numerically assess the reduction of uniaxial compressive strength of thermally pretreated specimens compared to intact ones. We also compare the performance of these two pretreatments (conventional heating and microwave irradiation) in terms of consumed energy and induced damage. Rock fracture is modelled by a damage-viscoplasticity model, with separate damage variables in tension and compression. A global solution strategy is developed for solving the thermo-mechanical problem (conventional heating) and the electromagnetic–thermo-mechanical problem (microwave heating). The electromagnetic part of the microwave heating problem is solved in COMSOL Multiphysics software Version 6.1 first. The electromagnetic solution is used as an input for the thermo-mechanical problem, which is finally solved by means of a staggered explicit solution method. Due to the predominance of the external thermal sources, the thermal and the mechanical parts of the problem in both cases are considered as uncoupled. Three-dimensional finite element simulations are utilized to study the damage-viscoplasticity model. An ore-shaped three-mineral numerical rock specimen is used in uniaxial compression tests. | 10.3390/geosciences13050132 | English | Journal Article | Geosciences | 13 | 5 | 132 | ||||
| B166 | 1984 | A study of electrothermomechanical destruction of hard rocks with a rotary heading machine | Protasov, Yu. I.; Kuznetsov, V. V.; Merzon, A. G.; Chernikov, V. A.; Retinskii, V. S. | http://link.springer.com/10.1007/BF02498201 | 10.1007/BF02498201 | English | Journal Article | Soviet Mining Science | 20 | 6 | 462-467 | |||||
| B167 | 2023 | Effect of Microwave Radiation on the Compressive Strength of Solid Ceramic Brick | Průša, David; Šuhajda, Karel; Žajdlík, Tomáš; Svobodová, Kateřina; Šťastník, Stanislav; Hobzova, Klara; Venkrbec, Vaclav | https://www.mdpi.com/2075-5309/13/4/1018 | Microwave radiation is widely utilized in construction practice, especially for drying building materials, remediating damp masonry, or sterilization of biotic pests that have infested building structures. The available scientific and technical literature reports that certain materials exposed to microwave radiation do not change their physical and mechanical properties, although this has not yet been adequately verified. This paper builds on many years of research in the area, adding to and refining existing information, providing new insights into the mechanical and physical properties of commonly available building materials that have been exposed to controlled microwave radiation, and comparing them with reference values. The experimental research on a set of clay brick samples is carried out using tests according to European standards, and it focuses on the effect of microwave radiation on compressive strength and water absorption. The experimental samples were compared to reference samples that had not been subjected to prolonged exposure to moisture and were subsequently treated with microwave radiation for dehumidification. | 10.3390/buildings13041018 | English | Journal Article | Buildings | 13 | 4 | 1018 | ||||
| B168 | 2022 | Microscopic liberation mechanisms of oolitic iron ore under microwave irradiation and optimization of irradiation parameters | Qin, Like; Chen, Guodong; Xu, Guoqiang; Zhen, Gang; Jia, Hailiang | https://linkinghub.elsevier.com/retrieve/pii/S0892687522000127 | Microwave liberation is a promising method for beneficiation of oolitic hematite but has not been used in industrial production. This is because the specific microwave energy requirements for iron ore applications is prohibitively high and there is a lack of quantitative references for microwave irradiation parameters. The cracking process of oolitic hematite under microwave irradiation is simulated using the discrete element method. Temperature field, force chain and cracking development during microwave irradiation are analysed, accordingly, the microscopic mechanisms are discussed. The results indicate that: the hematite ring is under compression and the quartz ring is under tension along the radius under microwave irradiation; radial cracking initiate on the edge prior to circular cracking along mineral boundary; location of circular cracks corresponds well to the position where the maximum temperature gradient occur; there is an optimal power density under given energy consumption and an optimal irradiation time under given power density for microwave liberation. | 10.1016/j.mineng.2022.107402 | English | Journal Article | Minerals Engineering | 178 | 107402 | |||||
| B169 | 2022 | Study on the Mechanism of Finite-Element Coupled Microwave Separation of Coarse Aggregate Under Multiple Factors | Qin, Like; Wei, Kun; Chen, Guodong; Zhen, Gang; Zou, Xiaolong | https://www.ssrn.com/abstract=4144026 | 10.2139/ssrn.4144026 | English | Journal Article | SSRN Electronic Journal | ||||||||
| B170 | 2020 | Study on Heating Characteristics and Prediction Model of Igneous Rock under Microwave Irradiation | Qinhua et al. | |||||||||||||
| B171 | 1989 | Microwave Induced Fracturing to Improve Grindability | Raddatz, Andrea E; Walkiewicz, John W; McGill, Sandra L | The Bureau of Minem conducted studiem to improve the grindability of ores uaing microwave induced stress fracturing. Iron ores were rapidly heated using microwave energy (2.45 GAz) at 3 kw in batch operations to temperatures between 840° and 940' C. Scanning electron microscope (SEM) photomicrographs verified fracturing along grain boundaries and throughout the gangue matrix. standard Bond grindability tests showed that microwave heating reduced the work index of these iron ores by 9.9 to 23.7 pct. A microwave applicator designed to simulate a continuous throughput operation allowed samples to be heated more uniformly and quickly than in batch operations. The grindability of a taconite ore was improved by 13 pct when heated at 3 kW to a temperature of 197" C. With this throughput procedure, stress fracturing was induced at lower temperatures with less energy consumed, thereby improving the cost effectiveness of microwaveassisted grinding. Additional tests were conducted to further increase the heating rates using higher microwave powers. To properly assess the economic feasibility of microwave-assisted grinding, factors such as increased throughput, less recycled ore, less wear and maintenance, and improved liberation of minerals must be considered. | English | Journal Article | ||||||||||
| B172 | )DNXOWlW *HRZLVVHQVFKDIWHQ *HRWHFKQLN XQG %HUJEDX | Ri, Dvwhu; Lq, Flhqfh | English | Journal Article | ||||||||||||
| B173 | 2011 | The effect of microwave pretreatment on impact breakage of copper ore | Rizmanoski, Vladimir | https://linkinghub.elsevier.com/retrieve/pii/S0892687511003074 | It has been shown that very short exposures to a high level of microwave power lead to reductions in ore strength. In this paper, the influence of modulated microwave power on copper ore breakage has been investigated. This approach to power delivery is applied to ascertain whether the strength of porphyry copper ore can be reduced with lower average modulated power levels than using continuous power. Changes in resistance to breakage of the treated and untreated ore were quantified by comparative drop weight tests. Mineralogical investigation for the ore was carried out with the Mineral Liberation Analyser (MLA) for surface identification of minerals and X-ray tomography for volumetric analysis. The comparative drop weight tests showed that material treated for 5 s at 5 kW of modulated power was weaker than untreated material. However, for this particular low grade ore, the degree of breakage which was achieved could be achieved with substantially less mechanical energy. It is possible that by using much higher level of microwave power, better liberation might be achieved than using conventional methods. Ó 2011 Elsevier Ltd. All rights reserved. | 10.1016/j.mineng.2011.08.017 | English | Journal Article | Minerals Engineering | 24 | 14 | 1609-1618 | ||||
| B174 | 2016 | Synthetic ore samples to test microwave/RF applicators and processes | Rizmanoski, Vladimir; Jokovic, Vladimir | https://linkinghub.elsevier.com/retrieve/pii/S0924013615001983 | Recent studies have shown that microwaves heat some minerals faster than others. This creates the opportunity to use microwaves to selectively heat minerals to enhance separation of valuable minerals from gangue minerals. This opportunity has been investigated by studying the heating process under controlled conditions. It involved creating synthetic samples of ore using pyrite grains suspended at known locations within a matrix made of quartz and poly(methyl methacrylate). | 10.1016/j.jmatprotec.2015.04.032 | English | Journal Article | Journal of Materials Processing Technology | 230 | 50-61 | |||||
| B176 | 2023 | Electromagnetic-thermo-mechanical coupled modelling of microwave-assisted TBM disc cutting | Rui, Fuxin; Zhao, Gao-Feng; Zheng, Yanlong; Gong, Qiuming; Zhao, Xiaobao | https://linkinghub.elsevier.com/retrieve/pii/S0886779823001918 | Microwave irradiation is regarded as a promising technology to assist mechanical rock breaking for its substantial advantages in reducing cutter wear and enhancing rock fracture. Due to the high cost of laboratory experiments and field tests, numerical simulation has become the primary method to investigate key issues of microwave-assisted tunnel boring machine (TBM) cutting. In this work, an electromagnetic-thermo-mechanical coupled approach is developed to implement the numerical modelling of microwave-assisted TBM disc cutting. Different numerical methods are coupled in our model to exert their respective advantages, including the electromagnetic-thermal solution of COMSOL, thermo-mechanical fracture simulation of the lattice spring model (LSM), and rock-cutter contact treatment of discontinuous deformation analysis (DDA). The conversion from the Euler to Lagrange domain is adopted to address the motion of the electromagnetic-thermal field in the disc cutting process. The proposed coupled numerical approach is first verified by the corresponding modelling of the microwave-irradiated rock experiment, in which the coupled approach can also provide the evolution process of three-dimensional spatial rock fracturing that is hard to obtain in the experiment. Implemented into the numerical full-scale rock linear cutting experiment, our coupled approach is further applied to simulate rock disc cutting assisted by microwave irradiation. Through the numerical results, it is concluded that a moving microwave irradiation is better for reducing the cutter normal force as a whole in the disc cutting process. For the moving microwave irradiation, the cutter normal force will decrease with the increasing microwave power or decreasing moving speed, in which the microwave power plays a more significant role when the total microwave energy input remains the same. Finally, the curve of average normal force reduction with the microwave energy input at the engineering scale is analysed based on the numerical results of our coupled model, which provides some insights and suggestions for the future practical application of microwave-assisted TBM tunnelling. | 10.1016/j.tust.2023.105171 | English | Journal Article | Tunnelling and Underground Space Technology | 138 | 105171 | |||||
| B177 | 1969 | On the intensification of superhigh-frequency rock breaking | Rzhevskii, V. V.; Protasov, Yu. I.; Dobretsov, V. B. | https://link.springer.com/10.1007/BF02501266 | 10.1007/BF02501266 | English | Journal Article | Soviet mining science | 5 | 5 | 509-511 | |||||
| B178 | 2005 | The influence of microwave pre-treatment on copper flotation | Sahyoun, C; Rowson, N A; Kingman, S W; Groves, L; Bradshaw, S M | https://www.researchgate.net/publication/43514121_The_influence_of_microwave_pre-treatment_on_copper_flotation | The influence of microwave treatment on copper flotation has been investigated. Comparative batch flotation tests carried out on ore treated at 5–12 kW for 0.1–0.5 s showed that improvements in copper recovery of between 6–15 % could be achieved compared with untreated ore. Both recovery and cumulative grade increased with increasing treatment time and power. A preliminary economic analysis showed that microwave treatment will be economically viable if recoveries similar to those determined on laboratory scale can be achieved on a plant. | English | Journal Article | |||||||||
| B179 | 1996 | Short-pulse microwave treatment of disseminated sulfide ores | Salsman, J.B.; Williamson, R.L.; Tolley, W.K.; Rice, D.A. | https://linkinghub.elsevier.com/retrieve/pii/0892687595001301 | Theoretical and experimental analyses are used to study thefeasibility of using short-pulse microwave energy as a pretreatment step in comminution. Ores of interest contain microwave-absorbing mineral in a low-absorbing gangue. A finite element numerical model is used to predict the thermomechanical response of a single pyrite particle in a calcite host rock during microwave heating. The effects of power density and mineral particle size are presented. Using microwave power densities within those expected in currently available equipment, significant temperature differences are predicted between the pyrite particle and the calcite matrix. Resulting thermomechanical stress exceeds typical strengths of these minerals. Laboratory tests verify rapid, selective heating of crushed sulfide minerals. Tests with mixtures of pure minerals show heating rates directly proportional to the mass of high-loss mineral; thus, shielding of mineral grains by other grains does not appear to be significant. A cursory energy-use analysis suggests that short-pulse microwave treatment can be accomplished with relatively small energy input compared with current energy consumption in comminution. Although improved comminution has yet to be experimentally demonstrated, initial results are promising from both a technical and an economic standpoint. | 10.1016/0892-6875(95)00130-1 | English | Journal Article | Minerals Engineering | 9 | 1 | 43-54 | ||||
| B181 | 2006 | Investigating microwave assisted rock breakage for possible space mining applications | Satish, H.; Ouellet, J.; Raghavan, V.; Radziszewski, P. | https://journals.sagepub.com/doi/full/10.1179/174328606X101902 | An optimal combination of mechanical means and microwave energy to break rock material could prove beneficial for space applications in terms of large scale production drilling or rock removal processes. In the present paper, application of low power microwave pulses was used to induce thermal cracks in rock samples, before use of mechanical breakage methods. The present investigation is conducted with the scope of possible space bound and terrestrial applications. Experimental studies were carried out to assess the low power (,150 W) microwave susceptibility of terrestrial basaltic rock samples (chosen for its close chemical similarity to lunar and Martian rocks). Point load tests were carried out on the microwaved rock samples in order to determine their strength before and after exposure to microwaves. The preliminary experimental results showed that the basalt rock samples used were quite susceptible to the exposure of low power microwaves. From the point load test results, a decreasing trend is observed in terms of strength of the rock samples with microwave exposure duration. Some rock samples even presented visible macro cracking and even splitting for the longest exposure duration used in this experimental program. | 10.1179/174328606X101902 | English | Journal Article | Mining Technology | 115 | 1 | 34-40 | ||||
| B182 | 2008 | The effect of microwave pretreatment on the liberation of a copper carbonatite ore after milling | Scott, G.; Bradshaw, S.M.; Eksteen, J.J. | https://linkinghub.elsevier.com/retrieve/pii/S0301751607001822 | The effects of microwave treatment on the liberation spectrum of a rod-milled South African carbonatite ore are presented based on quantitative mineralogical analysis. The treated ore was processed for 0.5 s at 10.5 kW in a single mode microwave cavity in batches of 1 kg. The ore selected for microwave treatment was a sample from a tertiary crusher product stream feed to a rod mill. The treated and untreated ore were subsequently grinded to 80%–800 μm. The microwave treated ore showed a significant increase in the amount of liberated copper minerals in the relatively coarse particle size range (106 to 300 μm). Similar significant shifts in the liberation spectra were noted for all the minerals in the ore. It is inferred that microwave treatment induces changes in the fracture pattern, favouring liberation of microwave susceptible minerals at larger particle sizes. | 10.1016/j.minpro.2007.08.005 | English | Journal Article | International Journal of Mineral Processing | 85 | 4 | 121-128 | ||||
| B183 | 1977 | Electrical Rock Breaking | Segsworth, R. S.; Kuhn, K. | http://ieeexplore.ieee.org/document/4503362/ | A technique has been developed for rock breaking which could be considered as an alternative to drilling and blasting. A series of tests and measurements involving initial dielectric breakdown achieved with high frequency power, followed by highly localized heating achieved by capacitor discharge energy is described. This heating causes relatively nonviolent shattering of the rock. | 10.1109/TIA.1977.4503362 | English | Journal Article | IEEE Transactions on Industry Applications | 0 | 1 | 53-57 | ||||
| B184 | 2019 | Comparative study on the deterioration of granite under microwave irradiation and resistance-heating treatment | Shou, He Zi; Hu, Qijun; Zeng, Junsen; He, Leping; Tang, Hexi; Li, Bingsheng; Chen, Shunzhang; Lu, Xirui | https://www.fracturae.com/index.php/fis/article/view/2435 | 10.3221/IGF-ESIS.50.54 | English | Journal Article | Frattura ed Integrità Strutturale | 13 | 50 | 638-648 | |||||
| B185 | 2009 | Mechanical property and cutting rate of microwave treated granite rock | Sikong, Lek; Bunsin, Thiti | https://thaiscience.info/Journals/Article/SONG/10615063.pdf | The purpose of this study is to investigate the effect of microwave treatment, especially at low power level on compressive strength and cutting rate of granite rock by using multimodal cavity. The power level and cooling rate of treated samples were found to have an effect on the compressive strength, and the cutting rate. This effect is due to the induction of the plastic zones and micro cracks in the rock matrix, especially at the grain boundaries induced by the thermal stresses of rock forming minerals which have the difference in dielectric properties after microwave heating for a certain exposure time together with the thermal-shock treatment after the heating. It was found that the strength of treated granite is less than 60% of the original after 30 minutes of exposure. | English | Journal Article | |||||||||
| B186 | 2018 | Ore pretreatment methods for grinding: journey and prospects | Singh, Veerendra; Dixit, Prashant; Venugopal, R; Venkatesh, K Bhanu | https://www.tandfonline.com/doi/full/10.1080/08827508.2018.1479697 | Pretreatment of ores to improve energy efficacy of grinding has been explored for decades. However, many of these techniques are still at developmental stages and a review has been presented in this paper to discuss the research journey and problems associated with commercialization of these techniques. This review reveals that a variety of stress-generating techniques have been used to treat the composition and morphology of particles to improve the grinding process. Grinding additives are used commercially successful technology while microwave pretreatment also has been successfully piloted. Newly developed techniques such as ultrasonics and electric disintegration have shown potential for success but the cost economics of these processes is still not as attractive as desired. Incipient techniques based on bio-milling, shock waves, and nuclear hold promise for the future. It is also expected that the technological advances around information technology, instrumentation, and energy science will help to solve techno-economic challenges associated with commercialization of the known technologies. Demand for energy-efficient grinding pretreatment methods will grow in the future considering the depletion of high-grade resources and stringent environmental constraints related to reject disposal. | 10.1080/08827508.2018.1479697 | Mineral Processing and Extractive Metallurgy Review | 40 | 1 | 45306 | ||||||
| B187 | 2013 | Formation of micro-fractures on an oolitic iron ore under microwave treatment and its effect on selective fragmentation | Song, Shaoxian; Campos-Toro, Ernesto Fabian; López-Valdivieso, Alejandro | https://linkinghub.elsevier.com/retrieve/pii/S0032591013002477 | 10.1016/j.powtec.2013.03.049 | English | Journal Article | Powder Technology | 243 | 155-160 | ||||||
| B192 | 2019 | Radio Frequency and Microwave Impact on Source Rock | Sultanguzhin, Ruslan; Kovaleva, Liana; Zinnatullin, Rasul | https://ieeexplore.ieee.org/document/8792780/ | 10.1109/RSEMW.2019.8792780 | English | conferencePaper | 2019 Radiation and Scattering of Electromagnetic Waves (RSEMW) | 45295 | |||||||
| B193 | 2024 | Response Mechanism of Dynamic Tensile Mechanics in Granite Under Microwave Irradiation: Insights from Experiments and Simulations | Sun, Bo-Wen; Yang, Sheng-Qi; Huang, Man; Li, Heng; Tian, Wen-Ling; Huang, Yan-Hua | https://link.springer.com/10.1007/s00603-024-03958-8 | Microwave-assisted mechanical rock-breaking can effectively solve the problems of low efficiency of hard rock-breaking and severe wear and tear of equipment. This study used granite as the research object and analysed electromagnetic–thermal characteristics and dynamic tensile characteristics of microwave-irradiated granite. The microwave irradiation problem was decomposed into the electromagnetic–thermal unidirectional coupling and thermal–mechanical unidirectional coupling problems for numerical solutions, and the weakening mechanism of microwave irradiation was discussed at the microscopic level. The results showed that the thermal stress generated by the rapid heating and selective heating characteristics of microwave irradiation is the dominant factor in microwave fracturing. The presence of thermal cracks affects the crack extension path, making the failure more complicated. Tensile failure is the primary mechanical mechanism that causes the macroscopic fracture of the specimen, and intergranular failure dominates the overall failure of the specimen. Microwave irradiation reduces the shear resistance of the specimen. Microscopically, the proportion of shear cracks gradually increases with the increasing of irradiation duration (TM). Macroscopically, the area of the wedge-shaped failure zone gradually increases. | 10.1007/s00603-024-03958-8 | English | Journal Article | Rock Mechanics and Rock Engineering | |||||||
| B194 | 2024 | Multiscale study of dynamic mode-I fracture characteristics of thermally treated granite: Comparison of conventional and microwave heating | Sun, Bo-Wen; Yang, Sheng-Qi; Li, Heng; Tian, Wen-Ling | https://linkinghub.elsevier.com/retrieve/pii/S0013794424006416 | High-temperature-assisted rock breaking is a promising technique, with conventional and microwave heating being widely used methods. Understanding the mechanisms of conventional and microwave heating on the dynamic mode-I fracture characteristics of rock is crucial for engineering applications. Dynamic mode-I fracture experiments were conducted on Notched SemiCircular Bending (NSCB) specimens at 25, 200, 300, 400, and 500 ◦C under both heating methods. Additionally, a finite element-discrete element coupled numerical method was developed to simulate the dynamic mode-I fracture process in high-temperature granite. The study investigated the effects of both heating methods on the fracture process and morphological features of the rocks, revealing differences in damage mechanisms across various scales. Results indicated that both heating methods similarly influence the fracture toughness of granite, with fracture toughness initially remaining nearly unchanged and then rapidly decreasing, with 200 ◦C identified as the threshold temperature. Moreover, the fractal dimension increased exponentially with temperature. The fracture mechanisms associated with conventional and microwave heating were also discussed. | 10.1016/j.engfracmech.2024.110478 | English | Journal Article | Engineering Fracture Mechanics | 310 | 110478 | |||||
| B195 | 2022 | Microwave heating and fracturing of granite: Insights from infrared thermal imaging | Sun, Tingwen; Ma, Zhongjun | https://www.tandfonline.com/doi/full/10.1080/01495739.2022.2100540 | Microwave heating has been considered as one of the promising rock breaking technologies. However, the non-uniform temperature distribution of microwave treated rocks has not been quantitatively studied and the microwave rock fracturing mechanisms have not been systematically revealed. In this paper, microwave heating tests were implemented using a 6 kW industrial microwave system. The ratio of maximum temperature to average temperature (RM=A) was studied to characterize the non-uniformity of temperature. The temperature gradient and maximum temperature difference were calculated to quantitatively characterize the thermal stress. Experimental results indicate that the granite fracture temperature threshold is about 200 C and cracking typically occurs at a minimum temperature gradient of 6 C/mm. As either power level or irradiation time increases, the thermal gradient and temperature difference increase. For a fixed microwave energy, microwave heating at higher power levels for a shorter duration has a higher RM=A and a greater temperature difference and temperature gradient, which explains that the combination of high power and short heating time yields better rock weakening effects. | 10.1080/01495739.2022.2100540 | English | Journal Article | Journal of Thermal Stresses | 45 | 9 | 762-771 | ||||
| B196 | 2012 | sure-2012-mech-maloney | ||||||||||||||
| B197 | 2012 | Radio wave emission from 1 MHz to 18 GHz due to rock fracture and the estimation of the emitted energy | Takano, T.; Kato, J.; Hirashima, M.; Saegusa, K. | http://ieeexplore.ieee.org/document/6328638/ | Radio wave emission due to rock fracture was measured at four frequency bands. Though the antenna gain is difficult to measure at the lowest frequency of 1MHz, the measuring system was successfully calibrated, and the emitted energy was estimated. The obtained results at 1MHz to 18GHz suggest the wave source to be quite narrow electrical signals, and show a possible application to the detection of an earthquake or volcanic activity. | 10.1109/ICEAA.2012.6328638 | English | conferencePaper | 2012 International Conference on Electromagnetics in Advanced Applications | 300-303 | ||||||
| B198 | 2024 | Failure characteristics of microwave heat-treated stressed sandstone: Implications for deep rock breakage using TBM cutting | Tao et al. | https://www.sciencedirect.com/science/article/abs/pii/S0360544224002603 | ||||||||||||
| B199 | 1999 | Evaluation of Thermally-Assisted Fracture of Particles Using Microscale Fracture Measurements | Tavares and King | https://www.jstage.jst.go.jp/article/kona/17/0/17_1999023/_article | ||||||||||||
| B200 | 1996 | Effect Of Microwave-Induced Damage On Single-Particle Comminution Of Ores | Tavares, L M; King, R P | https://onemine.org/documents/effect-of-microwave-induced-damage-on-single-particle-comminution-of-ores | English | Journal Article | ||||||||||
| B201 | 2020 | Representative temperature at minimum energy content of ore and mineral milling in super high frequency heating | Tazhibaev, K.T.; Sultanalieva, R.M.; Makanov, K.M.; Tazhibaev, D.K. | https://elibrary.ru/doi_resolution.asp?doi=10.25018%2F0236-1493-2020-9-0-65-76 | The ore milling method with preliminary heating of ore samples by SHF electromagnetic waves of different length is used in the studies. The SHF-treated sample and the unexposed initial sample were then separately milled in an impact testing machine by a gravity load falling from a certain height. As a result, the plots of specific energy content of milling as function of SHF treatment duration were obtained. The internal structural changes and micro cracking under SHF heating are connected with nonuniform heating of dissimilar minerals with different thermophysical properties. Different minerals of rocks and ore absorb energy of SHF waves and convert it to thermal energy. The relation of the heat capacity of rock and ore minerals and the SHF treatment duration and, consequently, temperature is obtained. Using the heat capacity formula and the functional relationship of the temperature and SHF treatment duration, the temperature–SHF treatment time curves are plotted for different rocks and for quartz. A new temperature characteristic of rocks and ore is experimentally discovered—the critical softening temperature fitting the minimum energy content of milling at the lowest temperature. Key words: rock, mineral, ore, milling, milling energy content, electromagnetic wave, heat capacity, thermal energy, softening. | 10.25018/0236-1493-2020-9-0-65-76 | ru | Journal Article | Mining informational and analytical bulletin | 9 | 65-76 | |||||
| B202 | 2019 | Numerical Investigations of the Single-Mode Microwave Treatment Effects on Rock Breakage | Teimoori, Khashayar; Hassani, Ferri; Sasmito, Agus Pulung; Madiseh, Ali Ghoreishi | http://ocs.editorial.upv.es/index.php/AMPERE2019/AMPERE2019/paper/view/9646 | In this study, a rock model which consists of a conceptual block (host rock and ore sample) is numerically modeled by using the finite element method. The rock model is subjected to several single-mode microwave treatments with different power levels, distances from the antenna, and exposure times in order to calculate and compare the corresponding effects including temperature distribution and mechanical stress/damage profiles. The main objective of the present study is to analyze the distribution of temperature and mechanical stress at the boundary of two different attached rocks when exposed to microwaves. This enables comparing the intensity of the distribution with respect to the applied microwave input operating parameters and, consequently, understanding rock preconditioning. The results of the present study verify that an increase in temperature by microwave treatment facilitates the rock weakening process. Also, a more efficient selection of the distance from the antenna and the power level can maximize the overall impact of the microwave treatment on rock preconditioning which ultimately helps with the rock breakage mechanism. | 10.4995/AMPERE2019.2019.9646 | English | conferencePaper | Proceedings 17th International Conference on Microwave and High Frequency Heating | |||||||
| B203 | 2021 | AI-based prediction of microwave effects on ore preconditioning and breakage | Teimoori, Khashayar; Hilscher, Brent; Ellison, Candice | https://www.researchgate.net/publication/361799701_AI-based_Prediction_of_Microwave_Effects_on_Ore_Preconditioning_and_Breakage | English | Journal Article | ||||||||||
| B204 | 2024 | Technological and economic considerations for the application of combined microwave assisted comminution and multi-sensor ore sorting | Tian, X.; Forster, J.; Bobicki, E.R. | https://linkinghub.elsevier.com/retrieve/pii/S0892687524000116 | Increasing pressure to develop more energy efficient and sustainable technologies has led to a recent surge in interest in innovative processes such as microwave-assisted comminution and ore sorting. In a comminution circuit, there are several levers that can be taken advantage of, such as the ore competency, feed grade, and particle size. By varying these process parameters, the operations can achieve energy savings. However, operations must be able to balance both the energy savings and the costs associated with the various unit operations. Microwave pre-treatment has several pathways of energy saving: reducing the ore competency, increasing the liberation, and improving the ore sortability. And these pathways can also bring economic benefits to the operations at different levels. This paper will discuss the impacts of these parameters regarding the energy consumption and economics. The relative combinations of various levers, in order to maximize the economic and energy savings, are presented. | 10.1016/j.mineng.2024.108582 | English | Journal Article | Minerals Engineering | 208 | 108582 | |||||
| B205 | 2017 | Numerical study of the influence of irradiation parameters on the microwave-induced stresses in granite | Toifl, Michael; Hartlieb, Philipp; Meisels, Ronald; Antretter, Thomas; Kuchar, Friedemar | https://linkinghub.elsevier.com/retrieve/pii/S0892687516303193 | Mechanical comminution of rocks is an energy intensive process with energy efficiency around 1%. A possible way to enhance the efficiency is the prior application of high-power microwaves. Microwave irradiation of a heterogeneous material introduces inhomogeneous electromagnetic and thermal fields which result in stresses and potentially in damage. In order to assess the industrial applicability, various 3D numerical analyses with either constant microwave power or constant energy were performed on granite samples. To this end dielectric and thermal properties were taken from measurements. For the numerical computations a realistic 3D microstructure was generated by a Voronoi tessellation algorithm. In order to calculate the electromagnetic field inside the rock sample, a finite difference time domain simulation was performed. The resulting temperature as well as stress field is evaluated in finite element analyses. The numerical results were corroborated by microwave irradiation experiments on granite samples. Ó 2016 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http:// creativecommons.org/licenses/by/4.0/). | 10.1016/j.mineng.2016.09.011 | English | Journal Article | Minerals Engineering | 103 | 78-92 | |||||
| B206 | 2016 | 3D numerical study on microwave induced stresses in inhomogeneous hard rocks | Toifl, Michael; Meisels, Ronald; Hartlieb, Philipp; Kuchar, Friedemar; Antretter, Thomas | https://linkinghub.elsevier.com/retrieve/pii/S0892687516300024 | The aim of this research is to assess the influence of microstructural details on the formation of thermo-mechanical stresses during microwave irradiation. For a realistic rock model a two-component 3D microstructure is generated by a Voronoi tessellation algorithm. The two components are microwave absorbing (plagioclase) and transparent (quartz), respectively. In order to calculate the electric field inside the inhomogeneous rock, a 3D finite difference time domain (FDTD) simulation is performed. The absorbed heat is computed and applied as temperature distribution in a subsequent thermo-mechanical finite element (FE) analysis in order to calculate the thermally induced stresses. Two irradiation times (15 s and 25 s) and a microwave power of 25 kW at 2.45 GHz as well as three different morphologies are analyzed. Moreover, the phase transformation of the quartz grains at 573 °C is considered in the FE model. The influence of the anisotropic nature of the grains is assessed by comparing the stress formation in the isotropic with those of the anisotropic case. A comparative analysis with a homogeneous model is performed in order to draw conclusions on the influence of the microstructure on the microwave induced stress formation. High maximum principal stresses on the boundaries of the microwave absorbing phase exceeding the tensile strength are observed in the 15 s irradiation model. After 25 s of microwave irradiation even higher stresses as a consequence of phase transformation of quartz are determined. In the anisotropic case significantly more areas with high maximum principal stresses especially in the quartz phase are observed. Microwave irradiation experiments on granite samples are performed in order to correlate the numerical results with experiments. | 10.1016/j.mineng.2016.01.001 | English | Journal Article | Minerals Engineering | 90 | 29-42 | |||||
