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.

doi:10.1016/j.jrmge.2020.09.001

Cited by 35 publications

(13 citation statements)

References 13 publications

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“…For instance, Lu et al [ 31 ] measured the permittivity of basalt, gabbro, and granite rocks employing the coaxial transmission line technique, shaping the rocks in the shape of a tube (7 mm outer diameter, 3 mm inner diameter, and 10 mm length) to fill the coaxial airline. Deyab et al [ 32 ] reported the dielectric properties of kimberlite and granite samples through the coaxial probe technique, which retrieves the permittivity of a considerable region surrounding the measurement tip. Similarly, Lovás et al [ 33 ] determined the permittivity of several minerals, such as andesite or magnesite, by a resonance cavity method using rod samples (3 mm diameter and 12 mm length).…”

Section: Introductionmentioning

confidence: 99%

High-Resolution Detection of Rock-Forming Minerals by Permittivity Measurements with a Near-Field Scanning Microwave Microscope

Gutiérrez-Cano

Catalá-Civera

López-Buendía³

et al. 2022

Sensors

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The identification of the minerals composing rocks and their dielectric characterization is essential for the utilization of microwave energy in the rock industry. This paper describes the use of a near-field scanning microwave microscope with enhanced sensitivity for non-invasive measurements of permittivity maps of rock specimens at the micrometer scale in non-contact mode. The microwave system comprises a near-field probe, an in-house single-port vectorial reflectometer, and all circuitry and software needed to make a stand-alone, portable instrument. The relationship between the resonance parameters of the near-field probe and the dielectric properties of materials was determined by a combination of classical cavity perturbation theory and an image charge model. The accuracy of this approach was validated by a comparison study with reference materials. The device was employed to determine the permittivity maps of a couple of igneous rock specimens with low-loss and high-loss minerals. The dielectric results were correlated with the minerals comprising the samples and compared with the dielectric results reported in the literature, with excellent agreements.

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Section: Introductionmentioning

confidence: 99%

High-Resolution Detection of Rock-Forming Minerals by Permittivity Measurements with a Near-Field Scanning Microwave Microscope

Gutiérrez-Cano

Catalá-Civera

López-Buendía³

et al. 2022

Sensors

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“…The compressive strength of granite subjecting to high‐temperature influence has been studied by many scholars 13–15 . Biró et al, 16 Liu and Xu, 17 and Xu et al 18 conducted the uniaxial compressive strength tests, studying the attenuation of strength for granite in the range of heat‐treatment temperature of 100–1,200°C.…”

Section: Introductionmentioning

confidence: 99%

“…The compressive strength of granite subjecting to high-temperature influence has been studied by many scholars. [13][14][15] Bir o et al, 16 Liu and Xu, 17 and Xu et al 18 conducted the uniaxial compressive strength tests, studying the attenuation of strength for granite in the range of heat-treatment temperature of 100-1,200 C. Jones et al, 19 Chen et al, 20 and Chaki et al 21 found that thermal damage in granite emerged above 100 C and studied the evolution of thermal damage in granite with heattreatment temperature through adopting the acoustic emission (AE) monitoring, ultrasonic velocity, porosity, and permeability measurements. Furthermore, Griffiths et al 22 and Yang et al 23 explained the change of compressive strength of granite at different thermal damage degrees based on the evolution of microcrack characteristics.…”

Section: Introductionmentioning

confidence: 99%

Saturated water‐weakening effects on the compressive behavior of thermally damaged granite

Zhao

et al. 2022

Fatigue Fract Eng Mat Struct

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A detailed understanding of the compressive behavior of granite under environments of high temperature and water is critical for deep resource exploitation. In this study, uniaxial compressive strength tests were conducted on dry and water-saturated granite with thermal damage at room temperature. A new phenomenon was discovered: With the increase of thermal damage degree of granite at different heat-treatment temperatures, the saturated water-induced weakening effects on the stress thresholds representing each crack development stage of granite present an obvious non-monotonic trend. Of the saturated water-induced weakening effects, 500 C is the key point, where the abrupt change occurs and the attenuation of compressive strength (peak stress) attains the maximum, reaching 41.77%. Further, the corresponding phenomenon was attributed to the form transformation of microcracks near 500 C based on the microstructural analysis. This study enriches the understanding of rock behavior deep underground and can provide a guide for more efficient hydraulic fracturing in deep resource exploitation, as well as the long-term safe and stable use of nuclear waste disposal projects within the granite.

