An exhaustive structural analysis was carried out on three Indian coals （ranging from sub-bituminous to high volatile bituminous coal） using a range of advanced characterization tools. Detailed investigations were c...An exhaustive structural analysis was carried out on three Indian coals （ranging from sub-bituminous to high volatile bituminous coal） using a range of advanced characterization tools. Detailed investigations were carded out using UV-Visible spectroscopy, X-ray diffraction, scanning electron microscopy coupled energy dispersive spectroscopy, Raman spectroscopy and Fourier transform infrared spectroscopy. The X-ray and Raman peaks were deconvoluted and analyzed in details. Coal crystallites possess turbostratic structure, whose crystallite diameter and height increase with rank. The tJdC ratio plotted against aromaticity exhibited a decreasing trend, confirming the graphitization of coal upon leaching. It is also found that, with the increase of coal rank, the dependency of I20/I26 on La is saturated, due to the increase in average size of sp2 nanoclusters. In Raman spectra, the observed G peak （1585 cm^-1） and the D2 band arises from graphitic lattices. In IR spectrum, two distinct peaks at 2850 and 2920 cm i are attributed to the symmetric and asymmetric -CH2 stretching vibrations. The intense peak at - 1620 cm^-1, is either attributed to the aromatic ring stretching of C=C nucleus.展开更多
In the present study an attempt has been made to carry out the detailed petrographic characterization of the Karharbari coals of Talcher coalfield and to reconstruct the paleoenvironment conditions of coal formation u...In the present study an attempt has been made to carry out the detailed petrographic characterization of the Karharbari coals of Talcher coalfield and to reconstruct the paleoenvironment conditions of coal formation using macerals and microlithtotypes as a tool. For these purposes a large number of samples were collected following the pillar sampling method and were subjected to detailed petrographic study. The petrographic observation shows that these coals are vitrinite rich followed by the liptinite and inertinite group of macerals. On microlithotype scale, these coals shows the dominance of the vitrite followed by clarite, vitrinertite and inertite. The concentration of liptite, clarodurite, duroclarite and vitriner- toliptite are insignificant. The vitrinite reflectance ranks the Karharbari coal as high volatile bituminous ＇C＇ to high volatile ＇B＇ bituminous. Coal petrography based depositional models suggest peat accumulation in forested telmatic swamp. Moreover, during the time of their evolution, there were alternate phases of oxic and anoxic moor conditions with good tissue preservation.展开更多
We collected eleven bench samples of No. 6 coal from the Heidaigou Surface Mine, Jungar Coalfield, Inner Mongolia, China, and four samples from the affiliated coal preparation plant. Based on these samples, we used in...We collected eleven bench samples of No. 6 coal from the Heidaigou Surface Mine, Jungar Coalfield, Inner Mongolia, China, and four samples from the affiliated coal preparation plant. Based on these samples, we used inductively coupled-plasma mass spectroscopy, X-ray diffraction, scanning electron microscope with an energy-dispersive X-ray spectrometer techniques, and borehole exploration data, to investigate the distribution, occurrence and enrichment causes of gallium （Ga） in the coals. Our results show： （1） Gallium is significantly enriched in the coal seams from the study area, with an average content of 18.8-26.0 ppm. Gallium is distributed heterogeneously in the coals, and reaches ore-forming scales only in No. 6 coal of Heidaigou Surface Mine, not in the other mining districts of Jungar Coalfield. （2） On the horizontal plane, Ga is enriched in the main minable coals from the northern and middle part of the coalfield. In the vertical profile, Ga content in the coal seams is higher at the base of Taiyuan Formation （Nos. 8 and 9） and Shanxi Formation （Nos. 3 and 4） than at the top of the Taiyuan Formation. Within the identical coal seam, Ga content is higher in the benches near the roof and floor than in the middle section. （3） Gallium in the coals is associated mainly with kaolinite and boehmite. Additionally, Ga may be adsorbed to some extent by humic acid, resulting in a high level in weathering coal. （4） Geological factors affect Ga enrichment in coal, such as the prop- erty of parent rocks in the source area, the sedimentary environment, organic matter, structure, and past magmatic hydrothermal activity. Especially, Ga content in parent rocks plays a leading role. （5） The mobility and precipitation of trace elements like Ga are controlled principally by the geochemical behavior of the major element A1. Terrestrial and transgressive environments can cause the precipitation of bauxite, whereas marine-continental depositional environments may cause the separation of Ga from A1. In addition, Ga may migrate in the form of gas tively enriched in high-volatile coal. and may be affected by the ground temperature. Thus, it is relatively enriched in high-volatile coal.展开更多
文摘An exhaustive structural analysis was carried out on three Indian coals （ranging from sub-bituminous to high volatile bituminous coal） using a range of advanced characterization tools. Detailed investigations were carded out using UV-Visible spectroscopy, X-ray diffraction, scanning electron microscopy coupled energy dispersive spectroscopy, Raman spectroscopy and Fourier transform infrared spectroscopy. The X-ray and Raman peaks were deconvoluted and analyzed in details. Coal crystallites possess turbostratic structure, whose crystallite diameter and height increase with rank. The tJdC ratio plotted against aromaticity exhibited a decreasing trend, confirming the graphitization of coal upon leaching. It is also found that, with the increase of coal rank, the dependency of I20/I26 on La is saturated, due to the increase in average size of sp2 nanoclusters. In Raman spectra, the observed G peak （1585 cm^-1） and the D2 band arises from graphitic lattices. In IR spectrum, two distinct peaks at 2850 and 2920 cm i are attributed to the symmetric and asymmetric -CH2 stretching vibrations. The intense peak at - 1620 cm^-1, is either attributed to the aromatic ring stretching of C=C nucleus.