| B207 | 2008 | Microwave Preheating of Sulphide Lead-Zinc Ore | Toraman & Cayirh | |||||||||||||
| B208 | 2015 | MICROWAVE ACTIVATED CRUSHING AND GRINDING OF TURKISH COALS AND SHALE FOR CLEANING AND DESULFURIZATION | Tosun, Y. | https://www.researchgate.net/publication/364345707_Microwave_activated_crushing_and_grinding_of_turkish_coals_and_shale_for_cleaning_and_desulfurization | coal; shale | The representative samples below 50mm are taken from the local coal area in Şırnak Province and other origin regions. As the coal samples and side rocks, Soma lignite, Tunçbilek lignite, Kütahya Gediz lignite, Şırnak asphaltite, Şırnak coal marl and coal shale were investigated. Heating with microwave of samples of 50 gr at time of 30-480 sec with 900W power in the Bosch laboratory type of Microwave Oven was carried out following roll crushing to minus 4mm and standard Bond Mill grinding. Microwave activated crushing and milling process was efficiently performed. Higher yields occurred about 52 % at 10-5 mm size fraction, 34% at grain size fraction of 3-1.5 mm, 12% at grain size of 0.5mm as grinding breakage. Microwave activated milling was also provided effective grinding with an increase in the Hardgrove Index about 43% for Şırnak asphaltite. Microwave activated milling also provided effective cleaning with a reduction of total sulfur content at 56% in the flotation and about 33% ash reduction in clean coal. As a result, the optimum microwave heat treatment process for coal cleaning plants was defined by making effective use in crushing, grinding and flotation, and the results are discussed. | English | Journal Article | ||||||||
| B209 | 2023 | Methane Seepage Characteristics in Coal Seams under Microwave Radiation | Tu, Yuying; Zhang, Yongli; Dong, Yubin; Ma, Yulin | https://pubs.acs.org/doi/10.1021/acsomega.3c02098 | Microwave radiation is an effective method for simulating the exploitation of coalbed methane (CBM). Herein, structural coal seepage is evaluated using a self-developed experiment system to explore the temperature and permeability response changes exhibited by coal samples under microwave radiation and stress loading. Microwave radiation experiments are used to conduct the numerical simulation of the microwave radiation, and the temperatures and permeability values of the coal samples under simulated and experimental conditions are compared and analyzed. The results show that the higher the microwave radiation power, the higher the temperature of coal samples within the specified time. Under the same effective stress conditions, the higher the microwave radiation power and the longer the action time, the greater the coal sample permeability. Moreover, effective stress is shown to be important for permeability. The curve change trends and numerical values of the experiment and simulation are consistent, and the accuracy of the experiment and simulation is verified in both directions. Furthermore, a numerical model of coal seams under microwave radiation is established to simulate the change law of pressure, gas seepage velocity, and free methane content of actual coal seams under microwave radiation. It is concluded that the fast heating and stable temperature resulting from microwave radiation are beneficial for the crack propagation of coal near reservoirs. The results of this study provide a new technological method for actual CBM exploitation and a new research direction for unconventional natural gas energy output. | 10.1021/acsomega.3c02098 | English | Journal Article | ACS Omega | 8 | 30 | 27092-27101 | ||||
| B210 | 2024 | State of the art of the fundamental aspects in the concept of microwave-assisted heating systems | Valverde, Cristóbal; Rodríguez-García, Margarita-Manuela; Rojas, Esther; Bayón, Rocío | https://linkinghub.elsevier.com/retrieve/pii/S0735193324003567 | As the processing of materials using clean energy becomes increasingly important, indirect conventional heating is being replaced by microwave-assisted heating. This method transforms energy directly into heat, providing rapid heating with instantaneous start-up, improved control and homogeneity of temperature distribution, and enabling a compact design. Therefore, the impact of microwaves in industry is growing in recent years. The complexity of incorporating microwaves into any industrial process resides in the need for a customised design. This is emphasised in the case of continuous flow microwave heating systems where the electromagnetic distribution and its transformation into heat, as well as the dynamics of the fluid to be heated under different operating conditions, are solved. For this purpose, and apart from the dielectric and magnetic properties of the material to be heated, which define how it behaves in relation to electric and magnetic fields when exposed to microwaves, there are several factors influencing the design of the process: the microwave generator and the transmission line, the geometry of the applicator where the electromagnetic field is distributed, the material container of the sample or the temperature measurement techniques to control the process. Additionally, numerical simulation is an essential tool for designing and predicting the suitability of any microwave system. This is the case of composite materials processing, where the application of numerical simulation tools arises from the need to achieve advanced materials more efficiently. In this paper, these fundamental aspects for the design of a microwave-assisted heating system are reviewed, presenting examples of various applications where this microwave technology is integrated. | 10.1016/j.icheatmasstransfer.2024.107594 | English | Journal Article | International Communications in Heat and Mass Transfer | 156 | 107594 | |||||
| B211 | 1989 | Microwave-Assisted Grinding | Walkiewicz et al. | |||||||||||||
| B212 | 1991 | Microwave-Assisted Grinding | Walkiewicz, John W; Clark, Andrea E; McGill, Sandra L | https://ieeexplore.ieee.org/abstract/document/73604 | The U.S.Bureau of Mines has conducted studies to utilize rapid microwave heating to stress-fracture ore samples. Iron ores containing hematite, magnetite, and goethite were subjected to microwave energy in batch operations at 3 kW and heated to average maximum temperatures between 840 and 940" C. Scanning electron microscope @EM) photomicrographs verified fracturing along grain boundaries and throughout the gangue matrix. Standard bond grindability tests showed that microwave heating reduced the work index of iron ores by 10 to 24%. Using a continuous feed belt in a microwave applicator, samples heated more uniformly and quickly than in batch operations. In a microwave chamber designed to simulate a continuous throughput operation at 3 k W , the grindability of a taconite ore was improved by 13% at a bulk temperature of 197" C. Because stress cracking occurred at a lower temperature, less energy was consumed, thereby improving the cost effectiveness of microwave-assisted grinding. To further improve the economics of microwave fracturing, preliminary tests were conducted to increase heating rates by using higher microwave powers. To appraise the economic feasibility of microwave-assisted grinding, the beneficial effects in the grinding circuit and in the extractive operation were considered. Factors such as increased throughput, less recycled ore, less wear and maintenance, and improved liberation of minerals will be addressed. | English | Journal Article | |||||||||
| B213 | 1993 | Grindability Of Taconite Rod Mill Feed Enhanced By Microwave-Induced Cracking | Walkiewicz, W | https://onemine.org/documents/grindability-of-taconite-rod-mill-feed-enhanced-by-microwave-induced-cracking | English | Journal Article | ||||||||||
| B216 | 2022 | Microwave heating mechanism and self-healing performance of asphalt mixture with basalt and limestone aggregates | Wang, Fu; Zhu, Hongbin; Shu, Benan; Li, Yuanyuan; Gu, Dengjun; Gao, Yangming; Chen, Anqi; Feng, Jianlin; Wu, Shaopeng; Liu, Quantao; Li, Chao | https://linkinghub.elsevier.com/retrieve/pii/S0950061822016439 | Traditional asphalt mixtures can’t absorb microwave energy efficiently, which limits the development of microwave heating technology in the field of road maintenance. Based on the microwave heating characteristics of basalt aggregates, the overall microwave self-healing rate of the asphalt mixture can be enhanced. The basalt was tested by XRF, XPS, XRD and electromagnetic parameters to reveal its microwave heating mechanism. Through the heating rate test, SCB test and fatigue test of asphalt mixture, its heating characteristics, flexural strength, fatigue resistance and self-healing performance were studied. The results showed that the excellent waveabsorbing properties of basalt are highly correlated with the elements of Si, Fe and Al. Its TanδM was slightly larger than TanδE, which indicated that basalt can absorb microwave energy through dielectric loss and magnetic loss. The aggregate type and particle size both affected the microwave heating rate of the aggregates. After microwave heating, the flexural strength and fatigue resistance of asphalt mixture with basalt and limestone aggregates can recover at least 65% and 23% respectively. | 10.1016/j.conbuildmat.2022.127973 | English | Journal Article | Construction and Building Materials | 342 | 127973 | |||||
| B217 | 2008 | Particle modeling simulation of thermal effects on ore breakage | Wang, Ge; Radziszewski, Peter; Ouellet, Jacques | https://linkinghub.elsevier.com/retrieve/pii/S0927025608000943 | The present study is primarily motivated to attain a better understanding of the microwave-assisted breakage in mining for the purpose of enhancing the excavation efficiency on the earth. The research results also offer NASA a new concept in manufacturing efficient excavators in exploration and in situ resource utilization in space. The ores are usually composed of non- and microwave-absorbing materials, e.g. calcite and pyrite. In this paper, first a thermal-based particle modeling (PM) is developed based on the first author’s previous work that could only account for mechanical parameters [G. Wang, M. Ostoja-Starzewski, Computational Materials Science 33 (2005) 429–442]. A global averaged fracture density concept is also defined so as to easily evaluate the total breakage effect of ores. Then the developed thermal-based PM is applied to a study of an ore material with a mixture of calcite and pyrite subject to a microwave exposure to explore microwave heating, thermal conduction, expansion, thermally induced fracturing and strain/stress curves associated with different input energy powers. Via this study, efficiency of fracturing and grinding on ores containing different calcite/pyrite ratios will be obtained. Finally, mechanical fracture approach performed on pyrite/calcite samples with different heating times is numerically simulated to investigate if and how much mechanical energy can be saved from the breakage cost resulting from thermal weakening of the material strength in advance. | 10.1016/j.commatsci.2008.02.005 | English | Journal Article | Computational Materials Science | 43 | 4 | 892-901 | ||||
| B218 | 2019 | Influence of microwave treatment on grinding and dissociation characteristics of vanadium titano-magnetite | Wang, Jun-peng; Jiang, Tao; Liu, Ya-jing; Xue, Xiang-xin | http://link.springer.com/10.1007/s12613-019-1720-1 | The effect of microwave treatment on the grinding and dissociation characteristics of vanadium titano-magnetite (VTM) ore were investigated using scanning electron microscopy (SEM), nitrogen absorption measurements, particle size distribution measurements, X-ray diffraction (XRD) analysis, Fourier transform infrared (FT-IR) spectroscopic analysis, and magnetic separation. SEM analysis showed that microfractures appeared in the microwave-treated VTM, which is attributed to the microwaves’ selective heating characteristic and the differential expansion between minerals and gangues. Nitrogen absorption showed that the microfractures were more pronounced when the microwave heating time was increased. Particle size distribution analysis showed that microwave treatment could improve the grindability of the VTM, thus increasing the weight percent of the fine-ground product. The increase in grindability was more significant with prolonged heating time. Moreover, the particle size distribution of the fine-ground product changed only slightly after the microwave treatment. XRD analysis showed that the crystallinity of the microwave-treated VTM increased with increasing microwave heating time. The magnetic separation tests revealed that the separation efficiency increased as a result of the intergranular fractures generated by microwave treatment. The Fe grade of the magnetic fraction of microwave-treated VTM was 1.72% higher than that of the raw ore. We concluded that the microwave treatment was beneficial, especially for the mineral processing characteristics. | 10.1007/s12613-019-1720-1 | English | Journal Article | International Journal of Minerals, Metallurgy, and Materials | 26 | 2 | 160-167 | ||||
| B219 | 2021 | Dynamic fragmentation of microwave irradiated rock | Wang, Shuai; Xu, Ying; Xia, Kaiwen; Tong, Tianyang | https://linkinghub.elsevier.com/retrieve/pii/S1674775520301359 | The microwave-assisted rock fragmentation has been proven to be a promising approach in reducing cutting tools wear and improving efficiency in rock crushing and excavation. Thus, understanding the influence of damage induced by microwave irradiation on rock fragmentation is necessary. In this context, cylindrical Fangshan granite (FG) specimens were exposed to microwave irradiation at a power of 6 kW for different durations up to 4.5 min. The damages of the specimens induced by irradiation were quantified by using both X-ray micro-CT scanning and ultrasonic wave measurement. The CT value and Pwave velocity decreased with increase of irradiation duration. The irradiated specimens were then tested using a split Hopkinson pressure bar (SHPB) system to simulate rock fragmentation. A momentum-trap technique was utilized to ensure single-pulse loading on the specimen in SHPB tests, enabling valid fragment size distribution (FSD) analysis. The dependence of dynamic uniaxial compressive strength (UCS) on the irradiation duration and loading rate was revealed. The dynamic UCS increased with increase of loading rate while decreased with increase of irradiation duration. Using the sieve analysis, three fragmentation types were proposed based on FSD, which were dictated by both loading rate and irradiation duration. In addition, an average fragment size was proposed to quantify FSD. The results showed that the average fragment size decreased with increase of loading rate. A loading rate range was identified, where a dramatic reduction of the average fragment size occurred. The dependence of fragmentation on the irradiation duration and loading rate was also discussed. | 10.1016/j.jrmge.2020.09.003 | English | Journal Article | Journal of Rock Mechanics and Geotechnical Engineering | 13 | 2 | 300-310 | ||||
| B220 | 2000 | Microwave assisted comminution and liberation of minerals | Wang, Y; Forssberg, E; Svensson, M | https://www.taylorfrancis.com/chapters/edit/10.1201/9780203747117-1/microwave-assisted-comminution-liberation-minerals-wang-forssberg-svensson | ||||||||||||
| B221 | 2005 | Dry comminution and liberation with microwave assistance | Wang, Yanmin; Forssberg, Eric | https://onlinelibrary.wiley.com/doi/10.1111/j.1600-0692.2005.00718.x | This paper presents the experimental results obtained from microwave-assisted comminution/liberation tests on various minerals. The effects of microwave energy intensity and exposure time on microwave heating behaviour and grind-ability of materials are discussed. The experimental results indicated that particle size has a significant effect. The coarser particles (−9.50 + 4.75 mm) of some minerals (limestone and quartz) were affected by microwave heating to varying degrees, resulting in an increased fineness of the ground product in a subsequent dry ball milling. It was observed that the silicate and carbonate minerals are difficult to heat at lower microwave energy intensities (<7 kW) during a short exposure (<30 min) due to their principally transparent or reflection to microwave energy. The thermal stress fractures in a copper ore in microwave exposure occurred readily, resulting in a better and cleaner liberation of sulphide minerals from the ore matrix. | 10.1111/j.1600-0692.2005.00718.x | English | Journal Article | Scandinavian Journal of Metallurgy | 34 | 1 | 57-63 | ||||
| B222 | 2007 | Enhancement of energy efficiency for mechanical production of fine and ultra-fine particles in comminution | Wang, Yanmin; Forssberg, Eric | https://www.sciencedirect.com/science/article/abs/pii/S1672251507000504 | This paper presents the energy requirements for mechanical production of fine and ultra-fine particles in comminution. Recent approaches for effective size reduction and energy saving in comminution are described, viz., (a) development and application of new mills/classifiers, (b) adjustment of the bead characterization in stirred bead mills, (c) hybrid comminution systems with roller-press and media mill, (d) assisted methods, and (e) simulation. | 10.1016/j.cpart.2007.04.003 | China PARTICUOLOGY | 5 | 3 | 193-201 | ||||||
| B223 | 2014 | Thermal stress FEM analysis of rock with microwave energy | Wang, Yicai; Djordjevic, Nenad | https://linkinghub.elsevier.com/retrieve/pii/S0301751614000817 | 10.1016/j.minpro.2014.05.012 | English | Journal Article | International Journal of Mineral Processing | 130 | 74-81 | ||||||
| B224 | 1968 | BREAKING OF CONCRETE | Watson, Alexander | https://linkinghub.elsevier.com/retrieve/pii/B9781483196794500203 | English | bookSection | Microwave Power Engineering | 111-114 | ||||||||
| B225 | 2022 | Analysis of Splitting Tensile Properties of Concrete Under Microwave and Conventional Heating Conditions | Wei, W; Zhang, H.; Shao, Z.; Jiang, Y. | https://www.engineeringmechanics.cn/en/article/doi/10.6052/j.issn.1000-4750.2022.05.0414 | ||||||||||||
| B226 | 2024 | Theoretical investigation of electromagnetic-thermal coupling of double-layer cylindrical concrete under microwave irradiation | Wei, Wei; Qiao, Rujia; Jiang, Yan Song; Shao, Zhushan | https://link.springer.com/10.1007/s40948-024-00780-y | Abstract Many experiments have been performed to study the heating properties of concrete under microwave irradiation. Microwave provides the non-uniform heating process, which cannot be reflected clearly through the experimental investigations. In this paper, a theoretical method is presented to investigate the electromagnetic-thermal coupling process of double-layer cylindrical concrete under microwave heating. The wave transmission and reflection were considered. An analytic solution is presented to predict transient heating process within a 3-dimensional double-layer concrete model induced by microwave heating. The inner aggregate is a microwave high loss material and the outer mortar was microwave low loss medium. Poynting theorem was employed to calculate the electric field distribution and microwave energy loss within concrete. Transient heat transfer process with an internal microwave heat source was investigated based on the classical heat transfer theory by employing integral transform technique. The results indicate that microwave heating effect depend on the concrete size, dielectric properties as well as microwave energy input. The temperature gradient was formed at the mortar-aggregate interface, which varied with the microwave heating parameters inputs. The analytical study will provide significant insight to promote the understanding of electric and temperature field in the two-layer composite concrete materials under microwave heating. | 10.1007/s40948-024-00780-y | English | Journal Article | Geomechanics and Geophysics for Geo-Energy and Geo-Resources | 10 | 1 | 72 | ||||
| B227 | 2019 | Fundamentals and applications of microwave energy in rock and concrete processing – A review | Wei, Wei; Shao, Zhushan; Zhang, Yuanyuan; Qiao, Rujia; Gao, Jiepu | https://linkinghub.elsevier.com/retrieve/pii/S1359431118369370 | Microwave heating is a green, efficient and sustainable technique for thermal process, which has been evaluated as an ideal candidate to satisfy the present and future sustainable technique requirement. This paper offers a comprehensive and systematic review of microwave heating assisted breaking of rock and concrete, with results of previous studies summarized, covering such areas as heating principle of microwave heating, materials response to microwave, the influence factors relating to microwave heating assisted breakage and also, the mechanism and advantage of heating processing. The status of practical application and future development trend of microwave assisted tunnelling, rock drilling and concrete aggregated recycling are analyzed. The difficulties involved in research and efforts should be made regarding the potential and opportunities of the future development of microwave technique for industry are also discussed. | 10.1016/j.applthermaleng.2019.113751 | English | Journal Article | Applied Thermal Engineering | 157 | 113751 | |||||
| B228 | 2024 | Study on Microwave-assisted TBM Double-edged Cutter Rock-breaking Efficiency and its Positional Relationship | Wen, Sen; Du, Lin; Kong, Qingmei; Zhang, Min; Ding, Xinru | https://ein.org.pl/Study-on-Microwave-assisted-TBM-Double-edged-Cutter-Rock-breaking-Efficiency-and,186447,0,2.html | In this study, based on a microwave test, the discrete element program (PFC) is used to establish a microwave-assisted disc cutter rock-breaking model and explore the influence law of the positional relationship between microwave radiation and disc cutter penetration on rock-breaking efficiency, and the results show that: The improvement of the positional relationship has a significant effect on improving the rock-breaking efficiency, and the double-edged cutter reaches and minimum rock-breaking specific energy when breaking the rock in the center position with a waveguide spacing of 90 mm and in the inner and outer positions with a waveguide spacing of 150 mm; When the waveguide spacing is 150mm, the double-edged cutter with cutter spacing of 110mm, 130mm, and 190mm have their advantages in rock-breaking efficiency and economic benefits, which should be selected according to the actual needs of the project. The follow-up research should also fully consider the rock type, microwave parameters, cutter profile, engineering environment, and other factors for in-depth investigation. | 10.17531/ein/186447 | English | Journal Article | Eksploatacja i Niezawodność – Maintenance and Reliability | 26 | 2 | |||||
| B229 | 2014 | Penetrating rock with intense millimeter-waves | Woskov, Paul P.; Einstein, Herbert H.; Oglesby, Kenneth D. | http://ieeexplore.ieee.org/document/6955993/ | 10.1109/IRMMW-THz.2014.6955993 | English | conferencePaper | 2014 39th International Conference on Infrared, Millimeter, and Terahertz waves (IRMMW-THz) | 45293 | |||||||
| B230 | 2012 | Millimeter-Wave Heating, Radiometry, and Calorimetry of Granite Rock to Vaporization | Woskov, Paul; Michael, Phil | http://link.springer.com/10.1007/s10762-011-9851-0 | Millimeter-wave (MMW) technologies can provide unique heating and diagnostic capabilities to research the thermal dynamics of materials to extreme temperatures. The MMW properties of rocks in the molten state up to their vaporization temperatures are not well known. Using a 28 GHz gyrotron beam collinear with a 130 GHz radiometry view in a calorimetric chamber, the transitions of granite rock specimens through solid phases, melting, and vaporization were observed, including release of trapped trace gas (<0.07%). The 28 GHz emissivity of molten granite was observed to be approximately constant at 0.66±0.03 up to vaporization where it increased to 0.70±0.03 at an equilibrated temperature of 2710±120°C. An analysis of the thermal power balance during a 76 s steady state vaporization time period indicates that the MMW emissivity of the molten granite is larger than in the infrared. The observations support the possibility that MMW thermal ablative penetration into hot crystalline rock formations could be a more practical approach than infrared laser drilling to access deep resources. | 10.1007/s10762-011-9851-0 | English | Journal Article | Journal of Infrared, Millimeter, and Terahertz Waves | 33 | 1 | 82-95 | ||||
| B231 | 2014 | The Improvement of Grindability and Floatability of Oxidized Coal by Microwave Pre-treatment | Xia, W.-C.; Yang, J.-G.; Zhu, B. | http://www.tandfonline.com/doi/abs/10.1080/15567036.2011.653621 | 10.1080/15567036.2011.653621 | English | Journal Article | Energy Sources, Part A: Recovery, Utilization, and Environmental Effects | 36 | 1 | 23-30 | |||||
| B232 | 2013 | Effect of microwave pretreatment on oxidized coal flotation | Xia, Wencheng; Yang, Jianguo; Liang, Chuan | https://linkinghub.elsevier.com/retrieve/pii/S0032591012006146 | 10.1016/j.powtec.2012.09.010 | English | Journal Article | Powder Technology | 233 | 186-189 | ||||||
| B233 | 2024 | Application and mechanistic insights of a washing/microwave/ultrasonic ternary pretreatment for enhancing barite flotation in waste drilling fluids | Xia, Yu; Mao, Hui; Tang, Shanfa; Xie, Shuixiang; Liu, Hongbo; Ren, Wen; Zhang, Mingdong | https://www.nature.com/articles/s41598-024-71441-z | A quantity of recoverable barite exists in high-density waste drilling fluid. Based on the inefficiencies and complexities of existing recycling methods, a novel pre-treatment approach which includes cleanbreaking, high-speed washing, ultrasonic dispersion, and microwave heating and a new depressant (Gellan Gum) was proposed. The floatability, separation efficiency and mechanism were discussed by SEM, adsorption capacity, zeta potential measurements and contact angle tests. The results of reverse flotation experiments results indicated that secondary water washing proves highly effective in enriching a significant quantity of barite solid phase. Subsequent microwave-ultrasonic and flotation can obtain barite of high quality with recovery and density reaching 81.5% and 4.238 g/cm3, respectively. It can be utilized directly in the preparation of drilling fluid. Mechanism studies shown that the per-treatments substantially enhances the barite grade while effectively eliminating lowdensity solid phases adhering to the barite surface, thus exposing additional contact points between the constituents so as to improve flotation separation. This new recovery scheme has environmental advantages and great reference value for the separation of barite within high-density waste drilling fluids. | 10.1038/s41598-024-71441-z | English | Journal Article | Scientific Reports | 14 | 1 | 20887 | ||||
| B234 | 2017 | Preliminary research on grindability improvement of coal by microwave pretreatment | Xiangnan, Zhu; Youjun, Tao; Qixiao, Sun; Ao, Song | http://www.minproc.pwr.wroc.pl/journal/pdf/ppmp53-1.644-655.pdf | Microwave pretreatment is an effective method to promote grindability of coal samples along with moisture reduction. A contrast test was designed to explore a mechanism of grindability improvement process of coal by microwave pretreatment. Coal samples of 2–1 mm were investigated. The moisture content, size distribution and density composition of grinding products of dry coal with thermal drying (DTD), dry coal with microwave pretreatment (DMP) and wet coal with microwave pretreatment (WMP) were measured. A scanning electron microscope analysis showed that DMP had more micron-sized cracks than WMP, meanwhile, WMP had more cracks than DTD after microwave pretreatment and thermal drying. The results of grinding tests showed that yield of -0.125mm size fraction increased with the decrease of moisture content, and was equal to 43.11, 45.03 and 47.09% of DTD, WMP and DMP, respectively, after 15 minutes grinding for the same moisture content. The results showed that cracks caused by dehydration and selective heating characteristics were the main factors responsible for improvement of grindability, however, thermal evaporation of inherent moisture within the coal structure had almost no effect on grindability of coal. | 10.5277/PPMP170150 | English | Journal Article | Physicochemical Problems of Mineral Processing; ISSN 2084-4735 | 538 kB | ||||||
| B235 | 2023 | Numerical analysis of mortar-aggregate separation induced by microwave heating | Xiao, Yihao; Shao, Zhushan | https://linkinghub.elsevier.com/retrieve/pii/S1290072922004859 | Microwave heating (MWH) is more and more popular for its high selectivity in mortar-aggregate separation that has been traditionally dominated by mechanical method. In this work, COMSOL Multiphysics software was used to predict the distribution of multi-field inside mortar and aggregate, and the reliability of the numerical model was verified by microwave heating experiment. The simulation results show that there are hot spots and cold spots in the sample, and the temperature at the edge is high, which is consistent with the experimental results. The separation is induced by the high temperature gradient at the interface due to thermal mismatch. The failure of the interface is mainly incurred by normal stress perpendicular to the interface. Microcracks are induced when it reaches the strength limit, which appear first at the edge of the interface. With the increase of time, the generation and interconnection of cracks lead to the increase of interface separation rate continuously. The separation rate of the interface and aggregate damage rate are also changing at varying positions. The separation efficiency has no direct relationship with the energy utilization rate. The aggregate damage rate is basically zero at the appropriate position, while the interface separation rate reaches 95%. In addition, the dehydration of calcium silicate hydrate and ettringite and steam migration are accompanied by the heating process. The model developed can also be helpful to predict the optimal location of effective separation of mortar-aggregate. | 10.1016/j.ijthermalsci.2022.107957 | English | Journal Article | International Journal of Thermal Sciences | 184 | 107957 | |||||
| B236 | 2023 | Investigation of thermally-induced separation in mortar-aggregate under microwave irradiation | Xiao, Yihao; Shao, Zhushan; Wei, Wei | https://linkinghub.elsevier.com/retrieve/pii/S0263822323003793 | Recycled aggregate demand is growing worldwide owing to the rapid development of public infrastructure. This paper aims to investigate the effect of multi-field coupling on the separation of mortar and aggregate based on theoretical analysis and numerical simulation, and the reliability of the model is verified by microwave heating experiment. The results indicate that the electric field intensity and temperature in mortar are greater than that in aggregate. The electric field is continuous at the interface, but there are jumps in temperature and stress. In the wave propagation plane, there are two neutral axes located respectively in mortar and aggregate. The neutral axis in mortar gradually moves towards the interface with heating time, resulting in the increasing of tensile stress on mortar surface. As the tensile stress exceeds the critical strength of mortar, microcracks are appeared on the surface and then gradually propagate towards the interface. The mortar is removed from the aggregate surface as the crack propagates to the interface. Moreover, during the heating process, dehydration of hydrous minerals and moisture migration in mortar also affect the separation of mortar and aggregate. This provides insight into the efficient separation of mortar and aggregate. | 10.1016/j.compstruct.2023.117035 | English | Journal Article | Composite Structures | 316 | 117035 | |||||
| B237 | 2023 | Study on mechanism of strength weakening of concrete subjected to microwaves in microwave-assisted concrete recycling | Xiao, Yihao; Shao, Zhushan; Wei, Wei; Jiang, Yansong; Chai, Sen; Zong, Zhenyang; Chen, Xingwang | https://linkinghub.elsevier.com/retrieve/pii/S0017931023004994 | This paper explores the multi-field distribution in concrete by coupling of the electromagnetics, heat transfer and solid mechanics in COMSOL Multiphysics software under microwave irradiation. The numerical model is validated by the temperature data captured from the experiment. The physicochemical reactions in mortar and aggregate during heating and evolution of surface cracks are further investigated by the tests. The results show that when the radiation effect is considered above 100 °C, the simulated temperature profile is in alignment with the experimental one. The hot spots formed by heating exist at surface edges and in aggregate area on the cross section. The maximum tensile stress and compressive stress appear at the boundary on the cross section. Although the stress in aggregate is greater than that in mortar, it maintains in the elastic deformation stage, whereas mortar will undergo the plastic strain with the strain over 0.04%, approximately rheological behavior. In the first 100 s of heating, the migration and evaporation of water and the dehydration of hydration products are the main factors of strength degradation of concrete, which is manifested by the generation and propagation of cracks and the decrease in density. The initial position of visible cracks has a lot to do with the path of moisture migration. The surface cracks have been coalesced over stress relief caused by the increase in open porosity after heating for 150 s. The pore pressure induced by moisture migration and thermal stress caused by temperature gradient initiate more internal cracks. This paper can provide reference and insight for effective strength weakening of concrete exposed to microwaves so as to make its weakened mechanical properties can work to recovery of high-quality aggregate after mechanical crushing. | 10.1016/j.ijheatmasstransfer.2023.124353 | English | Journal Article | International Journal of Heat and Mass Transfer | 213 | 124353 | |||||
| B239 | 2020 | Experimental study on effective microwave heating/fracturing of coal with various dielectric property and water saturation | Xu, Guang; Huang, Jinxin; Hu, Guozhong; Yang, Nan; Zhu, Jieqi; Chang, Ping | https://linkinghub.elsevier.com/retrieve/pii/S0378382019323458 | Microwave heating is a promising technology in coal processing and coal seam permeability enhancement. It is vital to investigate the influencing factors for microwave heating of coal to ensure the optimal heating effect and the best energy efficiency. To address this, different types of coal samples with various water saturation were treated with various microwave powers and irradiation times. Thermocouple and infrared thermal image system were used to measure the temperature of coal samples during and after microwave treatment. Through analysing the temperature, the effects of dielectric property and water saturation of coal, microwave power and treatment time on microwave heating were investigated. It was found the heating rate of coal samples increases with the loss factor at the initial heating period, which then changes as the composition changes under microwave irradiation. It was also found that coal samples with low water saturation have much better microwave heating effects. Moisture not only impedes microwave heating but also facilitates uniformed heating, which impedes the formation of thermal fractures. Additionally, the experiment results suggest the average temperature increases with microwave power and irradiation time. However, extending the microwave irradiation time is more effective when the microwave power increases to a certain extent. | 10.1016/j.fuproc.2020.106378 | English | Journal Article | Fuel Processing Technology | 202 | 106378 | |||||
