普阳煤矿新近纪M3煤层中钨的赋存状态与富集成因  

Modes of occurrence and origin of tungsten in the M3 coal seam of Neogene from the Puyang Coal Mine

作　　者：郭星星 汪小妹[1] 程海见 杨浩然 潘思东 GUO Xingxing;WANG Xiaomei;CHENG Haijian;YANG Haoran;PAN Sidong(Key Laboratory of Tectonics and Petroleum Resources of Ministry of Education,China University of Geosciences,Wuhan 430074,China)

机构地区：[1]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

出　　处：《煤炭学报》2024年第11期4563-4577,共15页Journal of China Coal Society

基　　金：国家自然科学基金资助项目(42372190,42172194);新疆维吾尔自治区重大科技专项资助项目(2022A03014-2)。

摘　　要：煤中战略性金属资源越来越受到人们的关注。随着传统钨矿储量的减少,煤中富集的钨极有可能成为一种新型的钨矿来源。沉积源区物质的输入和流体作用是煤中战略性金属元素富集的重要影响因素。在云南普阳煤矿新近纪M3煤层中发现了钨(W)的异常,但是缺乏对异常的成因以及元素赋存状态的研究。运用X射线衍射分析(XRD)、带能谱的扫描电镜(SEM-EDS)、X射线荧光光谱(XRF)、电感耦合等离子体质谱(ICP-MS)等技术对普阳煤矿新近纪M3煤层样品进行了矿物学和元素地球化学特征研究,通过逐级化学提取对W的赋存状态进行了研究,并通过碱萃取实验对比腐植酸、原煤中W元素的含量,来探究W与有机质(腐植酸)的结合能力。并探讨了物源区供给和流体作用对M3煤中战略性金属钨(W)的控制作用。结果表明:普阳M3煤属于低-中灰分、中高-高挥发分褐煤;M3煤的主要组成矿物包括石英、黄铁矿、方解石,以及少量的高岭石、伊利石、菱铁矿;M3煤中常量元素以Al_(2)O_(3)和SiO_(2)为主;与世界低阶煤相比,M3煤中高度富集W元素(富集系数C_(C)=59),钨平均质量分数为70μg/g(最高达到325μg/g),在煤灰中质量分数平均可达359.76μg/g(最高达到1432.35μg/g)。逐级提取实验以及相关性分析表明,M3煤中W可能主要赋存在有机质中,其次为硅酸盐和铝硅酸盐,少量的W可能赋存在黄铁矿中,还有一小部分W可能赋存在不溶性矿物或被有机质包裹的矿物中;通过碱萃取实验发现,腐植酸中W的质量分数范围在58.8~123μg/g,平均质量分数为86.4μg/g,是原煤中W质量分数的1.37倍,表明M3煤中W与有机质(腐植酸)的结合能力较强;普阳M3煤主要物源为文山地区酸性花岗岩,由于源岩的碎屑物质供给与流体作用,M3煤中W元素高度富集。Critical minerals in coal deposits have attracted much attention in recent years because of their potential eco-nomic significance.However,these critical minerals are becoming scarce and expensive as their resources in conventional ores are exhausted.One promising source of W is coal and/or coal combustion products.The input of terrigenous materi-als and hydrothermal-fluid are the main factors affecting the enrichment of strategic mineral elements in coal.The origin and mode of occurrences of valuable element W in the M3 coal seam of the Puyang Mine is still unclear,although W was found significantly enriched.The X-ray difflraction analyzer(XRD),Scamning Electron Microscope equipped with an en-ergy-dispersive X-ray spectrometer(SEM-EDS),X-ray fluorescence spectrometry(XRF),Inductively Coupled PlasmaMass Spectrometer(ICP-MS)and other instruments were used to analyze the composition of minerals and ele-ments in the M3 coal seam of the Puyang Mine.The main modes of W occurrence were established using selective leach-ing procedure.The content of W in humic acid and coal was compared by alkaline extraction to explore the binding abil-ity of W and organic matter(humic acid).The influence of sedliment-source region and hydrothermal-fluid on the enrich-ment of critical element tungsten in M3 coal seam of the Puyang Mine was discussed based on the study of mineralogy and element geochemistry of these coal seams of the Puyang Mine.The results show that:the M3 coal is of medium-high volatile lignite rank and has a low-medium ash yield;The minerals in the M3 coal are mainly quartz,pyrite and calcite,to a lesser extent,kaolinite,illite,and siderite;The major element oxides in the M3 coal are dominated by SiO_(2) and Al_(2)O_(3).Tungsten is significantly enriched in the M3 coal,with a weighted average of 70μg/g(maximum content 325μg/g),being 59 times of the world low-rank coal’s average.The average coal ash content can reach 359.76μg/g(maximum content 1432.35μg/g);The results of sequential leaching and correlation analys

关 键 词：钨 赋存状态 物源区 流体作用 新近系煤 普阳矿区 

分 类 号：P618[天文地球—矿床学]