摘要
在特定的地质条件下,煤中可以富集战略性金属元素并形成煤系战略性金属矿床。煤系战略性金属矿产的研究已成为当前煤地质学研究的主要方向之一。沉积源区物质的输入是影响煤中战略性金属元素富集的主要影响因素之一。运用X射线衍射分析(XRD)、带能谱的扫描电镜(SEM-EDS)、电感耦合等离子体质谱(ICP-MS)、X射线荧光光谱(XRF)等技术对广西百色盆地那读组下百岗段主采煤层样品进行了矿物学和元素地球化学研究,并探讨了物源区供给对该煤田煤中战略性金属铯富集的控制作用。结果表明:百色盆地古近纪煤中的矿物以伊利石、高岭石和石英为主,主要来源于盆地周缘三叠系碎屑岩风化产物;盆地西部煤层与东部煤层相比,具有相对高的黏土矿物含量;仅在盆地东部的州景4号和5号煤层中检测到了碳酸盐矿物方解石。与世界低煤阶煤均值相比,百色盆地古近纪煤中富集元素铷(Rb)、锑(Sb)和铯(Cs);但盆地西部的煤层中较为富集元素Rb和Cs,盆地东部的煤层较为富集元素Sb,Cs和U,并且Cs的富集不仅存在于煤中,也存在于顶底板和夹矸中,且顶底板和夹矸中Cs的含量要远高于煤中的,通过相关性分析Cs主要与黏土矿物相关,通过扫描电镜观察到黏土矿物多为陆源碎屑成因,表明沉积源区输入的陆源碎屑物是Cs异常的主要因素。百色盆地东部煤层和西部煤层的矿物组成和元素组成上的差异,可能与盆地西部和盆地东部煤层物源区性质,以及沉积环境上的差异有关。
Under specific geological conditions,strategic metal elements can be enriched in coal and subsequently form strategic metal ore deposits in coal-bearing strata.The research of strategic metal elements in coal-bearing strata is the main direction and frontier issue of coal geology.The input of terrigenous materials is one of the main factors affecting the enrichment of strategic metal elements in coal.X-ray diffraction analyzer(XRD),Scanning Electron Microscope equipped with an energy-dispersive X-ray spectrometer(SEM-EDS),Inductively Coupled Plasma Mass Spectrometer(ICP-MS),X-ray fluorescence spectrometry(XRF)and other instruments were used to analyze the composition of minerals and elements in the Palaeogene coal from the Baise Basin,Guangxi Province.The influence of sediment-source region on enrichment of critical element cesium in Paleogene coals from the Baise Basin is discussed based on the study of mineralogy and element geochemistry of these coal seams from under Baigang section of Nadu Formation in the Baise Basin.The minerals in Paleogene coal in the Baise Basin are mainly illite,kaolinite and quartz,which mainly come from the weathering products of Triassic clastic rocks around the basin;the percentage of clay minerals in western part of the Baise basin is higher than eastern part.Carbonate mineral calcite was detected only in Zhoujing No.4 coal seam and No.5 coal seam in the eastern part of the Baise Basin.Compared with the average values for world low-rank coals,rubidium(Rb),antimony(Sb)and cesium(Cs)are enriched in the Palaeogene coal from the Baise Basin;The coal seams in the western part of Baise basin are enriched in elements Rb and CS,while the coal seams in the eastern part of the Baise Basin are enriched in elements Sb,Cs and U.The enrichment of Cs in the current study occurs not only in coal but also in the non-coal samples,and the content of Cs in the non-coal is higher than that in coal.The correlation analysis show that Cs is predominantly associated with clay minerals,which were most likely derived from the terrigenous source region surrounding Baise basin,indicating that sedimentary source rocks are potential source of anomalous Cs.The mineral composition and enrichment characteristics of trace elements in different coal seams in Baise basin are different,which may be related to the difference sedimentary sources and sedimentary environment.
作者
严晓云
王倩
张蕊
梁阳
赵蕾
YAN Xiaoyun;WANG Qian;ZHANG Rui;LIANG Yang;ZHAO Lei(Department of Energy and Power Engineering, Tsinghua University, Beijing 100084, China;School of Geosciences & Surveying Engineering, China University of Mining & Technology-Beijing,Beijing 100083,China)
出处
《煤炭学报》
EI
CAS
CSCD
北大核心
2022年第5期1865-1875,共11页
Journal of China Coal Society
基金
煤炭资源与安全开采国家重点实验室开放基金资助项目(SKLCRSM21KFA03)
国家自然科学基金资助项目(42102211)
中央高校基本科研业务费专项资金资助项目(2021JCCXDC01)。
关键词
战略性金属
百色盆地
古近纪煤
物源区
矿物质
铯
critical element
Baise Basin
Paleogene coal
sediment-source region
mineral matter
cesium