| B240 | 2022 | Influences of controlled microwave field irradiation on occurrence space and state of shale oil: Implications for shale oil production | Xu, Yi; Lun, Zengmin; Wang, Haitao; Zhou, Xia; Zhao, Chunpeng; Zhang, Guanglei; Zhang, Dengfeng | https://linkinghub.elsevier.com/retrieve/pii/S0920410522009196 | 10.1016/j.petrol.2022.111067 | English | Journal Article | Journal of Petroleum Science and Engineering | 219 | 111067 | ||||||
| B241 | 2022 | Comparative study on microwave-assisted grinding of low-grade magnetite by continuous heating and pulsed heating | Yan et al. | https://jglobal.jst.go.jp/en/detail?JGLOBAL_ID=202202290797796411 | Chinese | Journal Article | ||||||||||
| B242 | 2021 | Effect of microwave treatment on the thermal properties and dynamic splitting behaviour of red sandstone | Yan, C.; Hassani, F.; Zhou, K.; Xiong, X.; Wawng, F.; Shao, Y | https://cdnsciencepub.com/doi/10.1139/cgj-2021-0313 | ||||||||||||
| B247 | 2022 | Exploration of weakening mechanism of uniaxial compressive strength of deep sandstone under microwave irradiation | Yang, Ben-gao; Gao, Ming-zhong; Xie, Jing; Liu, Jun-jun; Wang, Fei; Wang, Ming-yao; Wang, Xuan; Wen, Xiang-yue; Yang, Zhao-ying | https://link.springer.com/10.1007/s11771-022-4910-3 | Traditional mechanical rock breaking method is labor-intensive and low-efficient, which restrictes the development of deep resources and deep space. As a new rock-breakage technology, microwave irradiation is expected to overcome these problems. This study examines the failure characteristics, weakening law, and breakdown mechanism of deep sandstone (depth=1050 m) samples in a microwave field. The macroscopic and microscopic properties were determined via mechanical tests, mesoscopic tests, and numerical simulations. Microwave application at 1000 W for 60 s reduced the uniaxial compressive strength of the sandstone by 50%. Thermal stress of the sandstone was enhanced by uneven expansion of minerals at the microscale. Moreover, the melting of some minerals in the high-temperature environment changed the pore structure, sharply reducing the macroscopic strength. The temperature remained high in the lower midsection of the sample, and the stress was concentrated at the bottom of the sample and along its axis. These results are expected to improve the efficiency of deep rock breaking, provide theoretical and technical support for similar rock-breakage projects, and accelerate advances in deep-Earth science. | 10.1007/s11771-022-4910-3 | English | Journal Article | Journal of Central South University | 29 | 2 | 611-623 | ||||
| B248 | 2022 | Numerical investigation of TBM disc cutter cutting on microwave-treated basalt with an unrelieved model | Yang, Chun; Hassani, Ferri; Zhou, Keping; Zhang, Quan; Wang, Famin; Gao, Feng; Topa, Ameen | https://link.springer.com/10.1007/s43452-022-00463-z | Cutter wear or damage is a significant issue during tunnel boring machine (TBM) tunneling in hard rock. Microwave preconditioning has been verified as a promising approach to reduce cutter wear and enhance the TBM excavation efficiency. Thus, understanding the TBM cutting performance for microwave-treated hard rock is necessary. First, numerical verification of a cutting model was performed to examine the universality and reliability of the model. Then, the rock mechanical parameters of microwave-treated basalt were calibrated using linear Mohr–Coulomb theory. Finally, linear cutting simulations were conducted with an unrelieved rock model by considering the variables of the disc cutter penetration depth and microwave irradiation conditions. The numerical results indicated that the maximum reduction in the rolling and normal forces reached 38.38% and 44.95% (under a 5-kW microwave power and 3-mm penetration depth), respectively. A novel indicator of the linear friction energy was proposed to assess disc cutter wear, and the maximum reduction reached 36.81% under a microwave power of 5 kW and penetration depth of 4 mm. Considering the microwave weakening efficiency, TBM tunneling efficiency and cutter wear, microwave parameters including a high microwave power and short irradiation time were suggested for future practice. | 10.1007/s43452-022-00463-z | English | Journal Article | Archives of Civil and Mechanical Engineering | 22 | 3 | 147 | ||||
| B249 | 2022 | Evolution of pore-fracture structure and permeability of coal by microwave irradiation under uniaxial compression | Yang, Nan; Hu, Guozhong; Zhu, Jian; Duan, Haoran; Wang, Tonghui; Li, Yifan | https://linkinghub.elsevier.com/retrieve/pii/S1875510022003468 | 10.1016/j.jngse.2022.104759 | English | Journal Article | Journal of Natural Gas Science and Engineering | 107 | 104759 | ||||||
| B250 | 2018 | Microwave fragmentation of a synthetic alundum-pyrite ore | Yang, W.; Pickles, C.A.; Forster, J. | https://journals.sagepub.com/doi/full/10.1080/25726641.2018.1467603 | In the mining industry, the comminution process is very inefficient in terms of energy utilisation. Numerous research studies have investigated the use of microwave pre-treatment to fracture ore, prior to subsequent unit operations, such as grinding, flotation and leaching, therefore saving on energy consumption. The objective of the present work was to investigate the microwave fragmentation of a synthetic ore with controllable composition and particle size. The synthetic ore was composed of both a hyperactive material (pyrite) and an active material (alundum cement), which were compacted into a briquette. Heating behaviour, permittivity and thermogravimetric/differential thermal analysis (TGA/DTA) studies were conducted in order to understand the fundamental interactions of powdered samples with microwaves. The briquettes were processed in a microwave system followed by compression testing and image analysis to determine the effects of microwaving on the failure load and the fragmentation degree. It was found that the failure load of the briquettes decreased and the fragmentation degree increased with increasing pyrite particle size, pyrite content, and microwave energy absorption. | 10.1080/25726641.2018.1467603 | English | Journal Article | Mineral Processing and Extractive Metallurgy | 129 | 45355 | 251-266 | ||||
| B251 | 2024 | Microwave irradiation-induced deterioration of rock mechanical properties and implications for mechanized hard rock excavation | Yang, Zheng; Tao, Ming; Memon, Muhammad Burhan; Zhuang, Dengdeng; Zhao, Yan | https://linkinghub.elsevier.com/retrieve/pii/S1674775524003081 | 10.1016/j.jrmge.2024.03.034 | English | Journal Article | Journal of Rock Mechanics and Geotechnical Engineering | S1674775524003081 | |||||||
| B252 | 2024 | Microwave-assisted TBM cutter for efficient hard rock fracturing in high stress environments | Yang, Zheng; Tao, Ming; Yin, Tubing; Wu, Xingyu; Xiang, Gongliang; Xu, Yuanquan | https://linkinghub.elsevier.com/retrieve/pii/S0013794424006428 | Elucidating the effects and fundamental mechanisms of microwave-assisted mechanical excavation under high initial stress conditions is of paramount importance for enhancing the efficiency of deep resource extraction. In this study, indentation experiments were conducted on microwave-damaged rock under initial stress conditions using a tunnel boring machine (TBM) for the first time. By integrating acoustic emission, digital image correlation, and the discrete element method, we conducted a comprehensive analysis of the multifaceted effects of microwave irradiation and initial stress on rock fracturing. The rock-breaking efficiency was evaluated based on the volume of broken rock and the energy consumption. The indentation failure of the sample can be divided into three stages: microfracture closure, elastic deformation, and unstable crack propagation. The microwave irradiation reduced the peak load during the indentation process and simultaneously reduced the brittleness of the specimen. The experimental and simulation results jointly demonstrated the existence of an initial stress threshold in the rock fracturing process. When the initial stress is below the threshold, it suppresses the extension of rock fractures, which is unfavorable for rock fragmentation. When the initial stress exceeds the threshold, stress-induced rock failure occurs, which promotes rock fragmentation. A notable observation is that microwave irradiation alters the initial stress threshold of the rock, where a higher microwave power correlates with a lower initial stress threshold. This indicates that the optimal parameters for microwave equipment must be reconsidered when the initial stress changes. Methods for optimizing rock breakage at initial stress were suggested and examined. | 10.1016/j.engfracmech.2024.110479 | English | Journal Article | Engineering Fracture Mechanics | 310 | 110479 | |||||
| B253 | 2024 | Mechanical and fracture characteristics of weak microwave-absorbing sandstone under microwave irradiation: influence of pore water | Yao, Huayan; Fang, Qi; Jia, Yun; Liu, Jianjun; Lu, Gaoming; Yang, Fan | https://www.tandfonline.com/doi/full/10.1080/08327823.2024.2414709 | Microwave radiation is an effective method to weaken the strength of hard rock, but this weakening effect is not obvious enough for weak microwave-absorbing rocks. this work focuses on the role of water in amplifying the effect of microwaves on weak microwave-absorbing rocks, by examining the bursting characteristics of the rocks as well as their physical and mechanical properties before blasting. the experimental results show that when subjected to microwave irradiation, and the time taken for this bursting decreases with higher microwave power. in addition, the surface temperature of saturated sandstone gradually rises with increased irradiation power and duration. Under high microwave power, the uniaxial compressive strength (Ucs) of heated saturated sandstone notably decreases within the same irradiation duration. When the microwave power is low, the Ucs of saturated sandstone remains relatively unchanged over time. the Ucs of dry sandstone exhibits no significant alteration under identical irradiation power and duration. in conclusion, sandstone shows no significant change in its physical and mechanical properties during brief exposure to low-power microwave irradiation in its dry state. as water within the sandstone undergoes a phase transition from liquid to gas due to microwave irradiation, the resulting steam pressure causes the sandstone to rupture. | 10.1080/08327823.2024.2414709 | English | Journal Article | Journal of Microwave Power and Electromagnetic Energy | 45306 | ||||||
| B254 | 2024 | Comparison of microwave- and thermal-assisted rock fragmentation methods at different temperatures and loading rates | Yao, Wei; Wang, Shuai; Wu, Bangbiao; Xu, Ying; Xia, Kaiwen | https://linkinghub.elsevier.com/retrieve/pii/S2095268624000818 | Understanding the effects of microwave irradiation and thermal treatment on the dynamic compression and fragmentation properties of rocks is essential to quantify energy consumption in rock engineering. In this study, Fangshan granite (FG) specimens were exposed to microwave irradiation and heat treatment. The damage of FG specimens induced by these two methods was compared using X-ray CT scanning and ultrasonic wave method. The temperatures of FG after microwave irradiation and thermal treatment were effectively evaluated using a newly proposed technique. A novelty method for precisely determining the geometric features of fragments is developed to estimate the fragmentation energy. Thus, the dynamic uniaxial compressive strength (UCS), the dynamic fragmentation characteristics, and the fragmentation energy of FG after these two pretreatment methods can be reasonably compared. The noticeable distinction of loading rate effect on the dynamic UCS of FG between these two pretreatment methods is first observed. A relationship is established between the dynamic UCS and the damage induced by microwave irradiation and heat treatment. Moreover, fragmentation energy fan analysis is introduced to accurately compare the fragmentation properties of FG after two pretreatment methods in dynamic compression tests. | 10.1016/j.ijmst.2024.06.009 | English | Journal Article | International Journal of Mining Science and Technology | 34 | 6 | 799-819 | ||||
| B255 | 2022 | Determination of Dynamic Tensile Strength of Microwave-Induced Basalt Using Brazilian Test | Yin, Tubing; Wu, Bingqiang; Wang, Chao; Wu, You | https://link.springer.com/10.1007/s00603-020-02345-3 | Research on the dynamic tensile behaviour of microwave-irradiated rock is of great significance to microwave-assisted tunneling and mining. In order to study the effect of microwave heating and rapid cooling on the mechanical properties of basalt, dynamic Brazilian splitting tests were conducted using the split Hopkinson pressure bar (SHPB) equipment. Brazilian specimens were treated at microwave radiation (with different microwave powers and exposure times) and water cooling (after microwave processing) before the dynamic split test. The influence of microwave irradiation power (1–4 kW) and exposure time (10–40 s) on the surface temperature, P-wave velocity, and dynamic tensile strength of the basalt specimens have been studied. Test results indicate that the treatment has negative effect on the rock P-wave velocity and dynamic tensile strength, and high power and low time radiation can cause more damage than the specimens treated at low power and long time radiation, though equivalent microwave energy is exerted on the basalt samples. For example, the average rock dynamic tensile strength for the specimen treated at 1 kW for 40 s, 2 kW for 20 s, and 4 kW for 10 s is 37.51 Mpa, 37.98 MPa, and 31.94 MPa, respectively, which decreases by 13%, 12%, and 26% compared with the untreated specimens. When the specimens were heated at 4 kW for 28 s and longer, they break into debris abruptly and accordingly lost their bearing capacity. The internal structural characteristics of the treated basalts were studied using scanning electron microscopic (SEM) technique. These photographs showed that micro-cracks appear on the rock surface after microwave radiation and water cooling treatment. It confirms the damage caused by microwaves to basalt specimens on the microscopic level and provides an internal reason for the reduction in dynamic tensile strength and P-wave velocity. The research can provide certain experimental support for microwave-assisted mechanical rock breaking. | 10.1007/s00603-020-02345-3 | English | Journal Article | Rock Mechanics and Rock Engineering | 55 | 3 | 1429-1443 | ||||
| B256 | 2022 | Investigation of the effect of cyanidation after microwave roasting treatment on refractory gold/silver ores by characterization studies | Yoğurtcuoğlu, Emine | https://www.journalssystem.com/ppmp/Investigation-of-the-effect-of-cyanidation-after-microwave-roasting-treatment-on,157487,0,2.html | In this article, the efficiency of microwave pretreatment, which is an environmentally friendly, low-energy consuming method for recovery from refractory gold-silver ores, was investigated. The ore sample belonged to the oxidized Bolkardağ deposit, which contains carbonate (calcite, dolomite, smithsonite, hydrozincite), silicate (quartz, hemimorphite), sulfate (beudantite, plumbo-jarosite), and iron oxy/oxyhydroxide (hematite, limonite) minerals. Sulfur/sulfate-bearing silver and gold minerals are found either together with gangue minerals or in inclusions. Approximately 90% gold and 48% silver recovery efficiencies were achieved with the cyanide process after microwave preroasting from the ore. Additionally, the ore, heat treatment product, and waste samples were investigated by characterization studies. In these studies, bond structures, mineral content, sample mass losses, element percentage content differences, and mineral percentage content differences in the samples were determined. As a result, the microwave pretreatment application in cyanidation was presented as a new research topic in terms of its application in the valuable refractory content of this type of oxide. | 10.37190/ppmp/157487 | English | Journal Article | Physicochemical Problems of Mineral Processing | |||||||
| B258 | 2021 | A model for focused-beam microwave heating on rock fracturing | Yu, Hongwen; Li, Yuanhui; Cui, Guanglei; Elsworth, Derek; Liu, Jianpo; Liu, Mingfei | https://link.springer.com/10.1007/s40948-021-00242-9 | 10.1007/s40948-021-00242-9 | English | Journal Article | Geomechanics and Geophysics for Geo-Energy and Geo-Resources | 7 | 2 | 40 | |||||
| B259 | 2016 | Effect of magnetic pulse pretreatment on grindability of a magnetite ore and its implication on magnetic separation | Yu, Jian-wen; Han, Yue-xin; Li, Yan-jun; Gao, Peng | http://link.springer.com/10.1007/s11771-016-3376-6 | The pulsed power is a potential means for energy saving and presents an alternative to the conventional mechanical communication for minerals. The effect of magnetic pulse treatment on grindability of a magnetite ore was investigated by grindability tests. The results of the investigation show that the pulsed treatment has little effect on the particle size distribution of the magnetite ore. Significant micro-cracks or fractures are not found by SEM analysis in magnetic pulse treated sample. Magnetic separation of magnetic pulse treated and untreated magnetite ore indicates that iron recovery increases from 81.3% in the untreated sample to 87.7% in the magnetic pulse treated sample, and the corresponding iron grade increases from 42.1% to 44.4%. The results demonstrate that the magnetic pulse treatment does not significantly weaken the mineral grain boundaries or facilitate the liberation of minerals, but is beneficial to magnetic separation. | 10.1007/s11771-016-3376-6 | English | Journal Article | Journal of Central South University | 23 | 12 | 3108-3114 | ||||
| B260 | 2021 | Quantifying damage evolution within olivine basalt based on crack propagation behavior under microwave irradiation | Yuan, Yuan; Shao, Zhushan; Qiao, Rujia; Fei, Xinshuang; Wu, Dandan | https://journals.sagepub.com/doi/10.1177/10567895211017318 | Application of microwave heating technique is highly promising in assisting rocks breakage and recycling coarse aggregate in waste concrete. This work focus on crack propagation behavior and hence damage of hard rocks subjected to microwave irradiation. Heating effects of basalt and its main mineral components are investigated experimentally using a multimode industrial microwave system. Crack characterization of basalt after irradiating are observed using scanning electron micrograph (SEM). A theoretical model based on heating effects of mineral components is established to deduce crack propagation within basalt under microwave irradiation. Temperature rise of magnetite is drastic while that of other mineral components are tardy. Fracture of basalt is induced by predominant radial crack propagation around the rapidly heated mineral particle. Cracks can be divided into short cracks and long cracks by a characteristic length during extending. Microwave energy required for extension of cracks with characteristic length is minimum. Propagation of initial short cracks results in greater extent of damage evolution instantaneously. Moreover, damage increases with the mineral content of magnetite and decreases with crack density. | 10.1177/10567895211017318 | English | Journal Article | International Journal of Damage Mechanics | 30 | 10 | 1617-1641 | ||||
| B261 | 2022 | Crack damage evolution in concrete coarse aggregates under microwave-induced thermal stress | Yuan, Yuan; Shao, Zhushan; Qiao, Rujia; Guo, Xuan; Wang, Weitao | https://link.springer.com/10.1007/s43452-022-00419-3 | Coarse aggregates of waste concrete can be efficiently separated from mortar under microwave irradiation. However, the microwave-induced damage in aggregates are restricting mechanical properties of the aggregates for replacing natural aggregates. Since damage evolution in rocks treated by microwave are influenced by mineralogy and microwave operating parameters, such as power and irradiation time, understanding the microwave weakening mechanism of rocks is necessary to assess and control the damage of aggregates for recovery of high-quality concrete coarse aggregates. This article develops an approach for evaluating crack damage evolution in aggregates exposed to microwave by combining theoretical analysis with experimental investigation. A theoretical heat source-matrix model based on electromagnetic and thermal properties of mineral components is established for microwave heated aggregates. Substituting microwave irradiating parameters and mineralogy of the aggregates into the model, corresponding temperature fields and thermal stress fields are solved. Cracks in aggregates after microwave exposure are observed using scanning electron microscopy (SEM) and quantified in terms of crack length, density and intensity. Crack damage varied with microwave energy is assessed by crack length and density. Crack propagation is further discussed by contrast of stress intensity factor (SIF) at the crack tip and fracture toughness of the aggregate. Cracking behavior analyzed by SIF of cracks is consistent with that obtained from quantitative analysis on SEM images. The results suggest that granite shows a stronger resistance to thermal stress damage compared with basalt under microwave exposure, and a multistage microwave treatment should be adopted for recovery of various aggregates. | 10.1007/s43452-022-00419-3 | English | Journal Article | Archives of Civil and Mechanical Engineering | 22 | 3 | 108 | ||||
| B262 | 2024 | Analysis of Microwave-Induced Damage in Granite Aggregates Influenced by Mineral Texture | Yuan, Yuan; Zhao, Shuang | https://www.mdpi.com/2075-5309/14/5/1348 | The use of microwave energy to recycle high-quality coarse aggregates from waste concrete or assist hard rock breakage in underground building engineering is promising. Controlling or promoting the damage of coarse aggregates, i.e., hard rocks, under microwave irradiation is a crucial issue faced by these techniques. Understanding the damage mechanisms of hard rocks exposed to microwaves is thus urgent. Fracture toughness is a significant mechanical parameter of rocks that reflects their ability to resist crack propagation and damage evolution. In this study, the fracture toughness degradation of microwave-heated granite was investigated by combining experimental investigations and numerical simulations. A three-point-bending (TPB) experiment was conducted on granite specimens after microwave irradiation. A coupled electromagnetic–thermal–mechanical model considering the actual mineral texture of the granite specimen was established. The evolution of the temperature gradient and stress field near the initial notch tip were investigated. The results suggest that the microwave-induced maximum temperature gradient and stress in granite are at the plagioclase–quartz (Pl–Qtz) interfaces or inside the Pl near the boundary. The region of cracking initiation was defined as the damage zone, which could be obtained by comparing the microwaveinduced thermal stress with the critical value. The fracture toughness degradation, which corresponds to the evolution of the damage zones, can be divided into two stages. A relatively rapid decrease in fracture toughness in the first stage is primarily caused by the spread of the scattered damage zones along the Pl–Qtz interfaces; subsequently, a gentler fracture toughness degradation results mainly from the extension of the previous damage zones. | 10.3390/buildings14051348 | English | Journal Article | Buildings | 14 | 5 | 1348 | ||||
| B263 | 2022 | The investigation of concrete damage and recycled aggregate properties under microwave and conventional heating | Zhang, Hongliang; Wei, Wei; Shao, Zhushan; Qiao, Rujia | https://linkinghub.elsevier.com/retrieve/pii/S095006182201532X | Microwave-assisted concrete coarse aggregate recycling technology is considered as a potential concrete recycling technology, which is of great significance to environmental protection and sustainable development of the construction industry. In order to study the damage evolution process of concrete and the properties of recycled coarse aggregate (RCA) under microwave and conventional irradiation, the heating effect of concrete under different heating paths was studied. The heating efficiency, crack propagation law, failure mode and energy consumption of concrete under different heating conditions were obtained. The uniaxial compressive strength (UCS) test was carried out after heat treatment to explore the concrete strength weakening law. The apparent density, water absorption, point load strength and surface micro-crack characterization of RCA after heat treatment were comprehensively analyzed. The results show that microwave heating technology has greater advantages than conventional heating methods that can effectively promote the development of interfacial cracks between mortar and aggregate, weaken the strength of concrete and liberate high-quality RCA under certain conditions. The research results can provide reference and contribution for microwave-assisted concrete crushing and aggregate recovery process. | 10.1016/j.conbuildmat.2022.127859 | English | Journal Article | Construction and Building Materials | 341 | 127859 | |||||
| B264 | 2022 | The characteristics and mechanism of microwave-induced borehole fracturing of hard rock under true triaxial stress | Zhang, Jiuyu; Feng, Xia-ting; Yang, Chengxiang; Lin, Feng; Li, Shiping; Tong, Tianyang; Su, Xiangxin | https://linkinghub.elsevier.com/retrieve/pii/S0013795222002538 | High stress induced by excavation disturbance in deep hard rock can cause rockburst accidents. Microwave-induced borehole fracturing of hard rock is a promising technique for preventing rockbursts, the principle of which is to induce thermal fracture of rock mass through microwave heating. The characteristics and mechanism of microwave-induced borehole fracturing of hard rock under different true triaxial stresses were experimentally investigated. After microwave-induced borehole fracturing under different σ1 and σ2 conditions, a complex crack network dominated by tensile cracks was generated in the rock specimen, which is consistent with the results obtained by AF and RA. According to the P-wave velocity before and after the test, the degree of thermal fracture is positively linearly correlated with σ1 and σ2 as a whole, and has good consistency with the length and number of thermal cracks. The results show that the technique has better applicability and higher fracturing efficiency in high-stress areas. The thermal fracture process of basalt specimens under different σ1 and σ2 conditions is similar, which can be divided into a silent period, quiet period, dense period, and persistent period. In addition, thermal fracture exerts a significant threshold temperature effect, and fracture rate increases rapidly when the temperature reaches 150-192 °C (average about 172 °C). The relationship between thermal fracture and stress provides guidance for parameter design. | 10.1016/j.enggeo.2022.106768 | English | Journal Article | Engineering Geology | 306 | 106768 | |||||
| B265 | 2022 | Multifield coupling study on random aggregate concrete under microwave irradiation | Zhang, Pengju; Wei, Wei; Shao, Zhushan | https://linkinghub.elsevier.com/retrieve/pii/S0950061821037570 | Microwave-assisted concrete aggregate recycling is a new green technology with minute pollution and low energy generation during the heating process. In this study, a random aggregate concrete model is established based on a real industrial microwave heating system. The secondary development of a MATLAB and COMSOL Multiphysics interface is applied to realize a multifield coupled numerical analysis of the electromagnetic field, heat transfer field, and mechanical field of concrete under microwave irradiation. The model is validated by experimental tests. The results show that the dielectric loss is the main factor that influences the concrete temperature variation. Tensile stress and shear stress are generated at the mortar–aggregate interfaces. A high microwave energy input leads to significant temperature and stress gradients between the aggregates and the mortar. Compared to the aggregates, the mortar suffers a larger deformation in a microwave field, finally leadings to its damage. Thus, the investigation of the thermal responses of aggregates and mortars under microwave irradiation will provide reference for the further development of microwave-assisted concrete recycling technology. | 10.1016/j.conbuildmat.2021.126025 | English | Journal Article | Construction and Building Materials | 318 | 126025 | |||||
| B266 | 2022 | Thermal Response and Mechanical Behaviors of Compact Basalts Induced by Microwave Irradiation | Zhang, Xiao-Wu; Xu, Jin-Hai; Chen, Liang; Cao, Yue; Sun, Lei; Shaikh, Faiz | https://www.hindawi.com/journals/geofluids/2022/6211437/ | Microwave pretreatment could be an invaluable method to improve the efficiency of the rock breakage in the excavation and comminution operations. To investigate the influence of microwave irradiation on the thermal response and mechanical behavior of compact rocks, a series of physical and mechanical experiments were conducted on the nontreated and treated basalts. The mineral compositions of the basalts were obtained by X-ray diffraction (XRD) test. Scanning electron microscope (SEM) images and geological sketch were utilized to analyze the propagation pattern of the microcracks and macrofractures caused by the microwave irradiation. High power density microwave can induce the complication of the microcracks and exchange the pattern of the macrofracture network. Based on the uniaxial compression strength (UCS) test, the mechanical performance of the basalts was evidently reduced with the increase of the microwave power and exposure time. The experimental results prove that microwave-assisted method has significant potential application to preweakening rocks in civil and mining engineering. | 10.1155/2022/6211437 | English | Journal Article | Geofluids | 2.022 | 45310 | |||||
| B267 | 2024 | Effect of Microwave Irradiation on Mechanical Properties and Microstructures of Minerals | Zhang, Zhiqiang; Zhang, Qi; Zou, Guanqi; Chen, Fangfang | https://www.mdpi.com/2075-163X/14/6/623 | Microwave-assisted rock breaking is a new and promising technology for the tunneling and drilling industry. Minerals in rocks have an important influence on the effect of microwaveassisted rock breaking. In this paper, common minerals in rocks such as potash feldspar (hereafter referred to as K-feldspar), calcite and pyroxene were selected as samples, and a lot of microwave irradiation tests were carried out by using a hamilab-v1500 microwave oven. The mass, strength and microstructure of the rock samples were tested before and after microwave irradiation. The change law of the mineral mass, strength and microstructure with regard to temperature was analyzed, and the influence mechanism was discussed. The results show that the strength of K-feldspar increases from 20 °C to 400 °C but decreases significantly when it is higher than 400 °C; the strength of pyroxene increases from 20 °C to 600 °C but decreases when it is higher than 600 °C; the strength of calcite decreases with the increase in temperature. As for the weakening pattern, pyroxene shows drawstring, step and flow with the increase in temperature, but K-feldspar and calcite show that failure occurs along the cleavage plane of the crystal structure. The higher the temperature of microwave irradiation, the finer the pattern at the fractured zone is, and the more fragmented it becomes; the loss of mineral mass increases with the increase in the temperature of microwave irradiation. | 10.3390/min14060623 | English | Journal Article | Minerals | 14 | 6 | 623 | ||||
| B268 | 2022 | Preliminary study on the weakening effect of microwave irradiation on Singapore Bukit Timah granite and its influence on mechanical excavation performance | Zhao, X. B.; Zhao, Q. H.; Gong, Q. M.; He, J. L. | https://link.springer.com/10.1007/s40948-022-00417-y | 10.1007/s40948-022-00417-y | English | Journal Article | Geomechanics and Geophysics for Geo-Energy and Geo-Resources | 8 | 4 | 110 | |||||
| B269 | 2022 | Dielectric anisotropy effects on the microwave-induced thermodynamic response of coal: Numerical simulations and experiments | Zhao, Yixin; Gao, Yirui; Sun, Zhuang; Gao, Sen; Sun, Chuncheng | https://linkinghub.elsevier.com/retrieve/pii/S0016236122018804 | Microwave heating technology is a promising solution in underground engineering, such as mining, coalbed methane extraction, and oil/gas production, that primarily depends on the conversion of microwave energy due to dielectric properties. However, inadequate understanding of the effects of dielectric properties on microwave irradiation limits further development of microwave techniques. In this study, based on the dielectric anisotropy of coal, an electromagnetic-thermomechanical coupled model was used to numerically investigate the thermodynamic response under microwave irradiation at 2.45 GHz and 1 kW for 180 s. We performed experimental verification via indoor test. Results show that the sensitivity of microwaves to the dielectric direction in the TE10 mode is x > z > y. In different dielectric anisotropy models, the temperature and maximum principal stress increase synchronously and linearly with increasing heating time, and the curve growth rate is positively correlated with the equivalent dielectric permittivity. There are also marked temperature and stress concentrations in the sample. The compressive stress is concentrated in the center of the sample, while the tensile stress is around the outer edge. For bedding coal, tensile fractures occur under microwave irradiation along the bedding, and shear fractures run through the bedding. With the increase of the input microwave energy, the failure mode of coal gradually expands from single fracture to fracture network. | 10.1016/j.fuel.2022.125038 | English | Journal Article | Fuel | 326 | 125038 | |||||