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“…Microwave exposure represents a good alternative for coal modification due to the advantages of instantaneous penetration, selective heating, feasible control, and environmental friendliness. 25 Currently, microwave exposure has been preliminarily applied in the fields of coal dehydration, 26−28 coal/oil desulfurization, 29,30 hard rock fracturing, 31,32 aid grinding, 33,34 coal/biowaste pyrolysis, 35,36 coking, 37,38 oil shale exploitation, 39,40 and heavy oil thermal recovery. 41,42 Microwaves, as ultrahigh-frequency electromagnetic waves (3 × 10 8 to 3 × 10 12 Hz) that consist of magnetic and electric fields perpendicular to each other, can cause high-frequency vibrations (billions for microwaves with a frequency of 2.45 × 10 9 Hz) and friction of polar molecules or free electrons within their penetration range.…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Response of Molecular Structures and Methane Adsorption Behaviors in Coals Subjected to Cyclical Microwave Exposure

Zhang

Kang

et al. 2021

ACS Omega

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To better understand the methane adsorption behavior after microwave exposure, the importance of quantitatively characterizing the effect of cyclical microwave exposure on the molecular structures of coals cannot be overemphasized, with implications for enhancing coalbed methane (CBM) extraction. Thus, cyclical microwave exposure experiments of three different metamorphic coals were conducted, and the methane adsorption capacity before and after each microwave exposure (10 in total) for 120 s was evaluated. Fourier transform infrared spectroscopy analysis and peak fitting technology were applied to quantitatively characterize the changes in the structural parameters of coal molecules. The results showed that after modification, the structural parameters like aromatic carbon fraction (f a–F), aromaticity (I 1 and I 2), degree of condensation (DOC 1 and DOC 2), and the maturity of organic matter (“C”) gradually increased with increasing exposure times, while the length of the aliphatic chain or its branching degree (CH 2/CH 3) and the hydrocarbon generating capacity (“A”) showed a decreasing trend. The Langmuir volume (V L) of three different rank coal samples decreased from 29.2, 32.8, and 40.4 mL/g to 25.7, 29.3, and 35.7 mL/g, respectively; the Langmuir pressure (P L) increased from 0.588, 0.844, and 0.942 MPa to 0.626, 1.007, and 1.139 MPa, respectively. The modification mechanism was investigated by analyzing the relationship between the methane adsorption behaviors and molecular structures in coals. The release of alkane side chains and the oxidation of oxygen-containing functional groups caused by microwave exposure decreased the number of methane adsorption sites. As a result, the methane adsorption capability decreased. In addition, the decomposition of minerals affects methane adsorption behaviors in coals. This work provides a basis for microwave modification of coal as well as in situ enhancement of CBM extraction using microwave exposure.

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Experimental investigation on the effects of microwave irradiation on kimberlite and granite rocks

Cited by 35 publications

References 13 publications

High-Resolution Detection of Rock-Forming Minerals by Permittivity Measurements with a Near-Field Scanning Microwave Microscope

High-Resolution Detection of Rock-Forming Minerals by Permittivity Measurements with a Near-Field Scanning Microwave Microscope

Saturated water‐weakening effects on the compressive behavior of thermally damaged granite

Response of Molecular Structures and Methane Adsorption Behaviors in Coals Subjected to Cyclical Microwave Exposure

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