文摘In the present study an attempt has been made to carry out the detailed petrographic characterization of the Karharbari coals of Talcher coalfield and to reconstruct the paleoenvironment conditions of coal formation using macerals and microlithtotypes as a tool. For these purposes a large number of samples were collected following the pillar sampling method and were subjected to detailed petrographic study. The petrographic observation shows that these coals are vitrinite rich followed by the liptinite and inertinite group of macerals. On microlithotype scale, these coals shows the dominance of the vitrite followed by clarite, vitrinertite and inertite. The concentration of liptite, clarodurite, duroclarite and vitriner- toliptite are insignificant. The vitrinite reflectance ranks the Karharbari coal as high volatile bituminous ＇C＇ to high volatile ＇B＇ bituminous. Coal petrography based depositional models suggest peat accumulation in forested telmatic swamp. Moreover, during the time of their evolution, there were alternate phases of oxic and anoxic moor conditions with good tissue preservation.
基金supported by National Natural Science Foundation of China (Grant Nos. 40772102 and 40730422)Program for New Century Excellent Talents in University (Grant No. NCET-08-0839)+2 种基金National Key Basic Research and Development Program of China (Grant No. 2007CB209400)the Fundamental Research Funds for the Central Universities (Grant No. 2010LKDZ02)Sci-Tech Project "Evaluation of coal resources in first batch national planning mining areas" of the Ministry of Land and Resources
文摘We collected eleven bench samples of No. 6 coal from the Heidaigou Surface Mine, Jungar Coalfield, Inner Mongolia, China, and four samples from the affiliated coal preparation plant. Based on these samples, we used inductively coupled-plasma mass spectroscopy, X-ray diffraction, scanning electron microscope with an energy-dispersive X-ray spectrometer techniques, and borehole exploration data, to investigate the distribution, occurrence and enrichment causes of gallium （Ga） in the coals. Our results show： （1） Gallium is significantly enriched in the coal seams from the study area, with an average content of 18.8-26.0 ppm. Gallium is distributed heterogeneously in the coals, and reaches ore-forming scales only in No. 6 coal of Heidaigou Surface Mine, not in the other mining districts of Jungar Coalfield. （2） On the horizontal plane, Ga is enriched in the main minable coals from the northern and middle part of the coalfield. In the vertical profile, Ga content in the coal seams is higher at the base of Taiyuan Formation （Nos. 8 and 9） and Shanxi Formation （Nos. 3 and 4） than at the top of the Taiyuan Formation. Within the identical coal seam, Ga content is higher in the benches near the roof and floor than in the middle section. （3） Gallium in the coals is associated mainly with kaolinite and boehmite. Additionally, Ga may be adsorbed to some extent by humic acid, resulting in a high level in weathering coal. （4） Geological factors affect Ga enrichment in coal, such as the prop- erty of parent rocks in the source area, the sedimentary environment, organic matter, structure, and past magmatic hydrothermal activity. Especially, Ga content in parent rocks plays a leading role. （5） The mobility and precipitation of trace elements like Ga are controlled principally by the geochemical behavior of the major element A1. Terrestrial and transgressive environments can cause the precipitation of bauxite, whereas marine-continental depositional environments may cause the separation of Ga from A1. In addition, Ga may migrate in the form of gas tively enriched in high-volatile coal. and may be affected by the ground temperature. Thus, it is relatively enriched in high-volatile coal.