| B270 | 2024 | Experimental Investigation on the Effects of Microwave Irradiation in Pore Structures of LN2 Freezing Coal for Coalbed Methane Extraction | Zhao, Yu; Yang, Zairong; Wang, Chaolin; Bi, Jing | https://link.springer.com/10.1007/s00603-024-03883-w | Liquid nitrogen (LN2) fracturing, an effective method in stimulating reservoirs, contains freezing and thawing. In general, frozen rocks are air-thawed in past studies. Microwave fracturing not only enhances pore structures but also removes pore water. To investigate the influence of the thawing process, microwave irradiation is used to thaw the coal samples after LN2 freezing, and is compared with air-thawing. The magnetic resonance imaging (NMR) results illustrate that the increased rates of the seepage pores of the air-thawing samples decrease first from 13.01% (30 min) to 8.76% (120 min) and then gradually increase to 15.49% (270 min) after the freeze–thaw treatments, in which the microwave performs greater than air at the same freezing time. The results of the wave velocity of the samples are similar to that of NMR. The infrared thermal imaging (ITI) results indicate that after microwave thawing, the variance of the surface temperature slowly decreases to the minimum value of 373.9 (120 min) from 636.3 (30 min), and then peaks at 270 min (1243.0). The fractures of the air-thawed samples become more obvious with the increasing freezing time and are further developed after microwave thawing; the development of the fractures influences the distribution of the surface temperature. The SDR permeability variations perform a similar rule to that of the seepage pore. The results can be a possible reference in thawing the LN2 freezing coal by microwave. | 10.1007/s00603-024-03883-w | English | Journal Article | Rock Mechanics and Rock Engineering | 57 | 9 | 7495-7513 | ||||
| B271 | 2022 | Heating-Dominated Fracturing of Granite by Open-Ended Microwave: Insights from Acoustic Emission Measurement | Zheng, Yanlong; Ma, Zhongjun; Gong, Qiuming; Zhang, Penghai; Zhao, Xiaobao; Li, Jianchun | https://link.springer.com/10.1007/s00603-022-02887-8 | Microwave fracturing of hard rocks holds great promise in the civil, mining and tunnelling industries. The role of heating and cooling in the fracturing of rocks and when and where cracks initiate from and propagate to remain unclear and need to be addressed for future field applications of the technology. This study treated an alkali feldspar granite using a 6 kW industrial microwave source and a customised open-ended dielectric-loaded converging waveguide antenna. The real-time acoustic emission (AE) characteristics in the microwave heating and natural cooling phases were recorded and investigated. The surface temperature and P-wave velocity reduction of the specimens were also measured to quantify the thermal damage. The fracturing of granite is found to be tensile failure and is heating-dominated. Although a considerable amount of AE hits and events was detected in the cooling phase, they were of low energy, and therefore, the role of cooling in rock fracturing by open-ended microwave can be neglected. Fractures initiated from the exterior of the antenna and propagated towards the edges and the interior of the specimens. The cracks obtained from the AE localisation were in good agreement with those observed. With the increase of power level, the time for crack initiation was shortened, confirming the high-power effect. | 10.1007/s00603-022-02887-8 | English | Journal Article | Rock Mechanics and Rock Engineering | 55 | 8 | 4577-4589 | ||||
| B272 | 2024 | Thermal behaviors of cement and mortar under microwave treatment and the influencing factors: An experimental study | Zheng, Yanlong; Su, Ziqiang; Fu, Huanyu; Zhang, Qi; Li, Jianchun | https://linkinghub.elsevier.com/retrieve/pii/S0950061823039090 | Microwave-assisted breakage of cementitious materials has emerged as a promising green and low-carbon method for dismantling cementitious structures. To understand the mechanism of microwave-induced cracking in structures, it is essential to study the thermal behaviors of cement and mortar under microwave treatment. In this paper, the effects of mixture ratio, water content, and microwave power on the microwave heating characteristics of cement and mortar specimens were investigated through real-time temperature and mass monitoring. In particular, the influence of microwave power on the bursting effect of cement and mortar specimens was analysed, and the mechanism of specimen bursting was explained. The results show that moisture content, water-cement ratio, and microwave power significantly impact the heating rate and mass loss of cement and mortar during microwave treatment. Based on the heating rate, the heating process of cement and mortar under microwave treatment can be divided into three to four stages, depending on the moisture content. The primary reasons for variations in the heating rate are water evaporation and the decomposition of hydrolysis products. The thin-wall ball model based on steam pressure theory can explain the bursting of cement and mortar specimens. Our findings suggest that increasing microwave power and water content in mortar specimens can lead to microwave-induced cracking. | 10.1016/j.conbuildmat.2023.134191 | English | Journal Article | Construction and Building Materials | 411 | 134191 | |||||
| B273 | 2021 | Effect of Microwave Pretreatment on Leaching of Tetrahedrite | Znamenácková, Ingrid; Dolinská, Silvia; Hredzák, Slavomír; Cablík, Vladimir | https://iopscience.iop.org/article/10.1088/1755-1315/906/1/012111 | In mineral processing, the use of microwave radiation is important especially in pretreatment processes. At present, there is an acceleration of processes as well as an increase in the efficiency of metal recovery. One of the main problems in copper recovery from complex sulphide ores is the removal of impurities such as antimony, arsenic, mercury. In the hydrometallurgical processing scheme, the key step is the leaching. The extraction process can be influenced by the selection of suitable leaching reagents or by suitable pre-treatment of the ore. The article describes the effect of microwave radiation on the leaching Sb, As and Hg of tetrahedrite and tetrahedrite concentrate. The samples were irradiated at the power 900 W for 30 seconds. The leaching of irradiated and non-irradiated samples was realized in an alkaline sodium sulphide. The positive effect of microwave radiation was confirmed by an increase in the recovery of Sb and As already after 15 min of extraction. After microwave leaching of irradiated tetrahedrite samples, the yield of Sb was 43.2 %, in irradiated tetrahedrite concentrate, the yield of Sb was 81.3 %. | 10.1088/1755-1315/906/1/012111 | English | Journal Article | IOP Conference Series: Earth and Environmental Science | 906 | 1 | 12111 | ||||
| B274 | 2014 | Utilization of Microwave Radiation at the Heating of Magnesite | Znamenáčková, Ingrid; Dolinská, Silvia; Lovás, Michal; Hredzák, Slavomír; Dimitrakis, Georgios | https://www.researchgate.net/publication/288717301_Utilization_of_microwave_radiation_at_the_heating_of_magnesite | The paper deals with an influence of microwave energy on magnesite heatEng. The understanding of dielectric properties of heated materials predicts the running of microwave heatEng. The values of real and imaginary component of the complex dielectric permittivity of magnesite are described. The temperature distribution in the sample of magnesite during microwave heating was described by COMSOL Multiphysics programme. It followed the influence of microwave pretreatment on magnesite failure. The comminution process intensification of studied samples was evaluated by relative work index. | English | Journal Article | |||||||||
| B275 | 2016 | Ore impact breakage characterisation using mixed particles in wide size range | Zuo, Weiran; Shi, Fengnian | https://www.sciencedirect.com/science/article/abs/pii/S0892687515301394 | The Drop Weight Tester (DWT) for ore impact breakage characterisation uses particles in five narrow size fractions, and the JKMRC Rotary Breakage Tester (JKRBT) uses four size fractions, both with three impact energy levels for each size fraction. It is time consuming to prepare these narrowly sized particles and to carry out size analysis on the 15 DWT or 12 JKRBT products, so a Wide-size JKRBT characterisation method was developed. In this method, the mixed particles in 13.2–45mm size range are tested as one size class in the JKRBT by single-particle breakage mode. The wide-size feed is then divided into several virtual narrow size fractions by simulation, based on which the impact product size distributions are calculated using a size-dependent breakage model. Four sets of measurement data, consisting of two feed samples in the 13.2–45mm size range with different size distributions tested with two impact energy levels, are adequate to determine the three model parameters. In the case where a benchmark ore of known breakage characteristic parameters is available, one Wide-size JKRBT impact treatment can determine the ore competence change parameter using a t10-based model. | 10.1016/j.mineng.2015.12.007 | Minerals Engineering | 86 | 96-103 | |||||||
| B277 | 2023 | Microwave Heating Impacts on Ore Breakage Phenomena of Kimberlite Rock in Crusher | https://www.researchgate.net/publication/373485438_Microwave_Heating_Impacts_on_Ore_Breakage_Phenomena_of_Kimberlite_Rock_in_Crusher | kimberlite | ||||||||||||
| C001 | 2025 | 滚刀结构对微波辅助破岩效率的影响研究 | 杜林; 温森; 孔庆梅; 张敏 | https://link.cnki.net/doi/10.15991/j.cnki.411100.2025.04.005 | 滚刀破岩;微波辅助;滚刀结构;比能;离散元 | 为探究滚刀结构对微波辅助破岩效率的影响，以花岗岩在微波前后的温度变化、强度损伤和裂纹特征为依据，采用离散元程序(PFC2D)建立微波辅助TBM双刃滚刀破岩模型，从滚刀法向力、裂纹扩展和破岩效率对不同刃形和刃宽的滚刀进行破岩效果分析.结果表明：在贯入度16 mm和刀间距180 mm范围内，滚刀平均法向力和平均破岩比能随着滚刀刃宽的增加而增加，且相同刃宽时，弧形滚刀的平均法向力、岩体破碎面积和破岩比能均小于锥形滚刀；弧形滚刀和锥形滚刀在微波辅助破岩时产生的损伤裂纹均以垂直于滚刀贯入方向的侧向裂纹为主，随着刃宽的增加，岩体底部在滚刀挤压作用下产生沿滚刀贯入方向的纵向裂纹，其中，锥形滚刀产生的裂纹效果更为显著；综合破岩效率和耐磨性能的考虑，选用弧形截面、刃宽18 mm、刀间距90 mm的双刃滚刀与微波进行联合破碎此类硬岩较为合理. | 10.15991/j.cnki.411100.2025.04.005 | Chinese | China | Journal Article | 河南大学学报(自然科学版) | 55 | 04 | 461-475 | ||
| C002 | 2025 | 白云鄂博低品位铌矿物选冶联合富集铌的工艺研究 | 王振华 | https://link.cnki.net/doi/10.27724/d.cnki.gnmgk.2025.000373 | 白云鄂博矿;微波焙烧;机械活化;浸出 | 铌是战略性稀有金属,因高熔点、高沸点等优异性能成为高科技产业重要原料。随着我国发展及中美贸易局势变化,其战略地位愈发重要。我国白云鄂博矿区铌储量大,但矿石复杂、品位低等问题制约其高效开发。研究选取我国储量可观的白云鄂博矿物作为原料,构建“微波钠盐磁化焙烧-弱磁选-机械活化浸出”协同处理工艺体系。系统开展单因素试验,探究各工艺参数对白云鄂博矿分解过程的影响规律。通过优化试验,明确微波钠盐焙烧、弱磁选分离、酸浸提取等关键环节的最佳工艺条件,并在此基础上深入开展选冶联合技术富集铌元素的工艺研究。在微波钠盐磁化焙烧过程中,最佳焙烧温度为650℃,保温时间为40min,配碳量为2%,Na2CO3含量为10%。在此条件下,磁化率可达2.36,接近理论值2.33。弱磁选过程粗选最佳球磨时间和磁场强度为15min和200mt,精选最佳球磨时间和磁场强度为6min和100mt。铁精矿中铁的品位为62.83%,铁回收率为85.56%。磷品位为0.33%,脱磷率为93.23%,磁选尾矿中Nb2O5的品位0.228%,Nb2O5的回收率为90.74%,REO的品位为9.51%,REO的回收率为92.91%。磁选产物的分析结果显示,铁元素主要赋存于磁性精矿之中,而其余元素则多富集于磁性尾矿内。白云鄂博磁选尾矿的铁氧化物、磷化物、稀土氧化物及其他成分纳米级嵌布在一起包裹着铌元素,很难通过物理分选富集铌元素,需采用化学处理将铁、磷、稀土氧化物等杂质脱除,才能实现铌元素的富集。机械活化可以增强盐酸浸出白云鄂博磁选尾矿中磷、铈、镧、钕、铁的浸出效果。增强矿物的溶解率,使Nb2O5的含量提高。通过实验确定了盐酸浸出白云鄂博磁选尾矿中磷、铈、镧、钕、铁和铌元素的优化条件:球磨时间30min、初始HCl浓度4mol/L、浸出温度80℃、浸出时间60min、液固比15:1。在此条件下,磷、铈、镧、钕、铁和铌元素浸出率分别达到97.81%、86.95%、88.63%、90.90%、96.64%和23.59%。此时矿物溶解率为84.29%,Nb2O5含量为1.11%。通过对浸出渣的分析可知钙、铁、磷、铈等元素得到浸出,铌元素主要富集在浸出渣中。盐酸浸出使浸出渣矿相构成简单,为后续对铌提取创造了条件。 | 10.27724/d.cnki.gnmgk.2025.000373 | Chinese | China | Thesis | ||||||
| C003 | 2025 | 微波辐射下铁尾矿石水泥混凝土的破碎技术研究 | 康宪章 | https://link.cnki.net/doi/10.27864/d.cnki.gsjtd.2025.000132 | 铁尾矿石;水泥混凝土;微波辐射;温度梯度 | 建筑业高速发展三十多年,许多水泥混凝土的基础设施已进入更新周期,结合目前的国家发展方向,绿色、高效的可重复利用建筑材料日渐凸显其价值。另一方面,以铁尾矿为代表的大宗矿废材料占地闲置,得不到高值利用。本文从铁尾矿石的高吸波特性入手,以其作为骨料,设计出一种微波辐射下易破碎的水泥混凝土,在高值利用固废的同时可降低基础设施循环利用成本。本文以掺入铁尾矿石骨料的水泥混凝土为对象,聚焦于微波辐射下其破碎性能变化规律,利用理论分析、试验验证、仿真模拟等手段,探索破碎机理和控制参数之间的关系,并从以下三个方面展开工作:首先对铁尾矿石的微波敏感性设计了试验方案并检测,深入分析升温规律;其次,制作含铁尾矿骨料的水泥混凝土试块,利用工业微波装置进行辐射后采集其温度场变化数值,以超声测损和强度衰减的方式评价了辐射前后的损伤程度;最后,利用COMSOL仿真工具,模拟混凝土内部三场耦合,得到了破碎发展的关键位置和过程。经过深入分析和研究,得到以下结论并揭示了相关规律:(1)利用XRD试验,对不同骨料进行物相分析,经过同条件下的微波辐射后,发现5min下铁尾矿石与石灰石温度差异明显,其升温速率为石灰石的3倍,其中9.5-16mm粒径骨料的升温速率比4.75-9.5mm粒径提高了18.3%。(2)阐述微波破碎水泥混泥土机理,提出微波破碎水泥混凝土的控制指标体系;制备不同铁尾矿骨料含量的水泥混凝土试件,进行不同条件下的微波辐射后,可发现在6k W和3min工况下能显著加大水泥混凝土温度场梯度,使铁尾矿骨料和周围产生内应力,达到开裂效果;以超声波声速衰减率与抗压强度折减率为破损程度的量化指标,经过数据对比和深入分析,表明强度折减率与辐射时间、功率及铁尾矿石含量呈正相关的规律,并得出回归模型y=(0.01c+0.03)x+0.93c-2.37。(3)通过宏观表象标记和微观电镜(SEM)扫描破坏界面的方法,得到水泥混凝土试件的破坏特征。宏观下显示粗骨料与砂浆结合的界面过渡区有明显裂缝产生,试块由表面裂缝扩展逐步演化为整体破碎;微观下能观察到错综复杂的裂纹网络,结构松散化导致界面黏结力下降,呈现易碎特性。(4)基于COMSOL建立随机骨料模型及电磁-温度-力多物理场耦合模型,通过仿真模拟对试件的电磁场分布、温度梯度演变以及热应力分布进行深入分析,揭示了各物理场参数的关联性。混凝土模型的温度场分布特征与电场分布保持一致,模型呈现出“外拉内压”的应力状态,5min下混凝土最大热应力值达到48.4 MPa。根据以上研究,本文结论能够从铁尾矿石水泥混凝土的设计、施工和快速破碎回收的角度,提供理论分析、配合比设计控制、施工工艺参数以及破碎装置开发等方面的参考和指导,为可更新式基础设施的发展提供助力,具有很大的社会经济价值。 | 10.27864/d.cnki.gsjtd.2025.000132 | Chinese | China | Thesis | ||||||
| C004 | 2025 | 矿物选择性解离：理论、技术与应用综述 | 尚保忠; 姜望龙; 黄业豪; 崔瑞 | https://link.cnki.net/doi/10.20244/j.cnki.fjsk.202503119 | 选择性解离;预处理技术;磨矿制度;矿物材料 | 矿物解离是一个极为复杂的过程，通常会受到多种因素的影响。传统的粉碎技术虽然能使矿物解离，但选择性较差，不利于节能降耗和绿色发展。本文从理论层面分析了矿物选择性解离的可行性，综述了能够促进矿物在加工过程中选择性解离的条件和技术，并介绍了目前常采用的各项预处理技术对矿石的作用机理，从实验室研究层面概括了各项预处理技术的研究进展，从实际生产层面总结了各项技术的应用概况，对未来选择性解离技术发展进行了展望。 | 10.20244/j.cnki.fjsk.202503119 | Chinese | China | Journal Article | 非金属矿 | 48 | 03 | 119-123 | ||
| C005 | 2025 | 赤泥选矿过程中有价元素回收技术研究 | 杨永亮; 徐昊 | https://kns.cnki.net/kcms2/article/abstract?v=wScU5_zS5CMydZ1GN25bTcOvyPCETPDp7fAxEZtAoNXmf08u-XNCjvReXuKZV9gXdhKNVD5vrt1E2wHNgriXEEgK3QTZrLGeWc0jukkyv5eu2qokDdudC3gU_wU0Qh9WgN23YwlO1SwqtnkyIK1QPn04QKWGVmHkEDZc0mBgHgn1Swva35sh-VX7SZJAcAn7&uniplatform=NZKPT&language=CHS | 赤泥选矿;有价元素;回收 | 赤泥是铝土矿生产氧化铝过程中生成的废弃物，其中含有铝、钪、钛、钒、镓等多种有价元素，具有重要的资源化利用价值。针对赤泥成分复杂、金属赋存状态多样的特点，文章系统综述了赤泥中有价元素的回收技术研究进展，主要包括铝、钪和钛，以及钒等有价元素的回收技术，在此基础上，进一步探讨了回收过程中的挑战与对策，以期为赤泥选矿过程中有价元素的高效回收提供参考。 | Chinese | China | Journal Article | 冶金与材料 | 45 | 04 | 65-67 | |||
| C006 | 2025 | 利用ICP-MS测定岩石样品中铬、镉、铅的两种前处理方法对比研究 | 姜欢 | https://kns.cnki.net/kcms2/article/abstract?v=wScU5_zS5CNAyqUCoOJZmogoxgpOCIyECZTlZ5DyYou5P_B9PgogaT8v_QlvHtLz0hWiXG5IBuj2mmYPMdHgT8u4A861VU-UiyYzPhoNy_kxaENaoqgj1ZIGV2LRpbK0BjZbGLQ-Hd_sLWAxOstc6MPxkE4tdLTPj4Wi_YjpLNcD1X6VvOomgt2DUJfhqSPh&uniplatform=NZKPT&language=CHS | ICP-MS前处理;微波消解;元素损失;基体干扰;记忆效应 | 本文系统研究了ICP-MS分析岩石样品中铬、镉、铅时不同前处理方法对检测结果的影响。通过样品测试结果对比微波消解与电热板消解两种前处理方法的优缺点，同时探讨了在酸体系选择、元素回收率、基体干扰及记忆效应等因素对样品消解的影响。结果表明，微波消解结合HNO3-HF混合酸体系对矿石样品的消解效率显著优于电热板消解；Fe基体干扰可通过He/He碰撞模式联合103Rh内标校正有效抑制，Cr检测偏差由23.8%降至2.0%；Pb的记忆效通过采用超纯水与2% HNO3交替冲洗（总时长≥120s），残留信号降幅达95%。本方法探讨的内容适用于高硅、高铁地质样品中痕量重金属的消解前处理，为矿石样品中痕量重金属的准确检测提供了优化方案。 | Chinese | China | Journal Article | 世界有色金属 | 07 | 199-201 | ||||
| C007 | 2025 | 不同微波加热方式下花岗岩损伤分析 | 段智博; 曾姝; 杨军; 马少坤 | https://link.cnki.net/urlid/11.2595.O3.20250428.1653.072 | 同轴天线;矩形波导;花岗岩损伤;电磁-热-力耦合;数值模型 | 在隧道工程和采矿工程通过微波技术对岩石进行预处理可弱化岩石力学性能。为探究不同微波加热形式下花岗岩损伤规律，该文建立了矩形波导和同轴天线加热的两种电磁-热-力耦合的数值模型并引入损伤变量，分析了不同微波作用下电场分布规律、花岗岩温度分布规律、应力分布规律以及损伤区变化规律。结果表明：同轴天线加热方式相比于矩形波导可有效将微波馈入到花岗岩内部，辐射更加精准；两种微波加热方式下在孔洞高度范围内均产生拉应力，孔洞下方产生“内压外拉”的应力状态；损伤区形态上同轴天线加热可使得孔内外损伤区联通，但损伤区范围较小；而矩形波导加热方式下短时间内可产生损伤区，损伤区范围较大，但损伤区不聚焦，未使孔内外损伤区联通。研究结果表明：若要对孔内某一特定区域进行精准微波辐射建议采用同轴天线加热方式，若想快速获得大面积损伤区弱化岩石建议采用矩形波导的微波加热方式。 | Chinese | China | Journal Article | 工程力学 | 42 | S1 | 283-289 | |||
| C008 | 2025 | 基于磨矿动力学研究微波预处理对钒钛磁铁矿磨矿特性影响 | 王俊鹏 | https://kns.cnki.net/kcms2/article/abstract?v=wScU5_zS5CNfJnd0223SpTYg3O_B33sO912G3gXhAAPWwr-j4qef5g_Q-j0Qbvl6OSsfm1ANaqU_MO8EoXaKOeToY8Jv8rVA-h1ur-E7wjxKmlE97znT5r6q4xyqC4mYcsrDO9aMSkW7pMQjKIl_N95dwG62JLd8Ymee8tRScCy6dWPL_ZiI38ZtA5iKQYnS&uniplatform=NZKPT&language=CHS | 钒钛磁铁矿;微波预处理;磨矿动力学;磨矿速度 | 对微波预处理前后钒钛磁铁矿进行不同磨矿时间的分批磨矿试验，建立了微波预处理前后钒钛磁铁矿的m阶磨矿动力学模型，分析了矿石粒度与磨矿时间对磨矿速度的影响。在磨矿初期，微裂纹数量是影响磨矿速度的主要因素，在磨矿中后期，磨矿概率成为影响磨矿速度的主要因素。微波预处理后粗粒级矿石（-3.350～+1.700 mm）的磨矿速度远高于未处理矿石，而细粒级矿石（-0.057～+0.045 mm）的磨矿速度变化很小。采用微波热力辅助钒钛磁铁矿磨矿有益于改善磨矿产品的粒度组成，从而提高选别效率及精矿质量。 | Chinese | China | Journal Article | 钢铁钒钛 | 46 | 01 | 107-111 | |||
| C009 | 2025 | 微波辅助双压头冲击岩石类材料的细观-宏观分析 | 王鹏; 岳中文; 徐胜男; 高丹; 任猛; 李阿康; 刘伟俊 | https://link.cnki.net/doi/10.13225/j.cnki.jccs.2024.0256 | 微波辅助;冲击破碎;比能耗衰减度;损伤;临界应变能密度 | 由于炸药使用受限以及响应国家“双碳”目标，微波+机械冲击破碎岩石类材料的新方法，因其环保、破碎能力强而在硬岩巷道掘进、混凝土结构拆除等工程中拥有广阔前景，但其内在机理还不够明确。以灌浆料混凝土为研究对象，依托建立的双压头同步冲击试验系统(DHPB)和电镜扫描(SEM)设备，通过理论推导和试验验证的手段，探究双压头冲击下混凝土试件宏观比能耗和细观损伤随不同微波辐射时间的变化规律，尝试建立以临界应变能密度为媒介的宏观比能耗衰减度-细观损伤的定量函数关系。结果表明：微波辐射劣化混凝土力学性能具有阈值特性，当混凝土吸收的应变能密度小于初始裂纹扩展所需的应变能密度时，混凝土试件内部基本无损伤，而当混凝土吸收的应变能密度较大时，试件损伤随应变能密度近似线性累积；混凝土试件内部的细观裂纹扩展具有瞬时特性，随着微波辐射时间增加先静态扩展后转为动态扩展，扩展过程中由于大量能量在较短时间内释放会引起整个试件瞬间破碎；微波辐射能够显著影响混凝土试件在双压头冲击下的破坏形态，无微波辐射时混凝土试件的最终断裂路径与双压头连线方向基本一致，有微波辐射时的最终断裂路径则与双压头连线方向夹角较大，且会出现多条宏观裂纹；微波辐射下混凝土试件受双压头冲击的宏观比能耗最大值为0.69，相应的细观损伤为0.68，两者基本一致，意味着细观裂纹长度和数量的增加能够定量降低宏观比能耗，揭示微波辐射削弱岩石类材料抵抗冲击破坏能力的内在机理。研究结果为微波+机械冲击在工程中的应用提供了参考。 | 10.13225/j.cnki.jccs.2024.0256 | Chinese | China | Journal Article | 煤炭学报 | 50 | 04 | 2108-2122 | ||
| C010 | 2024 | 微波预热强化某难浸氧化铜矿浸出行为及机理 | 李阳; 寇珏; 傅钰辉; 王培龙; 邓洁; 孙春宝 | https://kns.cnki.net/kcms2/article/abstract?v=wScU5_zS5COYWwuXTkJ2us2o3UhsCmdrwpjxbi3pEu-rBgwk_8Y16G-5nDF-NExsvH0iYTLjsly230EWMEcciDCMK4ux2P6AqamwUVpcKQmA7rk5b8QiGYsT9Yq4bT7gGr7hBE2_64Db8BRz-9iKlMwG5SD8LiWQwpYDsAENDX914GSPa0bf4c0u2zAERVKH&uniplatform=NZKPT&language=CHS | 氧化铜矿;含铜黑云母;加温搅拌酸浸;微波预热;浸出能耗 | 非洲某难浸氧化铜矿中的铜主要赋存于云母层间结构中，当地湿法冶炼厂采用加温搅拌酸浸工艺处理，浸出时间长，浸出温度高，导致作业能耗高。为提高铜的浸出率，降低浸出温度、缩短浸出时间，开展了微波预热强化该氧化铜矿浸出研究。首先，研究了原矿的工艺矿物学特征；其次，研究了不同影响因素下该难浸氧化铜矿的浸出行为；最后，分析了微波预热强化该难浸氧化铜矿浸出的机理。研究结果表明：该矿石黑云母中赋存大量铜，绢云母中并不含铜；提高微波预热功率、增加微波预热时间，铜的浸出率会随之上升，但预热时间过长时铜的浸出率不再上升，且会导致能耗增加；提高硫酸用量和浸出温度、增加浸出时间均有利于铜的浸出，其参数可在微波预热处理的基础上进一步优化；在微波预热功率为350 W、微波预热时间为10 min、硫酸用量为75 kg/t、浸出温度为55℃、浸出时间为200 min的条件下，铜的浸出率最高可达到77.05%；与当地湿法冶炼厂采用的加温搅拌酸浸工艺相比，硫酸用量降低15 kg/t，铜的浸出率提高1.92%，同时可将浸出温度降低10℃、浸出时间缩短40 min，降低了浸出能耗。微波预热可使原矿中黑云母层间距变大，使黑云母的比表面积增加，有利于硫酸进入黑云母层间与更多的铜直接接触并发生反应，提高铜的浸出率。 | Chinese | China | Journal Article | 中南大学学报(自然科学版) | 55 | 11 | 4274-4282 | |||
| C011 | 2024 | 岩体弱化方法及其在深部高应力硬岩机械化开采中的应用 | 李夕兵; 郭懿德; 陈江湛; 黄麟淇 | https://kns.cnki.net/kcms2/article/abstract?v=wScU5_zS5CMHOr4Z3IabmI4t4wPDcIHJNW-GSL9ArhECEGplWgCjd79kN4RpNjsx5VRgmqdKMRR_zmLVwZ0qHGbdq1HK2vWXA2jTeqo7EisMfsg2DuJFsJsofR0V-NG65DyTjzHOHGVLvTLikWLOYWY831LdgYWA4BGxiRfRSKC_Bx9qGUYZ4x6uCIZNnXh_&uniplatform=NZKPT&language=CHS | 深部矿产;动静组合加载;高应力硬岩;岩体弱化;机械破岩;岩石破裂 | 战略性矿产资源的安全保供是国家重大战略需求，向地球深部要矿产资源在未来相当长一段时间内具有不可替代的战略性。为了保障矿产资源需求，深部高应力硬岩的安全高效开采是深部采矿必须解决的重大问题。首先，本文阐述了深部高应力硬岩采矿的技术挑战及“变害为利”的采矿变革思路，提出了高应力硬岩弱化后再开展机械破岩以实现商业化开采的关键技术对策。然后，总结了“接触式”和“非接触式”岩体弱化方法的机理、具体特点与发展现状，并对比分析了两类岩体弱化方法在辅助高应力硬岩机械破岩领域的发展潜力。最后，展望了以深部高应力硬岩热剥落损伤弱化辅助机械破岩为代表的安全高效连续采矿技术，为深部战略性矿产资源安全保供与深地工程发展提供了有益指导。 | Chinese | China | Journal Article | 有色金属(矿山部分) | 76 | 06 | 51-63 | |||
| C012 | 2024 | 不同微波加热方式下花岗岩损伤分析 | 段智博; 曾姝; 杨军; 马少坤 | https://link.cnki.net/doi/10.26914/c.cnkihy.2024.023332 | 同轴天线;矩形波导;花岗岩损伤;电磁-热-力耦合;数值模型 | 在隧道工程和采矿工程通过微波技术对岩石进行预处理可弱化岩石力学性能。为探究不同微波加热形式下花岗岩损伤规律,本文建立了矩形波导和同轴天线加热的两种电磁-热-力耦合的数值模型并引入损伤变量,分析了不同微波作用下电场分布规律、花岗岩温度分布规律、应力分布规律以及损伤区变化规律。结果表明:同轴天线加热方式相比于矩形波导可有效将微波馈入到花岗岩内部,辐射更加精准;两种微波加热方式下在孔洞高度范围内均产生拉应力,孔洞下方产生"内压外拉"的应力状态;损伤区形态上同轴天线加热可使得孔内外损伤区联通,但损伤区范围较小,而矩形波导加热方式下短时间内可产生损伤区,损伤区范围较大,但损伤区不聚焦,未使孔内外损伤区联通。研究结果表明:若要对孔内某一特定区域进行精准微波辐射建议采用同轴天线加热方式,若想快速获得大面积损伤区弱化岩石建议采用矩形波导的微波加热方式。 | 10.26914/c.cnkihy.2024.023332 | Chinese | China | Conference Proceedings | 7 | |||||
| C013 | 2024 | 磁铁矿矿石组构对微波的响应机制研究 | 孙琪; 李明宇; 高文元; 赵福德; 刘波; 黄菲 | https://link.cnki.net/urlid/52.1045.P.20240902.1118.001 | 微波;磁铁矿;磁铁矿矿石;响应机制;微波吸收性 | 我国铁矿石品位低、成分复杂、嵌布粒度较细，粉碎矿石过程中需要消耗大量能量，所以亟需提高磁铁矿矿石粉碎效率。本文对Fe3O4分析纯试剂和铁矿石成分分析标准物质的物相结构、静磁性能和电磁特性进行测定，分析讨论了矿石组分含量对其微波吸收性的影响因素以及磁铁矿的微波响应机制。磁铁矿属于强吸波物质，当矿石中磁铁矿的含量越高，其复介电常数和复磁导率越接近Fe3O4分析纯试剂的电磁物理特性。微波能量进入磁铁矿内部后，磁铁矿Fe—O离子键中的电子在电磁场的作用下产生极化作用，形成的偶极子在加速迁移运动中不断碰撞摩擦产生热量，开始吸收并消耗微波场中的电场能量。磁铁矿亚磁晶格中的磁畴也会受到电磁场的作用产生极化作用，从而吸收并消耗微波场中的磁场能量。 | Chinese | China | Journal Article | 矿物学报 | 44 | 06 | 870-878 | |||
| C014 | 2024 | 石灰岩微波致裂规律研究 | 古傲林; 马占国; 文佳豪; 李阳; 陈达 | https://link.cnki.net/doi/10.20174/j.JUSE.2024.04.14 | 石灰岩;微波破岩;单轴压缩;微波激励;最佳处理时间;最佳处理功率 | 为探求微波激励对坚硬石灰岩力学特性与致裂效果的影响，选取徐州地区典型石灰岩进行微波处理和单轴压缩试验，并建立二相岩模型开展数值试验，分析石灰岩的损伤程度随微波激励功率、时间的变化规律。结果表明：微波激励对石灰岩力学性质的改变包括在两成分的交界面由温度应力引起细小裂缝，此外，微波功率恒定时，两成分交界面的温度增长梯度、应力增长梯度均与处理时间呈负相关；压缩破岩的最佳微波激励功率和时间为3.0 kW/m3的微波处理岩石10 min;随着载荷作用点距中轴线的距离增加，各激励功率下的断裂应力曲线不断收缩，不同激励功率的效率趋于一致；3.0 kW/m3作为岩石受微波激励的裂缝增长关键功率节点，对岩样不同区域裂缝增长梯度影响显著。研究结果可为坚硬石灰岩致裂工作提供参考。 | 10.20174/j.JUSE.2024.04.14 | Chinese | China | Journal Article | 地下空间与工程学报 | 20 | 04 | 1191-1209 | ||
| C015 | 2024 | 铁元素含量及含水状态对砂岩微波辐射升温损伤的影响 | 陈登红; 鲁德沛; 王智鹏; 汪朝家; 施伟 | https://link.cnki.net/doi/10.13532/j.jmsce.cn10-1638/td.2024.04.009 | 微波辐射;铁元素含量;含水状态;升温损伤特征 | 为研究砂岩的铁元素含量与含水状态对微波辐射升温损伤的影响规律，开展了砂岩试件微波辐射对比试验，试验分为12组，包含3种铁元素含量和4种含水状态(干燥、自然、浸水24 h与饱和)。试验采用X射线荧光光谱测量(XRF)技术检测试件表面铁元素含量，通过实时红外热成像监测表面升温过程，运用对比方法分析辐射前后P波波速与抗拉强度的关联特征。试验结果表明：(1)干燥状态下，砂岩试件升温过程均呈前期缓慢、中期活跃、后期稳定的趋势；铁元素含量越高，升温速率峰值就越高(2.66, 2.40, 1.66℃/s)、也就越早达峰(70, 100, 110 s);(2)干燥、自然、浸水24 h状态下，升温速率峰值平均值分别为：2.26, 3.34, 3.24℃/s,达峰时间分别为：90, 70, 20 s;饱和状态下，升温速率峰值为1.3℃/s,达峰时间为80 s;(3)含水状态对砂岩结构损伤的影响最为显著，饱和状态砂岩辐射180 s的损伤大于其他含水状态辐射300 s的损伤；铁元素含量直接影响岩石表面温度分布的均匀程度，铁元素含量越高，岩石表面温差越大；(4)相较于干燥和自然含水状态，浸水24 h和饱和状态下砂岩辐射后巴西劈裂初始压密阶段占比增加，起裂模式由端部起裂向中心起裂转变。研究成果可为类似原生和再生状态下微波辅助破岩效果的研究提供借鉴与参考。 | 10.13532/j.jmsce.cn10-1638/td.2024.04.009 | Chinese | China | Journal Article | 采矿与岩层控制工程学报 | 6 | 04 | 34-51 | ||
| C016 | 2024 | 考虑强吸波矿物含量的微波照射岩石弱化模型研究 | 李铧辰 | https://link.cnki.net/doi/10.27398/d.cnki.gxalu.2024.000404 | 微波照射岩石;强吸波矿物;能量机制;本构模型 | 微波辅助破岩技术具有大幅降低岩石强度且节约能源的优势,强吸波矿物含量是影响破岩效果非常重要的因素。本文基于微波辅助机械破岩课题的研究,充分考虑强吸波矿物含量影响微波照射岩石弱化的控制性效果,建立考虑强吸波矿物含量的岩石微波能量演化分析框架,研究微波照射下岩石内部能量耗散与强度变化之间的联系。论文通过细观力学均匀化的方法,描述了强吸波矿物含量与整体力学参数之间的关系;通过分析微波照射下岩石内部单元能量耗散与整体强度变化之间的关系,建立了考虑强吸波矿物含量的岩石微波照射能量演化分析模型。分析了岩石在微波照射后的储能与耗能规律。通过微波照射岩石能量特征值分析岩石强度的弱化效果。最后通过定义微波照射损伤因子和单轴压缩能量损伤因子,得到了微波照射岩石的整体损伤因子,基于岩石整体损伤因子建立微波照射后岩石试样一次加卸载单轴压缩的统一损伤本构模型。利用不同岩石在不同温度下的一次加卸载单轴压缩试验曲线验证了模型的有效性。本文主要研究成果如下: (1)揭示了强吸波矿物含量对岩石微波照射效果影响分析规律。岩石中强吸波矿物虽占比较低,但在微波照射过程中起着重要作用,是影响岩石力学特性变化的重要因素。随着强吸波矿物含量的增加,经辐照后岩石抵抗外力作用的属性逐渐降低,并和强吸波矿物含量之间呈负线性相关关系。随着强吸波矿物含量增加,岩石经微波照射产生的裂纹数量逐渐增多,裂纹萌生速率增快,裂纹数量增加趋势与强吸波矿物含量之间近似呈正线性相关关系。 (2)建立考虑强吸波矿物含量的微波照射岩石弱化模型。通过细观力学均匀化的方法,描述了强吸波矿物含量与整体有效力学参数之间的联系;之后基于微波照射下岩石内部单元能量耗散与整体强度变化之间的联系,建立了考虑强吸波矿物含量的岩石微波照射能量演化分析模型。 (3)得到了微波照射岩石能量演化规律以及其与力学特性规律。对玄武岩、花岗岩和石灰岩在微波照射前后进行了单轴压缩试验和单次加卸载单轴压缩试验,计算并分析了三类岩石的应变能变化特征及能量演化规律。微波照射不同温度下岩石的应变能虽然呈现非线性演化趋势,但是其储能与耗能的规律满足线性相关关系,即总应变能与弹性应变能和总应变能与耗散应变能的比值始终为定值。岩石中强吸波矿物含量影响岩石储能及耗能能力,当岩石含有较多的强吸波矿物时,岩石储能能力逐渐减弱,同时耗能能力逐渐提高。 (4)建立了一个考虑微波照射损伤的岩石本构模型。基于微波照射后岩石试样弹性模量和耗能系数的变化,定义了微波照射后岩石试样的损伤因子和加载损伤因子,并提出了微波照射岩石的综合损伤因子表达式。利用岩石压密阶段和准弹性变形阶段的特征,建立了微波照射后岩石试样一次加卸载单轴压缩的统一损伤本构模型。利用微波照射不同温度以及不同岩石试样的一次加卸载单轴压缩试验曲线验证了模型的有效性。 | 10.27398/d.cnki.gxalu.2024.000404 | Chinese | China | Thesis | ||||||
| C017 | 2024 | 微波照射下大理岩孔隙结构变化特征及能量演化规律 | 李想; 杨建国; 杨博; 李杰林; 周科平 | https://kns.cnki.net/kcms2/article/abstract?v=wScU5_zS5CMt84ev4OGAGzZiLx4QiFR8333aAIMg6rsXTvRJtRPZAJzXkuQUwfDJpg096Q8ymploxMD9yvxFtqlpKbaWbMzUqaO3P7ojcY-6Mx0lC62Vvfx9zweIpqPZ2lTYaHFiP4o1cKI8hZTq5joauZhrYDJfCcXSt93Vh4ehxzzlJnd1jwneSJDLyNWu&uniplatform=NZKPT&language=CHS | 微波照射功率;微波辐射时间;孔隙结构;损伤模型;能量演化;岩石损伤 | 为研究大理岩在不同微波照射功率和辐射时间下的孔隙结构变化及强度劣化特征，基于核磁共振技术分析不同微波照射功率和辐射时间下大理岩的孔隙结构演化特征，并通过声波和岩石力学强度等测试工作进行验证。同时，建立微波照射下岩石的损伤劣化模型，并基于能量耗散理论分析了大理岩的能量演化过程。结果表明：随着微波照射功率和辐射时间的增加，大理岩的质量、硬度、波速、峰值强度和弹性模量等参数均呈现不同程度的下降，孔隙度升高；随着微波照射功率和辐射时间的增加，试样内部能量发生转换，耗散能能量占比不断增加，弹性能能量占比不断减少。研究结果揭示了微波照射下大理岩内部孔隙结构变化及能量演化规律，对其他类型岩石损伤演化机理具有一定的借鉴意义。 | Chinese | China | Journal Article | 黄金科学技术 | 32 | 03 | 470-480 | |||
| C018 | 2024 | 微波辐射深井砂岩升温损伤特征与钻进效果对比研究 | 陈登红; 鲁德沛; 王智鹏; 汪朝家; 杨理想; 汤允迎 | https://link.cnki.net/doi/10.19614/j.cnki.jsks.202406013 | 微波辐射;深井砂岩;侧压受限变形;钻进效果;路径优化 | 为了研究微波辐射深井砂岩升温损伤特征与钻进效果,采用恒源煤业标高-940 m回风辅助石门取芯的深井砂岩为研究对象,分析其深井砂岩在相同输入能量微波辐射后温度、质量、纵波波速及钻进实验后的机械钻平均转速、扭矩随不同路径处理下的变化规律。研究结果表明:在模拟试件单面辐射时,高功率短时间(1.4 k W,214 s)比低功率长时间(1.0 k W,300 s)微波辐射后质量变化、试件前侧后表面最高温度变化更大,且波速差值和损伤因子随试件表面温度升高而增大;微波辐射前后测量试件对应5个标记点位置处的纵波波速,发现波速差值和损伤因子较大的地方主要集中在试件表面升温最高的地方;在对比有无受限变形条件下钻进实验效果分析开展了A组微波未辐射、有受限变形(路径1),B组微波功率为1.0 k W、微波辐射时间为300 s、有受限变形(路径2),C组微波功率为1.0 k W、微波辐射时间为300 s、无受限变形(路径3),D组微波功率为1.4 k W、微波辐射时间为214 s、有受限变形(路径4)4种路径的处理方式,得到钻进效果从优到差的路径依次为:路径3>路径4>路径2>路径1;分析得到在相同输入能量有受限变形条件制约下,功率在1.4 k W微波辐射下钻进效率是功率在1.0 k W微波辐射下的1.3倍左右,而有受限变形条件制约下,微波辅助钻进法的效率是无微波辐射常规法的8.5倍左右,即有受限变形条件制约下机械钻进较为困难。研究成果为较弱吸波能力深井砂岩的损伤路径优化及低能耗高效率破岩提供了借鉴与参考。 | 10.19614/j.cnki.jsks.202406013 | Chinese | China | Journal Article | 金属矿山 | 06 | 94-104 | |||
| C019 | 2024 | 微波辅助破碎岩石的有源温度场和应力场的理论研究 | 白宇龙 | https://link.cnki.net/doi/10.27393/d.cnki.gxazu.2024.000517 | 岩石;微波;温度;应力;解析解 | 岩石破碎在隧道开挖、矿物加工、采矿等基础工程中必不可少,采用微波加热劣化岩石性能提高机械破碎效率在实际工程应用中具有广阔的发展前景。为了推动该项技术发展,提供更加可靠的理论指导,迫切需要根据实际处理岩石的电磁及物理性能,给出最优微波照射参数设置,这对微波辅助破岩机理的理论分析也提出了更高的要求。考虑实际微波辅助破岩中电场强度是由边界条件决定的非均匀分布,因此理论模型需要满足非均匀分布热源。使用分离变量法求解理论模型时,缺少可以满足多相介质中非均匀分布热源的正交函数系,本文通过两相介质界面处连续条件,构造了可以满足多相介质下的非均匀分布热源的新的正交函数系,并使用该正交系给出了非均匀分布热源下两相介质球对称模型的温度场和应力场解析解。经过与数值解在多种情况下的误差分析确定理论解的有效性,用该理论解对具有不同介电性能、热传导性能、及热膨胀性能的两相矿物在多种微波功率密度和微波作用时间情况下的温度场和应力场进行了分析,考虑了最佳的微波功率密度与微波作用时间产生的机理,并给出了黄铁矿-方解石界面开裂的能量最大化利用方案。本文主要研究内容包括三个部分,总结如下: (1)针对含有非均匀分布热源的两相介质球对称模型,两种介质分别为黄铁矿和方解石。假设温度场与应力场是单向耦合。在常系数的模型下,采用分离变量法给出了满足模型中心和最外侧边界条件的通解。特征值由两种矿物间的连续条件确定,研究发现黄铁矿与方解石内的通解在各自的区域上不具有正交性,但通过连续条件可以在整个黄铁矿-方解石区域上得到一种间断的正交函数系。通过该间断的正交函数系恰好可以满足温度场的连续条件和任意的初始温度分布。 (2)基于分离变量法求得了可以满足任意初始温度分布的解析解后,采用热传导方程中处理热源项的正交函数系展开的方法,求得了可以满足非均匀分布热源的两相介质球对称模型的温度场,基于热弹性力学中的球对称模型以及两相介质单骨料模型的位移场和应力场的边界条件和连续条件,建立和求解了两相介质球对称模型下的应力平衡方程、几何方程和物理方程等。给出含有非均匀分布热源的应力场解析解。基于常系数情况下的温度场解析解,进一步给出了含有非均匀分布热源的一维变系数模型的温度场解析解。研究发现热传导方程中的变系数项按照已知的正交函数系展开后,变系数模型可以采用分离变量法求解。给出含有非均匀分布热源的两相介质变系数模型的温度场的公式化精确解。 (3)对比解析解与数值模拟结果高度一致,具体指在4种给定的不同初始条件和不同参数的组合情况下误差均小于5%。根据不同情况下的温度场和应力场分析得到以下结果:吸波矿物的热膨胀系数对整个微波加热过程中的应力分布规律有较大影响。低吸波矿物中的热膨胀系数对应力的分布规律影响较小。温度峰值可以决定应力场峰值的上限,在温度峰值确定的情况下,在方解石内,温度梯度决定应力场的峰值能否达到上限,同时温度梯度还决定应力峰值的位置。拉应力峰值出现在方解石的界面附近。在本文的两相矿物的球对称模型中,固定的微波能量作用下,最佳的微波功率密度与微波作用时间的组合,所产生的温度和温度梯度能恰好使得拉应力峰值达到上限,基于此,根据方解石的抗拉强度给出能使矿物界面开裂的,微波能量最大化利用的方案。 | 10.27393/d.cnki.gxazu.2024.000517 | Chinese | China | Thesis | ||||||
| C020 | 2024 | 微波热解油页岩的渗透特性影响研究 | 陆丹丹 | https://link.cnki.net/doi/10.27210/d.cnki.glnju.2024.001201 | 油页岩;微波热解;覆压;孔隙度;渗透率;孔裂隙 | 在能源需求日益增长和常规能源日益枯竭的今天,油页岩因其巨大的资源潜力而受到越来越多的关注。微波加热油页岩技术通过高效的微波能量传输,实现对地下油页岩的精确加热,可降低水耗、提高能源利用效率,并减少环境影响,是一种环保、高效的非常规能源开采方式。对微波加热油页岩技术在不同地区的适用性应用分析至关重要,可为确定技术应用的最佳实践提供指导,促进油页岩资源的可持续开发和利用。因此,开展油页岩原位热解的渗透特性研究对其开采和非常规油气的应用具有重要意义。 本文以辽宁抚顺地区油页岩、新疆吉木萨尔地区油页岩为研究对象,利用微波热解实验装置,热解失重实验研究、覆压孔渗实验以及CT扫描等研究方法,研究微波热解后油页岩的渗透特征。采用有限元法进行数值模拟,探究在微波加热过程中油页岩储层的温度、渗流、应变等变化规律,并根据实验与模拟结果进行加热优化分析。 研究表明,随着温度的升高,两地样品都出现了由微细裂缝向广泛裂缝网络过渡的现象,反映了热解过程中有机物质的分解和气体的释放。随着升温速率的增加,油页岩的反应活化能降低,因此高速升温更有利于油页岩的热解过程。研究揭示了在微波加热条件下,油页岩的热解反应受到温度和升温速率的共同影响。通过对抚顺和新疆两地区油页岩的覆压孔渗实验分析发现,油页岩基质的孔隙度和渗透率在有效应力增加时呈现负指数规律变化。有效应力导致油页岩基质发生机械压缩,孔隙度急剧减小,渗透率降低。针对此现象,从温度、有效应力以及微波时间入手,构建了微波热解后油页岩孔隙度和渗透率的动态方程,以指导微波原位开采油页岩的电磁-热-流-固多物理场耦合模型研究。模拟结果表明,在储层内部,随着微波温度的升高,孔隙度和渗透率也增大。抚顺地区的应变累积速率在加热过程中超过新疆地区,尤其在后期300至350天更为明显。通过采用阶梯式加热模式,成功避免了过热现象,确保开采作业的安全与效率。因此,微波热解油页岩在两个地区都具有良好的适用性,可广泛应用于实际生产中。 该论文有图58幅,表6个,参考文献110篇。 | 10.27210/d.cnki.glnju.2024.001201 | Chinese | China | Thesis | ||||||
| C021 | 2024 | 微波辐射砂岩升温损伤规律与辅助破岩路径优化研究 | 王智鹏 | https://link.cnki.net/doi/10.26918/d.cnki.ghngc.2024.001469 | 微波辅助破岩;升温特征;路径优化;水流冲击冷却 | 微波辅助破岩是实现硬岩高效破碎、实现硬岩地层快速掘进的技术手段。岩石的微波热响应对微波辅助破岩效果具有重要影响,因此微波辐射下,岩石升温损伤机理研究被认为是助力微波破岩技术成功应用的前提,要使微波辅助破岩真正应用于实际工程,仅仅讨论岩石升温损伤机理是不够的,需要针对研究对象,开展应用路径优化研究。本文针对取样自地表的地表砂岩和取样自千米深井的深部砂岩开展研究,采用红外热成像仪对辐射过程中岩石表面温度进行实时监测,获得地表与深部砂岩微波辐射升温特征;对比微波辐射前后P波波速、抗拉强度、裂纹扩展变化规律,结合成岩矿物微波敏感性分析与介电特性,揭示微波辐射地表与深部砂岩升温损伤机理。提出了基于水流冲击冷却的路径优化设计,并验证了路径优化效果。建立了可供参考的工程应用面微波辐射岩体数值模型,对比分析了地表砂岩与深部应力环境下的深部砂岩的升温损伤特征;基于面微波辐射后机械钻进试验,对比了不同路径下微波辅助破岩效果与钻进比能。主要工作及结论如下: （1）深部砂岩拥有更高的质量密度、P波波速和抗拉、抗压强度,微波敏感性也略高于地表砂岩。但在辐射在172 s后,深部砂岩升温速率低于地表砂岩;辐射300 s后地表与深部砂岩的P波波速均呈下降趋势,且深部砂岩的波速降幅显著高于地表砂岩。地表砂岩的抗拉强度,随微波辐射时间的增加先增加后减小,辐射300 s后降幅仅为9.5%,而深部砂岩的抗拉强度,随辐射时间的增加线性下降,辐射300 s后强度降幅达56.14%。声发射特征表明:微波作用后,岩石受外部荷载时岩石的结构变化程度减弱,破坏时所释放的能量减少,有相当数量的能量在0.25?_t～0.55?_t阶段被释放,相较于地表砂岩,破坏过程中深部砂岩释放的能量更多。 （2）实时高温状态下、自然冷却和水流冲击冷却后,地表与深部砂岩强度变化规律表明:在高温状态和自然冷却后,地表砂岩的抗拉强度随辐射时间的增加先上升后下降;深部砂岩的抗拉强度,则随辐射时间的增加而下降,在实时高温状态下,其下降趋势是线性的,而在自然和水流冲击冷却路径下,抗拉强度的下降趋势是阶段性的。以抗拉强度降幅为损伤指标,相同损伤程度下,水流冲击冷却路径较自然冷却路径节省了50%的能量消耗。 （3）类井下环境微波辐射模拟结果表明,在微波辐射下,温度分布特征为中间高,周围低。应力场分布呈现与温度场分布相对应的双峰分布。在1.4 k W照射120 s后,深部砂岩岩体产生的温度梯度最大,为80 751 K/m;地表砂岩为44912 K/m。应力演化特征结果表明,微波辐射后地表与砂岩岩体沿水平方向可划分为扰动卸荷区（0～25 mm）,扰动劣化区（25～68.6 mm）和初始应力区（68.6～450mm）3个区域;沿深度方向传递特征为扰动卸荷区（0～10 mm）,扰动劣化区（10～223.7 mm）,初始应力区（223.8～460 mm）。 （4）基于铜箔包裹下的微波辐射试验、限定变形条件下的机械钻进试验,开展了模拟应力加持下微波辅助钻进效果研究,结果表明:微波辐射功率越高,钻进时转速越高、扭矩越小,钻进深度越深。相同的微波功率辐射下,无侧限变形下钻进比能是侧限变形下钻进比能的56.7%,相同输出能量的条件下,功率在1.4 k W微波辐射（路径4）下钻进效率是功率在1.0 k W微波辐射（路径3）的1.3倍左右。在有侧限变形的路径中钻进比能按从小到大排序为:路径5>路径6>路径4>路径7>路径2>路径1。由此得出,本文设计的7种路径中,最优路径是路径5（1.4 k W辐射214 s后浸水冷却,侧限变形下钻进）。 图66表19参考98 | 10.26918/d.cnki.ghngc.2024.001469 | Chinese | China | Thesis | ||||||
| C022 | 2024 | 微波照射岩石裂纹扩展机制及对多裂隙岩体力学性质影响研究 | 张迪 | https://link.cnki.net/doi/10.27398/d.cnki.gxalu.2024.000108 | 微波加热;裂隙岩体;数值模拟;裂纹扩展;单轴压缩 | 近几年来,开挖地下工程的主要方法是钻爆法和机械法,当开挖遭遇硬岩时,微波辅助机械破岩能够克服传统机械开挖的缺陷,获得更新的效率。自然界中,裂隙岩体是工程实践中最为常见且对岩体稳定性具有重要影响的地质介质。岩石,作为天然的地质材料,在复杂环境作用下常含有大量微裂纹、节理和孔隙等缺陷,这些缺陷导致岩石具有各向异性、非均质等特性。本文开展裂隙岩体在微波照射下性质变化规律,研究选用吸波能力较强的玄武岩,进行了典型物理试验研究,对微波照射前后含不同裂隙倾角玄武岩试样进行表面细观观测及单轴压缩试验,研究了不同裂隙布置下的岩石在微波照射过程中的温度分布情况、裂纹的产生与扩展规律、在微波照射对不同裂隙布置下岩石的应力应变曲线、峰值强度。利用离散元软件PFC分别对含不同裂隙布置下裂隙岩体试样进行微波照射数值模拟,研究单裂隙、多裂隙、随机裂隙对微波照射岩石裂纹扩展以及照射效果影响研究。本文将从宏观、细观角度出发,通过物理试验和数值试验研究微波照射下的裂纹扩展机制以及其力学特性。本文主要研究内容和成果如下: (1)揭示了裂隙对微波照射效果的影响规律。微波功率为2KW、照射时间为2min的条件下,含裂隙玄武岩试样表面高温区域主要位于预制裂隙下部。这主要是因为微波能量进入岩石内部,岩石中的裂隙会影响微波能量的吸收和分布,裂隙的存在会增加岩石对微波能量的吸收,使得岩石内部温度分布更加不均匀,最终热应力更易于在裂隙尖端集中,进而促进裂隙的进一步扩展和贯通。因此,试样表面的高温区域表现为随着裂隙角度的变化而变化,从而表现出明显的局部加热效应。此外,试验还发现在同一照射条件下,含裂隙的试样强度小于完整试样以及未照射时的试样,随裂隙倾角的增大,试样的峰值强度总体上呈现增大的趋势;对于照射后的试样,不同裂隙倾角试样产生的破坏也不同,当预制裂隙角度较小,如裂隙倾角为0°时,裂隙试样在微波照射下主要产生的是轴向的裂纹,试样的破坏模式更偏向于剪切破坏或拉-剪破坏;而随着裂隙倾角的增大,试样的破坏则主要表现为裂隙尖端产生的翼裂纹扩展,呈现出更明显的张拉破坏特征;当裂隙倾角为90°时,微波照射后虽然产生的裂纹较低裂隙角度时有所增加,但是照射后的试样产生的裂纹与预制裂隙之间的扩展以及贯通不如低裂隙倾角时明显。 (2)揭示微波照射裂隙岩体过程中次生裂纹扩展规律与机制。过微波照射的玄武岩,在单轴压缩过程中展现出的破坏情况尤为显著,主要归因于两方面:一方面,预制裂隙尖端次生裂纹的萌生、扩展与贯通;另一方面,单轴压缩过程对先前微波照射产生的裂纹起到了促进作用,这些裂纹在轴向压力下进一步扩展,直至裂隙之间形成贯通的裂隙网络,导致破坏面积相较于未照射试样更为广泛。。具体来说,不同预制裂隙角度会导致不同的次生裂纹分布模式,对于0°倾角的预制裂隙产生的次生裂纹分布主要在预制裂隙周围,30°-60°倾角的预制裂隙产生的次生裂纹主要分布在预制裂隙的尖端产生并扩展贯通,而90°倾角预制裂隙产生的次生裂纹分布则较为分散。微波照射后的试样更易产生拉伸裂纹,其数量虽相近但经单轴压缩后呈现出上升的变化趋势。对于随机裂隙试样,微波照射会促进次生裂纹和原生裂纹的扩展贯通,增加岩石损伤。无裂隙试样的裂纹扩展主要呈X状,而随机裂隙试样的裂纹扩展虽无明显规律,但对于裂隙倾角较小的部分次生裂纹主要是分布于裂隙周围以及裂隙中部,对于裂隙倾角较大部分次生裂纹主要是分布于裂隙尖端,随着轴向应力的增加产生的次生裂纹倾向于沿有利于扩展贯通的路径扩展。最终,微波照射产生的裂纹与单轴压缩产生的裂纹相互连通,促进了最短路径的贯通。 (3)建立了裂隙岩体微波可照射性评价方法。用层次分析法对裂隙岩石微波可照射性的影响因素进行了评价分析,基于强度弱化规律,构建了一套的评价分级体系以量化不同裂隙布置对微波可照射性的影响程度。通过构建层次结构,明确了各层次之间的逻辑关系并计算出了不同影响因子之间的权重值,从而揭示了各因素在影响岩石微波可照射性方面的相对重要性。 | 10.27398/d.cnki.gxalu.2024.000108 | Chinese | China | Thesis | ||||||
| C023 | 2024 | 微波辐射及冷却方式对石英型赤铁矿石弱化效果及机理研究 | 王泽 | https://link.cnki.net/doi/10.27352/d.cnki.gylgu.2024.001963 | 铁矿石;微波辐射;冷却作用;升温特性;裂隙结构;力学性质;损伤变化 | 铁矿石作为我国的战略矿产资源,在国民经济发展中占据重要地位。由于其质地坚硬,无论采用常规钻爆法还是机械破碎法,其破碎效率都较低。因此,探讨其开采新技术、新理论就成为了振兴金属采矿业的必由之路。国内外学者发展了多种新兴方法,有激光破岩、高压泡沫、微波处理等。与其他方法相比,微波辅助机械破岩有高效、环保等优势。在近些年来,国内外学者对微波辅助破岩理论及技术的应用进行了研究,特别是针对坚硬岩石。证明了通过微波预处理弱化岩石的强度,可以显著提高破岩效率。本文以太钢集团袁家村露天铁矿的石英型赤铁矿石为研究对象,利用单模微波发生器组成的微波试验装置对赤铁矿石开展微波辐射及冷却方式试验,借助工业热成像仪、XRD衍射仪、工业显微CT、非金属探伤仪和声发射检测设备等手段,研究了微波辐射及不同冷却方式处理后的赤铁矿试样的升温速率、表面及内部裂隙扩展规律、力学特性及声发射特征等。论文主要的工作及取得的成果如下:(1)采用自行研制的单模微波辐射装置对赤铁矿石试样进行了微波辐射试验。具体试验方案为微波辐射功率为1、2、3 kW;辐射时间为1、2、3、4 min;将微波功率3 kW辐射时间3 min的试样进行自然冷却、泡水冷却、液氮冷却10 min、液氮冷却2 h四种冷却方式处理。采用红外成像仪对微波辐射后的试样进行了温度测定并拍摄其表面裂隙变化情况,分析了微波辐射对试样的表面温度变化情况及裂隙演化特征。结果表明,微波辐射后赤铁矿石试样出现了明显的热裂解现象,试样整体温度随微波辐射功率及辐射时间的增加而增大,呈线性增加的关系;试样温度越高的区域表面裂隙越发育。(2)采用CT检测技术对不同冷却方式处理后的试样的微裂隙演化情况进行了分析,并引入分形维数对不同冷却方式处理后的裂隙分布复杂度情况进行了定量表征,结果表明,随着冷却降温幅度的增大,试样的裂隙宽度、裂隙体积占比、裂隙分布复杂度的分形维数呈线性趋势增加。(3)采用非金属探伤仪对微波辐射及冷却方式处理后的试样纵波波速变化情况进行了分析,并将波速为损伤变量研究试样的损伤程度。结果表明,试样的纵波波速随微波辐射功率及辐射时间的增加下降明显,自然冷却、水冷却、液氮冷却10 min、液氮冷却2 h试样的波速分别下降了64.7%、73.9%、78.7%、83.9%,试样累计损伤因子分别为0.88、0.92、0.95、0.97。(4)通过对赤铁矿石试样进行常规力学试验,得到了其应力-应变曲线、抗压强度及抗拉强度与微波辐射参数及冷却方式之间的变化规律。得出试样的抗压强度、抗拉强度随辐射功率及时间的增加而下降,经泡水冷却、液氮冷却10 min、液氮冷却2h试样的抗压强度较自然冷却试样分别降低了12.4%、20.3%和25.6%,试样的抗拉强度较自然冷却试样分别降低了24.1%、61.2%、86.2%。(5)通过对赤铁矿试样单轴压缩试验过程进行声发射监测,微波辐射及冷却方式作用后试样会经历初始压密阶段、弹性变形阶段、裂纹稳定扩展阶段、裂纹剧烈发育阶段及破坏阶段,研究了各个阶段振铃撞击数以及全过程累计振铃数的变化关系,进一步揭示了微波辐射及冷却方式对赤铁矿石弱化效果的影响规律。得出试样的累计振铃数随着微波功率的增大而不断增长,单轴压缩时声发射信号的高频活动区大多集中在试样的峰值应力点处,经水和液氮两种冷却介质冷却处理后试样的声发射振铃数在各个阶段较自然冷却试样更为频繁。 | 10.27352/d.cnki.gylgu.2024.001963 | Chinese | China | Thesis | ||||||
| C024 | 2024 | 间歇式微波预处理对花岗岩型铀矿石破磨与浸出性能的影响 | 费鹏 | https://link.cnki.net/doi/10.27234/d.cnki.gnhuu.2024.001176 | 间歇式微波;强度弱化;损伤演化;花岗岩铀矿石;磨细与浸出 | 当前铀矿石破磨工艺面临着能耗颇高、利用率低下等问题,传统预处理方式效果不佳。微波技术因其选择性加热和快速加热等特性成为矿石破磨领域的研究热点,但目前的研究主要集中在一次性连续微波辐照方面,仍存在辐照时间长、能耗较高等问题,亟需对传统微波预处理方式进行改进。因此,探索新的微波预处理工艺,提高矿石破磨效果的同时减少能量的消耗,对改善铀矿石磨细与浸出性能,提高铀矿石堆浸回收利用率具有重要的实际意义和理论价值。本文以花岗岩和花岗岩铀矿石为研究对象,采用间歇式微波预处理,探究间歇微波脉宽、单个周期时间和预处理总时间等因素对花岗岩强度劣化和损伤演化的影响及对花岗岩铀矿石磨细与浸出性能的影响,通过对比连续微波预处理,验证了间歇式微波预处理的可行性,为花岗岩型铀矿石的开采利用提供了一种更加节能有效的预处理方式,对微波辅助破磨技术的发展起到了一定的促进作用。主要研究结论如下: (1)采用间歇式微波对花岗岩进行预处理,并通过对比连续微波预处理,研究了不同微波预处理下花岗岩强度劣化和损伤演化机制。结果表明:微波预处理可以有效弱化岩石强度,促进岩石内部孔隙发育并增大内部孔隙总体积,加剧岩石损伤。间歇式微波预处理时,适当减小微波脉宽,延长间歇时间有利于加大花岗岩的损伤和强度弱化。 (2)间歇式微波最佳工艺参数预处理下花岗岩抗压强度为148.02 MPa,纵波波速较未处理前下降了28.5%,损伤变量D为48.86%,该条件下花岗岩强度劣化和损伤效果虽略低于连续微波预处理,但微波能量输出时间减少了400 s,节省了一半以上的微波能耗,综合来看,间歇式微波预处理具有一定的可行性。 (3)基于不同微波预处理对花岗岩强度劣化和损伤演化的影响研究,采用间歇式微波对花岗岩铀矿石进行预处理,并对比连续微波预处理,研究了不同微波预处理对铀矿石磨细与浸出性能的影响,研究表明:铀矿石在间歇微波脉宽30 s,单个周期时间70 s,预处理总时间210 s时为间歇式微波预处理最佳助磨工艺参数,该参数下铀矿石-0.15 mm的磨细质量分数为70.57%,浸出率为75.42%,相比于连续微波预处理分别提高了1.6%、2.44%,并减少了25%的微波能量输出。综合分析得出,间歇式微波预处理总体效果优于连续微波预处理,能够在提升铀矿石磨细与浸出性能的同时减少能量的消耗,是一种更为节能有效的微波预处理方式。 | 10.27234/d.cnki.gnhuu.2024.001176 | Chinese | China | Thesis | ||||||
| C025 | 2024 | 微波辐照下花岗岩的损伤与能量演化规律研究 | 费鹏; 伍琴琴; 李天义; 黄爱武; 刘天明; 汪雨婷; 喻清 | https://link.cnki.net/doi/10.19431/j.cnki.1673-0062.2024.02.002 | 微波辐照;花岗岩;能量演化;脆-延性转变 | 通过控制不同微波预处理工艺参数，基于能量守恒定律，对微波预处理后的花岗岩进行单轴压缩试验研究，分析了花岗岩破坏过程中总应变能、弹性能、耗散能的演化规律。研究结果表明：在微波功率相同的情况下，随着微波辐照时间的增加，试样的纵波波速和抗压强度均呈下降趋势。根据变形破坏中花岗岩的各能量占比及能量演化曲线的变化规律，可将微波辐照下的花岗岩演化过程划分为耗散能初始增长阶段、耗散能稳定增长阶段、耗散能平稳发展阶段、峰前加速耗能阶段和耗散能急剧上升阶段。花岗岩能量演化过程随微波辐照时间的增加呈现出一定的规律性，其第Ⅰ阶段占比随着微波辐照时间的增加逐渐增大。微波辐照时间为600 s时，耗散能占比由未经微波辐照时的17.53%增加至27.07%,基于能量的脆性指数由0.82下降至0.73,岩石的吸能能力和储能极限均有所降低，岩石塑性增强，表明微波有助于岩石从脆性到脆延性的转变。 | 10.19431/j.cnki.1673-0062.2024.02.002 | Chinese | China | Journal Article | 南华大学学报(自然科学版) | 38 | 02 | 11-20 | ||
| C026 | 2024 | 微波热力冲击下硬脆砂岩冲击倾向性演化规律试验研究 | 滕腾; 贾文建; 易鹏; 赵毅鑫; 朱笑颜; 徐铎 | https://link.cnki.net/doi/10.19606/j.cnki.jmst.2024.02.008 | 冲击地压;微波;热力冲击;冲击倾向性;试验研究 | 冲击地压是深部资源开采的主要灾害类型，冲击倾向性是表征冲击地压风险的重要指标。为了探索微波热力冲击对岩石冲击倾向性的影响，本文对典型强冲击倾向性硬脆砂岩开展了微波热力冲击和单轴压缩试验，分析了微波热力冲击后砂岩的物理力学性质和冲击倾向性指标响应规律。研究结果表明：(1)微波作用后，砂岩表面温度随着热力冲击时间增加持续升高，直至150 s发生热破断；(2)微波热力冲击120 s后，砂岩内部结构发生微破裂，岩石冲击倾向性明显减弱，纵波波速与弹性模量分别下降了15.12%、8%;(3)单轴压缩变形破坏过程各阶段声发射信号密度增大，砂岩最终破坏时的绝对能量最大值下降42.3%;(4)岩石动态破坏时间增长了259%,冲击能量指数减小95%,弹性能量指数下降92%,砂岩由强冲击性岩石变为弱冲击性岩石。研究结果为煤炭深部开采冲击地压防治和深地工程高效破岩具有参考价值。 | 10.19606/j.cnki.jmst.2024.02.008 | Chinese | China | Journal Article | 矿业科学学报 | 9 | 02 | 209-216 | ||
| C027 | 2024 | 微波预处理对中性条件下石英长石浮选行为影响研究 | 黄宏 | https://link.cnki.net/doi/10.27108/d.cnki.ghelu.2024.001072 | 微波预处理;石英;长石;浮选分离;影响规律 | 对采用微波预处理的方法改变石英和长石的表面性质,增大石英长石可浮性的差异,实现石英长石的有效分离进行可行性研究。探究微波预处理对中性条件下石英与长石浮选行为的影响,以寻找提高浮选效率和降低环境影响的创新途径。 以浮选回收率和精矿品位为指标,对微波预处理和未经处理的石英与长石分别在中性条件下进行浮选试验,对比相同条件下的浮选试验结果,通过药剂吸附、XRD、Zeta电位、红外光谱分析等方法阐述微波预处理对浮选过程的影响。结果表明: 1)微波预处理前中性条件下,最佳药剂用量为油酸钠0.5×10-4mol/L、十二胺2.5×10-4mol/L、六偏磷酸钠4.5×10-5mol/L,最佳分离指标为纯矿物浮选回收率差值77.75%、混合矿的回收率59.44%、精矿品位13.035%。 2)微波预处理后中性条件下,最佳微波条件为微波功率为400W、微波时间为20min,最佳药剂用量为油酸钠0.5×10-4mol/L、十二胺2.5×10-4mol/L、六偏磷酸钠4.5×10-5mol/L,最佳分离指标为纯矿物浮选回收率差值89.62%,混合矿的回收率70.63%,精矿品位15.495%。对比微波前的浮选试验结果,浮选回收率差值提高了11.87%,混合矿回收率提高了11.19%,精矿品位提高了2.46%。 3)中性条件下油酸钠和十二胺吸附量测定结果表明,微波预处理使石英对捕收剂的吸附量下降,长石对捕收剂的吸附量上升;XRD检测显示,微波预处理后石英的晶相含量下降,结晶度相较于微波前有所降低,可浮性下降;长石的晶相含量上升,结晶度相较于微波前有所上升,可浮性提高。Zeta电位分析结果表明微波预处理后石英Zeta电位上升,长石Zeta电位下降,其差值增大了15.8m V,说明微波预处理增大了石英与长石的表面性质差异。红外光谱分析进一步表明微波后长石对捕收剂的吸附作用提高,而石英与捕收剂的吸附作用降低,从而提高了石英和长石浮选分离效果。 图63幅;表5个;参83篇。 | 10.27108/d.cnki.ghelu.2024.001072 | Chinese | China | Thesis | ||||||
| C028 | 2023 | 微波作用对岩石孔隙的影响 | 薛轲; 朱吉喜; 唐健; 谢元勋; 黄烈阳; 熊海旭 | https://link.cnki.net/doi/10.26914/c.cnkihy.2023.102716 | 微波作用;核磁共振;孔隙度;孔径分级 | 为研究微波作用下黄砂岩内部孔隙的变化特征,对黄砂岩试样进行微波作用,采用核磁共振技术测试黄砂岩试样的孔隙度及T2谱曲线。通过拟合分析,得到黄砂岩试样孔隙度与微波作用功率的关系。研究表明:微波作用功率对黄砂岩孔隙度影响较大,当微波作用功率达到4kw时,岩石试样内部饱和孔隙度变化率达到28%,束缚流体孔隙度变化率达到30%;黄砂岩试样内部大中小孔隙均出现不同程度的增长,且随着微波作用功率的增加,该效果越明显,岩石试样的单轴抗压强度减小。 | 10.26914/c.cnkihy.2023.102716 | Chinese | China | Conference Proceedings | 4 | |||||
| C029 | 2023 | 基于核磁共振技术下的岩石孔隙结构微波作用损伤试验研究 | 薛轲; 谢元勋; 唐健; 朱吉喜; 郜江晶; 王祖国 | https://link.cnki.net/doi/10.26914/c.cnkihy.2023.102732 | 破岩;核磁共振;微波作用;孔隙结构;单轴抗压强度 | 为研究微波辅助机械破碎岩石的技术,为此本文采用核磁共振技术研究了不同微波作用功率下岩石内部细观结构的演化规律,同时结合单轴抗压测试试验,对于微波辅助机械破碎岩石这一研究具有重要的科学意义。结果表明:青砂岩经微波作用后,内部孔隙度增大,且随着微波作用功率的增大,青砂岩孔隙度增大越明显。通过对试样进行单轴抗压强度测试,结果与孔隙度变化规律相似。分析结果表明,微波作用岩石有助于其内部结构发生损伤,有助于岩石的破碎,验证了微波辅助机械破碎岩石的可行性。 | 10.26914/c.cnkihy.2023.102732 | Chinese | China | Conference Proceedings | 3 | |||||
| C030 | 2023 | 微波作用对砂岩物理力学性质影响的试验 | 姚华彦; 姚家李; 方琦; 潘鹏志; 鲁建国; 管瑞东 | https://kns.cnki.net/kcms2/article/abstract?v=wScU5_zS5CP9hgAjmCTfYoRGZYIz_v8jPBmE-QLq2ap0uLEzFbYog_IfeeiQSuWxC3-E_jFHQv-GGEj3jWsygKplcn6Br_l3tpi17wDErkTtdkxEKEPtkVi3i1pjSgMwmaW7M9Sv3XtFPK-uARTUguFbZgXTktArma8bq5P-uCejk_5lN9pZ1xe6YVDmZpxq&uniplatform=NZKPT&language=CHS | 微波;力学特性;波速;扫描电镜;微裂纹 | 对微波作用后的砂岩试样开展了波速测试和单轴压缩试验，并结合差热分析和扫描电镜试验探讨了微波加热对砂岩物理力学性质的影响机制。试验表明：在微波作用下试样温度迅速升高，且功率越大，升温速率越大；微波作用后，试样纵波波速随着微波加热功率、时间的增大迅速降低；随着微波功率的增加，试样的单轴抗压强度和弹性模量先增大后减小；随着加热时间的增加，试样的单轴抗压强度先增加后减小，弹性模量则都降低。微波加热导致砂岩内部产生了不同程度的结构变化，表现为黏土矿物的失水收缩裂纹、沿颗粒边界裂纹、颗粒内部裂纹等。低功率、短时间加热时，微波加热对砂岩的强度有增强作用；高功率且长时间微波加热条件下，砂岩试样温度较高并产生明显损伤，使得强度降低。 | Chinese | China | Journal Article | 应用力学学报 | 40 | 06 | 1335-1342 | |||
