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.

doi:10.1007/s00603-023-03327-x

Cited by 5 publications

(5 citation statements)

References 26 publications

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“…A complete exposition of the recent contributions to the application of numerical methods in microwave heating of rocks is undoubtedly beyond the scope of this study. Interested readers can refer to [9,[23][24][25][26] for more comprehensive accounts of these investigations. In most of these studies, the contribution of the electromagnetic field in the cavity was either neglected or accounted for by imposing constant electric and magnetic boundary conditions [27,28].…”

Section: Introductionmentioning

confidence: 99%

Energy Efficiency of Microwave-Induced Heating of Crushed Rocks/Ores

et al. 2023

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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.

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Section: Introductionmentioning

confidence: 99%

Energy Efficiency of Microwave-Induced Heating of Crushed Rocks/Ores

et al. 2023

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“…Combining the results of fracture toughness with the temperature rise in the m of the notch tip reveals that before the temperature of the notch tip reaches 293 fracture toughness has an upward trend. However, the fracture toughness of bas creases continuously during the whole microwave heating process [29]. Variation i The contrast between temperature gradient evolution and stress field evolution in microwave-heated granite shows the effects of the thermal expansion properties of minerals on the stress field.…”

Section: Fracture Toughness and Degradation Mechanism Of Granitementioning

confidence: 99%

“…Combining the results of fracture toughness with the temperature rise in the middle of the notch tip reveals that before the temperature of the notch tip reaches 293 • C, the fracture toughness has an upward trend. However, the fracture toughness of basalt decreases continuously during the whole microwave heating process [29]. Variation in fracture toughness at the initial microwave-heating stage is the consequence of the competition between the closure of pre-existing cracks and the initiation of new cracking.…”

Section: Fracture Toughness and Degradation Mechanism Of Granitementioning

confidence: 99%

“…Recent advancements in numerical methods may lead to significant improvements in addressing this issue. A finite-element-based numerical model was employed by Deyab et al [29] to maximize the microwave energy absorption of the sample, and the minimum required diameter of the basalt rock specimen for fracture toughness experiments after microwave treatment was determined. Further investigation of the mechanism of fracture toughness degradation in hard rocks subjected to microwave energy is urgently required.…”

Section: Introductionmentioning

confidence: 99%

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Analysis of Microwave-Induced Damage in Granite Aggregates Influenced by Mineral Texture

Yuan,

Zhao

2024

Buildings

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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 microwave-induced 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.

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“…The main drawback of these studies is their focus on the outcome of the microwave treatment without considering the input microwave energy, which is a determinative factor in evaluating the efficiency of the method. For example, Deyab et al [7] studied the effect of microwave treatment on mode I fracture toughness for Basalt. They showed that increasing the microwave exposure time at constant power can reduce the fracture toughness value.…”

Section: Introductionmentioning

confidence: 99%

Investigating the Efficiency of Microwave Treatment in Mine-to-Mill Operations: An Energy-Based Analysis

Ahmadihosseini,

Aslam,

Hassani

et al. 2024

Preprint

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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.

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Investigating Microwave Treatment of Rocks Based on Fracture Mechanics Analysis in Mode I Fracture Toughness Test

Cited by 5 publications

References 26 publications

Energy Efficiency of Microwave-Induced Heating of Crushed Rocks/Ores

Energy Efficiency of Microwave-Induced Heating of Crushed Rocks/Ores

Analysis of Microwave-Induced Damage in Granite Aggregates Influenced by Mineral Texture

Investigating the Efficiency of Microwave Treatment in Mine-to-Mill Operations: An Energy-Based Analysis

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