| 河南省平顶山一荥巩煤田不同变质程度煤的煤岩学特征 |
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| 引用本文：.1988.Petrological characteristics of coals in different metamorphic ranks in the Pingdingshan-Xingong coalfield, Henan province[J].Mineral Deposits,7(3):89~96 |
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| 中文摘要:对不同变质程度的煤进行了手标本和显微镜下研究、物理性质测定、化学成分分析以及X射线、红外光谱和顺磁共振分析。阐明了煤化过程中不同变质程度煤所表现出的一系列特征，探讨了其中的变化规律，确定出煤化过程是不可逆的渐变过程，是非芳环结构不断破坏，芳环结构不断稠合的过程。内部结构的变化使煤的物理化学性质和岩石学特征发生相应的变化，并伴随围岩粘土矿物组合和含量的变化。 |
| 中文关键词:煤 煤化作用 煤级 煤变质 |
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| Petrological characteristics of coals in different metamorphic ranks in the Pingdingshan-Xingong coalfield, Henan province |
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| Abstract:The matamorphism of Carboniferous-Permian Pingdingshan, Yuxian, Xinmi and Xinggong coalfields shows zoned distribution, i. e., the coal rank grows higher from south to north in order of gas coal. fat coal, coking coal, lean coal, meager coal and anthracite coal. Various experimental tests have been made on coal in different metamorphic ranks, which include hand specimen examination and microscopic study, determination of physical properties, chemical analysis, X-ray diffraction, infrared spectroscopy and electron spin resonance.On such a basis, a series of characteristics shown by coal in different metamorphic ranks during the coa!ification are described with the variation regularities discussed. It is demonstrated that the coalification is an irreversible progressive process in which aromatic compounds a re gradually concentrated through the unceasing splitting of other eompouds. The variation in internal structures of the coal leads to the corresponding change in physical-chemical properties and petrological characteristics of the coal. With the evolution of coal from low rank to high rank, the free radical concentration becomes higher, the characteristic vibrations of aliphatic structures in infrared spectra are eonsiderably reduced or even disappear, the ratio of alipb atic to aromatic fracfion decreases, the coal nuclei grow larger in size, the distance between lameb lae of aromatic structures is reduced, the contents of volatile componepts and hydrogen decrease, the hydrogen/carbon atomic ratio gets lower, and the aromaticity increases. With the increase in reflectivity of coal, the surface color and reflection color of the vitrinite group becme lighter, the powder color and transmission color grow darker, and the luster gets intensified. The heightening of coaI rank also causes a gradual decrease in the size of coal nuclei and the regularization of the arrangement parallel to the lamellae in the concentrated aromatic clusters, thus resulting in the intensification of anisotropy of coal as well as the increase in the value of R0max –R0min and the vichers microhardness and density of the vitrinite. In addition, the free radical concerttration, the indices of coal nuclei and the aromaticity, which all reflect interhal structural characteristics of the coal, tend to decrease after progressively rising to the maximum. In contrast, the ratio of aliphatic to arematic fractions tends to increase after being gradually reduced to the minimum. With the evolution of coalification, the association and content of clay minerals in country rocks also show corresponding changes. |
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