| C031 | 2023 | 微波致裂火成岩机理及辅助机械破岩应用研究 | 马中骏 | https://link.cnki.net/doi/10.27014/d.cnki.gdnau.2023.003888 | 微波辅助破岩;可微波致裂性指数(MFI);缩径天线;缩径介质填充天线;节理岩体;尺寸效应;裂纹扩展 | 机械破岩方法因其对围岩扰动强度低、施工效率高以及安全可靠等优势被广泛用于隧道和采矿等地下工程领域。然而,当掘进过程中遭遇硬岩或者极硬岩时,机械破岩效率将急剧降低,刀具磨损严重,导致破岩成本提高、工期延长。微波技术因其具有体积加热、高效和环境友好等优点,在岩石破碎领域极具应用前景。已有的研究主要聚焦于微波处理前后岩石的物理力学性质变化,验证了微波(辅助)破岩技术的可行性,但仍然存在诸多关键性问题亟待解决。例如,微波弱化岩石的机制、主导因素及难易程度的量化指标,微波诱导岩石实时损伤演化过程及损伤区的范围和分布特征,微波致裂岩石的尺寸效应及其机制及微波辅助机械破岩效率量化。针对上述问题,本文采用理论分析、单模式以及面照射物理试验和数值模拟方法系统地分析了微波作用下火成岩试样的响应特征,具体研究内容和主要结论如下: (1)基于15种火成岩单模式微波加热试验结果,提出了火成岩可微波致裂性指数(MFI)以定量描述微波致裂岩石的难易程度,建立了火成岩可微波致裂性评价模型,明确了微波弱化岩石机制和主导影响因素。研究结果表明,可微波致裂性指数MFI与平均粒径、体积不均匀性系数以及等效介电损耗因子呈正相关,而与初始P波波速呈负相关;等效介电损耗因子和平均粒径对微波致裂效果的影响最为显著,其次是体积不均匀系数,最后是初始P波速度。 (2)基于微波传输理论,综合考虑岩石表面最高温度、高温区分布特征以及二者随辐射距离增加的衰减特性,研发并优化了缩径天线,并基于升温试验和破碎试验进一步验证、评估了缩径天线的破岩性能。研究发现,E面压缩至30 mm的缩径天线具有最佳的破岩性能,其可在较低微波功率下高效致裂黑云母闪长岩。在缩径天线的基础上,首次提出缩径介质填充天线的概念,并基于理论分析和数值模拟方法对缩径介质填充天线进行设计、优化,利用升温试验以及微波致裂岩石试验对其进行验证。结果表明,缩径介质填充天线的峰值微波功率密度分别为缩径天线与标准波导的4.8倍与2.8倍,相较于标准波导天线以及30 mm缩径天线,缩径介质填充天线在辐射距离小于30 mm时具有显著优势。 (3)基于本研究提出的岩石可微波致裂性指数MFI以及设计的微波聚焦天线,构建了基于岩石MFI的微波破岩天线优选方法。使用四种不同类型的微波破岩天线对不同MFI的坚硬火成岩进行了微波照射试验,详细探究了微波处理后试样的最高温度、最大P波速度衰减、破碎特性和岩石破坏模式等变化规律。对比分析发现,MFI介于0～0.3之间时,缩径介质填充天线具有最佳破岩性能;而对于MFI处于0.2～0.4的硬岩,缩径天线是最佳选择;MFI位于0.4～0.7,标准波导天线的作用效果最为显著;MFI大于0.7的岩石,喇叭口天线将成为微波破岩的最优类型。 (4)利用声发射技术实时监测微波加热以及冷却阶段的实时损伤演化特征,探明了微波诱导裂纹的萌生、扩展以及贯通的全过程,揭示了微波诱导花岗岩的破裂模式以及加热和冷却在花岗岩破裂中的作用。研究结果表明,微波诱导的岩石破裂主要是拉伸破坏;裂纹起始于天线开口外缘边界附近,并向试样中心以及边界方向扩展;微波加热主导了岩石损伤。 (5)利用缩径介质填充天线开展了微波加热闪长岩试验,系统研究了微波功率、照射时间和辐射距离对岩石表面最高温度、超声波速度衰减以及微波诱导裂纹特征的影响;提出了一种空间P波速度衰减校正的方法,定义了微波诱导岩石损伤区,探明了微波诱导损伤区的尺寸、分布特征及其演化过程;根据微、宏观裂纹分布特征以及形成机理对微波诱导损伤区进行划分,并探索了微波诱导损伤区的演化特征。研究表明,微波诱导试样损伤区可划分为破碎区、裂纹密集区和裂纹稀疏区;切割试验表明,所提出的P波速度空间校正方法和等效损伤区的确定方法是可行的。 (6)基于物理试验和数值模拟的方法,探明了不同尺寸试样微波诱导裂纹的起裂位置、起裂时间及演化过程,并构建了尺寸效应相关的微波诱导裂纹模型;揭示了微波致裂岩石的尺寸效应、阐明了其内在机制。研究结果表明,对于小尺寸试样,微波诱导裂纹萌生于试样边界,同时向试样中心和厚度方向扩展;对于中等尺寸和大尺寸试样,微波诱导裂纹形成于天线开口外缘边界,然后向试样中心和试样边界扩展;从脆性材料断裂准则分析,局部断裂能的边界效应是微波致裂岩石存在尺寸效应的内在原因。 (7)开展了微波致裂节理岩体试验以及组合点微波照射后试样的单齿截割试验,总结了微波诱导裂纹—节理相互作用的模式,量化了微波辅助悬臂掘进机破岩效率。研究发现,微波诱导裂纹和节理之间的相互作用模式可以总结为四类:分别为截止、穿透、偏转以及跟随;微波预处理可以显著降低截割破岩的三向力和破岩比能,法向力、截割力以及破岩比能的最大降幅分别可达24.7%、25.3%与26.4%。 | 10.27014/d.cnki.gdnau.2023.003888 | Chinese | China | Thesis | ||||||
| C032 | 2023 | 矿物扩散度对微波照射矿石内部损伤效果的影响 | 祁培培; 张国伟 | https://link.cnki.net/doi/10.13612/j.cnki.cntp.2023.21.028 | 微波照射;岩石;矿物;扩散度;损伤 | 微波照射岩石会加剧内部损伤，降低岩石强度，利用微波辅助机械破碎硬岩能大幅度提高工作效率。岩石内部矿物颗粒扩散程度对微波照射岩石的损伤程度有影响。该文建立3种吸收模态面积相同，矿物颗粒扩散程度不同的二维二元介质矿石模型，研究强吸波矿物颗粒的扩散度对微波辐射矿石内部损伤效果的影响。在相同试验条件下，3种不同扩散度矿物在仿真微波照射下的结果表明，矿物颗粒扩散度越低，矿石内部温度越高，温度梯度越大，第一主应力越大；扩散性较低的矿石存在较大的温度梯度，产生的热应力会导致更多损伤；当总输入能量相同时，影响规律为岩石内部的矿物颗粒越聚集，微波照射后损伤效果越好。 | 10.13612/j.cnki.cntp.2023.21.028 | Chinese | China | Journal Article | 中国新技术新产品 | 21 | 96-98 | |||
| C033 | 2023 | 微波照射煌斑岩力学特性研究 | 郭向辉; 杨永康; 张慧军 | https://link.cnki.net/doi/10.13301/j.cnki.ct.2023.11.002 | 煌斑岩;微波;力学特性 | 为探究煌斑岩在不同功率微波强度照射后力学特性以及微观结构的变化，利用SEM分析煌斑岩试样在照射前后内部微裂隙的变化，通过单轴和三轴压力机对煌斑岩的抗压强度和抗拉强度进行分析，并使用COMSOL数值模拟软件建立岩石均质模型对实验结果进行验证。研究表明：SEM图像证实了微波可以加速裂纹的扩展和新裂隙的产生；试样在微波照射后单轴抗拉强度和单轴抗压强度均减小，试样表面粗糙度升高，出现细小的颗粒物和孔隙，试样整体结构出现了一定程度的松散，内部胶状物质散落程度加大，并生成次生矿物小颗粒，促使原生裂隙发育和新裂隙的产生，煌斑岩的内部体系受到破坏，力学特性发生改变，使得煌斑岩的硬度降低；煌斑岩试样随着微波功率和照射时间的增加，温度逐步升高，幅值逐渐减小。 | 10.13301/j.cnki.ct.2023.11.002 | Chinese | China | Journal Article | 煤炭技术 | 42 | 11 | 9-13 | ||
| C034 | 2023 | 不同微波功率照射下花岗岩损伤劣化特征试验研究 | 刘梦寅; 刘洲; 李杰林; 闫杰; 李向东 | https://link.cnki.net/doi/10.13828/j.cnki.ckjs.2023.05.014 | 花岗岩;微波照射功率;微波照射;孔隙结构;损伤劣化 | 为了研究花岗岩经微波照射后的损伤演化及强度劣化特征,采用4种不同参数的微波对花岗岩进行照射,试验研究不同微波照射功率下花岗岩的孔隙结构演化和损伤劣化特征。开展了微波照射后岩石试样硬度测试、表面温度测量和声波波速测试等试验,总结了花岗岩经过微波照射试验后的硬度、表面升温特性和波速等宏观力学参数变化规律。同时,利用微波照射后花岗岩试样的孔隙度分布、核磁共振T2谱和单轴抗压强度等研究成果,对花岗岩在不同微波功率下的损伤劣化特征进行了验证。结果表明:随着微波照射功率的增加,花岗岩试样的硬度和波速降低、试样内部的孔隙度增大、单轴抗压强度降低,试样内部的微裂隙不断发育且损伤劣化特征越加明显。 | 10.13828/j.cnki.ckjs.2023.05.014 | Chinese | China | Journal Article | 采矿技术 | 23 | 05 | 74-78 | ||
| C035 | 2023 | 微波辐射下油页岩的渗流特性可视化定量研究 | 张永利; 陆丹丹; 程瑶; 赵龙飞 | https://link.cnki.net/doi/10.13722/j.cnki.jrme.2023.0276 | 岩石力学;微波辐射;油页岩;绝对渗透率;流场分布;CT扫描 | 为研究油页岩在微波辐射下的渗流特性演化规律，采用高分辨率X射线CT扫描技术对微波热解后的抚顺油页岩进行可视化分析。通过三维图像重建技术获取油页岩的三维孔隙结构，并对渗流和压力场的特征信息进行量化分析。结果表明：(1)微波功率对抚顺油页岩孔隙结构的影响较大。800W和600℃的条件下，油页岩的孔隙率为16.61%；在400 W和600℃条件下，油页岩的孔隙率为8.42%。孔隙和裂隙的分布和形态也受到微波功率的影响。(2)较高的微波功率可以提高油页岩的分形维数及孔隙的长宽比，使表面更加粗糙且孔隙结构更为复杂，孔隙度更高，更容易发展成裂缝，这些都会提高油页岩的可渗透性。(3)通过对中等流速值和孔隙中等压力值的分析，发现800 W微波功率下的中等流速值是400 W微波功率下的中等流速值的1.25倍，是600 W微波功率下的中等流速值的8.68倍，中等压力值随微波温度与功率的提高而降低。这些研究结果增强了对微波辐射油页岩热效应的理解，并发现了微波功率对油页岩孔裂隙结构和渗透性具有显著性影响。 | 10.13722/j.cnki.jrme.2023.0276 | Chinese | China | Journal Article | 岩石力学与工程学报 | 42 | 12 | 2919-2931 | ||
| C036 | 2023 | 开放式微波致裂模拟节理岩体试验及辅助破岩评估 | 郑彦龙; 马中骏; 李建春; 赵晓豹 | https://kns.cnki.net/kcms2/article/abstract?v=wScU5_zS5CPyqwPbsKINvQpdSyz4HNCEv4Pch3n3i8orK8mq5379ielDB8IHWb5B3pwXVUDMA-RxBBt_H70bkqE4Hi8w6YA4hnysw3XVK7nXwyhTYGhchASlAVt4bcDKl-tXc58lk7e04LeWBXaPNEVIZrppnzQ5BpEhiRA0a7QYe_N3AzRNxoTgQ3I1yQl9&uniplatform=NZKPT&language=CHS | 开放式微波;岩体;RQD;破岩效率;刀具损耗 | 为研究开放式微波作用下节理岩体的破裂特征,并评估微波辅助悬臂掘进机的破岩效率,开展微波致裂模拟节理岩体试验。首先,利用9块尺寸为0.5 m×0.5 m×0.3 m(长×宽×厚)的闪长岩岩样垒成1.5 m×1.5 m×0.3 m(长×宽×厚)的人造节理岩体,以模拟节理间距为0.5 m的岩石开挖面;然后,利用6 k W的工业微波系统及缩径介质填充天线对该节理岩体进行微波照射加热致裂试验,研究不同微波照射点间距(15 cm和20 cm)下岩体的破裂特征,分析节理与照射点间距对微波致裂的影响,测量微波处理后岩体的等效岩石质量指标(RQD)和磨蚀性指数(CAI);最后,基于Bilgin经验模型评估微波照射前后刀盘功率为200 k W的悬臂掘进机的破岩效率和刀具磨损变化。结果表明:1)2种照射点间距下,岩体的等效RQD从100降低到62和50,微波预处理可使悬臂掘进机在该闪长岩岩体中的破岩效率提高170%～280%; 2)照射点间距为20 cm时,CAI从4.0减少到3.4,可使刀具损耗降低11%。 | Chinese | China | Journal Article | 隧道建设(中英文) | 43 | 08 | 1338-1347 | |||
| C037 | 2023 | 微波照射下岩石的升温与破碎特性研究 | 刘超尹; 卢高明; 周建军; 姚华彦; 姜礼杰; 范文超 | https://kns.cnki.net/kcms2/article/abstract?v=wScU5_zS5COCW882U5AlUe9-bLVG5gfgjnz053ZsN_8XBc2ZxNz6arzJjsUg_CvjBMj2vkz_NbDd9rtE3Gv8T7HG9sxeyiftDu8tFkSpqRxqQvp1xCbrNQ4jL3XuhMOLqvwT569xST6OikW0mVYh3um5lEgzkLMnfdhcMIRdjmhfQfx4smMs4yy37KaR1PS4&uniplatform=NZKPT&language=CHS | 微波辅助破岩;温度特性;电场强度;COMSOL;破碎特性 | 为论证微波辅助破岩过程中岩石的升温破碎理论,选取玄武岩作为岩石试样,对不同微波功率和照射时间下的岩石试样进行了5组微波照射试验,获得了岩石表面的温度分布和破碎状态。利用COMSOL多物理场建模软件进行仿真模拟,研究岩石内部的电场和温度场分布,揭示岩石的破碎机制。试验结果表明,随着微波发射功率和照射时间的增加,岩石表面的温度、破碎面积、破碎点深度、裂缝数量和裂缝长度均有所增加。模拟结果表明,微波由喇叭天线传递至岩石上表面时电场强度急剧降低,岩石内部电场强度整体呈倒锥形分布;微波照射下的岩石破碎损伤主要与电场强度有关,电场强度的强弱导致不同部位能量密度分布不均匀,进而引起温度梯度变化,产生不同的热膨胀,导致破碎损伤的发生。岩石的破碎损伤演化分为3个阶段,根据岩石试样升温过程进行数学模型回归分析发现,微波发射功率对温度特性的影响更为显著,当微波照射功率为26.645 k W时,微波能在极短的时间内使岩石达到破碎损伤状态,照射效果最佳。 | Chinese | China | Journal Article | 隧道建设(中英文) | 43 | 08 | 1348-1359 | |||
| C038 | 2023 | 硬岩金属矿石大功率微波机械连续开采与磨矿技术研究 | 林峰 | https://link.cnki.net/doi/10.27007/d.cnki.gdbeu.2023.000229 | 硬岩金属矿石;微波致裂机理;真三轴;大功率微波;微波机械一体化采矿;连续化微波磨矿 | 矿产资源是国民经济发展及高新技术产业发展的物质基础,是国家安全的重要组成部分,实现矿产资源安全、绿色、高效开采利用是工业可持续发展的重要保障。金属矿山从开采到磨矿的本质就是矿石不断破碎的过程,金属矿石具有坚硬、难磨的属性,采用传统的矿石破碎方法(钻爆法采矿和机械法磨矿)已经难以满足矿山安全、绿色和高效的要求。在众多新型破岩方法中,微波破岩技术被认为是一种极具应用潜力的破岩方法。其优点在于环保、对环境扰动小、体积加热、易与机械搭载,通过降低硬岩的力学性质,从而降低机械破岩的机械损耗,提高破岩效率。然而,对于矿石的微波作用机理认识不清,缺乏大功率、连续化的矿石微波致裂装备与技术,制约了微波破岩技术在金属矿山开采与磨矿环节的应用。 鉴于此,本文首先在小尺寸试样条件下开展了不同类型、不同形态硬岩金属矿石的微波照射室内试验,揭示了不同类型矿石的微波作用机制,研究了矿石介电加热性能与矿物属性的一般性规律,建立了矿石的微波敏感性评价方法。充分认识矿石的微波作用机制与一般性响应规律后,选择思山岭铁矿石为研究对象,进一步扩大试样尺寸与微波设备功率,还原现场环境,分别对微波机械采矿和磨矿开展研究。为了实现微波机械采矿,研究了真三向应力下层状铁矿石的微波致裂特征、机理与影响因素,开展了大功率微波致裂铁矿石的现场试验,最后研发了大功率微波机械一体化连续采矿装置。为了实现微波机械磨矿,研发了矿石厚度可调的连续化大功率微波致裂磨矿装置,开展了大功率微波致裂磨矿试验并提出了微波磨矿参数设计方法。主要研究内容包括: (1)以三种金属矿物含量差异显著的硬岩金属矿石为研究对象,对不同形态、不同粒度矿石开展了微波照射试验,发现了矿石升温和致裂特征受矿石形态、尺寸和金属矿物含量的影响规律。揭示了矿石介电加热-放电-反射效应的耦合作用机制,矿石形态、粒度和金属矿物含量会改变矿石的微波作用机制。该研究为矿石微波作用的一般性响应规律研究提供基础。 (2)基于合成矿石介电性能测试方法,研究了金属矿物导电性、含量、微波频率和高温等因素与合成矿石介电性能(穿透深度、吸收系数)的关系。最后基于研究结果提出了矿石的微波敏感性评价方法。该研究为微波敏感矿石及矿石微波加热顺序的选择提供了依据。 (3)考虑金属矿山开采大多处于深部应力环境开展,以思山岭深埋(1000m)层状铁矿石为研究对象,开展了真三向应力下的矿石微波(15 kW)致裂室内试验。揭示了深部高应力下层状铁矿石的微波致裂过程及机理,分析了微波照射对机械采矿的作用。研究了微波参数(微波加热器类型,微波功率和工作距离)对矿石反射系数及升温特性的影响,设计了最佳的微波参数并验证了参数的合理性。该研究为开展深部矿山大功率微波照射矿体的现场试验提供了指导。 (4)微波机械采矿时,微波致裂设备需要实现快速破岩以匹配机械开采速度,在思山岭铁矿-960 m水平,首次开展了大功率(60 kW)微波致裂矿石的现场试验,发现了大功率敞开式微波“快速、大范围”破岩的先进性,同时证明了该装置对现场高温、高湿环境的适应性。该研究为大功率微波机械一体化连续采矿装置的研发提供了科学依据。 (5)结合上述微波机械采矿的研究认知,研发了国际首台大功率微波机械一体化连续采矿装置,设备采用“主动随从盘刀交替侧向截割破岩”技术,从破岩原理上改进了破岩方法,搭载微波照射后破岩效率大幅提高。该装置的研制为微波机械连续化采矿的现场应用提供了技术基础。 (6)综合上述矿石微波作用机制与响应规律的认知,设计了一种双管结构可调矿石厚度的连续化大功率微波致裂磨矿装置。以思山岭铁矿石(低品位、难解离、介电常数较高)为研究对象,试验验证了设计参数的合理性,最后提出了不同微波敏感性矿石处理参数(管径、矿石粒径)的设计方法。该研究为微波连续化致裂磨矿的现场应用提供了技术基础。 | 10.27007/d.cnki.gdbeu.2023.000229 | Chinese | China | Thesis | ||||||
| C039 | 2023 | 微波照射下花岗岩单轴压缩损伤本构模型 | 戴俊; 杨清清; 张敏; 蒋昊轩; 王林涛; 任一平 | https://kns.cnki.net/kcms2/article/abstract?v=wScU5_zS5CMZd_HdbFi75x4SsJ07rE-ZfORoPg9urI1_ufa4Y02gImW5J6HFd6xETgHFz_Jp_oAlpD-8xr33-Q9rrNqxa0AOBDNhYo1sUn6fGzEzHvYncfMbOblMe3v-5vQJI80fWixyyaXK9ckqLkf4C0jg5z7dR2hvFem7-Fxc2VzseHkL1FeHroyQspDu&uniplatform=NZKPT&language=CHS | 微波照射;损伤力学;本构模型;Weibull分布 | 为深入研究微波照射花岗岩的损伤演化过程以及探讨微波照射过的花岗岩进行单轴压缩后花岗岩应力-应变关系，首先以微波照射花岗岩的损伤特性为基础，综合考虑花岗岩在微波照射以及荷载作用下受到的损伤，将Weibull分布与损伤力学结合，得到考虑多因素作用的花岗岩损伤演化方程。然后根据Lemaitre应力等效原理及Hook定律，推导出考虑微孔隙闭合的花岗岩损伤本构模型。最后，采用微波循环照射花岗岩试验和单轴压缩试验对模型进行验证。验证结果显示，本研究建立的本构模型与试验结果拟合的曲线能较好吻合，证明了模型的合理性及参数取值的正确性。为岩石微波损伤理论的研究以及微波辅助破岩提供思路。 | Chinese | China | Journal Article | 科学技术与工程 | 23 | 19 | 8350-8357 | |||
| C040 | 2023 | 岩石微波可照射性评价方法及评价系统研发 | 侯宇杰 | https://link.cnki.net/doi/10.27398/d.cnki.gxalu.2023.001270 | 微波照射岩石;强吸波矿物;原生裂隙;围岩压力;致裂效果;可照射性评价 | 微波辅助破岩技术已成为TBM掘进长大隧道研究热点,新型的“微波照射+机械破岩”相结合技术能极大提高掘进效率、降低刀盘磨损率。岩石矿物成分、原生裂隙等岩石自身因素及围岩压力等环境因素是影响岩石微波照射效果的重要因素。为探究矿物成分、原生裂隙、围岩压力等可量化分析客观因素对微波照射岩石弱化效果影响程度及基于此研发一款岩石微波可照射性评价系统。本文以控制变量法为准则,利用离散元软件P FC(Particle Flow Code)分别对不同相对强吸波矿物含量、不同原生裂隙参数、不同围岩压力大小的六种代表性岩石进行微波照射数值模拟,研究相对强吸波矿物含量、原生裂隙角度、长度、密度、围岩压力大小对微波照射岩石裂纹扩展规律及致裂效果影响程度,及对微波照射前后力学性能、TBM刀具磨损的影响规律,最后利用HTML+CSS+JavaS cript构建了岩石微波可照射性评价系统平台,本文主要研究成果如下:(1)微波照射岩石过程中,裂纹萌生的部位位于相对强吸波矿物与其他矿物交界处且易发生在矿物微波敏感性差异剧烈处,内部颗粒间接触以拉破坏为主,压破坏次之,断裂形式主要为穿晶裂纹,相对强吸波矿物周围产生沿晶裂纹后会转向扩展从而与岩石内部其他位置裂纹寻找最短路径互连,在互连路径上其扩展行为会致裂沿途其他矿物进而产生大量穿晶裂纹,并围绕相对强吸波矿物形成贯通裂隙网络;照射后较照射前各岩石试样产生损伤增加、单轴压缩试验峰值强度和弹性模量降低显著、应力-应变曲线起伏态势增强、峰值发生点提前且前移幅度变大、试样塑性阶段越发明显且韧性增强;经照射试样强度对应TBM刀具磨损量与相对强吸波矿物含量具有线性或二次函数关系,良好的函数关系使得在实际工程中可根据岩石的矿物成分来预测判断岩石的微波照射效果。(2)原生裂隙的倾角、长度、密度对微波照射岩石裂纹产生的影响,主要体现在不同倾角、长度、密度裂隙对裂纹的产生、扩展及互连路径具有不同的局部影响效果,在局部区域切断原贯通路径的形成或者原生裂隙与微波照射岩石产生次生裂纹形成长裂隙增加损伤度;裂隙的倾角、长度、密度的增加,使得照射后较照射前岩石试样整体应力-应变曲线起伏态势越发增强、峰值前应力-应变曲线斜率有所降低、压密阶段开始显现且越发显著、峰后起伏程度及频率高于峰前、峰值强度降低显著、试样塑性阶段越发明显、韧性增强;经照射试样强度对应TBM刀具磨损量与原生裂隙角度、长度、密度具有线性或二次函数关系,良好的函数关系使得在实际工程中可根据岩石的原生裂隙情况来预测判断岩石的微波照射效果。(3)围岩压力对裂纹的产生具有抑制效果,降低微波照射产生裂纹数,减小及缩短微波照射产生裂纹汇聚形成的裂隙宽度及长度,显著影响岩石各部位内部及交界处的断裂率,并且各围岩压力条件下微波照射裂纹生长规律相似程度较高,降低微波照射岩石弱化效果;照射前岩石双轴压缩破坏模式表现为X状共轭斜面剪切破坏,照射后岩石双轴压缩破坏模式表现为在微波照射产生裂纹基础上进行扩展连续形成的带网状显著断裂破坏转变为X状共轭斜面剪切破坏;照射后应力-应变曲线较照射前存在压密阶段,峰值前非线性变化阶段明显增加,峰值强度发生点皆有所提前,峰后应变阶段皆有所延后;经照射试样强度对应TBM刀具磨损量与围岩压力具有良好线性函数关系,良好的函数关系使得在实际工程中可根据岩石所处围岩压力环境来预测判断岩石的微波照射效果。(4)利用层次分析法建立了逻辑严密的岩石微波可照射性评价分级标准及评价体系,计算得出了各层级不同影响因子的权重值,建立了岩石微波可照射性评价计算准则;利用HTML、CSS、JavaScript编写构建了登录界面、参数输入界面、结果输出界面,并建立了严密的运行逻辑、完善了网页的跳转、参数计算等细节,最终形成了岩石可微波照射性评价系统平台。 | 10.27398/d.cnki.gxalu.2023.001270 | Chinese | China | Thesis | ||||||
| C041 | 2023 | 微波辐射下花岗岩的断裂韧性劣化规律研究 | 邵珠山; 郭轩; 袁媛; 王维涛 | https://link.cnki.net/doi/10.15986/j.1006-7930.2023.03.001 | 微波;花岗岩;矿物组成;断裂韧度;热应力 | 微波辐射下，岩石中矿物成分微波敏感性的差异会造成岩石内温度场的不均匀，诱发热应力，导致岩石的力学性能劣化，提高破岩效率并减少能源消耗.以常见的硬岩——花岗岩为研究对象，以矿物结构显微图像为基础，建立二维数值模型，探讨了微波辐射下，矿物间温度场和应力场演化规律.实验分析了微波辐射对岩石断裂韧性的影响规律.结果表明：微波辐射下，矿物非均匀温度场诱发的热应力可使岩石的断裂韧性下降28%.岩石内部应力分布状态受到矿物分布和矿物体积含量的影响，石英边界处的应力远大于长石—黑云母边界处的应力.随着加热时间的持续，热应力可引发裂纹萌生及扩展，造成岩石的断裂韧性随辐射时间持续下降. | 10.15986/j.1006-7930.2023.03.001 | Chinese | China | Journal Article | 西安建筑科技大学学报(自然科学版) | 55 | 03 | 317-323 | ||
| C042 | 2023 | 菱铁矿微波磁化焙烧磁选工艺及机理研究 | 周廷波; 魏晓彤; 孙永升; 韩跃新 | https://link.cnki.net/doi/10.19614/j.cnki.jsks.202306016 | 菱铁矿;微波磁化焙烧;磁选;物相转化;微观结构 | 菱铁矿是我国重要的铁矿资源,然而由于其铁品位低、矿物组成复杂,尚未得到大规模开发利用。提出采用微波磁化焙烧技术处理菱铁矿,考察了微波焙烧温度、微波焙烧时间、CO2浓度、磨矿细度以及磁场强度对焙烧产品分选指标的影响规律,同时采用XRD、VSM、SEM-EDS等检测技术分析了微波磁化焙烧过程机理。结果表明:菱铁矿石微波磁化焙烧磁选适宜的工艺参数为焙烧温度650℃、焙烧时间10 min、CO2浓度20%、磨矿细度-0.038 mm占85%、磁选场强136.19 k A/m,此时可获得铁精矿品位61.62%、回收率82.87%的技术指标;随着焙烧反应的进行,弱磁性的菱铁矿石逐渐转变为强磁性磁铁矿,焙烧后样品的磁性显著增强。在焙烧时间10 min时,焙烧产品最大比磁化系数为31.14×10-5 m3/kg。焙烧过程中菱铁矿按照由颗粒边缘至内部的空间顺序转变为磁铁矿,且随着反应的进行,裂纹由外向内生成发育。研究结果为菱铁矿资源的高效利用提供了一种新思路。 | 10.19614/j.cnki.jsks.202306016 | Chinese | China | Journal Article | 金属矿山 | 06 | 107-112 | |||
| C043 | 2023 | 微波作用下油页岩热解力学特性及渗流规律研究 | 赵龙飞 | https://link.cnki.net/doi/10.27210/d.cnki.glnju.2023.000666 | 油页岩;微波热解;CT扫描;数字岩心;孔隙度;渗透率;数值模拟 | 油页岩又被称为“油母页岩”,内部的有机质被称为干酪根,在高温状态的能够热解成为烃类产物。在油页岩的原位开采过程中,油页岩储层在高温的作用下的物理力学参数演化对储层的油气产出有着重要影响。本文以辽宁抚顺油页岩为研究对象,利用微波热解实验装置,含油率测试仪、单轴压缩试验机以及CT扫描仪等试验设备,研究微波热解后油页岩的物理力学特征。采用COMSOL软件对微波热解油页岩储层进行数值模拟,研究在微波加热过程中油页岩储层的温度、渗流、位移等变化规律。具体研究内容和主要结论如下:利用微波热解实验和含油率测试仪进行不同微波功率下的油页岩热解并对热解后的油页岩进行含油率分析。研究发现,在不同微波热解终温下油页岩内部结构发生较大变化,随着温度的上升,油页岩的孔裂隙与裂缝逐渐发育完善,内部能够形成有利于油气的运移的连通孔裂隙以及裂缝。油页岩半焦产量占比逐渐上升,剩余油气占比随着温度上升逐渐减少。采用单轴压缩试验设备对热解前后的油页岩进行测试,发现不同微波功率不同热解终温会对油页岩力学性质产生较大影响,随着热解终温的升高,油页岩的抗压强度与弹性模量总体呈下降趋势。当热解终温达到600℃时,油页岩内部矿物质出现改性致使强度上升,弹性模量稍有回升。通过X射线显微CT对热解前后的油页岩进行扫描并重构,选取合适的REV模型进行油页岩孔裂隙三维重构,利用最大球算法构建孔隙网络模型,对岩心的孔隙度、等效孔隙半径、等效喉道长度等进行定量表征,获得孔隙度随温度的变化规律,研究发现随着温度的上升岩石内部孔隙率逐渐增大,内部孔隙网络逐渐发育完整。基于傅里叶定律对岩心进行热导率分析,探究不同微波热解终温下的油页岩热导率变化规律。发现油页岩中裂缝的数量与长度会对油页岩内部的热传递产生重要影响。最后利用COMSOL软件,建立油页岩多场耦合模型,对微波原位热解油页岩储层进行数值分析,研究发现,微波功率的大小会影响升温速率,储层温度场的变化与微波热解时间密切相关,储层内部的渗透率随着微波热解时间的增加而增大,储层孔隙度的增大会对油气渗流产生促进作用。在高功率下储层会产生较大位移。综合来看,600W是三种功率下最适宜的功率。该论文有图57幅,表3个,参考文献101篇。 | 10.27210/d.cnki.glnju.2023.000666 | Chinese | China | Thesis | ||||||
| C044 | 2023 | 低品位金矿石预选抛尾工艺研究进展与应用探讨 | 王俊杰; 陈艳波; 梁魏峰; 秦广林 | https://link.cnki.net/doi/10.19319/j.cnki.issn.1008-021x.2023.11.007 | 金矿石;低品位;预选抛尾;工艺原理;脉石 | 随着金矿石品位下降、浅部资源日益枯竭和采选成本增加，越来越多的黄金矿山企业和科研机构开始关注低品位金矿石的高效分选工艺。采用适合的工艺对低品位原矿进行预选抛尾，可以有效提高矿石入选品位，减少提升和破磨的矿石总量，提高设备利用率，在增产降耗和环境保护等方面均能起到积极的作用。 | 10.19319/j.cnki.issn.1008-021x.2023.11.007 | Chinese | China | Journal Article | 山东化工 | 52 | 11 | 110-112+116 | ||
| C045 | 2023 | 波导及其布置对微波辅助破岩效果影响规律与机制研究 | 吴占强 | https://link.cnki.net/doi/10.27397/d.cnki.gxaku.2023.001006 | 微波辅助破岩;波导布置;照射距离;波导型式;波导孔径;波导间距 | 微波辅助破岩是一种相较于纯机械法和爆破法效率更高、成本更低、更安全的新兴岩石破碎技术,在矿物加工和地下空间开挖等工程中具有广阔的应用前景。本文针对TBM刀盘微波波导布置问题,采用数值模拟与物理试验相结合的方法,研究微波照射距离、波导型式和孔径以及波导间距对辅助破岩效果的综合影响。首先开展开放式微波照射岩石物理试验,通过分析微波照射后岩石热性质及超声波速查明微波照射距离对岩石温升及损伤影响规律。基于实际微波辅助TBM开挖岩石场景探究微波开放式照射岩石数值模型与边界条件等基本问题,建立具有实际工程参考意义的微波照射岩石数值模型。结合数值方法进一步探究微波照射距离对岩石照射效果影响机制,继而研究不同照射距离下波导型式及其孔径对岩石微波照射效果的影响。最终通过分析模型电场及分布特征、岩石温升特性及分布、岩石塑性区分布特征等得出TBM刀盘微波波导布置对岩石照射效果影响规律及机制,并得到适用于TBM刀盘的微波波导布置思路及参数。主要研究成果如下: (1)通过微波开放式照射方式开展了微波照射距离影响物理试验。结果表明:岩石温升和损伤效果随着照射距离增加而降低,但在6cm和12cm照射距离时出现小幅上升。岩石高温区随照射距离增加呈现扩大-集中-扩大分布的变化规律,该变化规律与电磁波正弦式传播特征相关。封闭式照射条件下,岩石温升相对较高,但无明显线性规律,且照射距离增大,岩石高温区出现于岩石边缘而非中心位置,表明微波开放式照射方式与封闭式照射具有较大差别。 (2)根据微波辅助TBM刀盘开挖岩石实际场景,探究了数值模型边界条件、合适的波导尺寸及岩石尺寸,得到符合实际开挖状态的微波开放式照射数值模型,为后续研究作基础。进一步的微波开放式照射岩石数值模拟研究发现,微波照射距离对岩石照射效果并非线性规律,岩石温升及塑性区面积随照射距离增加呈波浪形递减现象。根据岩石温升曲线,定义了 5cm和8cm、11cm和15cm、18cm和21cm分别是近、中、远距离下的波峰和波谷距离,距离恰为波峰距离时,岩石温度较高,塑性区面积较大,高温区和塑性区分布集中;波谷距离时,岩石温升则较低,塑性区面积较小,但高温区和塑性区面积较大,整体上随照射距离增加而扩展。 (3)相同距离照射下,不同波导型式及孔径对岩石照射效果研究发现,会聚波导在波峰距离处对岩石温升和损伤效果较好,尤其5cm距离处效果明显,65mm孔径会聚波导对岩石微波照射效果较好。喇叭波导照射下,孔径大于200mm时,岩石温升和塑性区无明显规律,在86.4mm至200mm孔径范围内,岩石电场强度、温升在波峰距离处降低,在波谷距离处增大,且峰值较波峰距离处大,因此200mm孔径喇叭波导对岩石微波照射效果较好,喇叭波导照射时,波导孔径对岩石塑性区整体面积影响较小,但塑性区覆盖岩石表面面积随孔径增大而增加。 (4)分别对65mm会聚波导、86.4mm矩形波导及200mm喇叭波导进行微波波导布置综合评价研究。矩形波导布置照射下,5cm照射距离下,岩石温升不随间距变化,8cm、11cm和15cm距离时,岩石获得了较高的温升,但随波导间距增加而降低,近距离及波峰位置照射下的岩石塑性区较大,在15cm波导间距下达到最大。会聚波导布置照射下,同样在5cm近距离及波峰位置处具有明显的岩石温升和损伤优势,同样随着间距增大岩石温升降低,但塑性区面积在15cm间距时达到最大。喇叭波导布置照射下则是在15cm波谷位置处获得了较高温升,且在波谷位置岩石塑性区面积也较大,但波导间距影响较小,喇叭波导布置总体均不如布置矩形波导和会聚波导照射效果。综合对比下,可选择在5cm照射距离,选用65mm孔径会聚波导或86.4mm孔径矩形波导进行15cm间距微波波导布置。 | 10.27397/d.cnki.gxaku.2023.001006 | Chinese | China | Thesis | ||||||
| C046 | 2023 | 不同围压下玄武岩微波损伤研究 | 任一平 | https://link.cnki.net/doi/10.27397/d.cnki.gxaku.2023.000619 | 微波照射;玄武岩;围压;离散元;岩石损伤;裂纹扩展;抗压强度 | 围压的存在通常会抑制岩石内部裂纹的产生,所以围压条件下岩石破碎相比普通岩石更加困难,而微波照射后的岩体内部会产生损伤,形成微裂隙从而导致岩石强度降低,因此可采用微波对围压条件下岩石进行预处理,提高破岩效率。基于此,开展了不同围压下玄武岩微波损伤研究。本文首先进行了微波照射引起玄武岩损伤的物理试验。然后,在基本物理试验基础之上,采用数值模拟方法,建立了基于PFC的微波照射岩石模型,并开展不同围压下微波照射引起岩石损伤的研究,分析围压条件下微波作用后岩石内部裂纹扩展、应力应变曲线、强度特征及破坏模式等指标随围压和微波参数变化情况,得出围压对微波破岩效果的影响规律,提出了围压条件下提高破岩效率的方法。主要结论如下: (1)随微波功率增加,微波照射引起玄武岩的损伤加剧。当功率较低时,玄武岩在微波照射后,仅温度随微波照射功率和时间增加而逐渐升高;当功率达到1.6kW时,岩石表面开始出现碳化现象;功率达到2 kW时,表面出现宏观裂纹,甚至出现熔融现象,熔融临界条件为2 kW照射3min;玄武岩弹性模量和抗压强度均随功率增大而降低,2 kW微波照射3min时,弹性模量降低49%,抗压强度降低50%,表明微波辐射可显著造成岩石损伤,在破碎玄武岩时最优的参数为2 kW微波照射3min。 (2)利用PFC建立围压下微波照射岩石模型,从能量角度将模拟与试验结果进行了对比验证,发现模拟结果与试验结果随输入能量的变化趋势保持一致,即抗压强度值随微波能量的增加逐渐降低。当输入能量超过200kJ时,模拟结果与试验结果偏差较大,高功率短时间的微波照射使岩石抗压强度和弹性模量下降程度高于低功率长时间照射的情况,微波功率提高比照射时间增长对岩石损伤更不利。 (3)研究了围压条件对微波破岩效果的影响规律,发现围压会显著抑制裂纹产生,弱化微波致裂岩石的效果,围压越大弱化效果越显著,在40MPa围压下裂纹数量明显减少;有围压和无围压条件下,微波照射均可以降低岩石抗压强度,但随围压增大,强度降低的幅度越来越小,表明围压的存在会弱化微波破岩效果,40MPa围压下强度劣化效果减半;岩石的弹性模量随围压增大而增大,但增大幅度不大,微波照射会使岩石弹性模量均变小,围压越大岩石弹性模量的减小程度越小。 (4)围压会抑制裂纹产生,弱化微波致裂岩石的效果,考虑采取增大微波功率与照射时长的措施来提高岩石损伤达到预期效果,开展了 20MPa围压条件下,微波功率和照射时长对岩石损伤的研究,并得出结论:增加微波功率与照射时长两种方法,均可使岩石继续产生裂纹,达到无围压状态时的裂纹数量;随微波功率和照射时长的增加,岩石抗压强度会一直下降,当功率增加到1.5倍或照射时长增长到2倍时,强度减小幅度可达到无围压状态时的折减幅度;弹性模量随微波功率增大或照射时长增加而减小,利用弹性模量定义损伤变量,增加微波功率与照射时长后岩石内部损伤均会增加,且增加微波功率的方法相比较增加照射时长来说,其造成岩石损伤的效率更高,证明增加微波功率与照射时长两种方法的可行性。 | 10.27397/d.cnki.gxaku.2023.000619 | Chinese | China | Thesis | ||||||
| C047 | 2023 | 岩石对不同频段电磁波作用下的介电性质响应 | 白国刚 | https://link.cnki.net/doi/10.27397/d.cnki.gxaku.2023.000909 | 介电性质;频率;岩石电阻率;微波破岩;应用 | 电磁波所衍生的电法勘探和破岩技术对于提高地球资源开发效率、加快岩石掘进速率,存在着极大的潜力。机械破岩目前是破岩工程中最常见的方式,然而硬岩的掘进会使机械破碎效率降低、成本增加,进而影响地下破岩进展。此外,电阻率法勘探因其具有无损性,应用广的特点被广泛研究,因此探索电阻率法和微波破岩技术对于提高地球资源开发效率和地下空间利用率具有重要意义。本文以砂岩和花岗岩为研究对象,以室内试验为主要手段,结合理论分析方法,探究了低频阶段(0.01-200kHz)岩石电阻率变化规律,揭示了微波(300M-300GHz)作用岩石后温度和力学性质的变化机理,总结了不同频段电磁波的地质工程应用。本文主要取得了以下认识: (1)对花岗岩和两种不同砂岩进行了不同频率(0.1-200kHz)以及不同含水饱和度(0-100%)的岩石电阻率测试实验。结果表明:花岗岩和砂岩饱和度较低的情况下,岩样在激发极化效应的作用下,其电阻率会随饱和度的增大而增大,而随着饱和度增加到峰值电阻率所对应的饱和度时,孔隙水对电阻率的影响代替了激发极化效应作用的主导地位,此时岩样电阻率会随饱和度的增大而减小。此外,峰值饱和度与频率之间呈正相关的指数函数关系,且在由于104-105Hz处界面极化的消失,峰值饱和度会随着频率的增加而快速增大,增大幅度约为60%。 (2)以带有预制裂缝的半圆型SCB花岗岩为研究对象,在对岩样进行了不同加热时间(240s、480s、720s、960s)、不同循环次数(1、4、7、10次)的微波加热过后,进行了Ⅰ型断裂韧度测试试验。结果表明:岩样表面温度与微波加热时间呈正相关,本次试验中,微波循环次数对岩样表面温度的影响不大。由于花岗岩内部辉石和黑云母对微波的敏感程度高,与其他各矿物表现出明显的吸波差异性,随着微波加热时间的推进,岩样表面裂纹开始出现并扩展,SCB花岗岩断裂韧度下降明显,下降幅度可达35%左右。声发射振铃计数和声发射能量也阐明了岩石断裂的各个阶段,此外,通过荷载-时间曲线可以看出微波加热时间越长,岩样断裂破坏所用的时长越短。 (3)通过对低频阶段岩石电阻率变化、微波照射岩石后温度和力学性质变化的研究,再加上对前人研究的总结与学习,得出不同频段电磁波的地质工程应用。主要结论如下:低频阶段的电磁波在电法勘探领域的应用广泛,常见的电磁波勘探方法有电阻率法和地质雷达;红外线频段的红外热成像技术可以将岩石发出的红外能量转换为图像,这种技术也广泛应用于地质体的分析和研究中;电磁波破岩技术是一种新型破岩技术,主要分为微波破岩和脉冲破岩,前者是基于矿物之间的吸波差异性,后者则是因为压缩波产生的拉应力破岩,电磁波破岩可以辅助机械破岩,达到预先损伤岩石的效果,节约破岩成本,提高破岩效率。 | 10.27397/d.cnki.gxaku.2023.000909 | Chinese | China | Thesis | ||||||
| C048 | 2023 | 水对石英砂岩微波辐射升温损伤的影响规律研究 | 陈登红; 汪朝家; 王智鹏; 鲁德沛; 汤允迎; 杨波 | https://link.cnki.net/doi/10.19614/j.cnki.jsks.202305016 | 微波辐射;石英砂岩;含水率;升温损伤;抗拉强度 | 相较于钻爆法与机械破岩方法,微波辅助破岩因其具有选择性加热、效率高、可控性强等诸多优点,被认为是硬岩开掘的一种极具前景的新方法。为探寻水对较低吸波能力的石英砂岩微波辐射辅助破岩效果的影响,采用功率1.4k W微波对不同含水率石英砂岩辐射0～300s探究其升温、损伤与含水率之间的关系,通过波速表征的损伤因子Dm、微波辐射后表面温差FT和巴西劈裂抗拉强度σ_t综合分析了其升温损伤影响规律。研究结果表明:微波辐射干燥状态下石英砂岩呈现前期快速升温、后期趋缓趋稳且温差先增加后减小的变化趋势;除了饱和水外,不同含水率试件辐射90s时升温速率由快趋缓且在吸水6h处（平均含水率1.88%）拉开差距;FT、Dm及σ_t的变化幅度并不随浸水时长的升高而梯度变化,其中浸水4～6h（含水率1.69%～1.88%）为波速及其表征的损伤因子Dm出现下降与升高的“拐点”,前者平均降幅增加了5.18%,后者增加了0.092,σ_t下降了25.9%;岩石微波场内的升温损伤过程是水—岩耦合影响下的多尺度、多介质综合响应结果,特定的含水率（1.69%～1.88%）和辐射时长（90s以上）能够促进石英砂岩吸收微波后热应力梯度的产生,从而造成孔隙损伤、极限抗拉强度降低,使其更易破坏。分析结果可为类似条件下水对硬岩微波辐射升温损伤的研究分析提供可靠的借鉴。 | 10.19614/j.cnki.jsks.202305016 | Chinese | China | Journal Article | 金属矿山 | 05 | 155-164 | |||
| C049 | 2023 | 典型结构金属矿石微波辐射破裂机制研究 | 于洪雯 | https://link.cnki.net/doi/10.27007/d.cnki.gdbeu.2023.000841 | 金属矿开采;微波辐射;嵌套结构;层状结构;热应力 | 在金属矿开采中,岩石的破碎方法直接影响金属矿的开采效率。传统破岩方法中存在的一系列问题严重影响了开采效率。为解决传统破岩方法存在的问题,提高开采效率,微波辅助破岩技术作为新型破岩技术被提出并广泛研究。在微波辐射下,大多数硫化物、砷化物和金属氧化物表现出较好的微波热效应,而金属矿石中上述矿物的富集程度明显高于其他种类岩石,使其在微波辐射下热效应及热破裂效果更显著。因此,将微波辐射技术应用于金属矿开采更有前景。已有研究结果表明,不同结构岩石微波辐射下的破裂模式不同。本文根据不同结构岩石微波辐射下破裂模式和矿物分布特征,提出了嵌套结构和层状结构两种具有代表性的典型结构。嵌套结构由吸波矿物富集区及其外部一定范围的吸波能力较低或透波的矿物包裹体组成。层状结构金属矿石中矿物层状分布且相邻岩层吸波矿物的含量存在明显差异。以上两种结构作为构成岩石的基本结构单元在金矿、铁矿等众多金属矿体中广泛存在。本文以金属矿安全、高效开采为背景,采用实验研究、理论分析和数值模拟等手段,深入研究了嵌套结构和层状结构两种典型结构金属矿石微波辐射下的破裂机制,为提出基于微波辐射的金属矿开采方案、建立基于微波辐射的金属矿开采技术提供理论依据。主要内容如下:(1)开展了嵌套结构金属矿石的微波辐射实验,借助红外热像仪获取微波辐射后岩石表面温度场,利用扫描电镜、能谱分析、矿物成分分析及压汞测试等手段,观测到高温区存在吸波矿物富集现象,分析了矿物在微波辐射产生的高温环境下发生的化学变化,建立了孔隙、温度分布特征与矿物分布特征的相关性,揭示了嵌套结构特征对微波辐射后金属矿石温度和孔隙分布的影响机制。(2)开展了层状结构金属矿石的微波辐射实验,研究了微波热效应对层状结构金属矿石微观结构、矿物成分、热物性能以及各向异性的影响,观测到层状结构金属矿石的主要破坏模式为层间破裂,分析了层状结构对微波辐射过程中矿石热物性能各向异性的影响,揭示了层间破裂与导热性能的耦合效应。(3)基于嵌套结构金属矿石微波辐射后的温度分布特征,建立了嵌套结构球体力学模型,定义了温度梯度耦合系数和热膨胀耦合系数,分析了嵌套结构几何参数和耦合系数对最大压、拉应力的位置和热应力分布的影响,确定了径向裂纹的起裂位置,揭示了嵌套结构金属矿石微波辐射下应力演化及裂纹扩展规律。(4)通过理论分析,建立了考虑层状结构各向异性的电磁-热-固耦合模型,分析了层间剪切应力、层内正应力、剪切应力与温度增量、温度梯度、岩层厚度及微波功率的关系,确立了影响微波聚焦辐射下破岩效率的主控因素,揭示了层状结构金属矿石微波辐射下应力演化及裂纹扩展规律。(5)基于微波聚焦辐射技术,提出了长壁式微波预裂综合机械化采矿方法。基于嵌套结构和层状结构理论模型,制定了相关参数的设计原则,分析了长壁式微波预裂综合机械化采矿方法的优势。 | 10.27007/d.cnki.gdbeu.2023.000841 | Chinese | China | Thesis | ||||||
| C050 | 2023 | 微波-水分耦合作用下煤（岩）体的热-力响应机制 | 姚俊辉 | https://link.cnki.net/doi/10.27661/d.cnki.gzhnu.2023.000436 | 微波致裂;温变机制;结构演化;力学特性;应用设想 | 煤(岩)吸收微波后会发生破裂甚至破碎,因此微波技术被研究用于煤(岩)层动力灾害的防治领域。在应用微波致裂技术防治煤层动力灾害的工程现场,微波在煤层中传播时与孔隙水交互耦合并最终到达岩石顶板,针对微波对煤(岩)材料的致裂先后经历温度变化、结构演化和力学性能劣化这一基本过程,研究煤与常见煤层顶板岩石—砂岩吸收微波后在热、结构和力学行为上的响应特征,尤其是水分对煤与砂岩微波作用效果的影响。本文对煤(岩)孔隙水在微波场中岩石类材料热-力学响应问题上的研究,可进一步丰富煤层的微波泄压控制理论。主要研究结果如下: (1)研究分析了微波传播方向上砂岩的温度分布特征,并结合理论分析确定了微波对岩石类材料的穿透深度。随着微波加热的进行,微波-水分耦合产生的热效应是导致微波传播方向上岩石温度分布特征发生转变的主要原因。根据微波传播方向上砂岩结构的分布特征,确定晶内断裂是导致砂岩微波损伤甚至致裂的主要原因。砂岩中的含水量与微波的加热时长和传播距离有关,三者之间的相关性可用poly函数进行确定。 (2)研究了微波-水分耦合作用下烟煤的燃烧现象,发现烟煤点燃所需时长随微波功率的增加而缩短,随煤渗透率的提高而延长。一定微波功率加热下煤样存在一个渗透率阈值。低于该阈值时含水煤样的微波点燃比干燥煤样用时要短,高于该阈值时情况则相反。输出微波能总量一定的条件下,微波功率的提高可以改变孔隙蒸汽压力的加载特征,使其产生类似定容膨胀的力学作用效果。高功率的微波输出更加有利于在煤内部形成裂隙网络。 (3)研究了不同微波加热时长后含水烟煤的动态和静态力学性质,发现含水煤样的微波致裂具有时效性。随着微波加热时长的增加,煤样静态破坏时由剪切-拉伸的复合破坏模式向单一的拉伸破坏模式转变,动态破坏时的破碎块度也愈加均匀。煤样的峰值弹性能密度随微波加热时长的增加而不断降低,同时受载破坏时煤样也由强动力破坏向弱动力破坏发展。基于损伤力学理论建立了考虑微波损伤和受荷损伤的力学本构模型,并进行了验证。 (4)研究了微波加热路径对受载过程中煤岩组合结构的能量演化规律和破裂信号特征的影响。在高功率的微波致裂作用下,煤岩组合体中煤体和岩体的储能能力分别发生明显下降和少许提高,从而导致煤岩系统内部弹性能密度差的下降。煤岩结构体受载过程中产生破裂声信号主要来自于煤体,并且由于煤体中的微裂隙密度的增加导致波形信号向低能量、长时长的方向集中。最后,在以上研究的基础上提出煤层微波泄压技术的工程应用方案,并建立了确定煤层致裂所需合理微波时长的实验方法。 图93幅,表17个,参考文献141篇 | 10.27661/d.cnki.gzhnu.2023.000436 | Chinese | China | Thesis | ||||||
| C051 | 2023 | 预损伤干热岩力学特性及水力压裂裂缝扩展规律研究 | 庄登登 | https://link.cnki.net/doi/10.27661/d.cnki.gzhnu.2023.000809 | 预损伤干热岩;水力压裂;裂缝扩展规律;微波辐射;化学刺激;爆破损伤;机器学习 | 干热岩压裂造储是增强型地热系统（EGS）工程的核心步骤,造储后要求热储层中形成连通注采井的复杂裂缝网络。而目前干热岩水力压裂普遍面临着破裂压力高、形成裂缝单一,裂缝扩展方向不可控等难题。辅助水力压裂方法通过在压裂前对干热岩进行预损伤,能够有效降低压裂时的破裂压力,提高压裂后缝网尺寸和密度,是未来干热岩开发利用中必不可少的技术手段。本文通过实验探究、理论推导以及数值分析等方法,围绕预损伤干热岩力学特性和水力压裂裂缝扩展规律开展研究,主要研究方法与结果如下: （1）在福建漳州盆地干热岩地层露头新鲜面采集了四种岩性岩块,并对各岩性样品加热到不同温度后再分别进行微波辐照、化学刺激或者爆破预处理,然后分析不同岩性和温度干热岩在各处理方式中的响应规律。结果显示在不同岩性干热岩中,所含对微波、溶蚀处理敏感矿物组分和占比的差异,导致了其在微波或化学预处理后升温速率和化学反应程度的差异;不同岩性干热岩波阻抗的差异导致了其在爆破预处理中所受的孔壁环向应力峰值的差异。此外,温度因素通过改变干热岩的孔隙结构和波阻抗来影响其在各预处理方式中的响应。 （2）基于扫描电镜和核磁共振技术分析了不同预处理方式对不同岩性和温度干热岩微观结构损伤和孔隙结构变化的影响;基于实时高温下的环压试验获得了拉伸强度的变化规律。结果显示干热岩在不同预处理方式下响应越强烈,其微观结构损伤越严重,整体的孔隙结构越复杂,孔隙率越大,孔隙的连通性也越强。此外,微波或化学预处理后主要诱导大孔隙产生进而形成预损伤,微孔对干热岩预损伤的贡献率降低;经爆破预处理后主要由微孔和大孔共同发育进而形成预损伤。环压试验结果表明预处理后不同岩性和温度干热岩拉伸强度变化规律与其预损伤规律基本一致。 （3）开展预损伤干热岩实时高温下的真三轴水力压裂试验,以及水力压裂过程中的断裂试验,以获得预损伤干热岩起裂压力、破裂压力和断裂压力。同时借助3D激光扫描技术获得水力断裂面的三维形貌,通过构建基于分形理论的断裂韧度理论模型,获得预损伤干热岩考虑分形裂纹的断裂韧度,并分析分形维数对其影响规律。结果表明不同岩性和温度干热岩在不同预处理方式下预损伤越严重,则其起裂压力、破裂压力和断裂压力相对未经预损伤时降低越明显。各岩样分形裂纹的断裂韧度始终大于直线型裂纹断裂韧度,并且二者比值与分形维数呈正相关,均随预损伤程度加剧而增大。 （4）基于水力压裂起裂压力理论模型,结合试验结果分析了不同预损伤干热岩的起裂模式,以及压裂裂缝扩展形态的变化规律。根据水力断裂面特征获得压裂裂缝表面的单位表面积和细观形貌特征。通过构建干热岩水力压裂重张压力理论模型,基于断裂试验结果验证模型,并分析了重张压力的影响参数。结果表明不同岩性和温度干热岩经不同方式预处理后表现出了不同的起裂模式,以及不同的压裂裂缝扩展形态,并且裂缝面单位表面积和细观形貌特征也产生了差异。此外,相比传统重张压力理论,基于断裂力学的重张压力理论模型的预测值更加接近实测值,更符合工程实际。 （5）基于单位表面积、均方根高度Sa、峰度Sku和最大高差Sz四种细观形貌特征参数,通过建立主成分分析模型以获得表征水力裂缝面细观形貌特征的唯一参数。然后将该参数与起裂压力、破裂压力和重张压力一起作为因变量,通过构建TOPSIS评价模型,获得预损伤可行性评价得分指数。进一步根据不同预损伤方式下干热岩水力压裂的数据特征,选取不同的机器学习算法以建立最优的微波、化学和爆破的预损伤模型,再将不同预损伤模型得到的综合得分指数进行对比,最终实现了不同温度和岩性干热岩经微波、化学或爆破预损伤后,其水力压裂可行性的综合预测和评价。 图126幅,表36个,参考文献230篇 | 10.27661/d.cnki.gzhnu.2023.000809 | Chinese | China | Thesis | ||||||
| C052 | 2023 | 微波辐射下玄武岩动态力学特性与微观损伤机理研究 | 金飞燕 | https://link.cnki.net/doi/10.27661/d.cnki.gzhnu.2023.004918 | 微波辐射;热损伤;核磁共振;动态压缩特性 | 微波辅助破岩在采矿、选矿、地质钻探等领域潜力巨大。本文以玄武岩为实验研究对象,采用INSTRON 1346电液伺服控制材料试验机进行静态压缩实验,分析了微波处理前后玄武岩的静态压缩力学性能,同时借助改进的分离式霍普金森压杆试验系统(SHPB)进行动态压缩试验,探究了微波辐射对玄武岩的动态力学性能及失效模式的影响,最后通过超声波无损检测技术和核磁共振技术(NMR)定量、直观地表征了微波处理后玄武岩的内部热损伤情况。本研究揭示了微波诱导玄武岩损伤的微观机理,提出影响微波诱导损伤效果的参数,同时对微波作用下玄武岩的静动态力学特性进行定性分析,为工程实践提供理论基础与指导性意见。本文主要研究成果如下: (1)微波辐照处理对玄武岩物理、力学性能的影响非常显著。随着微波功率和微波照射时间的增加,纵波波速、动态抗压强度和动态弹性模量不断减小,而孔隙率大致增大。 (2)在静态压缩实验中,微波照射处理后玄武岩的压密阶段变长,弹性阶段变短且弹性模量明显下降。随着微波照功率水平及微波照射时间的增加,玄武岩的静态抗压强度逐渐降低。 (3)随着微波功率水平和照射时间的增加,玄武岩的动态抗压强度持续下降,而峰值应变持续增大。由动态应力-应变曲线的峰前阶段可以看出,随着照射时间的增加,弹性变形减小,而塑性变形增大。 (4)在动态压缩试验中,对于较高微波功率、较长时间照射处理后的玄武岩,其动态破坏模式往往是一种更复杂的断裂模式。由于反射拉伸波和泊松效应的综合作用,微波处理后的玄武岩在冲击应力作用下的破坏模式逐渐由轴向分裂转变为复合破坏模式。这两种失效模式都是由拉应力引起的。 (5)根据玄武岩的全尺寸孔隙分布和核磁共振图像可以看出,随着微波照射时间的不断增加,玄武岩的孔隙结构变化可以分为两个阶段,前期主要是微孔的生成和积累,后期主要是微孔的扩张。 (6)微波辐照下玄武岩的微观损伤机理分析表明,热冲击引起的拉应力是微波作用下玄武岩损伤的重要原因。微波功率和照射时间的增加可以增大强微波吸收矿物与弱微波吸收矿物之间的温差和接触传热系数,从而增强热冲击,导致玄武岩的劣化。 图48幅,表3个,参考文献85篇 | 10.27661/d.cnki.gzhnu.2023.004918 | Chinese | China | Thesis | ||||||
| C053 | 2023 | 微波照射岩石的改性实验及截齿截割数值模拟研究 | 何银东 | https://link.cnki.net/doi/10.27661/d.cnki.gzhnu.2023.003559 | 微波辅助破岩;强介电材料;损伤力学;应变能;颗粒流模拟;镐形截齿 | 爆破法由于其灵活性高、技术成熟等优点在矿山破岩中仍占主导地位,但其安全性差、工序周期复杂、环境负面影响大等缺点促使了非爆破岩手段的迅速发展。为了克服金属硬岩矿山机械掘进刀具磨损严重、掘进效率较低的缺点,微波辅助机械破岩以其安全、经济、高效等优点得到众多学者、工程师的青睐。经过大量的理论与实验研究,微波照射能够明显损伤岩石,造成岩石强度降低,在岩石破碎领域具有非常广泛的应用前景。而岩石矿物介电特性是影响微波处理效果的主要因素,大量微波弱敏感矿物的存在将会制约微波辅助机械破岩的进一步发展。本文围绕“如何提高岩石的微波吸收能力”这一问题开展了岩石的改性实验,同时揭示了微波损伤岩石机理,随后基于能量演化的视角对微波处理后硬岩的力学特性进行了分析并建立截齿截割岩体模型,通过模拟的手段对微波损伤岩体的截齿截割性能展开研究,具体研究内容及结论如下: （1）开展了微波辅助吸波试剂改善岩石的微波吸收能力实验,借助温度传感器和手持式热像仪监测了岩石在微波照射下的内外升温情况,结果表明微波辅助吸波试剂在一定程度上加快了岩石的升温速率,并且增大了岩石内外温度差值。 （2）采用声波测试仪、核磁共振设备等从细观层面表征岩石的损伤程度,进行了单轴压缩实验从宏观层面观察岩石的破坏形式与强度劣化特征。结果表明钛酸钡悬浮液、水均可作为一种良好的微波辅助吸波试剂,降低了岩石P波波速、增加了岩石孔隙度、降低了岩石的强度,其中钛酸钡悬浮液在促进岩石微波吸收能力上效果更好。 （3）开展了不同微波照射时间下花岗岩的单轴压缩实验,基于能量守恒理论,对微波损伤后花岗岩试样的能量演变规律、力学特性、脆性指标进行了分析。结果表明微波照射后花岗岩试样的能量转化能力下降,弱化了花岗岩的脆性特征,表现出塑性和延展性的增强。 （4）通过Rhino软件及PFC3D软件建立了截齿截割岩石模型,基于不同微波照射下花岗岩的应力应变曲线对模型进行细观参数标定,开展了不同截齿截割角度下的线性截割试验。结果表明,微波预处理岩体可以大大改善截齿的受力情况,且截齿在截割过程中存在最优截割角度。 图64副,表25个,参考文献144篇 | 10.27661/d.cnki.gzhnu.2023.003559 | Chinese | China | Thesis | ||||||
| C054 | 2023 | 基于热图像和神经网络的煤矸石分选研究 | 张焱鑫 | https://link.cnki.net/doi/10.27105/d.cnki.ghbgu.2023.001145 | 煤矸石;微波加热;水浴加热;热图像;特征差异;图像识别 | 传统的煤矸石图像识别方法分为可见光图像识别方法和射线识别方法,基于可见光图像的煤矸石识别方法受生产现场光源以及煤和矸石表面煤泥分布的影响,图像中煤和矸石的特征难以清晰地辨识,以致基于可见光图像的煤矸石识别方法的精度难以提升。基于射线的煤矸石识别方法所需的设备昂贵,同时还需要加装特殊防护设施来防止辐射,维护成本较高。本文以提高图像识别方法中的煤矸石识别精度为研究目标,提出了基于热图像和神经网络的煤矸石分选方法,通过实验研究对基于热图像和神经网络的煤矸石分选方法进行有效性分析,具体研究内容如下: (1)为了提高煤和矸石在图像中的特征差异对比度,提出了以红外热图像替代传统的可见光图像的改进方法,基于煤和矸石的物理性质差异以及常见的加热方式的特点,分别搭建了微波加热平台数据采集系统和水浴加热平台数据采集系统对煤和矸石进行热处理并收集红外热图像,并对煤和矸石的热图像进行了特征差异分析。 (2)为了获得具有稳定且明显特征差异的煤和矸石热图像数据集,开展了扩大煤和矸石热图像特征差异对比度的实验研究,对水浴加热后的煤和矸石分别进行鼓风和静置实验,通过分析水温、加热时间和加快空气流动速度对煤和矸石表面温差的影响规律,进一步得到了特征对比度较高的煤和矸石热图像,完成了煤和矸石原始热图像数据采集工作。 (3)为了丰富煤和矸石热图像数据集,对原始煤和矸石热图像进行图像翻转、对比度增强、亮度增强、添加高斯噪声和椒盐噪声等数据增强操作,并对扩充后的数据集进行随机划分,得到训练集、验证集和测试集,随后对构建的煤和矸石热图像样本进行特征提取,构建了颜色特征直方图,最终对煤和矸石热图像样本标签化,得到了煤和矸石热图像数据集。 (4)为了测试热图像对于分选煤和矸石的效果,选择卷积神经网络模型对煤和矸石热图像展开识别实验。通过对网络模型的主干特征提取网络进行优化,并将注意力机制融入主干特征提取网络中,完成了神经网络模型的改进。结合煤和矸石热图像训练集建立了煤矸石识别模型,通过载入测试集得到各个模型的识别效果,验证了基于热图像和神经网络的煤矸石识别方法的有效性。研究表明,基于热图像和神经网络的煤矸石分选方法对于剔除煤炭中的煤矸石来说起到增益效果。 | 10.27105/d.cnki.ghbgu.2023.001145 | Chinese | China | Thesis | ||||||
| C055 | 2023 | 微波照射花岗岩型铀矿石试样热裂响应与裂纹演化试验研究 | 林郁森 | https://link.cnki.net/doi/10.27234/d.cnki.gnhuu.2023.001532 | 微波照射;花岗岩型铀矿石;力学特性;裂纹演化规律;数值模拟 | 天然铀资源是保证我国核威胁力长期有效和核军工可持续发展的重要保障。花岗岩型铀矿床分布于我国的南方地区,因其品位高、储量大一直是我国天然铀资源的重要组成部分,常采用堆浸提铀或搅拌浸出提铀的方式回收铀资源,但这两种方法需将大块的铀矿石破磨成40目以下小细颗粒,由于花岗岩型铀矿石的强度高、硬度大、解离难,采用机械破碎时对设备本身损伤大、能耗高、利用率低,已成为花岗岩型铀矿企业难以解决的技术瓶颈。由于微波照射将使矿物内部产生大量的微裂纹,有效地降低矿物强度,有利于矿物的解离,有助于提高铀矿石的破磨效果。因此,本文采用室内试验的方法,揭示微波照射花岗岩型铀矿石试样的力学特性变化规律;采用数值模拟的方法,揭示微波照射下不同温度的花岗岩型铀矿石试样的热应力分布规律和裂纹演化规律,以及揭示微波照射作用下不同吸波矿物含量、不同吸波矿物形状和含原生裂纹的花岗岩型铀矿石试样的热应力和裂纹演化规律,取得了如下研究成果: （1）利用JYC-3型微波高温焙烧炉对花岗岩型铀矿石试样进行加热,使用水淬冷却和自然冷却试样后,采用RMT-150B液压伺服控制岩石力学试验系统对其进行力学性能测试。测试结果表明:花岗岩型铀矿石试样的抗压强度随微波功率的增加和照射时间的延长而降低;自然冷却的试样,在照射时间为30min,照射功率分别为1k W、2k W和3k W时,其抗压强度分别降低了2.54%、14.16%、31.30%,在微波照射时间为45min,照射功率分别为1k W、2k W和3k W时,其抗压强度分别降低了13.12%、26.21%、40.98%;在相同条件下,水淬冷却试样的抗压强度比自然冷却试样的抗压强度低10%左右。 （2）采用PFC2D颗粒流软件,并利用FISH语言对其内嵌的平行黏结的热力耦合模型进行了二次开发,模拟了微波照射花岗岩型铀矿石试样的温度分布、应力变化和裂纹演化规律。模拟结果表明:微波照射作用下,花岗岩型铀矿石试样内部吸波矿物聚集区域的温度高、热应力大,在此区域试样内部微裂纹开始出现并沿热应力大的方向扩展;当微波照射试样的温度达到200℃时,试样内部开始产生微裂纹,热应力变化比较均匀,此后微裂纹数量随温度的升高而缓慢增加;当温度达到450℃时,试样内部的微裂纹急剧增加,试样的热应力出现大幅度波动;当温度达到700℃以上时,试样已形成贯通裂隙,此时试样已完全破坏,热应力呈现下降的趋势。 （3）采用PFC2D颗粒流软件,分析了吸波矿物含量、吸波矿物形状和含原生裂纹对微波照射花岗岩型铀矿石试样的热应力和裂纹演化规律。模拟结果表明:在微波照射作用下,试样吸波矿物含量越高,其内部的微裂纹极易在短时间内大量出现;当试样的吸波矿物含量相同时,微波功率越高加热速率越快,微裂纹越容易产生和扩展;当试样吸波矿物的形状越尖锐,越容易在此区域产生微裂纹并急剧扩展形成宏观裂纹,而当试样吸波矿物的形状越圆滑,则产生的宏观裂纹数量越多;在微波照射下,含原生裂纹试样的热应力分布规律与完整试样的热应力分布规律基本一致。 | 10.27234/d.cnki.gnhuu.2023.001532 | Chinese | China | Thesis | ||||||
| C056 | 2023 | 微波–水交互作用下富油煤岩渐进性破坏规律试验 | 单鹏飞; 杨攀; 来兴平; 孙浩强; 郭中安; 顾合龙; 李伟; 张帅 | https://link.cnki.net/doi/10.13722/j.cnki.jrme.2022.1003 | 岩石力学;富油煤;微波辐射;含水率;能量演化;破坏特征;分形维数 | 陕北富油煤储量大，其组分内含有较多页岩气，同时其内部裂隙少、致密、强度大，井下开采过程呈现“三大一快”，容易形成顶板大面积悬顶和其他次生灾害。常规治理顶板动力灾害的手段存在诸多不足，故此引入微波辐射，制作不同含水率的富油煤样，通过微波照射不同含水率下的富油煤，分析微波照射前后煤样的物理力学性质，研究微波作用下不同含水率煤样的裂隙扩展规律、煤样最终破坏形态和基于煤样碎块等效边长–质量下的分形维数。试验结果表明：(1)同一微波辐射条件下，煤岩试样能量积聚和耗散与含水率呈负相关，富油煤纵波波速平均下降幅度分别为4.22%,7.23%,11.76%，能量积聚和耗散进一步降低。(2)随着含水率增大，富油煤破坏模式由压剪破坏逐步转变为拉剪混合破坏，引入微波辐射，富油煤破坏程度继续增大，破坏模式由剪切破坏逐步转变为柱状拉伸破坏。相较于水，微波对煤样的改造作用更强，水的参与使得微波作用效果提升明显。(3)随含水率增大，分形维数呈现递减趋势，引入微波后，分形维数递减速率更为明显。因此两者对于分形维数递减均呈促进作用。揭示富油煤经微波与水交互作用下的渐进性破坏规律，为微波与水力交互压裂机制提供有效参考，为顶板动力灾害防治措施提供基础性理论支撑。 | 10.13722/j.cnki.jrme.2022.1003 | Chinese | China | Journal Article | 岩石力学与工程学报 | 42 | S2 | 3884-3896 | ||
| C057 | 2023 | 微波照射下砂岩的力学性能试验与分析 | 方琦 | https://link.cnki.net/doi/10.27101/d.cnki.ghfgu.2023.001524 | 砂岩;微波;力学性能;饱和度;微观分析 | 目前,岩石破碎主要采用爆破、机械破碎的方法,其中机械破岩的刀具磨损是破碎岩石过程中面临的主要问题。微波加热由于其选择性快速加热、整体加热等特点,能够显著降低岩石强度,被认为是一种非常有潜力的辅助破岩技术。本文以砂岩为研究对象,研究了微波照射下砂岩力学性质的变化、含水率对砂岩破裂和力学性能的影响等,然后通过COMSOL软件对微波炉腔内的电磁演化和砂岩的温度和电磁场的变化进行了测量和分析,再结合热重分析、电镜扫描和图像处理等手段,从试宏微观的角度对微波照射下影响砂岩力学性能变化的主要因素进行了研究,得出的主要结论如下: (1)不同尺寸的干燥砂岩表面平均最高温度,随着微波时间和微波功率的增加呈现逐渐上升的趋势,样品在微波照射下具有尺寸效应,同时随着微波功率和微波时间的增加,试样表面的颜色逐渐由灰白色向焦黑色转变,甚至表面会出现大量裂纹。在微波照射下,干燥砂岩的质量损失率会随着微波功率和微波时间的增加而增加,P波波速则出现相反的规律,而砂岩的平均单轴抗压强度、平均抗拉强度和弹性模量呈现出相同的变化趋势,即先增加后降低。 (2)通过COMSOL模拟软件,得知微波加热主要受微波炉中电场的分布影响,且随着微波时间的增加,砂岩表面的温度差和温度梯度差呈现逐渐上升的趋势,不均匀性逐渐的增加,进而产生温度应力,使砂岩产生裂纹。 (3)在微波照射下,不同饱和度的砂岩在破裂时间、破裂温度和破裂形态上有着不同的变化规律,而不同饱和度的砂岩的峰值强度随着微波时间和功率的增加而呈现缓慢下降的趋势,而0%饱和度(干燥状态下)基本未发生变化,弹性模量的变化规律和单轴抗压强度类似。 (4)在热重试验中,砂岩的质量变化曲线整体呈下降趋势,其中共发生两次明显的失重,分别为25～120℃和400℃～800℃区间;在SEM试验中,在高功率、长时间微波加热下,砂岩试样内部微裂纹和微孔隙相较于低功率、短时间明显增多;利用IPP软件对图像进行处理,得出随着微波时间和微波功率的增加,微孔和小孔的占比逐渐增大,而中孔和大孔的占比逐渐减少,孔隙数量则呈现逐渐增大的趋势。 | 10.27101/d.cnki.ghfgu.2023.001524 | Chinese | China | Thesis | ||||||
| C058 | 2023 | 微波作用下硬岩弱化致裂机理及应用 | 王云龙 | https://link.cnki.net/doi/10.27623/d.cnki.gzkyu.2023.002758 | 微波辅助破岩;连续-离散方法;破裂特征;力学行为;滚刀破岩 | 微波辅助破岩具有绿色、高效、低能耗等优点,是有望实现深部煤炭资源开发中硬岩地层高效掘进的技术手段,其机理引发了工程与学术界的关注。本文基于花岗岩组分矿物微波吸收以及升温差异,借助连续介质微波电磁分析及离散元力学模型,实现了微观矿物温度离散赋值,提出了微波照射下花岗岩力学性质的计算分析方法,从温度场分布、力学性质和破坏形态验证了方法的可靠性,揭示了微波照射下花岗岩破裂规律、单/三轴加载条件下的力学行为及破裂机制。随后进行了微波损伤花岗岩的滚刀破岩模拟,并分析了不同波导位置以及微波功率对微波辅助破岩效果影响。本文主要工作及结论如下:(1)建立并验证了非均质花岗岩晶质模型(Grain-Based Model,GBM)。建立了花岗岩的颗粒流模型,分析了各个接触微观参数对花岗岩单轴强度、弹性模量、泊松比等宏观力学参数的影响,得到宏观力学参数和微观力学参数的对应关系。研究发现:单轴压缩强度受微观黏结强度影响较大,宏观弹性模量与微观接触模量相关,泊松比主要受刚度比影响。最终构建了非均质花岗岩GBM模型,并验证了其可靠性。(2)建立了微波作用下的花岗岩破裂过程的连续-离散计算方法并针对微波作用下花岗岩升温规律以及破裂机制进行了探究。借助连续介质框架的微波电磁分析,描述了微波照射下花岗岩温度的宏观表征,基于矿物对微波吸收升温特征及GBM模型,实现了微观矿物的温度离散赋值,完成了微波作用下花岗岩力学性质分析的连续-离散计算方法,从温度场分布、力学性质等验证了方法的可靠性。并且发现微波照射下,试样出现2个相对低温区域和1个热点区域,且这两个区域随照射功率的增加而越发明显。在低微波功率(≤2k W)情况下,试样内部微裂纹数量极少;高微波功率(≥3k W)下,试样内部微裂纹以晶粒边界拉伸破坏为主导逐渐发育,并以热点区域为中心向四周延拓形成裂纹网络,最终出现宏观裂纹。(3)完成了微波作用后损伤花岗岩模型的单轴压缩模拟及力学行为与破裂机理研究。将微波照射后的标准试样模型进行单轴压缩模拟实验,发现试样峰值应力、弹性模量和损伤阈值均随着微波功率增加而降低,且在高微波功率(≥3k W)下,上述力学参数跌落更加明显。结合破裂现象可知:当低微波功率(≤2k W)时,受载试样裂纹演化及破坏形态无明显差别;当照射功率较高(≥3k W)时,微波照射后初始裂纹主导了受载过程中试样裂纹演化,试样呈现沿初始裂纹扩展的趋势且出现显著的局部破坏,导致试样失去承载能力。(4)模拟分析了不同围压与不同照射条件下花岗岩的三轴压缩力学行为与破裂特征。将微波照射后的试样模型进行三轴压缩模拟实验,结合单轴压缩结果,发现对于三轴压缩,随着照射功率的增加,初始围压对试样强度提升效果越发强烈;低微波功率(≤2k W)下围压对弹性模量的增加效果并不明显,高微波功率(≥3k W)情况下,初始围压对弹性模量的提升效果格外显著。通过破裂现象可解释为:随着照射功率增加,围压促进了破碎颗粒的继续承载及应力传递,使得试样破坏由晶间破坏主导向晶内破坏主导转变,进而促进裂纹网络的充分发育,抑制了高功率(≥3k W)照射引起的局部结构集中破坏。(5)建立了微波作用后二维常截面滚刀侵入岩体模型,结合不同波导布置位置研究了微波功率对于微波辅助滚刀破岩的影响。结果表明:波导正对单滚刀中线的情况下,随着微波功率的不断增大,整个侵入过程中的侵入力峰值先不变后减小,破碎程度也随着微波功率上升不断加大;波导正对双滚刀中缝情况下,侵入力峰值下降趋势同波导正对单齿情况类似,但是破碎程度降低情况很差。最终认为在波导口正对单滚刀中线进行布置的情况下,可以达到更好的微波辅助破岩效果,且微波功率选取30-60k W较为恰当。 | 10.27623/d.cnki.gzkyu.2023.002758 | Chinese | China | Thesis | ||||||
| C059 | 2023 | 微波照射-红外探测主动式煤矸识别方法 | 刘闯; 李化敏; 常发展; 鲁智豪; 刘超月 | https://link.cnki.net/doi/10.13827/j.cnki.kyyk.2023.02.020 | 综放工作面;煤矸识别;微波照射;红外探测 | 煤矸石的自动识别一直制约着综放面的智能化开采。基于煤、矸石在物理、化学属性上的差异，提出一种微波照射-红外探测主动式煤矸识别方法，该方法利用微波照射的方式增大煤与矸石之间的外在热敏差异，再利用红外探测技术获取该差异，从而对煤矸进行识别和判断。在实验室条件下，运用该方法对同忻煤矿的煤、矸石样品进行微波照射试验，试验结果表明，煤、矸石在相同的微波照射条件下，按照颗粒尺寸从小到大的顺序，煤颗粒微波照射前后温度升高量分别为矸石的1.3倍、1.7倍、2.0倍和2.3倍，验证了该煤矸识别方法的可行性，为综放面智能放煤过程中煤矸自动识别提供了技术借鉴。 | 10.13827/j.cnki.kyyk.2023.02.020 | Chinese | China | Journal Article | 矿业研究与开发 | 43 | 02 | 184-188 | ||
| C060 | 2023 | 微波作用下花岗岩的强度劣化规律与劣化机理分析 | 王皓天; 王涛; 周永顺 | https://kns.cnki.net/kcms2/article/abstract?v=wScU5_zS5CP6pjFKHcNERUxOUU7EA8mJqA7BUEWbEQs1aBVSxVqHyJQuCYq_ABd1GrH8CsnuPTkH0OzwRl6By6OBC-DIEyw_Jf9-bDeXZmx0wxqkWQpxs_3W8MH2K208LTglgizvtGBIDEFj-U6dFKUXI0YmlRNgU4VRsFL3dbQHyXuNDoKZ3wO3NWuTcrrz&uniplatform=NZKPT&language=CHS | 微波;纵波波速;劈裂抗拉强度;热应力;水 | 采用工业微波炉对花岗岩试样进行加热，微波功率固定为4 kW,改变微波时间，并设置相应的饱水花岗岩与干燥花岗岩进行对照，微波照射后测量试样的表面温度、纵波波速、劈裂抗拉强度。研究了不同时间的微波作用下，花岗岩的升温特性、波速变化以及抗拉强度的变化规律，并分析其劣化机理。结果表明：微波作用后，花岗岩表面温度逐渐上升，纵波波速和劈裂抗拉强度降低，且随着微波时间的增加，降低的幅度更大。通过磨片分析和热分析试验可知，微波加热劣化花岗岩的根本原因是微波对吸波能力不同的矿物进行选择性加热，产生热应力，热应力大于矿物间或矿物内的极限强度时，对岩石造成损伤。此外，岩石内部的水能够促进微波对岩石的劣化作用。 | Chinese | China | Journal Article | 工程与建设 | 37 | 01 | 367-370 | |||
| C061 | 2023 | 岩石矿物测试中微波能的运用 | 黎乔 | https://link.cnki.net/doi/10.13487/j.cnki.imce.023257 | 微波能;岩矿分析;岩石矿物测试;微波能分解法 | 在现代经济不断发展的背景下，我国矿产行业发展成果斐然，取得了显著的成就，为我国的社会生产与生活给予了资源支持。微波能测试岩石矿物为整个矿产业提供了开采理论依据。本文着重分析微波能分解的运用原理、特点及实际操作中面临的问题，探究微波能在岩石矿物分析中的应用与影响。 | 10.13487/j.cnki.imce.023257 | Chinese | China | Journal Article | 内蒙古煤炭经济 | 03 | 163-165 | |||
| C062 | 2023 | 金矿石处理方法研究现状及进展 | 吴卫煌 | https://kns.cnki.net/kcms2/article/abstract?v=wScU5_zS5CNeaQtDQz_ljafyYJXhxAJBq-Eii4_hA9IVcuQ-6xG4q0hICtj1p4SBy7BMtlEX7F2u-uAuOFmNf6RgDhxdv4uJNCnaqBi9gaCQsUVdTFEOmCWDyDNrBfVkVbhUvnlmUfoqf1pIPhawfmAXaYXqF05hyzNgM3OZsXFI3AHLdpS99ZNsXn2O5oAT&uniplatform=NZKPT&language=CHS | 难处理金矿;非氰;焙烧;生物氧化;加压氧化;微波;超细磨;硫代硫酸盐 | 随着环保要求日益严格与金矿资源品位逐渐下降，非氰提金技术与难处理金矿石预处理技术受到广泛关注，如何高效、绿色地提金成为目前冶金工业的研究热点之一。总结了近年来金矿石浸出技术及难处理金矿石预处理技术的现状及进展，并通过分析各方法的作用机理对比了其优缺点，为金矿提金技术的发展及推广应用提供参考与借鉴。 | Chinese | China | Journal Article | 黄金 | 44 | 01 | 42-48 | |||
| C063 | 2023 | 基于连续-离散方法的微波照射下花岗岩力学行为与破裂特征 | 高亚楠; 王云龙; 张垚; 蔚立元; 邵晓爽; 张广凯 | https://link.cnki.net/doi/10.13225/j.cnki.jccs.2022.1557 | 微波辅助破岩;连续-离散方法;热破裂;力学行为;破裂特征 | 微波辅助破岩具有绿色、低能耗等优点，是有望实现深部煤炭资源开发中硬岩地层高效掘进的技术手段，其机理引发了工程与学术界的关注。基于花岗岩组分矿物微波吸收升温差异，借助连续介质微波电磁分析及离散元力学模型，实现了微观矿物温度离散赋值，提出了微波照射下花岗岩力学性质的计算分析方法，从温度场分布、力学性质和破坏形态验证了方法的可靠性，揭示了微波照射下花岗岩破裂规律、单/三轴加载条件下的力学行为及破裂机制。计算结果表明：(1)微波照射下，试样出现2个相对低温区域和1个热点区域。在低照射功率(≤2 kW)情况下，试样内部裂纹数量极少；高照射功率(≥3 kW)下，试样内部裂纹以晶粒边界拉伸破坏为主导逐渐发育，并以热点区域为中心向四周延拓形成裂纹网络。(2)对于单轴压缩，试样峰值应力、弹性模量和损伤阈值均随照射功率增加而降低，在高照射功率(≥3 kW)下，力学参数跌落更加明显；当照射功率较高(≥3 kW)时，微波照射后初始裂纹主导了受载试样的裂纹演化，试样呈现沿初始裂纹扩展趋势并出现显著的局部破坏。(3)对于三轴压缩，随照射功率增加，初始围压对试样强度提升效果越发强烈；低照射功率(≤2 kW)下，弹性模量随围压变化不明显，高照射功率(≥3 kW)下，初始围压对弹性模量的提升格外显著；随照射功率增加，围压促进了破碎颗粒的继续承载及应力传递，试样破坏由晶间破坏主导向晶内破坏主导转变，进而引发裂纹网络充分发育，抑制了高功率(≥3 kW)照射产生的局部结构集中破坏。 | 10.13225/j.cnki.jccs.2022.1557 | Chinese | China | Journal Article | 煤炭学报 | 48 | 02 | 693-713 | ||
| C064 | 2022 | 基于微波辐照的铜镍矿石富集可行性研究 | 张永玺; 李彪; 韦克举; 周科平 | https://link.cnki.net/doi/10.13827/j.cnki.kyyk.2022.10.024 | 矿石富集;微波辐照;微波矿物加热;图像识别 | 随着矿山可采品位的逐渐下降，实现原矿矿石富集对矿山生产的降本增效及资源的综合利用具有重要意义。为了富集某铜镍矿矿石，采用微波技术对该矿石与废石样本进行微波辐照试验研究，分析矿石样本与废石样本在不同功率与时间的微波辐照下温度分布的变化差异，探讨微波辐照富集矿石的可行性。结果表明：该铜镍矿石在不同微波辐照功率与照射时间下，矿石与废石可体现出明显的色温差异，具有较好的直观识别特征，且矿石样本的温度变化与微波辐照功率及照射时间呈正相关，表明微波辐照可用于该铜镍矿石与废石的区分识别，结合人工智能的图像识别技术，可形成一种新型图像色选的矿石预富集技术。 | 10.13827/j.cnki.kyyk.2022.10.024 | Chinese | China | Journal Article | 矿业研究与开发 | 42 | 10 | 69-74 | ||
