原位微区分析华北典型富锂煤中关键金属赋存规律  

In-situ microanalysis of critical metal occurrences in high-lithium coals of North China

作　　者：孙蓓蕾[1,2] 王瑶 李宝庆 刘超[1,2] 郭沾明[1] 张星星[4,5] SUN Beilei;WANG Yao;LI Baoqing;LIU Chao;GUO Zhanming;ZHANG Xingxing(College of Mining Engineering,Taiyuan University of Technology,Taiyuan,Shanxi 030024,China;Key Laboratory of Coal Science and Technology,Ministry of Education,Taiyuan,Shanxi 030024,China;China University of Geosciences(Wuhan),Wuhan,Hubei 430074,China;Shanxi Institute of Coal Geology and Exploration Co.Ltd,Taiyuan,Shanxi 030006,China;Shanxi Coal-Bearing Mineral Comprehensive Exploration Technology Innovation Center,Taiyuan,Shanxi 030006,China)

机构地区：[1]太原理工大学矿业工程学院,山西太原030024 [2]煤科学教育部重点实验室,山西太原030024 [3]中国地质大学(武汉),湖北武汉430074 [4]山西省煤炭地质勘查研究院有限公司,山西太原030006 [5]山西省煤系矿产综合勘查技术创新中心,山西太原030006

出　　处：《地质学报》2024年第8期2424-2438,共15页Acta Geologica Sinica

基　　金：国家重点研发计划项目(编号2021YFC2902002);国家自然科学基金项目(编号42372203);山西省科技创新人才团队专项项目(编号202304051001028)联合资助的成果。

摘　　要：煤是特殊的沉积有机岩石,在其形成过程的特定地质条件下,可以富集战略性金属,并在煤系中形成大型或超大型金属矿床。目前已经在华北聚煤区多处煤田发现煤系锂矿化现象,为了查明锂的载体及其赋存规律,本文在矿物组成分析的基础上,采用微区原位分析的方法研究了不同矿物和显微组分中关键金属的赋存特征,为煤系关键金属的富集成因和勘查提供了新的思路。研究结果表明:高岭石是煤中锂的最重要载体,表现为Li-Ga、Li-Zr-Nb-Hf-Ta和Li-Y-Sr不同的元素组合特征,分别代表碎屑物源控制型、火山灰输入型和流体活动参与型三种不同的关键金属富集成因类型。镜质结构体中富集Zr-Hf-Th元素组合,胶质结构体表现为轻度的Li富集;脉状含钠黏土矿物富集Ga-Ba-Tl,脉状磷灰石表现为Ba-Sr-Y富集特征,这些脉体矿物元素的富集是成煤后期流体活动的产物。Coal,a significant organic sedimentary rock,possesses the potential to serve as a source of various critical metals.Lithium mineralization in the coals of North China has been extensively documented.This study employed a suite of in-situ analytical techniques,including LA-ICP-MS,SEM-EDX,Micro-Raman,and Micro-FTIR,to investigate the host phases of Li and other enriched critical metals in high-Li coals from North China.This study offers a new perspective on the understanding of the enrichment mechanisms and exploration potential of critical metals within coal deposits.The results indicate that lithium is predominately hosted within kaolinite,exhibiting three distinct assemblages:Li-Ga,Li-Zr-Nb-Hf-Ta,and Li-Y-Sr.Kaolinite with Li-Ga and Li-Zr-Nb-Hf-Ta enrichments originated from detrital input and ash supply during peat formation.The Li-Y-Sr enrichments in kaolinite are a result of epigentic fluid activity in the coal.Telinite presents enrichment with zirconium(Zr),hafnium(Hf),and thorium(Th).Additionally,sodium-bearing clay veins display elevated concentrations of gallium(Ga),barium(Ba),and thallium(Tl),while apatite veins exhibit enrichments in Ba,strontium(Sr),and yttrium(Y).These critical metal enrichments in mineral veins are attributed to fluid activity during coalification.

关 键 词：关键金属 原位分析 富锂煤 赋存状态 

分 类 号：P618.11[天文地球—矿床学] P618.2[天文地球—地质学]