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宁东煤田横城矿区太原组煤中关键金属的物质来源和富集机理OA北大核心CSTPCD

The origin of detrital material and enrichment mechanism of critical elements of Taiyuan Formation coals within Hengcheng mining area in Ningdong coalfield

中文摘要英文摘要

对宁东煤田横城矿区太原组9号煤层进行了矿物学和地球化学研究,以便查明煤中关键金属的分布、赋存和富集特征,并评价其综合利用前景.研究结果表明:①横城矿区9号煤以高的镜质组含量、特低—低灰分产率和中—高硫含量为特征.②煤中矿物主要由高岭石组成,以细胞充填状、透镜状和薄层状等形式存在.煤层底板中矿物主要由石英、高岭石和白云母组成,其主要为碎屑成因.③煤层中常量元素主要由SiO2和Al2O3组成,煤中Li、Zr、Nb、Hf、Pb和Th的含量达到轻度富集—富集程度,其中Li、Pb和Th主要赋存于高岭石,Zr和Hf赋存于锆石,Nb赋存于高岭石和锐钛矿.矿区9号煤层形成于受海水影响的潮坪-潟湖环境,煤层下部形成于铁源供给不足的低位沼泽环境,煤层上部形成于铁源严重不足的高位沼泽环境,故下部煤层中硫以黄铁矿硫为主而上部以有机硫为主.煤中碎屑物质主要来源于阴山古陆和阿拉善地块,阴山古陆主要提供了元古宙的陆源碎屑物质,阿拉善地块主要供给了早石炭世的碎屑物质,此外也有少量的火山灰和奥陶系灰岩风化残积物进入到含煤盆地.煤中的Li、Zr、Nb等关键金属的富集主要受控于长英质的碱性—过碱性物质输入量的多少,同时水/岩作用过程也导致了关键金属的活化、迁移和重新分配.煤灰中Li2O含量超过其边界品位,REO、Ga、Zr和REY接近相应边界品位,故可考虑Li-Ga-Zr-REY等的综合开发利用.

The mineralogy and geochemistry of No.9 coal seam within the Taiyuan Formation of the Hengcheng mining area,Ningdong coalfield,were studied to determine the distribution,occurrence,and enrichment characteristics of critical elements in coal and to evaluate its potential for comprehensive utilization. The results revealed that:① No.9 coal in the Hengcheng mining area is characterized by high vitrinite content,extremely low-low ash yield,and medium-high sulfur content. ② The dominant mineral in the coal is kaolinite,occurring as cell fillings,lenticular shapes,and thin layers. The coal seam floor mainly consists of quartz,kaolinite,and muscovite,which are mainly of clastic origin. ③ Major elements in the coal seam are mainly SiO2 and Al2O3. The coal exhibits slight enrichment in Li,Zr,Nb,Hf,Pb,and Th. Li,Pb,and Th are mainly hosted by kaolinite,Zr and Hf are found in zircon,and Nb is present in kaolinite and anatase. The No.9 coal seam in this mining area formed in a tidal flat-lagoon environment affected by seawater. The lower part of the coal seam developed in a low swamp environment characterized by limited iron source supply,while the upper part formed in a high swamp environment with a severe iron source deficiency. This resulted in a distinct sulfur distribution:pyrite sulfur dominates the lower coal seam,whereas organic sulfur is prevalent in the upper part. The detrital material in the coal mainly originates from two sources:the Yinshan ancient land,which contributed Proterozoic terrigenous detrital material,and the Alashan block,which supplied detrital material from the early Carboniferous. The enrichment of critical elements such as Li,Zr,and Nb in the coal is mainly controlled by the input of alkali-peralkaline materials. Water/rock interactions also contribute to the activation,migration,and redistribution of these critical elements. The Li2O content in coal ash exceeds the cut-off grade,and REO,Ga,and Zr are close to the corresponding cut-off grade. Therefore,comprehensive development and utilization of Li-Ga-Zr-REY resources from this coal seam is a promising prospect.

黄鹏程;马少东;郭雅杰;史禹韬;曹佳亮;李宝庆;田继军;姬晓燕;上官云飞;庄新国

中国地质大学(武汉)地质调查研究院,湖北武汉,430074||宁夏回族自治区煤炭地质局,宁夏银川,750001宁夏回族自治区煤炭地质局,宁夏银川,750001中国地质大学(武汉)构造与油气资源教育部重点实验室,湖北武汉,430074

关键金属赋存状态富集机理宁东煤田太原组

critical elementmode of occurrenceenrichment mechanismNingdong coalfieldTaiyuan Formation

《地质学报》 2024 (008)

2336-2350 / 15

本文为国家重点研发计划项目(编号2021YFC2902005)、国家自然科学基金项目(编号42272207)和宁夏地质事业发展专项(编号640000233000000011005)联合资助的成果.

10.19762/j.cnki.dizhixuebao.2024198

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