| D001 | 2023 | Dielectric properties of minerals and ores and the application of microwaves for assisted comminution and ore sorting | Forster, J. | https://utoronto.scholaris.ca/server/api/core/bitstreams/409d4dfe-72cf-4b0a-82fb-40a49eb75d7d/content | gold sulphide; nickel sulphide; nickel-copper sulphide; silver sulphide; chromite; iron ore; ovoid nickel; gold-copper; ultramafic nickel; zinc silicate; massive sulphide; net nextured; disseminated sulphide; argillite; peridotite; baggro; lead-zinc sulphide; porphyry copper; lithium; kimberlite; serpentine; olivine; pentlandite; chalcopyrite; pyrite; pyrrhotite; molbdenite; galena; sphalerite; barite | comminution; liberation; microwaves; minerals; permittivities; sorting | Upon exposure to microwave radiation, most valuable minerals heat very well, while in general, gangue minerals do not. This selective heating leads to differential thermal expansion across phase boundaries and causes microfractures, which can improve liberation and reduce ore competency. During ore sorting, the heat signature is detected using infrared sensors to accept or reject valuable or gangue rock, respectively. A comprehensive literature review identified research gaps in the field of microwave-assisted comminution and ore sorting and found that developments have been limited by complexities associated with scaling up from bench- to pilot-scale. Dielectric properties were measured on key sulphide and silicate minerals and select ores at various frequencies and temperatures using the cavity perturbation technique. In combination with data from the literature, experimental data were used to ascertain which minerals could be defined as highly microwave-amenable phases (HMAPs). Bench-scale microwave heating experiments were completed on 42 ores. These data were then combined with the total wt.% HMAPs and the ore dielectric property data to create a database that can be used to predict the bench-scale heating behaviour of any ore based on the wt.% HMAPs. High-power microwave tests were done on select ores, which were subsequently ground using the SAGDesign test, and the degree of liberation of valuable minerals was obtained via QEMSCAN® (quantitative evaluation of minerals by scanning electron microscopy). Microwave treatment increased mineral liberation from most ores but reduced the competency of only a few ores. Massive sulphide ores could not be treated on the pilot-scale system given their very high conductivities, which caused severe arcing. A study on a Cu porphyry ore found that an upper boundary exists for the power density, above which the ore will experience excessive arcing. Bench-scale microwave infrared and conductivity sorting tests on a Cu-Ni ore found general agreement between rock conductivity and its overall sortability. Optimization tests were completed to determine the limitations of the pilot-scale system. Recommendations for high-power microwave treatment include microwave pulsing, quenching, and treatment of iron ores. | N/A | English | Canada | PhD Thesis | N/A | 0 | - | - | 0 |
| D004 | 1968 | Novel drilling techniques-compressed | Maurer | |||||||||||||
| D006 | 1988 | Rapid Microwave Heating in Mineral Processing | McGill & Walkiewicz | |||||||||||||
| D007 | 2016 | Comparison of microwave irradiation and oxidation roasting as pretreatment methods for modification of ilmenite.. | Mehdilo & Irannajad | |||||||||||||
| D011 | 2025 | Meso–macro‑theoretical Analysis and Experimental Verification of Microwave-Assisted Breaking Rock Under Double-Indenter Impact | Wang, P.; Yue, Z.; Xu, S.; Gao, D.; Li, A.; Ren, M. | https://link.springer.com/article/10.1007/s00603-025-04700-8 | limestone; C50 concrete | Microwave radiation; Impact rock breaking; Specific energy consumption attenuation; Damage; Strain energy density | In light of the constraints on explosives and the national "dual carbon" strategic goals, microwave-assisted impact rock breaking has emerged as a promising method for hard-rock roadway excavation due to its environmental benefits and efficient rock-breaking capabilities. However, the underlying mechanism of this method remains poorly understood. This study establishes a meso–macro-unified theory for microwave-assisted impact rock breaking by linking macro-level specific energy consumption attenuation to meso-level damage through strain energy density, based on thermodynamics and energy conservation principles. Using a self-designed dual-indenter impact test system (DHPB) and SEM, we investigated the variations in specific energy consumption and damage in limestone specimens under different microwave radiation durations. The results demonstrate that microwave radiation-induced degradation exhibits a threshold effect, heavily influenced by the initial crack length. When the strain energy density absorbed by the rock is below the threshold required for crack propagation, minimal internal damage occurs. Conversely, once the threshold is exceeded, damage accumulates nearly linearly with strain energy density. Experimental data show that the maximum specific energy consumption attenuation in limestone specimens reaches 0.58, accompanied by a damage increase of 0.59. These findings align with the meso–macro-unified theory, confirming that the increase in meso-level crack length and density quantitatively reduces macro-level specific energy consumption. This reveals the mechanism by which microwave radiation weakens rock resistance to impact. The study provides a theoretical foundation for the engineering application of microwave-assisted impact rock breaking in hard-rock environments. | https://doi.org/10.1007/s00603-025-04700-8 | English | China | Journal Article | Rock Mechanics and Rock Engineering | 58 | 12069-12090 | ||
| D015 | 2021 | Microwave-based extractive metallurgy to obtain pure metals: A review | Mizuono, N.; Kosai, S.; Yamasue, E. | https://www.sciencedirect.com/science/article/pii/S2666790821002664 | ||||||||||||
| D021 | 2022 | Evaluation of pre-treatment methods for gold recovery from refractory calcine tailings | Mutimutema et al. | https://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S2225-62532022001000004&lng=en&nrm=iso | ||||||||||||
| D026 | 2025 | Modelling microwave fracturing of rocks: A continuum numerical approach | Nie et al | https://www.sciencedirect.com/science/article/abs/pii/S136516092400340X | ||||||||||||
| D028 | 2014 | Influence of microwave irradiation on ilmenite surface properties | Nuri, O.; Mehdilo, A.; Irannajad, M. | https://www.sciencedirect.com/science/article/abs/pii/S0169433214009635 | ilmenite | Ilmenite; Flotation; Microwave irradiation; Surface properties; Zeta potential | In this study, the effect of microwave irradiation on ilmenite surface properties and its flotation behavior was investigated. After microwave irradiation, Fe2+ ions on the ilmenite surface are oxidized to Fe3+ ions. XPS analysis indicated that the relative content of Fe3+ increased from 48.5% to 66% after microwave irradiation for 2.5 min. This conversion decreased the ilmenite surface zeta potential in a wide pH range and resulted in the shift of PZC from a pH of 5.4 to a pH of 2.7. FTIR spectra and zeta potential measurements showed that the microwave irradiation enhances the adsorption of oleate ions on the ilmenite Helmholtz layer. The greater stability of chemisorbed ferric iron oleate than ferrous iron oleate resulted in the increase of contact angle and the decrease of surface zeta potential. Therefore, the microwave irradiation pretreatment improves the ilmenite hydrophobicity and floatability in a wide pH range. The maximum floatability of ilmenite occurring at a pH of 6.3 was 73.5% and 94% for non-irradiated and irradiated ilmenite, respectively. | 10.1016/j.apsusc.2014.04.187 | English | Iran | Journal Article | Applied Surface Science | 311 | 27-32 | ||
| D070 | 2023 | Circuit Energy Savings of Microwave-Assisted Comminution and Ore Sorting | Tian, X.; Forster, J.; Bobicki, E. | https://www.researchgate.net/publication/373435036_Circuit_Energy_Savings_of_Microwave-Assisted_Comminution_and_Ore_Sorting | nickel sulphie ore; copper sulphide ore; gold sulphide ore; silver sulphide ore | microwaves; comminution; sorting; energy | CanMicro, a Pan-Canadian consortium, investigated the benefits of microwave-assisted comminution and sorting.in mineral processing circuits during the Crush It! Challenge. Our goal was to achieve the maximum energy savings.with combined microwave pre-treatment and sorting technology. Minerals respond differently to microwave.irradiation (MW), which causes differential heating to occur, as well as thermal stress at the grain boundaries.between the minerals. The heat signature generated after microwave treatment could also be combined with X-ray.transmission (XRT) sensing to make accurate decisions about whether to accept or reject a rock. Over 15 different types of ores were investigated, and four with the most common commodity types were reported: nickel, copper, silver, and gold. The highest energy savings was reached by the nickel ore, which is.46.5% compared with the conventional process. Three major means of energy-saving using the technology of MW-assisted comminution and sorting are rejecting gangue, reducing ore competency, and increasing mineral liberation. This paper goes through the process of the combined microwave and sorting technology and the results of the pilot test campaign during the Crush It! Challenge. | English | Canada | Conference Proceeding | SAG Conference, Vancouver, September 24-28, 2023 | 22 pages | ||||
| D079 | 2020 | Microwave Treatment of Rocks: Effect of specific gravity, whiteness, and grindability | Sefiu, O.A.; Hussin, A.M.A.; Haitham, M.A.A. | https://www.rudmet.ru/journal/1930/article/32671/?language=en | ||||||||||||
| D092 | 2025 | 16-AMPERE-2025 | SRA-vol | |||||||||||||
| D094 | 1957 | Search for new methods of destruction of strong rocks | State Mining Authority | |||||||||||||
| D095 | 2010 | Experimental Study on Microwave Pretreatment with Some Refractory Flotation Gold Concentrate | Su, X.; Mo, Wei; Ma, S. Yang, J.; Lin, M. | https://www.scientific.net/AMR.158.71 | ||||||||||||
| D096 | 2024 | Experimental and Simulation Studies on Microwave Treatment for Enhancing Conical Pick Indentation of Granite | Su, X.; Li, D.; Ranjith, P.; Liu, Z.; Zhao, J. | https://link.springer.com/article/10.1007/s00603-024-04251-4 | granite | Microwave irradiation; Rock fracture; Indentation test; Numerical modeling; Microwave-assisted conical pick-cutting | Microwave radiation can be employed to pre-damage hard rock to reduce the cost of cutting and excavation in mining. In this paper, laboratory experiments and electromagnetic thermo-mechanical simulations are conducted to investigate the effects of different microwave treatment times on the indentation efficiency of granite using a conical pick. The results show that microwave heating simplifies the indentation stages, and reduces peak pick force and indentation depth. Similarly, acoustic emission (AE) activity and accumulative AE energy decrease as the exposure time increases. Scanning electron microscopy (SEM) analysis confirms that microwave pretreatment causes thermal microcracking, altering the failure mode, surface roughness, and fracture mechanisms around the indentation pit. Numerical simulations further validate that the inhomogeneous temperature distribution within the rock leads to tensile damage, which weakens the mechanical properties of the granite and reduces compressive damage during pick-cutting. The analysis of microwave heating efficiency, specific cutting energy, cutting work, and acoustic emission energy over various exposure times reveals significant energy efficiency at 120 and 180 s. This study elucidates the mechanisms of microwave-assisted cutting and provides insights into optimizing microwave treatment time to reduce energy costs. | https://doi.org/10.1007/s00603-024-04251-4 | English | China | Journal Article | Rock Mechanics and Rock Engineering | 58 | 2185-2202 | ||
| D097 | 2025 | Experimental Investigation into the Law of Rock Breaking Through the Combination of Microwave Irradiation and Cutting Tools Under Multiple Conditions | Su, X.; Li, Z.; Zhou, Y.; Li, S. | https://www.mdpi.com/2075-5309/15/17/3082 | Chifeng basalt | microwave-induced cracking; microwave mining; microwave machinery; rock-breaking tools; true triaxial stress; mixed rock breaking | Microwave irradiation of rocks can reduce the strength of rocks and ease their subsequent excavation. Exploring the combination of microwave and cutting tools for rock breaking under different conditions is important to the practical engineering application of microwaves. Based on a true triaxial microwave-assisted dual-mode mechanical rock-breaking test system, high-power microwave irradiation of rocks was investigated under different true triaxial stresses, durations of microwave irradiation, and cutting tool conditions such as mechanical drilling tools and tunnel boring machine (TBM) hobs. This research provides important data support for improving the rock-breaking efficiency of mine mining and tunneling as well as mechanical cutting tools and TBM hobs. In this experiment, Chifeng basalt with a relatively high strength was adopted as the research object. A 15 kW (2.45-GHz) open high-power microwave device was used to irradiate 200 mm × 200 mm × 200 mm cubic Chifeng basalt samples under conditions of different burial depths, and a cone drill bit was used for staged excavation. After microwave irradiation of Chifeng basalt measuring 400 mm × 400 mm × 400 mm, a 4-inch (102 mm) rotary cutter was employed to conduct round-by-circle cutting and rock-breaking tests in the microwave irradiation area. The results show that under true triaxial stress, the law of rock breaking by microwave irradiation combined with cone drill bits is as follows: the cutting force shows a trend of increasing–decreasing–increasing again–decreasing again. After microwave irradiation combined with hob cutting, the effective range of the influence of the hob is within the third cutting circle, with a range of diameters of approximately 200 mm. The results also indicate that the open microwave device can pre-crack rocks under deep stress, and there is obvious crack propagation. This research has good applicability to microwave-combined cantilever road-headers and TBM as well as in the mining field, and has a promising development prospect. | https://doi.org/10.3390/buildings15173082 | English | China | Journal Article | Buildings | 15 | 24 pages | 3.082 | |
| D098 | 2018 | Loss of Strength of Rocks Under the Influence of Microwaves | Sultanalieva, R.; Konushbaeva, A. | https://www.researchgate.net/publication/329456887_Loss_of_Strength_of_Rocks_Under_the_Influence_of_Microwaves | limestone; diorite; gray phillite; quartz | mechanical grinding of ore; method of softening; mineral grains; impact to the ore microwaves | One of the main tasks of mining science is the development of new technologies for mining and enrichment, allowing to reduce material and energy costs and loss of mineral resources. For the development of modern technologies of mineral processing requires the full use of knowledge about the physical properties and processes occurring in rocks, as well as the ability to manage the properties of rocks. In mineral processing, to recover metals and mineral components, processes of crushing and milling involved a large amount of hard comminuted ores and minerals. It is known that ores of non-ferrous, rare and noble metals mainly have high strength. Using these traditional methods of ore grinding leads to increased energy consumption, increased wear of metal parts of the mill, to significant losses of recoverable metals. In this regard, the need to develop methods and means of purposeful change of the technological properties of the grinding of mineral raw materials is difficult to ensure efficient processing of a stimulus of new studies. This paper proposed a method of softening hard optimum ores and minerals, which allows to save energy during grinding, increasing the useful component output (the metal being recovered) by acting on the rocks microwave electromagnetic waves. | 10.2507/29th.daaam.proceedings.146 | English | Kyrgyzstan | Conference Proceeding | 29th DAAAM International Symposium | 0 | - | 1026-1031 | 0 |
| D105 | 2024 | Effect of microwave irradiation on the breaking and linear cutting of hard rock | Sun, C.; Zhao, Y.; Gao, Y.; Gao, S.; Zhu, G.; Guo, X.; Xie, R.; | https://www.sciencedirect.com/science/article/abs/pii/S0013794424008920 | hard rock; microwave irradiation; thermal fracture; linear cutting; cutting effect | Microwave technology, emerging as a novel approach to rock-breaking, holds significant promise in the realm of auxiliary mechanical pick rock breaking. In view of the problems existing in the hard rock breaking such as low efficiency and difficulty in one-time cutting, this study conducted experimental research using a method combining microwave irradiation and linear cutting with conical picks. The comprehensive temperature distribution of the rock is reproduced by 3D technology after microwave irradiation, defined the high-temperature zone and calculated the surface area. Moreover, analyzing the relationship between temperature and cutting force. And the effect of microwave-assisted conical pick rock breaking was quantified in terms of cutting force, cutting effect, and energy consumption. The results indicate that microwave irradiation induces heating in hard rock, leading to the formation of fissures and even partial fragmentation of rocks. The thermal damage effect of microwave is determined by the differences in the physical and mechanical properties of different rocks. In the experiment, basalt has the best heating effect and sandstone has the best fracturing effect. Compared to non-microwave, microwave (6 kW,60 s) irradiation reduces the cutting force, improves the effect of rock breaking, and reduces the work done (E) by the cutting force and the mechanical specific energy (MSE). Microwave irradiation-assisted mechanical rock breaking is better for sandstone, moderate for basalt, and inferior for granite in this study. | https://doi.org/10.1016/j.engfracmech.2024.110729 | English | China | Journal Article | Engineering Fracture Mechanics | 314 | 0 | |||
| D106 | 2024 | Effect of microwave irradiation on thermal damage behavior of granite Uniaxial compression test and finite-discrete approach | Sun, B.; Yang, S.; Du, S.; Tian, W.; Tang, S.; Li, H.; Zhu, Z. | https://www.sciencedirect.com/science/article/pii/S1674775524005468 | granite | Microwave-assisted rock breaking; Granite; Electromagnetic-thermal-mechanical (ETM) coupling; Finite-discrete approach; Three-dimensional (3D) grain-based model (GBM) | Microwave-assisted rock-breaking technology, as a novel hybrid approach, is anticipated to facilitate the efficient excavation of complex rock formations. It is therefore crucial to understand the damage and failure mechanisms of rocks that have been subjected to irradiation. In this study, uniaxial compression experiments were conducted on granite specimens after 1.4 kW microwave irradiation for varying durations. Furthermore, a numerical method was proposed to solve electromagnetic-thermal-mechanical coupling problems by integrating finite and discrete elements. The results demonstrated a differential temperature distribution (high temperature in the middle and low-temperature areas at the ends) in the granite specimens under microwave irradiation, which resulted in a notable reduction in their physical and mechanical properties. As the duration of irradiation increased, the rate of heating and the extent of strength reduction both diminished, while the morphology and distribution of cracks at ultimate failure became increasingly complex. The numerical method effectively addresses the simulation challenges associated with the electromagnetic selective heating of granite containing multiple polar minerals under microwave irradiation. This approach accounted for the non-uniform thermal expansion of the minerals and provided a comprehensive model of damage progression under compression. | https://doi.org/10.1016/j.jrmge.2024.09.050 | English | China | Journal Article | Journal of Rock Mechanics and Geotechnical Engineering | 17 | 2 | 827-844 | |
| D111 | 2025 | A novel multi-functional microwave-assisted rock breakage system | Tang, R.; Yang, B.; Xie, J.; Bai, Y.; Zhang, Y.; Gao, M. | https://www.sciencedirect.com/science/article/abs/pii/S0263224125026697 | monozite; sandstone | energy exploitation; experimental system; microwave fracturing; dynamic monitoring; size effect | Microwave fracturing is a promising technology in assisting deep hard rock efficient breakage and drilling. This work designs and develops a multi-functional microwave-assisted rock breakage system. Through the development of the dynamic monitoring system, capturing temperature, morphology, and mass real-time evolution characteristics during the microwave fracturing process is possible. Multiple-condition microwave experiments are conducted to validate the reliability and stability of this system. The results show that the microwave-induced crack mainly occurs after 20% irradiation time. The size effect of microwave fracturing is governed by endsurface coupling and hot-spot effects, affecting the temperature, failure time, and crack complexity. Surface microwave fracturing is with great application prospects in drilling engineering, but the optimization of fracturing parameters is necessary. The development of this experimental system provides equipment foundation for promoting the engineering application of microwave in energy exploitation. | https://doi.org/10.1016/j.measurement.2025.119310 | English | China | Journal Article | Measurement | 258 | 0 | ||
| J112 | 2025 | Microwave Heating and Fracturing Characteristics of Basalt: Insights from Infrared Thermal Imaging | Tang, R.; Yang, B.; Yang, Z.; Bai, Y.; Hao, H. | https://thermalscience.rs/pdfs/papers-2025/TSCI2502449T.pdf | basalt | microwave heating; non-uniform temperature distribution; fracturing characteristics; basalt | Microwave heating is a promising assisted rock-breakage technology. However, the non-uniform temperature distribution in microwave-heated rocks has not been quantitatively studied. In this work, the microwave heating experiment with power ranging from 1.5-7.5 kW was conducted to investigate the fracturing and heating characteristics of basalt. The results show that the fracture time of basalt decreases non-linearly with increasing power, while the surface temperature increases linearly with irradiation time. For a fixed time, the uniformity of temperature distribution is more affected by power, while for a fixed input energy, the uniformity remains essentially unchanged. Increasing microwave power is more effective in enhancing the non-uniformity of temperature distribution and the increase of thermal stress. | English | China | Journal Article | Thermal Science | 29 | 2 | 1449-1454 | ||
| D131 | 2020 | Heating potential of aggregates in asphalt mixtures exposed to microwaves radiation | Trigos et al. | |||||||||||||
| D132 | 2021 | Dielectric properties versus microwave heating susceptibility of aggregates for self-healing asphalt mixtures | Trigos et al. | |||||||||||||
| D135 | 2021 | IOP (Conf. Ser. Earth Environ. Sci. 942 12024) | Trigos | |||||||||||||
| D159 | 2024 | Thermal–Mechanical Coupling Model of Open-Ended Microwave-Induced Borehole Fracturing of Coal and Rock | Wang et al | https://link.springer.com/article/10.1007/s00603-024-04274-x | ||||||||||||
| D160 | 2025 | Evolution Characteristics and Mechanism of Microwave-Induced Fractured Structure in Loaded Coal for Enhancing Coalbed Methane Extraction | Wang et al | https://pubs.acs.org/doi/10.1021/acs.energyfuels.4c05545 | ||||||||||||
| J161 | 2025 | Reinforcing grinding and separation efficiency of titanomagnetite via microwave radiation | Wang, J.; Bo, L.; Zhang, Y.; Jian, T. | https://www.tandfonline.com/doi/full/10.1080/08327823.2025.2532531 | titanomagnetite | microwave radiation; titanomagnetite; bond ball mill work index; dissociation degree | The study investigated the effects of microwave irradiation pretreatment on titanomagnetite, a common but low-grade iron mineral in China. The impact of each microwave pretreatment parameter on crushing efficiency was assessed by analysing the crushing ratio. The Bond ball mill work index and separation efficiency of titanomagnetite were also examined before and after microwave treatment. The results showed that increasing microwave power resulted in a higher crushing ratio and finer particle size of the crushed products. Initially, the crushing ratio of the ore increased and then decreased with microwave heating time. The optimal crushing effect was observed at 4 kW microwave power with 150 s of heating time. Following microwave irradiation, the Bond ball mill work index of the ore decreased by 0.69 kW·h/t, indicating improved energy efficiency. Additionally, the particle size distribution of the ground products became more uniform, the ore particle surfaces became rougher, and there was a slight decrease in −0.075 mm particle size content, suggesting no overgrinding. The TFe recovery rate in iron concentrate remained stable after microwave treatment, while the TFe grade in iron concentrate increased by 1.27%, demonstrating that microwave-assisted grinding helps in enhancing the dissociation degree of titanomagnetite. | https://doi.org/10.1080/08327823.2025.2532531 | English | China | Journal Article | Journal of Microwave Power and Electromagnetic Energy | 59 | 3 | ||
| D162 | 2025 | Structural and Liberation Effect of Vanadium Titano-Magnetite by Microwave Treatment | Wang, J.; Liu, B.; Zhang, Y.; Jiang, T. | https://link.springer.com/article/10.1007/s11837-025-07143-2 | vanadium titanomagnetite | This study explored the impact of microwave pretreatment on the structural and liberation characteristics of vanadium titano-magnetite (VTM). Various methods such as x-ray diffraction, scanning electron microscopy, microhardness testing, particle size analysis, and mineral liberation analysis were utilized. Results indicated that microwave treatment improved the crystallization of titanomagnetite and ilmenite and generated numerous microcracks on the ore surface because of the selective heating by microwaves and differential expansion among minerals. This treatment also reduced the micro- hardness, particularly at grain boundaries, with a notable decrease of 78.09% at the grain boundary when treated at 4 kW for 150 s followed by water quenching. Additionally, the liberation degree of the grinding products from microwave-treated ore was superior to that of untreated ore, with increases of 4.92% for titanomagnetite and 8.13% for ilmenite when the grinding products with a particle size of 0.075 mm accounted for 35%. These findings suggest that microwave pretreatment enhances the selective grinding effect and promotes detachment dissociation of grinding products. | https://doi.org/10.1007/s11837-025-07143-2 | English | China | Journal Article | Journal of Mining | 77 | 7 | 5283-5292 | ||
| D163 | 2025 | Study on the Graded Thermal Response and Microstructure Damage Evolution | Wang, Y.; Yang, W.; Zhong, Y.; Lin, B.; Liu, T. | https://www.sciencedirect.com/science/article/abs/pii/S2213343725027861 | coal | microwave radiation; coal; thermal response; pore fissure network; structural damage | The microwave radiation heating of coal is an essential technique for the effective extraction of coalbed methane. The thermal response characteristics of coal under microwave radiation are unclear, considerably impeding the effectiveness of microwave heating in enhancing coal permeability. This paper clarified the dynamic thermal response of coal classification and the damage mechanism of pore fracture structures. The study found that during the microwave heating of coal, a distinct cold-hot boundary region persisted throughout, and the temperature rise increase occurred in three stages: rapid heating, decelerated heating, and re-accelerated heating. Before reaching 200°C, the primary processes involved the removal of free and bound water. Beyond this temperature, mineral decomposition and interface damage occurred. The hierarchical thermal response of coal encompasses two stages. In the first stage, vapor pressure from water evaporation caused cracking and fracture development. In the second stage, minerals absorbed microwave energy, inducing thermal stress and leading to mineral removal and disintegration, further accelerating the pore-fracture expansion. Experimental results indicated a 0.59 % increase in total porosity and a 0.33 % decrease in the bound water porosity. Additionally, the isolated pore cracks in the coal sample decreased from 1.15 % to 0.61 %, while the total pore cracks increased by 2.11 %. The average dimensions (length, width, and area) of the fractures increased, forming a more intricate fracture network. The hierarchical thermal response of the coal caused significant internal structural damage, evidenced by decreased longitudinal and shear wave velocities, with a damage degree (D) reaching 0.9. These findings provide theoretical guidance for thermal stimulation during coal seam extraction. | https://doi.org/10.1016/j.jece.2025.118090 | English | China | Journal Article | Journal of Environmental Chemical Engineering | 13 | 5 | 0 | |
| D184 | 2021 | Experimental and numerical investigations of microwave induced damage and fracture formation in rock | Xu, T.; He, L.; Zheng, Y.; Zou, X.; Badrkhani, V.; Schillinger, D. | https://www.tandfonline.com/doi/full/10.1080/01495739.2020.1865857 | China Black diabase | microwave-induced fracture; rock; thermal stress; discontinuous deformation analysis | Microwave technology is increasingly used in laboratory tests and field applications as an effective rock breaking technique. The underlying mechanism of rock fracturing induced by microwave energy, however, has not been well addressed. In this study, we employ experimental and numerical methods to investigate the global and local damage of rock in microwave radiation direction, including the fracture formation process. Our analysis focuses on three damage indicators under microwave irradiation, namely P-wave velocity attenuation, temperature distribution and fracture pattern. For a diabase sample, our experimental results indicate that the microwave power and irradiation time has a substantial influence on these three indicators. With increasing power level and irradiation time, we measured a lower P-wave velocity, higher temperature, and more fractures within the rock substrate. We observed that under the same energy, heating at higher power levels for shorter durations has a better weakening effect. Our numerical results show that thermal stress mismatch in the local high-temperature area is the main reason for crack initialization. Nucleation and propagation of microcracks depend on the thermal stress induced by global temperature increase, the geometry of the sample and existing fractures. | https://doi.org/10.1080/01495739.2020.1865857 | English | China | Journal Article | Journal of Thermal Stresses | 44 | 4 | 513-528 | |
| D186 | 2025 | Microwave irradiation power-induced energy evolution and rockburst failure characteristics in red sandstone | Xu, L.; Gong, F.; Ren, L. | https://www.sciencedirect.com/science/article/abs/pii/S1350630725006405 | red sandstone | rock mechanics; microwave irradiation; red sandstone; rochburst proneness; linear energy sorage and dissipation laws | Microwave radiation has been widely used in deep hard rock breaking with rockburst proneness. To explore the impact of microwave upon rockburst proneness, conventional uniaxial compression and single-cycle loading–unloading uniaxial compression tests were carried out on dried red sandstone specimens under five various microwave irradiation powers. The findings demonstrate that the microwave-irradiated specimens exhibit the linear energy storage and dissipation (LESD) laws. The peak strain energies of each microwave-irradiated specimens are obtained accurately by LESD laws, and six energy-type burst indexes and far-field ejection mass ratio are used to comprehensively determine the rockburst proneness. Importantly, it is demonstrated that the residual elastic energy index is the most effective method of identifying the rockburst proneness grade for microwave-irradiated specimens. As microwave irradiation power increasing, the degree of rockburst proneness for microwave-irradiated specimens initially rises and subsequently declines. The specimens in the range of 0 kW to 6 kW are high rockburst proneness, and the specimens of 8 kW is medium rockburst proneness. Moreover, it was discovered that the rock strength and energy storage capacity are the key parameters determining the degree of rockburst proneness for red sandstone. The rockburst proneness grade of microwave-irradiated specimens can be roughly evaluated by using the compressive strength and compression energy storage coefficient. | https://doi.org/10.1016/j.engfailanal.2025.109899 | English | China | Journal Article | Engineering Failure Analysis | 181 | 0 | ||
| D188 | 2025 | EFFECT OF ANTENNA SIZE ON ROCK MASS BREAKING | Xue et al | |||||||||||||
| D189 | 2025 | Experimental and theoretical analysis of hard rock warming and fracture in microwave field | Xue et al | |||||||||||||
| D190 | 2019 | microwave-assisted-pretreatment-of-coal-fly-ash-for-enrichment-and-enhanced-extraction-of-rare (1) | Yakaboylu et al. | |||||||||||||
| D201 | 2023 | Acoustic emission characteristics and damage evolution of basalt | Yang et al | |||||||||||||
| D207 | 2025 | Influence of microwave irradiation time on dynamic | Yang et al | |||||||||||||
| D208 | 2025 | Investigation of Microwave heating on Sandstone subjected to liquid freeze-thaw permeability evolution mechanism | Yang et al | |||||||||||||
| D215 | 2025 | Dynamic mode II fracture properties of saturated sandstone after microwave irradiation | Yao et al | |||||||||||||
| D216 | 2025 | Experimental and numerical investigation on the mechanical properties of sandstone under microwave irradiation | Yao et al | |||||||||||||
| D217 | 2025 | Study on SCB test of different types of rocks under microwave irradiation | Yao et al | |||||||||||||
| D220 | 2024 | Quantitative Analysis of Basalt Damage Under Microwave Radiation Utilizing Uniaxial Compression and Nuclear Magnetic Resonance (NMR) Experiments | Yin et al | |||||||||||||
| D222 | 2025 | Concentration study for low-grade refractory rhodochrosite by microwave calcination followed by magnetic separation | Yu et al al | |||||||||||||
| D224 | 2016 | Mechanical Strength of Lead-Zinc Ore Influenced by Microwave Irradiation | Yu et al. | |||||||||||||
| D227 | 2024 | The impact of bedding planes on microwave-induced damage in rock at the field scale a numerical model | Yu et al | |||||||||||||
| D228 | 2025 | Effect of intermittent and continuous microwave pretreatment on grinding and leaching of granite uranium ore | Yu et al | |||||||||||||
| D230 | 2024 | Analysis of Microwave-Induced Damage in Granite Aggregates Influenced by Mineral Texture | Yuan, Y.; Zhao, S. | https://www.mdpi.com/2075-5309/14/5/1348 | ||||||||||||
| D237 | 2022 | Thermal Response and Mechanic behaviours of compact basalts induced by Microwave Irradiation | Zhang et al. | |||||||||||||
| D242 | 2025 | Characteristics of microwave-induced borehole fracturing in hard rock with different heating rates and temperatures under true triaxial stress | Zhang et al | |||||||||||||
| D248 | 2025 | Bursting of Water‑Bearing Sandstones Under Microwave Irradiation | Zhao et al | |||||||||||||
| D249 | 2025 | Study on the performance degradation of iron ore tailings concrete under microwave irradiation | Zhao et al | |||||||||||||
| D251 | 2025 | Strength Degradation Mechanism and Thermal Damage Constitutive Model of Tar-Rich Coal Induced by Microwave Irradiation | Zhe et al | |||||||||||||
| D254 | 2024 | Impact of loading modes on the changes in microwave dielectric properties of diorite | Zheng et al | |||||||||||||
| D256 | 2025 | Developing a High‐Power Metal‐Plate Lens Antenna for Microwave Fracturing of Rocks | Zheng et al | |||||||||||||
| D257 | 2025 | Microwave heating and fracturing of concrete with different aggregates: An experimental and numerical study | Zheng et al | |||||||||||||
