中国煤型锗矿床中的关键金属和有害元素:赋存特征与富集成因

Critical metals and hazardous elements in the coal-hosted germanium ore deposits of China:Occurrence characteristics and enrichment causes

煤型锗矿床是全球工业用锗的主要来源,其中富集的关键金属和有害元素值得密切关注。论述了我国内蒙古乌兰图嘎和云南临沧煤型锗矿床中富集的关键金属和有害元素的含量、赋存特征和富集成因。乌兰图嘎锗矿床富集的关键金属有Ge,W以及贵金属元素Au,Pt和Pd,富集的有害元素包括Be,F,As,Sb,Cs,Hg和Tl。临沧锗矿床富集的关键金属有Ge,W,Nb和U,富集的有害元素包括Be,As,Sb,Cs等。锗矿床中富集的Ge,W和U主要存在于有机质中。乌兰图嘎煤中的有害元素As,Hg,Sb和Tl主要与黄铁矿有关,还有部分As存在于有机质中,Be,F和Cs分别与碳酸盐矿物/黏土矿物、黏土矿物和伊利石有关。临沧煤中的Nb,As和Sb具有有机-无机的混合亲和性,Be存在于有机质和硫酸铍矿物中,Cs的主要载体为伊利石。乌兰图嘎锗矿床中关键金属组合Ge-W和有害元素组合As-Hg-Sb-Tl的富集是不同的热液流体侵入泥炭或煤层造成的,而临沧锗矿床中富集的元素组合Ge-W和Be-Cs-Nb-U为含N 2的碱性热液和含CO 2的火山热液混合后对花岗岩基底强烈淋溶的结果。

Coal-hosted Ge ore deposits are the primary sources of germanium for industrial use worldwide,and the enriched critical metals and hazardous elements in these deposits warrant a close attention.In this paper,the concentrations,occurrence characteristics,and enrichment causes of the critical metals and hazardous elements in the Wulantuga(Inner Mongolia)and Lincang(Yunnan Province)coal-hosted Ge ore deposits are reviewed.The critical metals Ge and W and precious metals Au,Pt,and Pd are enriched in the Wulantuga deposit,so are the hazardous elements Be,F,As,Sb,Cs,Hg,and Tl.The Lincang deposit is not only enriched in the critical metals Ge,W,Nb,and U but also some hazardous elements,including Be,As,Sb,and Cs.Germanium,W,and U in the coal-hosted Ge deposits exist predominantly in the organic matter of coal.The hazardous elements As,Hg,Sb,and Tl in the Wulantuga coal are mainly related to pyrite,some As also exists in the organic matter,and Be,F,and Cs are associated with carbonate minerals/clay minerals,clay minerals,and illite,respectively.In the Lincang coal,Nb,As,and Sb have a mixed organic-inorganic affinity,Be exists in the organic matter and beryllium sulfate,and illite is the major carrier of Cs.The elevated concentrations of Ge-W and As-Hg-Sb-Tl assemblages in the Wulantuga deposit are derived from different hydrothermal fluids circulating through the peat and/or coal,and the enriched assemblages of Ge-W and Be-Cs-Nb-U in the Lincang deposit are attributed to the intense leaching of the batholith granite by a mixture of alkaline N 2-bearing and volcanogenic CO 2-bearing hydrothermal solutions.