Investigation on the changing law of magnetoelectric anomalies in variable temperature coal rocks
The changing law of magnetoelectric anomalies in the metamorphic process of coal rock bodies is of great significance to the prediction and study of fire in hidden coal fields. For this reason, this paper reveals the changing law of magnetoelectric anomalies in metamorphic coal rock bodies through t...
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Elsevier
2025-06-01
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| Series: | Results in Engineering |
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| author | Xiaokun Zhao Jun Ge An Zhang WenCai Wang |
| author_facet | Xiaokun Zhao Jun Ge An Zhang WenCai Wang |
| author_sort | Xiaokun Zhao |
| collection | DOAJ |
| description | The changing law of magnetoelectric anomalies in the metamorphic process of coal rock bodies is of great significance to the prediction and study of fire in hidden coal fields. For this reason, this paper reveals the changing law of magnetoelectric anomalies in metamorphic coal rock bodies through the study of pyrolysis characteristics, microcrystalline structural changes, and physical phase transfer of the coal rock bodies, based on the four coal samples with different metamorphic degrees, and captures and elucidates the thermal gravity (TG) curves and micro-thermogravimetric (DTG) curves of the coal. Thermolysis behavior and characteristics. The results show that the variation rule of electrical anomalies during the metamorphic process is small at the beginning of the process, the dielectric properties of the coal samples show a significant increase from T2 to T3, and the dielectric constant reaches its maximum value at the T4 temperature point. The X-ray diffraction test was used to comprehensively analyze the microcrystalline morphological parameters of the coal before and after heating. The results showed that the high temperature induced a denser stacking of the carbonaceous layers, which strengthened the van der Waals forces between the layers, shortened the aromatic layer spacing, enhanced the electronic coupling between the layers, and increased the dielectric constant of the coal, resulting in an increase in the dielectric loss as well as the tangent value of the dielectric loss, and a blockage of the charge transport pathway. Based on X-ray diffraction data from four coal and seven rock samples with different degrees of metamorphism, in-depth analyses were performed using JADE to identify multiple phases in the coal and rock samples using the Rietveld refinement program, and semi-quantitative compositional assessments of the phases were performed. The results indicate that the conversion of iron minerals to more magnetic ferromagnetic compounds such as hematite (Fe2O3) and magnetite (Fe3O4) enhances the magnetization of the coal, while decomposition and oxidation reactions during the warming of the rocks alter their ferromagnetic compound type and content. |
| format | Article |
| id | doaj-art-acaaaff5cbc9450aaa653eff133fff88 |
| institution | OA Journals |
| issn | 2590-1230 |
| language | English |
| publishDate | 2025-06-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Results in Engineering |
| spelling | doaj-art-acaaaff5cbc9450aaa653eff133fff882025-08-20T02:17:29ZengElsevierResults in Engineering2590-12302025-06-012610485010.1016/j.rineng.2025.104850Investigation on the changing law of magnetoelectric anomalies in variable temperature coal rocksXiaokun Zhao0Jun Ge1An Zhang2WenCai Wang3School of Coal Engineering, Shanxi Datong University, Datong 037000, ChinaSchool of Coal Engineering, Shanxi Datong University, Datong 037000, China; Corresponding author.School of Safety Science and Engineering, Liaoning University of Engineering and Technology, Fuxin 123000, ChinaSchool of Mining and Coal, Inner Mongolia University of Science and Technology, Baotou 014010, ChinaThe changing law of magnetoelectric anomalies in the metamorphic process of coal rock bodies is of great significance to the prediction and study of fire in hidden coal fields. For this reason, this paper reveals the changing law of magnetoelectric anomalies in metamorphic coal rock bodies through the study of pyrolysis characteristics, microcrystalline structural changes, and physical phase transfer of the coal rock bodies, based on the four coal samples with different metamorphic degrees, and captures and elucidates the thermal gravity (TG) curves and micro-thermogravimetric (DTG) curves of the coal. Thermolysis behavior and characteristics. The results show that the variation rule of electrical anomalies during the metamorphic process is small at the beginning of the process, the dielectric properties of the coal samples show a significant increase from T2 to T3, and the dielectric constant reaches its maximum value at the T4 temperature point. The X-ray diffraction test was used to comprehensively analyze the microcrystalline morphological parameters of the coal before and after heating. The results showed that the high temperature induced a denser stacking of the carbonaceous layers, which strengthened the van der Waals forces between the layers, shortened the aromatic layer spacing, enhanced the electronic coupling between the layers, and increased the dielectric constant of the coal, resulting in an increase in the dielectric loss as well as the tangent value of the dielectric loss, and a blockage of the charge transport pathway. Based on X-ray diffraction data from four coal and seven rock samples with different degrees of metamorphism, in-depth analyses were performed using JADE to identify multiple phases in the coal and rock samples using the Rietveld refinement program, and semi-quantitative compositional assessments of the phases were performed. The results indicate that the conversion of iron minerals to more magnetic ferromagnetic compounds such as hematite (Fe2O3) and magnetite (Fe3O4) enhances the magnetization of the coal, while decomposition and oxidation reactions during the warming of the rocks alter their ferromagnetic compound type and content.http://www.sciencedirect.com/science/article/pii/S2590123025009259Coalfield fireThermogravimetric analysisMagnetizationMagnetoelectric anomalyMicrocrystalline structure |
| spellingShingle | Xiaokun Zhao Jun Ge An Zhang WenCai Wang Investigation on the changing law of magnetoelectric anomalies in variable temperature coal rocks Results in Engineering Coalfield fire Thermogravimetric analysis Magnetization Magnetoelectric anomaly Microcrystalline structure |
| title | Investigation on the changing law of magnetoelectric anomalies in variable temperature coal rocks |
| title_full | Investigation on the changing law of magnetoelectric anomalies in variable temperature coal rocks |
| title_fullStr | Investigation on the changing law of magnetoelectric anomalies in variable temperature coal rocks |
| title_full_unstemmed | Investigation on the changing law of magnetoelectric anomalies in variable temperature coal rocks |
| title_short | Investigation on the changing law of magnetoelectric anomalies in variable temperature coal rocks |
| title_sort | investigation on the changing law of magnetoelectric anomalies in variable temperature coal rocks |
| topic | Coalfield fire Thermogravimetric analysis Magnetization Magnetoelectric anomaly Microcrystalline structure |
| url | http://www.sciencedirect.com/science/article/pii/S2590123025009259 |
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