| D260 | 2022 | Study on Microstructure Evolution of Oolitic Hematite during Microwave Fluidization Roasting | Zhou et al. | |||||||||||||
| D262 | 2025 | Electromagnetic–Thermal–Mechanical–Damage Coupling Simulation of Rock under Microwave Irradiation Based on the COMSOL-Peridynamics Methods | Zhou et al | |||||||||||||
| D263 | 2016 | Preliminary Research On Grindability Improvement of Coal by Microwave Pretreatment | Zhu et al. | |||||||||||||
| D264 | 2025 | Fracturing Behavior of Tight Sandstone Containing Hollow Double-wing Crack (HDWC) Under Microwave Irradiation | Zhu et al | |||||||||||||
| D266 | 2025 | Damage Characteristics and Tensile Strength in Hot Dry Rock with Diverse Lithologies Subjected to Microwave, Chemical, or Blasting Treatment | Zhuang et al | |||||||||||||
| D271 | 2008 | Experience in the use of microwave energy in mining | Rahmankulov et al. | |||||||||||||
| D272 | 2024 | Microwave Pretreatment of Critical Mineral Resources | Abedin, A.; Wildfire, C. | https://netl.doe.gov/sites/default/files/netl-file/24RS_CMM_Abedin.pdf | coal fly ash; black shale; mafic/ultramafic rocks | N/A | N/A | English | USA | Presentation | ||||||
| D273 | A Potential Rock‐Burst Prevention Technology | |||||||||||||||
| D275 | 2025 | Dynamic mechanical properties and crushing characteristics of | Chu et al | |||||||||||||
| D278 | 2018 | The effects of microwave pretreatment on the processing of a sulphide ore | da Silva | |||||||||||||
| D282 | Dictionary of Concrete Technology | |||||||||||||||
| D285 | 2025 | Experimental Study on Failure Characteristics and Energy Release Evolution of Coal Under Microwave Irradiation | Ding et al | |||||||||||||
| D286 | 2024 | Simulation Study of Rock-breaking Efficiency of Microwave-assisted TBM Disc Cutters | Du, L.; Wen, S. | https://front-sci.com/journal/article?doi=10.32629/aes.v5i3.2800 | granite | microwave-assisted rock-breaking; disc cutters; discrete element; specific energy | The research through the establishment of microwave-assisted disc cutter rock-breaking discrete element model, from the perspective of rock-breaking specific energy to analyze the change rule of disc cutter rock-breaking efficiency before and after microwave radiation. The results show that: in the cutter spacing 180mm range, the rock-breaking spe cific energy before and after microwave radiation with the increase of the cutter spacing show a “first decrease and then increase” trend, when the cutter spacing 90mm, to reach the minimum rock-breaking specific energy; through the compar ison, the microwave radiation to improve the rock-breaking efficiency of the disc cutter is effective, it is recommended to choose the spacing of 150mm waveguide and disc cutter for joint rock-breaking. | English | China | |||||||
| D287 | Effect of Combined Microwave‑Liquid Nitrogen Treatment on Mode I Fracture Properties of Granite | |||||||||||||||
| D288 | 2021 | Rock Excavation Efficiency Improvement by Microwave Treatment | Endre et al. | |||||||||||||
| D289 | 2025 | Energy efficiency analysis of microwave treatment in rocks: from mine to mill operations | Ahmadihosseini, A.; Aslam, A.; Rafiei, A.; Hassani, F.; Sasmito, A. | https://www.sciencedirect.com/science/article/pii/S0306261925003198 | basalt; kimberlite | Microwave treatment; Mine-to-mill operations; Energy efficiency; Rock pre-conditioning; Excavation; Comminution | As one of the most energy-intensive industries, mining faces challenges related to energy inefficiency, safety, and sustainability. These challenges prompt exploration of alternative methods, among which microwave-assisted mining stands out as significant. While existing research suggests the potential benefits of microwave treatment in mining, there remains a lack of comprehensive understanding regarding its field application. This study aims to address two key gaps in current knowledge: firstly, by examining the holistic impact of microwave treatment across the entire mine-to-mill process rather than focusing solely on individual operations, and secondly, by evaluating the energy efficiency of applying microwave treatment in the field, considering the energy required for microwave irradiation as a design factor. A novel methodology is introduced to capture the effect of microwave treatment in one operation on the subsequent ones, using a comprehensive set of experiments encompassing microwave treatment, calorimetric measurement, uniaxial compressive strength, rock cutting, and crushing tests. The results reveal that using microwave treatment in one operation has significant implications on subsequent ones, leading to an exponential increase in energy efficiency, which can be more than ten folds in some cases. Additionally, utilizing the energy efficiency-based approach, the achieved improvements are discussed per unit of input microwave energy, shedding new light on established concepts such as the effect of power and exposure time on the efficiency of microwave treatment. This study contributes to a deeper understanding of microwave treatment as a viable rock pre-conditioning method, aiming to lead the industry toward more sustainable mining practices. | https://doi.org/10.1016/j.apenergy.2025.125589 | English | Canada | Journal Article | Applied Energy | 386 | 0 | ||
| D290 | 2008 | Effects of Microwave Energy on Grinding of Colemanite | Eskibalci et al | |||||||||||||
| D292 | 2025 | Experimental Investigation of Microwave-induced Strength Reduction in Basalt for Efficient Rock Excavation | Hwang, J.; Ko, T. | https://sensors.myu-group.co.jp/article.php?ss=5656 | Vietnamese basalt; Cheorwon basalt | microwave irradiation; basalt weakening; uniaxial compressive strengt; thermal microcracking; rock excavation efficiency | Microwave irradiation has emerged as a promising technique for weakening high-strength rocks prior to excavation, with the potential to improve cutting efficiency and reduce mechanical energy consumption. In this study, we investigate the microwave-induced weakening behavior of two types of basalt—one from Vietnam and the other from Cheorwon, South Korea—under controlled laboratory conditions. Cylindrical rock specimens were exposed to 1000 W microwave energy for durations ranging from 1 to 10 min, and key physical and mechanical properties, including surface temperature, P-wave velocity, Schmidt rebound hardness, Leeb hardness, uniaxial compressive strength (UCS), and dry density, were measured before and after exposure. Results indicate that Cheorwon basalt is significantly more susceptible to microwave-induced weakening than Vietnamese basalt. Cheorwon basalt exhibited a UCS reduction of up to 20% after 5 min of exposure, a 28% decrease in Schmidt hardness, and a 10–12% decline in P-wave velocity, all of which point to internal microcrack propagation and surface degradation. Interestingly, the UCS of Cheorwon basalt partially recovered after 10 min of exposure, likely due to microcrack closure or stress redistribution at elevated temperatures. In contrast, Vietnamese basalt displayed only modest reductions in UCS and Schmidt hardness and only minimal changes in density or Leeb hardness. Dry density remained nearly unchanged in both rock types across all exposure durations, indicating that microwave damage is primarily microstructural and not volumetric. These findings demonstrate that microwave pretreatment can selectively and effectively weaken basalt without altering bulk geometry. The differential response between the two types of basalt highlights the influence of mineral composition and microstructure on microwave sensitivity. We conclude that microwave-assisted rock weakening offers a viable path toward more energy-efficient excavation in microwave-responsive lithologies. | https://doi.org/10.18494/SAM5656 | English | Korea | Journal Article | Sensors and Materials | 37 | 6(4) | 2697-2713 | |
| D293 | 2025 | Experimental research on the rotary rock-breaking effect of tunnel boring machine cutters assisted by microwave irradiation | Lu, G.; Lu, Z.; Liu, C.; Zhang, Y.; Fan, W.; | https://www.sciencedirect.com/science/article/abs/pii/S0886779825001506 | Tunnel boring machine; Microwave-assisted rock breaking; Microwave-cutter coupling; Cutter wear; Rock-breaking efficiency | To deeply analyze the rock-breaking effect of tunnel boring machine (TBM) cutters assisted by microwave irradiation, rock-breaking experiments were conducted on microwave-irradiated rocks using reduced-scale TBM cutters. Influences of parameters including the microwave exposure time, microwave power, cutter spacing, same rolling distance (different rock-breaking depths), and penetration rate on rock-breaking marks, rock removal, wear loss of cutters, average cutter thrust, average cutterhead torque, and rock-breaking specific energy were explored. Research results show that under the same rotation diameter, increasing the microwave exposure time and microwave power decreases the wear loss of cutters, average cutter thrust, average cutterhead torque, and rock-breaking specific energy while increases the rock removal. If the cutter spacing is too large, the rock between adjacent cutting marks cannot be effectively exfoliated, the average cutter thrust and cutterhead torque enlarge, and the rock-breaking efficiency reduces. The wear loss of cutters is directly proportional to the rock-breaking depth. Under the current experimental conditions, using a large rock-breaking depth can exfoliate rock debris and improve the rock-breaking efficiency. A high penetration rate reduces the rotation number of the cutterhead, promotes the generation of rock debris, enlarges the rock removal, and improves the rock-breaking efficiency. | https://doi.org/10.1016/j.tust.2025.106512 | English | China | Journal Article | Tunnelling and Underground Space Technology | 159 | 0 | |||
| D298 | 2022 | Study on the difference of microwave irradiation effect caused by the particle size distribution of rock minerals | Fangfang et al | |||||||||||||
| D308 | 2021 | Multimode microwave assisted comminution of a sulfide ore | Forster, J.; Olmsted, A.; Pickles, C.A.; Boucher, D.; Bobicki, E.R. | https://www.researchgate.net/publication/365446155_Multimode_Microwave_Assisted_Comminution_of_a_Sulfide_ore_Bench_Versus_Pilot_Scale | sulphide ore | microwaves; multimode; comminution; permittivity; frequency; absorption | N/A | English | Canada | Conference Proceeding | IMPI's 55th Microwave Power Symposium | 59-61 | ||||
| D313 | 2024 | Multi-scale evaluation of mechanical properties of granite under microwave irradiation | Gao, M.; Bai, Y.; Yang, B.; Xie, J.; Tang, R.; Yang, Z.; Zhang, Y. | https://www.sciopen.com/article/10.46690/ager.2025.01.04 | granite | granite; microwave irradiation; nanoindentation; uniaxial compression; upscaling | Nowadays, the depletion of shallow resources drives deeper mining operations. Microwave pre-treatment has shown promise for efficient drilling in deep hard rock. While previous studies have confirmed the feasibility of microwave-assisted crushing of hard rocks and analyzed their structural and mechanical property changes at various scales, the microscopic mechanisms behind the evolution of the macro-mechanical parameters of hard rock remain unclear. This study addresses this knowledge gap. At the microscopic scale, the mineral characteristics and the micromechanical properties of minerals (including interfaces) at different sites before and after microwave irradiation were tested in typical hard granites. At the macroscopic scale, the real-time monitoring of mass and surface heating-rupturing characteristics of granite during microwave irradiation was achieved. Meanwhile, acoustic wave and uniaxial compression tests were conducted to explore the evolution of the macroscopic physical and mechanical parameters of granite before and after microwave irradiation. Variability in the mineral structure and mechanical properties accounts for differences in the uniaxial compression strength of granites. To realize the macro-micro linkage, the micro-mechanical parameters of minerals in different granite sections before and after microwave treatment were upscaled. The upscaling results, obtained using the Mori-Tanaka method, closely matched those from uniaxial compression tests, and the upscaling of mineral micro-mechanical parameters in interior samples was found to accurately predict the weakening of macro-mechanical properties of granite. This study provides insights into how microwave irradiation affects the mechanical properties of granite at a microscopic level, offering a quick and efficient method for assessing microwave weakening in deep hard rock and establishing a theoretical foundation for microwave-assisted mechanical drilling in industrial applications. | https://doi.org/10.46690/ager.2025.01.04 | English | China | Journal Article | Advances in Geo-Energy Research | 15 | 1 | 27-43 | |
| D314 | 2025 | Mesoscopic Fracture Mechanism of Sandstone Subject to Microwave Irradiation: Insights from CT Scanning and Electrical Resistivity Testing | Gao, Y.; Zhang, Y.; Su, B.; Tan, D.; Yang, B.; Gao, M. | https://link.springer.com/article/10.1007/s00603-025-04456-1 | sandstone | microwave fracturing; CT scanning; electrical resistivity; pores and micro-crakcs; mesoscopic mechanism | Microwave fracturing and assisted mechanical breakage hold great potential for efficiency enhancement and energy conservation of hard rock excavation. However, the mechanism of microwave-assisted rock breaking has not yet been comprehensively revealed. In this study, the sandstone specimens are initially treated with the microwave power level of 1–5 kW. Subsequently, computed tomography (CT) scanning and image processing are employed to reconstruct and quantify the pores and micro-cracks within microwave-treated specimens. Afterward, electrical resistivity (ER) testing is used in conjunction with finite-element inversion to provide visualization and quantitative analysis for the connectivity of pores and micro-cracks. The conclusions are as follows: (1) the formation of macro-cracks induced by microwave irradiation can be attributed to the connection and penetration of pores and micro-cracks. It always initiates from the surface and propagates towards the interior. An increase in microwave power level results in a more extensive and complex distribution of microwave cracks within specimens. (2) Microwave triggers the distribution of ER transform from irregular into nearly multi-layer circular. With the increase in the duration of microwave irradiation, the maximum logarithm of the ER (LGERmax), the proportion in area of high electrical resistivity region (HERR), the minimum logarithm of the ER (LGERmin), and the proportion in area of low electrical resistivity region (LERR) all exhibit a parabolic trend. These indicators reach their extremums after irradiation for about 2/3 T. (3) The ER of specimens is significantly influenced by microwave energy. High microwave power levels (≥ 3 kW) have the potential to intensify damage within the interior of specimens, while increased microwave energy can enhance damage on the surface of specimens. (4) There is a stress equilibrium area at the center of the microwave-treated specimen, i.e., the stress is close to zero. In addition, the mechanism of microwave-assisted rock breaking is discussed from a mesoscopic perspective. | https://doi.org/10.1007/s00603-025-04456-1 | English | China | Journal Article | Rock Mechanics and Rock Engineering | 58 | 5981-6006 | ||
| D317 | 2026 | The effect of weathered joint surfaces on the microwave heating of marble | Ghabankandi, M.; Kahraman, S.; Comakli, R.; Fener, M. | https://www.sciencedirect.com/science/article/abs/pii/S0263224126009103 | Nigde marble | microwave heating; marble; weathering; regression analysis | The influence of microwaves on rocks has been studied by several scientists in anticipation of a potential application in microwave-assisted excavation. However, all these studies were performed on fresh rock samples such as cores and slabs. The impact of microwave heating on the altered surfaces of rocks has not been studied in the literature. This study aims to research how weathered joint surfaces affect the microwave irradiation of Nigde marble. Ten different block samples with weathered joint surfaces were collected from four different quarries. Small samples without weathered joint surfaces and those with weathered joint surfaces were prepared using a diamond saw from the same large blocks of each sample. Dry and saturated samples were microwaved at a power of 6 kW for various irradiation times, which ranged from one to five minutes. X-ray photoelectron spectroscopy (XPS) was used on the samples that were scraped from their weathered surfaces to determine the elements that constituted the samples. The results showed that the weathered surface consistently had higher temperatues than the unweathered one. The temperature differences between weathered and fresh surfaces increased as exposure duration increased. During the 5-minute exposure period, the temperature increments varied from 21.3 percent to 132.3 percent for wet samples and from 26.1 percent to 126.5 percent for dry samples. Some simple and multiple regression equations including elements were also developed for the prediction of temperature increments. It was demonstrated that weathered rock surfaces had substantially higher temperatures than unweathered rock surfaces. This should be taken into account when evaluating possible field applications for microwave heating. | English | Turkey | Journal Article | Measurement | 274 | 0 | |||
| D321 | 2025 | Microwave-enhanced heap leaching of porphyry copper ores part 1 | Giyani et al | |||||||||||||
| D322 | 2025 | Microwave-enhanced heap leaching of porphyry copper ores part 2 | Giyani et al | |||||||||||||
| D323 | 2025 | Micorwave Ore Pre-treatment Review and Process Flowsheet Conceptualization | Giyani | |||||||||||||
| D329 | 2021 | Microwave drying behavior, energy consumption, and mathematical modeling of sewage sludge in a novel pilot-scale drying system | Guo et al. | |||||||||||||
| D330 | 1973 | DRIVING OF WORKINGS BY A CUTTER-LOADER | GushchinRzhecvskiietal | |||||||||||||
| D336 | 2024 | Energy storage and fracture characteristics of brittle rock with rockburst proneness after microwave irradiation | Hao et al | |||||||||||||
| D347 | 2023 | The Impact of Microwaeve Treatment on the Andesite Rock Mechanical Properties | Heriyadi | |||||||||||||
| D351 | 2024 | Numerical Simulation of Microwave-Induced Cracking of Coal | Hong et al | |||||||||||||
| D354 | 2019 | Comparative study on the deterioration of granite under irradiation and resistance-heating treatment | Hu et al | |||||||||||||
| D356 | 2024 | Study on Microwave Assisted Grinding and Dissociation Characteristics of Bayan Obo Ore | Huan et al | |||||||||||||
| D357 | 2001 | Heating Characteristics and Decomposition of Pyrite and Marcasite in a Microwave Field | Huang and Rowson | |||||||||||||
| D360 | 2024 | An Experimental Study on the Effects of Microwave Irradiation on Basalt Properties for Lunar Deep Excavation | Hwang and Ko | |||||||||||||
| D362 | 2025 | IMPI Proccedings 2025 | IMPI | |||||||||||||
| D365 | 2024 | Influence of coal seam bedding on the effect of fracturing coal and enhancing permeability by microwave | Jian et al. | |||||||||||||
| D366 | 2024 | Effect of Microwave Roasting Pretreatment for Chromite on Its Oxidative Leaching Kinetics | Jian et al | |||||||||||||
| D367 | 2025 | Research on strengthening mechanism of microwave on magnetization transforamtion of Bayan Obo iron ore | Jiang et al | |||||||||||||
| D374 | 2024 | Access creation and its measurement in impermeable rock mass for the in situ recovery of metals from ore bodies | Kafashi | |||||||||||||
| D378 | 2022 | The effects of mineralogy on the microwave assisted cutting of igneous rocks | Kahraman et al | |||||||||||||
| D382 | 2024 | The efect of microwave treatment on the abrasivity of igneous rocks | Kahraman et al | |||||||||||||
| D386 | 2025 | Investigation of Phase Transformations in Technogenic Raw Materials Under Microwave Treatment for Enhanced Zinc Leaching | Kenzhaliyev et al | |||||||||||||
| D397 | 1974 | Design and economic constraints of thermal rock weakening techniques | Lauriello & Fritsch | |||||||||||||
| D407 | 2024 | Experimental Study on Differential Thermal Response and Pore Fracture Structure Evolution of Coals under Microwave Irradiation | Li et al | |||||||||||||
| D409 | 2025 | Microwave-liquid nitrogen synergy on granite fracture | Li et al | |||||||||||||
| D410 | 2025 | Progressive deterioration and fracture mechanisms of heterogeneous rocks in | Li et al | |||||||||||||
| D420 | 2024 | A continuous high-power microwave fracturing system for granular ore materials and its usage method | Lin et al | |||||||||||||
| D421 | 2025 | A high-power microwave continuous cracking system for hard ores | Lin et al | |||||||||||||
| D422 | 2025 | Field Tests Using High‑Power Microwaves to Crack Iron Ore of Different Grades | Lin et al | |||||||||||||
| D425 | 2022 | Coal and Gangue Active Identification Method Using Microwave Irradiation-Infrared Detection | Liu et al. | |||||||||||||
| D428 | 2022 | Mechanistic Study of a Microwave Field-Controlled Static Crushing | Liu et al | |||||||||||||
| D455 | 2024 | Micro-fracture mechanism of microwave induced fracturing of basalt based | Ma et al | |||||||||||||
| D456 | 2025 | Study on Measurement Method and Infuencing Factors of Surface | Ma et al | |||||||||||||
| D460 | 2017 | Investigating the reduction of cutting resistance of grainte specimen induced by microwave irradiation | Malovyk, H.A. | https://pure.unileoben.ac.at/ws/portalfiles/portal/1864537/AC13689890n01vt.pdf | granite | Microwave irradiation; Granite; Cutting resistance; Thermal stress; Rock weakening; Irradiation duration; Mechanical cutting | English | Germany | Masters Thesis | - | 0 | - | 141 pages | |||
| J001 | 2026 | Influence Of Microwave Pretreatment On Particle Breakage And Comminution Efficiency Of Mineral Ores | Amos-Judge, T.; Wu, R.; Asamoah, R. | https://www.min-eng.com/mineralprocessingcircuits26/drafts/session1/amos.pdf | ||||||||||||
| E002 | 2026 | Investigation Of Microwave Treatment In Kimberlite Beneficiation For Enhanced Separation Efficiency And Sustainable Fine Waste Reduction | Aslam, A.; et al. | http://ijmmm.ustb.edu.cn/en/article/doi/10.1007/s12613-026-3405-x | ||||||||||||
| E003 | 2026 | Heating And Fracture Spatiotemporal Evolution Characteristics Of Key Granite Minerals Under Microwave Irradiation | Bai, Y.; Yang, B.; Wang, J.; Xie, J.; Tang, R.; Gao, M.; Yuan, L. | https://link.springer.com/article/10.1007/s11771-026-6207-4 | ||||||||||||
| E004 | 2010 | Microwave Treatment Of Ores | Batterham, R.J.; Esdaile, L.; Shaw, R.W.; Cross, C.R. | https://patentimages.storage.googleapis.com/33/bd/76/8fbc96cd96748b/US7678172.pdf | A method of treating ore particles to facilitate subsequent processing of the ore particles to recover valuable components from the ore is disclosed. The method includes exposing the ore particles to microwave energy and causing structural alteration of the ore particles. In one embodiment structural alteration is achieve without significantly altering the mineralogy, i.e., composition, of the ore. In another embodiment structural alteration is achieved with minimal change to the sizes of the ore particles. In another embodiment the method includes exposing the ore particles to short duration, high energy pulses of microwave energy. | Patent | N/A | |||||||||
| E005 | 2011 | Crushing Material | Bearman, R.A.; Batterham, R.J.; Shaw, R.W. | https://patentimages.storage.googleapis.com/64/ea/3c/e44b42c04012be/US8070078.pdf | A method and an apparatus for crushing material, particularly mined material, are disclosed. In one embodiment two or more pairs of crushing rolls successively crush mined material. The pairs of crushing rolls are arranged and operated so that an upstream pair of rolls produces a feed, preferably a pressurized feed, for a downstream pair of rolls. In another embodiment, at least an upstream pair of rolls is driven intermittently, for example, by means of a stepping motor to provide stepped rotational movement of the rolls. | Patent | N/A | |||||||||
| E006 | 2006 | Development Of Theory And Methods For Modification Of Technological Properties Of Minerals in Separation Processes for Beneficiation of Refractory Ores of Non-Ferrous and Rare Metals | Chanturia, E. | Copper-Zinc Sulfide Ores; Pyritic Ores; Gold-Bearing Ores; Rare-Metal Ores (Ta-Nb); Quartz; Feldspar; Zircon; Columbite; Pyrite | The work addresses the development of theoretical and methodological approaches for modifying the technological properties of minerals in the beneficiation of complex, refractory ores containing non-ferrous and rare metals. It establishes relationships between mineral structure, composition, and technological behavior, particularly focusing on pyrite with varying gold content and rare-metal minerals. The study demonstrates that physical-chemical and energy-based treatments, including electrochemical modification using anolyte and catholyte, can significantly enhance mineral property contrast, improve flotation performance, increase metal recovery, and reduce losses. Mechanisms are proposed for surface modification, selective flotation, and improved grinding efficiency, supported by experimental and semi-industrial validation. | Russian | Russia | PhD Thesis | N/A | 0 | - | 50 pages | ||||
| E007 | 2021 | Experimental Study On The Feasibility Of Microwave Heating Fracturing For Enhanced Shale Gas Recovery | Chen, T.; Zheng, X.; Qiu, X.; Feng, X-T.; Elsworth, D.; Cui, G.; Jia, Z.; Pan, Z. | https://www.sciencedirect.com/science/article/abs/pii/S1875510021002791?via%3Dihub | ||||||||||||
| E008 | 2023 | System And Method For Treating Mined Material | Chenje, T.; Burger, N.; Kaplan, K.; Woestmann, T.; Duwendag, U.; Pienaar, D. | https://patentimages.storage.googleapis.com/a7/e0/ee/3ee633121cafa3/WO2023203526A2.pdf | A system for treating mined ores utilizing high intensity electromagnetic radiation, such as microwave radiation, and a method utilizing said system. The system comprises a main structure defining an internal volume between a floor, roof, and opposing sidewalls, a displacement arrangement, and a treatment device associated with a treatment zone within the internal volume. The displacement arrangement comprises a plurality of partitions that define a plurality of compartments within the internal volume. The plurality of partitions is configured to be displaced in use through the internal volume in a displacement direction. Material is operatively received in the compartments, displaced in the displacement direction by the displacement arrangement through the internal volume, and treated by the treatment device as it is displaced through the treatment zone. | Patent | N/A | |||||||||
| E010 | 2025 | S.H.O.T. – Selective Heat Ore Treatment In The Copper Industry | Craig, D.; Holmes, T.; Hartford, C.; Cabrejos, F.; Jones, A.; Kaplan, K. | N/A | English | USA | Presentation | The 12th International Copper Conference (Copper 2025), Pheonix, Arizona, November 2025 | ||||||||
| E011 | 2026 | Fragmentation Characteristics And Microscopic Fracture Mechanisms Of Magnetite Rock Under Explosive Impact After Microwave Irradiation | Cui, L.; Liang, W.; Chu, H.; Cheng, Z.; Li, H.; Sun, B. | https://www.sciencedirect.com/science/article/abs/pii/S001379442600113X | ||||||||||||
| E012 | 2026 | Damage And Fracture Evolution In Basalt Under Thermal Effect With Constitutive Model Development | Deng, X.; Liu, X.; Hu, R.; Fan, H.; Wang, J.; Yang, F. | https://link.springer.com/article/10.1007/s42452-026-08223-x | ||||||||||||
| E013 | 2025 | Using Microwave Thermal Treatment To Optimize Tunnel Excavation Efficiency: A Prospective Approach For Mining And Civil Projects In Libya | Deyab, S.M. | https://jer.ly/jer/index.php/jer/article/view/12 | ||||||||||||
| E014 | 2026 | Balancing recovery efficiency and environmental impact in microwave-assisted leaching of rare earth elements from red mud | Ebrahimi-Moghaddam, et al. | https://www.sciencedirect.com/science/article/abs/pii/S0255270125004957 | ||||||||||||
| E015 | 2022 | Gangue Rejection From Ores | Filmer, A.; Alexander, D. | https://patentimages.storage.googleapis.com/c7/ee/ee/44c91f002fe683/US20220325374A1.pdf | A process for recovering value metals from ore comprising rock , including the steps of preselection of a grade of ore to be microwaved to form an ore stream ; subjecting the ore stream to microwave energy to partially fracture rocks in the stream and form a partially fractured ore stream ; crushing the partially fractured ore stream to preferentially fracture the pre - weakened ore , to form a crushed ore stream ; and screening the crushed ore stream to form a fines fraction ore stream for further processing ; and a gangue fraction that may justify further processing. | English | UK | Patent | N/A | 0 | - | - | 0 | |||
| E016 | 2025 | Experimental Study On The Rock-Breaking Characteristics Of Basalt Under Microwave Irradiation | Gao, M.; Dai, Y.; Kuang, Y.; Xu, C.; Zhang, L.; Yang, L.; Wu, D.; Wang, X. | https://www.tandfonline.com/doi/full/10.1080/08327823.2025.2576653 | basalt | microwave; energy consumption; rock breaking; basalt | Microwave-Direct Rock Destruction (MDRD) is a non-contact method that utilizes pure energy to fracture rocks, effectively eliminating direct contact and mitigating issues associated with tool wear. To investigate the rock-breaking characteristics under MDRD, a single factor experiment was used to explore the influence of microwave power on rock-breaking effectiveness. Furthermore, a purging-ventilation airflow system was implemented to reduce dust concentration in the heating chamber, which alleviating microwave breakdown. The results indicated that excessively high or low microwave power can negatively impact both rock-breaking efficiency and energy consumption. Dust was primarily generated in Zone III, and the particle size of dust was predominantly less than 1 μm, which be identified as a critical factor influencing microwave breakdown in MDRD. The purging and ventilation airflow can alleviate microwave breakdown and improve the rock-breaking effect. At the microwave power of 5 kW, microwave breakdown under MDRD can be inhibited with a purging airflow pressure of 50 kPa and a ventilation airflow pressure of 0.3 MPa. Compared to the MDRD without a purging and ventilation system, all rock-breaking characteristics were improved, particularly the melt-hole volume, rock-breaking rate, and energy consumption. | https://doi.org/10.1080/08327823.2025.2576653 | English | China | Journal Article | Journal of Microwave Power and Electromagnetic Energy | 0 | |||
| E017 | 2026 | Numerical And Experimental Analysis Of Rock-Breaking Characteristics Of Basalt Under Microwave Irradiation | Gao, M.; Kuang, Y.; Wang, H.; Zhang, L.; Yang, L.; Wu, D.; Wang, X. | https://www.sciencedirect.com/science/article/abs/pii/S0892687525007046 | basalt | |||||||||||
| E018 | 2025 | Development Of A Laboratory-Integrated Microwave-Assisted Cutting Machine And Its Use In Carbonate Rocks | Ghabankandi, M.; Kahraman, S.; Comakli, R.; Fener, M.; Andras, A.; Popescu, F. | https://www.mdpi.com/2076-3417/15/24/12865 | ||||||||||||
| E019 | 2026 | Experimental Study On The Influence Of Water On Fracture Toughness In Microwave-Irradiated Granite | Gu, C.; Sun, Q.; Hu, J.; Geng, J.; Zhang, Y. | https://www.sciencedirect.com/science/article/pii/S2238785426001651 | ||||||||||||
| E020 | 2013 | Investigations On The Effects Of Microwaves On Hard Rock | Hartlieb, P. | https://pure.unileoben.ac.at/en/publications/investigations-on-the-effects-of-microwaves-on-hard-rock/ | microwave; hard rock; alternative rock cutting; microwave disintegration | This study investigates the response of various types of hard rock to microwave irradiation. Two basic laboratory setups have been implemented and the consequences of microwave irradiation on the behaviour of rock samples have been analysed. Small-scale low-power microwave irradiation was performed with a 3.2 kW standard household microwave. Large-scale experiments were performed with a self-designed high-power microwave apparatus operating at a maximum output power of 30 kW. Irradiation times vary from a few seconds to minutes. With the low-power apparatus only rocks with relatively good microwave absorption properties (basalt, gabbro) could be sufficiently heated and significantly damaged, represented by a reduction in sound wave velocity from 5000 to 3500 m/s after 120 s of irradiation. The influence of the sample geometry is obvious from the crack pattern. Evidence for consequences of differential heating, as proposed in various literature sources, could not be found. This can presumably only be achieved by short irradiation with higher power than applied in the present thesis. The occurrence of small amounts of water (1-2 wt.%) in porous rocks has a positive influence on the destruction of rock by building up vapour pressure leading to stresses in the rock exceeding its tensile strength. High-power microwave irradiation with up to 30 kW leads to heating and cracking of all investigated rock types. The different rock types (fine grained strong absorbers, coarse grained strong and weak absorbers, water bearing) show completely different effects of damage. Rocks with strong microwave absorption (greenstones) heat rapidly (ΔT = 270 °C in 6 s with 25 kW) with coinciding fast generation of temperature gradients and spallation of craters at the surface. Here cracks are not aligned to grain boundaries. In weakly absorbing rocks (sandstone, granite) temperature rises are less distinctive (ΔT = 240 °C in 30 s with 25 kW for granite) radial cracks develop originating in the centre of irradiation. Cracks are largely bound to grain boundaries or cleavage planes of single minerals but are assumed not to originate in intergranular temperature stresses but in the global stresses induced by the stronger heating of the centre of the irradiated volume. Small amounts of water in the porous volume of sandstone play a major role in high power irradiation as well. Excellent microwave absorption by water leads to fast generation of vapour pressure and explosive generation of craters with up to 6 cm of depth. An attempt was made to quantify damage induced by microwave irradiation by a linear cutting test-rig. Despite the observation of a trend towards a reduction of cutting forces after microwave irradiation the large scattering of results does not allow for a reliable conclusion. | - | English | Austria | PhD Thesis | - | 0 | - | 198 pages | ||
| E021 | 2016 | A 915MHz Pulsed Microwave Irradiation Assisted Crushing Device For Uranium Ore | Hu, N.; Ding, D.; Chen, W.; Li, G.; Yang, Y.; Yu, Q.; Li, F.; Wang, Y. | https://patentimages.storage.googleapis.com/af/c1/ca/e0276dbeff7931/CN105944810A.pdf | uranium ore | Chinese | China | Patent | - | 0 | - | - | ||||
| E022 | 2007 | The Influence Of Microwave Energy Delivery Method On Strength Reduction In Ore Samples | Jones, D.A.; Kingman, S.W.; Whittles, D.N.; Lowndes, I.S. | https://www.sciencedirect.com/science/article/abs/pii/S025527010600170X | ||||||||||||
| E023 | 2025 | Microwave-Induced Fracturing For Enhanced Permeability In Hard Rocks: A Novel Approach For In Situ Recovery In Mining | Kafashi, S.; Esteban, L.; Bona, A.; Nikoloski, A.N. | https://www.mdpi.com/2075-163X/15/11/1210 | ||||||||||||
| E024 | 1998 | Effects Of Microwave Radiation Upon The Mineralogy And Magnetic Processing Of A Massive Norwegian Ilmenite Ore | Kingman, S.W.; Corfield, G.M.; Rowson, N.A. | https://onlinelibrary.wiley.com/doi/abs/10.1155/1999/57075?msockid=2df15d11050e60b5226c4a17049461ac | ||||||||||||
| E025 | 2026 | Effect Of Microwave Heating On Shear Behaviour And AE Characteristics Of Intact Granite Under Variable Angle Shear Test | Li, D.; Zhou, A.; Su, X.; Zhang, C.; Zhao, J.; Tao, J. | https://link.springer.com/article/10.1007/s10409-024-23232-x | ||||||||||||
| E026 | 2019 | Fully Coupled Simulations Of Thermally Induced Cracking In Pegmatite Due To Microwave Irradiation | Li, J.; Kaunda, R.; Arora, S.; Hartlieb, P.; Nelson, P. | https://www.sciencedirect.com/science/article/pii/S1674775518302312 | ||||||||||||
| E027 | 2025 | Probabilistic Modeling Of Microwave Thermal Damage At Rough Rock-Cement Interfaces Using A Bayesian-ANN Framework | Li, J.; Rui, F.; Zheng, Y.; Zhao, G.; Senetakis, K. | https://www.sciencedirect.com/science/article/abs/pii/S0266352X2500758X | ||||||||||||
| E028 | 2025 | Method For Predicting The Microwave Heating Sensitivity Of Hard Rocks | Li, S.; Feng, X.; Yang, C.; Lin, F.; Su, X.; Tong, T.; Zhang, J. | https://www.sciencedirect.com/science/article/abs/pii/S0926985125003763 | ||||||||||||
| E029 | 2026 | Efficient Separation Of Iron And Manganese From Ferromanganese Ore By Microwave-Assisted Fluidization Magnetization Roasting | Li, S.; Zhou, W.; Chen, J.; Liu, X.; Li, S.; Yang, J.; Wang, D.; Zuo, Z.; Fan, Y.; Liu, Q. | https://www.sciencedirect.com/science/article/abs/pii/S0032591025014263 | ||||||||||||
| E030 | 2026 | Heating Rate Effect Of Thermal Expansion In Granite And Implications For Rock Breaking | Li, Y.; He, L.; Li, Y.; Zhu, W.; Xiao, H.; Wang, T. | https://www.sciencedirect.com/science/article/pii/S2095268626000303 | ||||||||||||
| E031 | 2026 | Unified Numerical Framework And Energy-Based Analysis For Identifying Multiple Failure Modes In Microwave-Irradiated Granite | Li, Y.; Liu, G.; He, L.; Zhu, W.; Xiao, H.; Wang, T.; Li, Y.; Bai, G. | https://www.sciencedirect.com/science/article/abs/pii/S0266352X26002594 | ||||||||||||
| E032 | 2026 | Investigation On The Fracture Characteristics And Mechanism Of Hard Rock By Microwave Irradiation In Underwater Environment | Lin, F.; Feng, X.; Tong, T.; Yang, Z.; Wang, Z.; Liu, Y. | https://link.springer.com/article/10.1007/s00603-025-05266-1 | ||||||||||||
| E033 | 1991 | Microwave Assisted Hard Rock Cutting | Lindroth, D.P.; Morrell, R.J.; Blair, J.R. | https://image-ppubs.uspto.gov/dirsearch-public/print/downloadPdf/5003144 | Hard Rock | Microwave cutting; Thermal pre-weakening; Mining | An apparatus for the sequential fracturing and cutting of subsurface volume of hard rock in the strata of a mining environment by subjecting the volume of rock to a beam of microwave energy to fracture the subsurface volume of rock by differential expansion, and then bringing the cutting edge of a piece of conventional mining machinery into contact with the fractured rock. | English | USA | Patent | ||||||
| E034 | 2025 | Study On The Temperature Distribution Characteristics And Its Influencing Factors Of Granite Under Microwave Surface Irradiation | Long, Y.; Zhao, X.; Zhu, F.; Ma, Z. | https://geology.nju.edu.cn/EN/10.16108/j.issn1006-7493.2024082 | granite | microwave facial treatment; temperature distribution characteristics; maximum temperature rise; high-temperature zone; influence zone | The essence of microwave-weakening rocks is thermal destruction. Accurately understanding the temperature distribution characteristics of rocks under microwave irradiation is of great importance for indicating the extent and degree of microwave weakening of rocks. In this paper, the numerical model was first calibrated through experiments, and then the temperature distribution characteristics of granite under microwave surface irradiation were studied using the calibrated numerical model. The influence of irradiation distance, tilt angle, and antenna type on the temperature distribution characteristics (surface maximum temperature rise, shape and size of the high-temperature zone and the influence zone) of rocks was also discussed. The research results show that the surface temperature rise of rocks is symmetrical around the center point and gradually decreases from the center to the edge, and the surface maximum temperature rise of rocks decreases with the increase of irradiation distance and rock tilt angle. The surface maximum temperature rise of microwave-treated rock using the converging waveguide antenna irradiation is 1.35 times that of the standard waveguide antenna, but it gradually decreases as the irradiation distance increases and ultimately lower than that of the standard waveguide antenna. The high-temperature zone on the rock surface is approximately circular when the irradiation distance and tilt angle are zero, and the shape of the high-temperature zone changes with the change of irradiation distance, tilt angle, and antenna type. The surface size and depth of the high-temperature zone are negatively correlated with the irradiation distance and tilt angle and the cross-sectional size of the high-temperature zone decreases gradually with depth until it disappears. Similarly, the surface influence zone of rocks is approximately circular when the irradiation distance and tilt angle are zero, and it also changes with the change of irradiation distance, tilt angle, and antenna type. The surface size of the influence zone is positively correlated with the irradiation distance and tilt angle, and the cross-sectional size of the influence zone initially increases and then decreases with increasing rock depth. | 10.16108/j.issn1006-7493.2024082 | Chinese | China | Journal Article | Geological Journal of China Universities | 31 | 5 | 552-561 | |
| E035 | 2025 | Exploration Of A Novel Technology For Waterless Fracturing In Shale Reservoirs Based On Microwave Heating | Ma, L.; Liu, T.; Cao, G.; Liu, Y.; Qi, M. | https://www.mdpi.com/2227-9717/13/11/3576 | ||||||||||||
| E036 | 2019 | The Effect Of Microwave Radiation On Flotation Of Copper Sulfide Minerals | Mirshekari, B.; Koleini, S.M.J.; Shahbazi, B. | https://www.researchgate.net/publication/331318966_The_Effect_of_Microwave_Radiation_on_Flotation_of_Copper_Sulfide_Minerals | copper sulphide minerals | microwave; flotation; copper; chalcocite; chalcopyrite | In this research, the effect of microwave radiation on the surface chemistry and liberation degree of copper sulfide minerals (Sarcheshmeh and Palangi ores) was investigated. In flotation studies on the effect of microwave radiation on the surface chemistry, after 90 seconds radiation, the concentrate grade and recovery of the Sarcheshmeh samples increased 7 and 2 percent; respectively but the concentrate grade and recovery of the Palangi samples decreased 4 and 8 percent, respectively. Also, in flotation studies on the effect of microwave radiation on the liberation degree, after 180 seconds radiation, the concentrate grade and recovery of the Sarcheshmeh samples increased 4 and 6 percent respectively but for the Palangi samples, a same increase in the grade and recovery was obtained in 600 seconds of microwave radiation. Furthermore, flotation rate constant of the Sarcheshmeh and Palangi samples increased 0.2 and 0.1 per minute respectively, after 120 seconds microwave radiation. | - | Farsi | Iran | Journal Article | Journal of Separation Science and Engineering | 11 | 1 | 1-12 | |
| E037 | 2015 | Physical And Mechanical Properties Of Rocks Exposed To Microwave Irradiation: Potential Application To Tunnel Boring | Motlagh, P.N. | https://mcgill.scholaris.ca/items/e7b3a850-145f-4158-9976-b8fa616ef5d0 | Mining companies and the market today are advancing toward faster, more efficient and productive continuous excavation within mining and civil applications. Explosives are not used in continuous excavation in hard rock formations; therefore, the interaction between mechanical rock breakage or cutter tools and the natural rock become increasingly important to understand. Rock cutter tools are highly advanced in terms of material quality, but limited in performance when they cut natural hard rocks. Comprehensive and collaborative research between McGill University and Natural Resources Canada on all possible explosive-free rock breakage techniques demonstrated that the use of microwaves in rock breakage techniques is highly advantageous and efficient. Microwave-assisted rock breakage machines, specifically tunnel boring machines or TBMs, represent a potential new avenue of rock cutting and breaking technology. This thesis research introduces the microwave-assisted TBM concept, describes the selection of the appropriate microwave wave guide applicator for the design (i.e., multi-mode vs. open ended), and quantifies the influence of microwave irradiation on temperature distributions and mechanical properties (i.e., uniaxial compressive and Brazilian tensile strength, CERCHAR abrasiveness index) of specimens of hard rock. Influencing parameters such as power level, distance from the antenna and exposure time were evaluated, as well as the physical damage that microwaves induce to the rock. Microwave irradiation with an open ended applicator was shown to heat the rock from the surface inward, when the rock is a good energy absorber. The failure mechanism (biaxial compression vs. shear failure) depended on the temperature difference inside the rock has been observed. A benchmark numerical model was developed for both types of microwave applicators, simulating the influence of microwave energy on the temperature profile under various conditions. Results of this study show that microwave-assisted rock breakage system is potentially viable in continuous hard rock excavation. | https://doi.org/10.82308/50286 | English | Canada | PhD Thesis | - | 0 | - | 268 pages | |||
| E038 | 2022 | Microwave-Based Mining Systems And Methods With Robotic Arm Waveguide | Murray, J.; Du Plessis, J.; Bezuidenhout, P.; Beech, R.; Delport, M.; Yazdani, M.; Pieiga, S. | https://patentimages.storage.googleapis.com/8e/2a/a0/2a6ffb49e132c1/CA3211530A1.pdf | A system for excavating a rock face using microwaves. The system may include a microwave generator, an articulable robotic arm with a plurality of rotatably connected rigid waveguide segments, an applicator attached to a distal end of the robotic arm, and a robotic control system. The system produces microwaves with the microwave generator and moves the robotic arm such that the applicator moves along the rock face as the microwaves exit the applicator to precondition the rock face for excavation. Various patterns of microwave treatment, and controls based on sensor feedback, may be implemented. | English | USA | Patent | - | 0 | - | - | 0 | |||
| E039 | 2024 | Microwave Energy Applicator | Murray, J.; Yazdani, M.; Ebrahimi, F.; Du Plessis, J.; Curto, H. | https://patentimages.storage.googleapis.com/48/55/68/f828c2d2a386ea/US12163428.pdf | Systems, devices, and methods for a microwave energy applicator. The applicator may define an internal channel having one or more longitudinal ridges inside the channel configured to focus energy. The ridges may be moveable. A reflector may be located near an exit of the applicator. In some embodiments, the applicator may define a channel having a decrease in cross-sectional area with a dielectric filler therein, acting to transition from a lower to a higher permittivity material. The various embodiments of the applicator may be attached to a waveguide, which may be an articulable robotic arm having rotatable waveguide segments attached with a microwave generator. The applicator may alter an energy level of microwaves travelling therethrough, for example, to concentrate the energy for application at a rock face in a mine site. | - | English | USA | Patent | - | 0 | - | - | 0 | ||
| E040 | 2014 | Analysis Of Physical Properties And Thermo-Mechanical Induced Fractures Of Rocks Subjected To Microwave Radiation | Nejati, H. | https://mcgill.scholaris.ca/items/b119eb41-75d7-4e49-99bf-2bb20213d33a | Microwave Heating; Fracture Toughness; Thermo-Mechanical Fracturing | This doctoral thesis investigates the microwave heating process, and its influence upon the physical properties and propagation of fractures in Rocks Under Illumination (RUI).In order to best understand microwave-assisted rock fracturing, it is critical to investigate the different aspects of this process. These range from the electromagnetic study (i.e., dielectric heating and heat generation), to the mechanical aspects (i.e., heat transfer, strength reduction material mechanics and fracture mechanics), and finally to the final fracturing behaviour of RUIs (i.e., fractography). In order to understand the various elements of the microwave fracturing of rocks, this research is divided into three investigations: 1) An investigation of the magnitude of heat generation within a rock body, and the extent to which illumination parameters can influence the efficiency of a microwave rock fracturing system. In addition, this research sought to expand the scope of microwave rock fracturing beyond the basaltic rocks utilized, and to apply this technique to other rock samples. This research investigates the possibility of substantially reducing the required energy input for a microwave-assisted rock fracturing system. This is made possible when operating at the optimal illumination parameters, with regard to each material property of the rock. To study the microwave heating process of rocks over a wide frequency range, the dielectric properties of some rocks are measured over frequencies ranging from 200 MHz to 20 GHz; with various water content, from fully dried to fully saturated; and at elevated temperatures ranging from 23ºC to 80oC.2) An investigation of the mechanical aspects of microwaves. This study sought to evaluate the influence of microwave illumination properties (i.e., input microwave power and exposure duration) on the fracture toughness of basalt samples and fracturing. It also attempted to experimentally quantify the fracture strength reduction of Chinese basalt after microwave illumination, at a variety of power levels and durations of exposure. Finally, the investigation sought to evaluate any correlation between the density of micro-cracks caused by microwave heating and any reduction in fracture toughness. This correlation was then modeled with the aid of numerical modeling (i.e., Discrete Element Modeling).3) A quantitative and qualitative investigation of the fracture development of Basalt Specimens Under Microwave Illuminations (BSUI) at macroscopic and microscopic scales. This research describes results of the visual investigations of the Fracture Growth Path (FGP) and the fracturing behaviour of SCBs after being exposed to microwave illuminations. FGPs are classified via their surface temperature level and the required input of microwave power. The Petrography Standard Test aided this approach, and allowed me to best describe fracture behaviour and the interactions between the fractures and mineralogical composition of Chinese basalt. A comprehensive fractographic investigation using Scanning Electron Microscopy (SEM) investigated microwave induced fracturing (i.e., fracture morphologies, fracture behaviours and the interaction of micro-fractures with rock forming minerals) in Chinese basalt fracture surfaces. Microwaves rock fracturing has potential to be employed for space applications: In Situ Resource Utilization (ISRU), sampling and In Situ material analysis sampling, in addition to mining and full face tunnelling applications on earth. | https://doi.org/10.82308/38510 | English | Canada | PhD Thesis | - | 0 | - | 258 pages | ||
| E041 | 2009 | An Investigation On The Influence Of Microwave Energy On Basic Mechanical Properties Of Hard Rocks | Nekoovaght Motlagh, P. | https://spectrum.library.concordia.ca/id/eprint/976521/1/MR63300.pdf | Light Granophyre; Dark Granophyre; Barre gray granite; Gabbro; Gneiss; Limestone; Basalt | N/A | Drilling and blasting is one of the most commonly used and convenient method for many mining and civil applications to break rocks, especially hard rocks. Because of many environmental, safety and productivity issues (i.e. Cycle time), the industry and contractors are looking for an alternative system of breaking of rocks. In underground rock breakage applications such as tunneling, continuous mechanical excavation method, normally with tunnel boring machines (TBMs) or road headers is becoming more popular and commonly used by contractors. One of the main disadvantages of such system is that, it cannot handle very hard rocks and uneconomical major disc or bit wear takes place. Today, novel explosive free rock breaking technologies (thermal, electrical, nuclear energy and microwave) are available and could be used on their own or assist mechanical conventional machines to be able to break harder rock material. This is possible because it is hoped that the microwave will reduce the strength of the rock prior to the impact of mechanical device. Three main mechanical parameters of rocks such as compressive strength, tensile strength and abrasivity index value were used to highlight the influence of microwave on to the mechanical properties of rocks. Seven different rock types were prepared and tested. Each individual specimen was exposed to the microwave energy in three power levels 800, 1250 and 3000 watts, within 0, 15, 30, 60, 120 and 240 seconds time of exposure. Different rocks due to their mineralogy behave differently when exposed to microwave energy. CERCHAR abrasivity index value of almost all samples shows reduction of about 30% as the power level of exposure increases. The tensile strength of certain samples reduces significantly as in basalt reduces of up to 80%. The unconfined compressive strength value of almost all samples reduces about 30% as well. The reduction of the strength and abrasivity of hard rock cause the penetration rate and the life time of cutter tools of a TBM to be increased by combining the microwave energy to the cutter head of the mechanical excavator. | English | Canada | Masters Thesis | - | 0 | - | 137 pages | ||
| E042 | 2014 | The Influence Of Microwave Radiation On Hard Rocks As In Microwave Assisted Rock Breakage Application | Nekoovaght, & Hassani | https://www.taylorfrancis.com/books/mono/10.1201/b16955/rock-engineering-rock-mechanics-structures-rock-masses-rafael-jim%C3%A9nez-alejano-%C3%A1urea-perucho-claudio-olalla | basalt | N/A | Novel rock breakage techniques are becoming more viable and attractive to industry. Microwave energy, as a thermal energy which is capable of inducing micro cracks through differential heating (therefore expansion of minerals), is a technology gaining considerable attention in mineral processing and ore comminution applications. Recently, use of microwave has been evaluated as a possible avenue for terrestrial and extraterrestrial drilling applications and full face tunneling or rock breaking machines. As part of an overall research on use of microwave in rock breaking systems, the influence of microwave energy on the mechanical properties of some common hard rock types has been investigated. Experimental and simulation results underlined the potential impact of the use of microwave energy in underground or surface excavation applications such as mining and tunneling. This will also contribute economically when mine-to-mill operation is fully considered. It also outlines the potential impact of a future microwave assisted tunnel boring machine enhanced with microwave and its performance. | https://doi.org/10.1201/b16955 | English | Canada | Book Section | - | 0 | - | 195-204 | |
| E043 | 2015 | The Behavior Of Rocks When Exposed To Microwave Radiation | Nekoovaght, P.; Gharib, N.; Hassani, F. | https://onepetro.org/isrmcongress/proceedings-abstract/CONGRESS13/CONGRESS13/ISRM-13CONGRESS-2015-380/165906 | basalt | Microwave; hard rock; multi-modes; single mode; open ended waveguide; COMSOL; plane wave | Novel rock breakage techniques are becoming more viable and attractive to industry. Microwave energy, as a thermal energy capable of inducing micro cracks through differential heating (therefore expansion) is a technology gaining considerable attention in mineral processing and ore comminution applications. Recently, the use of microwave radiation has been evaluated as a possible avenue for terrestrial and extra-terrestrial drilling applications as well as full face tunneling or rock breaking machines. As part of an overall research on use of microwave in rock breaking systems, the influence of microwave energy on the mechanical properties of common hard rock types as basalt has been investigated. The results revealed that microwave energy irradiation imposes micro and macro cracks to the surface of the rock being irradiated. In explosive free tunneling applications using TBM, jointed and cracked surface of rock eases the cutting process and increases penetration rate. The experimental setups have been simulated with the help of a multi-physics numerical modeling and the results have been compared with practical experiment. The wave propagation of microwave has been simulated and the distances where the power intensity is higher are identified. Experimental and simulation results underlined the potential impact of the use of microwave energy in underground or surface excavation applications such as mining and tunneling. This will also contribute economically when mine-to-mill operation is fully considered to improve the efficiency of rock crusher stages. | - | English | Canada | Conference Proceeding | 13th ISRM International Congress of Rock Mechanics | 0 | - | - | 0 |
| E044 | 2010 | Microwave Heating Of Dry And Water Saturated Basalt, Granite And Sandstone | Peinsitt, T.; Kuchar, F.; Hartlieb, P.; Moser, P.; Kargl, H.; Restner, U.; Sifferlinger, N.A. | https://www.researchgate.net/publication/245529191_Microwave_heating_of_dry_and_water_saturated_basalt_granite_and_sandstone | ||||||||||||
| E046 | 1969 | Apparatus For Heating Material By Means Of Microwave Device | Puschner, H.A. | https://patentimages.storage.googleapis.com/4a/42/4a/8604abce10052d/US3443051.pdf | A crane is fitted with a microwave system on the end of an adjustable boom for applying microwave energy to rock material to break apart the rock material. | English | Germany | Patent | - | 0 | - | - | 3.443.051 | |||
| E047 | 2026 | Study On The Microwave-Induced Cracking And Electromagnetic-Thermal-Mechanical Coupling In Concrete Using The Phase-Field Method | Qiao, R.; Yang, T.; Wei, W.; Shao, Z.; Li, S.; Gao, F.; Zhang, H. | https://www.sciencedirect.com/science/article/abs/pii/S2352710226008375 | ||||||||||||
| E049 | 2015 | Method And Device For Breaking Up Ore | Regenfuss, P.; Streek, A. | |||||||||||||
| E051 | 2026 | A High Fidelity 3D Electromagnetic-Thermal-Mechanical Coupling Model For Analyzing Mobile Microwave-Induced Heterogeneous Damage In Granite | Ren, J.; Yan, Q.; Wei, J.; Cui, Y.; Su, L. | |||||||||||||
| E052 | 2012 | Pulses Of Microwave Radiation To Improve Coke Grindability | Ruisánchez, E.; Arenillas, A.; Juárez-Pérez, E.J.; Menéndez, J.A. | |||||||||||||
| E053 | 2005 | Exploring Microwave Assisted Rock Breakage For Possible Space Mining Applications | Satish | |||||||||||||
| E054 | 2011 | The Influence Of Microwave Pre-Treatment Of The Leach Behaviour Of Disseminated Sulphide Ore | Schmuhl, R.; Smit, J.; Marsh, J. | |||||||||||||
| E055 | 2006 | Microwave Pretreatment Of A Low Grade Copper Ore To Enhance Milling Performance And Liberation | Scott, G. | |||||||||||||
| E056 | 2010 | Microwave Treatment Of Minerals | Shaw, R.W. | |||||||||||||
| E057 | 2026 | Unveiling Rock Heterogeneity-Driven Multiphysics Field Coupling Mechanisms Under Microwave Radiation By 3D Numerical Study | Shi, R.; Zhao, J. | |||||||||||||
| E058 | 2025 | Microwave-Assisted Pretreatment For Enhanced Rare Earth Element Recovery From Vietnamese Bastnaesite Ore | Song, W.; Kim, J. | |||||||||||||
| E059 | 2026 | Comparative Study Of HCl Leaching With And Without Microwave Pretreatment For Rare Earth Recovery From Vietnamese Bastnaesite Concentrate | Song, W.; Kim, J. | |||||||||||||
| E060 | 2026 | A Novel Phased Array Applicator For Efficient Microwave Pre-Conditioning Of Hard Rocks | Speck, R.; Morgenstern, R.; Behrend, R.; Krause, H. | https://www.scientevents.com/proscience/download/a-novel-phased-array-applicator-for-efficient-microwave-pre-conditioning-of-hard-rocks/ | Neuhauser granite | Rock Face Pre-Conditioning; Power Focusing; Selective Heating; Beam Steering; Simulation | In microwave rock pre-conditioning for mechanical excavation, selecting the right applicator is crucial for overall performance. To date, most studies have used air-filled or dielectric-loaded single waveguide applicators at relatively low power levels. In this paper, a high-power phased array consisting of multiple waveguide antennas fed by coherent microwaves is proposed and evaluated by using multi-physics simulations. The new design concentrates power deep within the rock instead of the surface layers, thus significantly increasing rock damage while at the same time enabling a large stand-off distance from the rock surface, reducing necessary rock temperature and overcoming the power limitations of single waveguides. Furthermore, it allows the selective heating of different regions of the rocks by means of beam steering. Following a description of the arrangement and the innovative, fully thermally coupled simulation model, benchmarking results are presented, with the phased array achieving an up to 2.4 higher rock-breaking performance at 70% lower rock temperatures. | 10.14644/microwave2025.013 | English | Germany | Conference Proceeding | International Conference on Microwave and High Frequency Applications - AMPERE 2025 | 10 | - | 71-76 | |
| E061 | 2026 | Experimental Validation Of A 144 KW, 2.45 GHz Phased Array For Rock Pre-Conditioning | Speck, R.; Ramopoulos, V.; Krause, H. | https://ieeexplore.ieee.org/document/11516440 | Neuhauser granite | 2.45 GHz phased array, rock pre-conditioning, high-power microwave, experimental validation | This work presents the first steps of experimental validation of a high-power 2.45 GHz phased-array microwave applicator designed for efficient rock face pre-conditioning in mining. Extending previous multi-physics simulation work, a modular solid-state generator system capable of delivering up to 144 kW at 2.45 GHz was implemented and tested on a purpose-built irradiation setup replicating mining-relevant conditions. The initial experiments verify key trends predicted by the numerical model, demonstrating targeted heating and spatial control of the power dissipation density in the rock by means of beamforming. | 10.1109/GeMiC71240.2026.11516440 | English | Germany | Conference Proceeding | 2026 17th German Microwave Conference (GeMiC); March 9-11, 2026, Karlsruhe, Germany | 0 | - | 4 pages | 0 |
| E062 | 2026 | Rock Failure Characteristics Under Dynamic Indentation Tests Of Granite Pretreated By Microwave Heating | Su, X.; Li, D.; Ranjith, P.; Luo, P.; Gong, H.; Zhu, Q. | https://link.springer.com/article/10.1007/s00603-026-05449-4 | ||||||||||||
| E063 | 2026 | Fracture Mechanism And Dynamic Compressive Strength Prediction Of Microwave-Assisted Stress Wave Magnetite Blasting | Sun, H.; Gan, D.; Liu, Z.; Xue, Z. | https://link.springer.com/article/10.1007/s10064-025-04711-3 | ||||||||||||
| E064 | 2025 | Effect Of Microwave Energy Output Modes On Mechanical Properties And Fracturing Characteristics Of Granite | Tang, et al. | https://link.springer.com/article/10.1007/s00603-025-04927-5 | ||||||||||||
| E065 | 2026 | Influence Of Microwave Irradiation On Thermal Properties And Fracturing Mechanism Of Basalt In Rock Excavation | Tang, R.; Yang, B.; Xie, J.; Yang, Z.; Yang, Z.; Bai, Y.; Gao, M. | https://link.springer.com/article/10.1007/s11771-026-6162-0 | ||||||||||||
| E066 | 2026 | Influence Of Cutterhead Cooling Water On Microwave-Induced Fracturing Of Hard Rocks During Microwave-TBM Synchronous Operation | Tong, T.; Feng, X.; Yang, C.; Lin, F.; Li, S.; Su, X. | https://www.sciencedirect.com/science/article/abs/pii/S0886779826003160 | ||||||||||||
| E067 | 2026 | |||||||||||||||
| E068 | 2021 | Dynamic Fragmentation Of Microwave Irradiated Rock | Wang, S.; Xu, Y.; Xia, K.; Tong, T. | https://www.sciencedirect.com/science/article/pii/S1674775520301359 | ||||||||||||
| E069 | 2026 | A Predictive Method For Open-Ended Microwave-Induced Borehole Fracturing Performance In Hard Rock | Wang, T.; Hu, G.; Li, G.; Yang, N.; Qin, W.; Wang, L.; Wang, S.; Yu, Z.; Duan, H.; Yang, P. | https://www.sciencedirect.com/science/article/abs/pii/S1350630726003493 | ||||||||||||
| E070 | 2025 | Multi-Physical Mechanism Of Rock Fracture Enhancement Under Near-Field Microwave Irradiation | Wang, T.; Li, Y.; Bai, J.; Wu, F.; He, L.; Xiao, H.; Zhu, W.; Li, Y.; Bai, G. | https://www.sciencedirect.com/science/article/pii/S1674775525004950 | Microwave rock-breaking; thermal stress; rock damage; multi-physical model; impedance matching layer | |||||||||||
| E071 | 2026 | Fracture Evolution Of Microwave-Treated Concrete Under Uniaxial Compression | Wei, W.; Song, B.; Cao, S.; Li, B.; Dong, Z.; Geng, Q.; Shao, Z. | https://www.sciencedirect.com/science/article/pii/S2238785426000748 | ||||||||||||
| E072 | 1994 | Modeling The Thermomechanical Response Of Ore Materials During Microwave Processing | Williamson, R.L.; Salsman, J.B.; Tolley, W.K. | https://link.springer.com/article/10.1557/PROC-347-347 | ||||||||||||
| E073 | 2026 | Multiphysics Numerical Study Of Oil Shale Pyrolysis Under Rotating Radiator Microwave Heating | Xie, T.; Ming, X.; Yang, Y.; Wang, D.; Zhao, L. | https://www.sciencedirect.com/science/article/abs/pii/S1359431126014304 | ||||||||||||
| E074 | 2025 | Effects Of Confinement And Microwave Irradiation Duration On Weakening Strength Of Hard Rocks | Yang, B.; Gao, M.; Cai, C.; Tang, R.; Xie, J.; Bai, Y.; Yang, L.; Zhang, Y. | https://www.sciencedirect.com/science/article/pii/S1674775525005608 | microwave; hard rock; confining pressure; strength; weakening mechanism | |||||||||||
| E075 | 2026 | Effect Of Real-Time Microwave Irradiation On Mechanical Behaviors Of Coal Subjected To Uniaxial Stress | Yang, N.; Li, G.; Hu, G.; Yang, H.; Zhou, J.; Qin, W.; Zheng, J.; Duan, H.; Wang, T.; Yang, P. | https://www.sciencedirect.com/science/article/abs/pii/S1350630726003808 | ||||||||||||
| E076 | 2026 | Experimental Investigation Of Macro And Microscopic Degradation And Damage Mechanisms In Granite Subjected To Microwave Radiation Under True Triaxial Compression | Yang, S.; Sun, B.; Li, H. | https://link.springer.com/article/10.1007/s00603-026-05284-7 | ||||||||||||
| E077 | 2025 | Microwave Irradiation-Induced Deterioration Of Rock Mechanical Properties And Implications For Mechanized Hard Rock Excavation | Yang, Z.; Tao, M.; Memon, M.; Zhuang, D.; Zhao, Y. | https://www.sciencedirect.com/science/article/pii/S1674775524003081 | ||||||||||||
| E078 | 2025 | Effects Of Microwave Radiation On The Anisotropy Of Heat Transfer And Mechanical Properties Of Layered Rocks | Yu, et al. | https://www.sciencedirect.com/science/article/pii/S2590123025047516 | ||||||||||||
| E079 | 2026 | Study On The Pore Structure Response And Damage Mechanism Of Saturated Sandstone During Cyclic Microwave Irradiation | Yuan, S.; Sun, Q.; Hu, J.; Geng, J.; Chi, M.; Zha, E.; Bai, G. | https://www.sciencedirect.com/science/article/abs/pii/S0926985126001722 | ||||||||||||
| E080 | 2026 | Thermally Driven Microscopic Fracture Evolution In Hard Rocks Under Microwave Irradiation: Effects Of Mineralogical Heterogeneity | Yuan, Y.; He, F.; Fang, J.; Qiao, R.; Shao, Z. | https://www.sciencedirect.com/science/article/pii/S245190492600243X | ||||||||||||
| E081 | 2026 | Influence Of Free Surface On Microwave-Induced Rock Fracturing: An Experimental And Numerical Study | Zheng, Y.; Su, Z.; Zhao, G.; Che, P.; Li, J. | https://www.sciencedirect.com/science/article/abs/pii/S1365160926000596 | ||||||||||||
| E083 | 2026 | Theoretical Feasibility Assessment Of Hydraulic Fracturing With Microwave Assistance: Insights From A Coupled Electromagnetic-Thermo-Hydro-Mechanical (ETHM) Phase-Field Simulation | Zhu, Z.; Xie, J.; Du, Y.; Ren, L.; Yang, B.; Zhou, Q.; Gao, M. | https://www.sciencedirect.com/science/article/abs/pii/S1365160926001681 | ||||||||||||
| E085 | 2026 | Review Of Fracturing Techniques Microwaves High-Voltage Pulses And Cryogenic Fluids For Application As Access Creation Method In Low-Permeability | https://www.tandfonline.com/doi/full/10.1080/08827508.2023.2196070 | |||||||||||||
| E086 | 2026 | Nonlinear Multi-Field Coupling Analysis And Prediction Of Thermo-Mechanical Response Of Oil Shale Under Microwave Heating Using Physics-Informed Neural Network | https://www.sciencedirect.com/science/article/abs/pii/S0952197626013011 | |||||||||||||
| E087 | 2024 | Investigation of High-Power Microwave Treatment of Kimberlites and Its Effect on Comminution and Downstream Processing | Borhan Mehr, R. | https://hdl.handle.net/1974/33134 | kimberlite | Comminution; DMS; Energy; Kimberlite; Liberation; Microwave; Characterization; Permittivities; Pilot-scale; Settling; PSD | Although microwave treatment has been proven to reduce the competency of kimberlites, the lack of information regarding the downstream processing of microwave treated kimberlites has led to limited application of this technology on a full scale. This thesis provides expansive research on the effects of microwave treatment on the processing of kimberlites, beginning with an in-depth literature review that evaluates its impact on the thermal, physical, and mechanical properties of various materials, as well as downstream processes such as flotation and leaching, and energy consumption. The research investigates microwave treatment at both bench-scale and pilot-scale to address the current gap in knowledge concerning the downstream processing of microwave-treated kimberlites. An extensive characterization of four unique kimberlite samples was performed, including mineralogical analysis, thermogravimetric analysis, and permittivity measurements. The bench-scale microwave treatments explored the heating behaviours and microwave amenability of the kimberlites with respect to different parameters, functioning as the precursor for pilot-scale studies which mainly aimed to reduce the kimberlite’s competency by promoting microfractures along the mineral grain boundaries. This microfracturing resulted in reduced energy consumptions during the comminution stages and has the potential to decrease diamond breakage. Comparative comminution studies, applying jaw and cone crushers followed by high-pressure grinding rolls (HPGR), indicated that the microwave treated samples not only consumed less energy by 16%, but also produced fewer ultra-fine particles (<38 μm) as compared to the untreated samples by 4.4%. Dense media separation (DMS) was then employed as the downstream processing stage to investigate the separation efficiency of the microwave treated versus the untreated samples, with a focus on liberation analysis for both the concentrates and the tailings. Settling studies on the fine particles (<1 mm) highlighted the improvements in solid-liquid separation, essential for tailings management and the design of thickeners. The key findings and the recommendations presented at the end of this thesis highlight the effectiveness of microwave treatment in the processing of kimberlites and offer comprehensive suggestions and directions for future research aimed at commercialization. | - | English | Canada | Masters Thesis | - | 0 | N/A | 248 pages | |
| Year | Author(s) | Material(s) Studied | Keywords | Language | Country of Corresponding Author | Document Type | Journal/Conference Name |