川滇黔相邻区古陆相沉积型稀土的发现及意义

文章报道了一种在川滇黔相邻区新发现的古陆相沉积型稀土矿床。稀土矿体赋存在二叠系峨眉山玄武岩之上，上二叠统宣威组底部，含矿建造为一套以高岭石及伊利石为主的黏土岩建造，分布广泛，连续性好，稀土氧化物TREO平均品位0.39%，最高可达1.60%。岩相古地理条件及地球化学特征显示，稀土元素源自西侧剥蚀区，经搬运-沉积-改造后富集；赋存状态方面，古陆相沉积型稀土除独立矿物态（<1%），类质同象态（<1%）和离子吸附态（0.02%~24%）外，75%以上的稀土元素以纳米矿物颗粒的形态被“束缚”在黏土矿物层状结构中；稀土元素配分曲线图显示其高价值关键稀土元素镨、钕、铽、镝占比累计达23.34%；通过短流程的选冶一体化工艺技术，全元素稀土浸出率达到90%以上，综合回收率达80%以上。这一新类型稀土资源具有极大的开发利用前景，有望成为中国新的关键稀土元素来源。

Significance and discovery of sedimentary REE deposits in adjacent areas of Sichuan, Yunnan and Guizhou

The paper reports a newly discovered paleocontinental sedimentary type rare earth elements(REE) deposits in the adjacent areas of Sichuan, Yunnan and Guizhou. REE ore bodies occur in the claystone at the bottom of the Permian Xuanwei Formation, which on the top of Emeishan Basalt. The ore-bearing clay rock is mainly composed of kaolinite and illite, which is widely distributed and has good continuity. The average grade of total rare earth oxide(TREO) is 0.39%, and the highest is 1.60%. The lithofacies, paleogeographic environment and geochemical characteristics show that the rare earth elements originated from the western denudation area of Emeishan large igneous provinces(ELIP) and were enriched after transport, deposition and transformation. In addition to the independent minerals(<1%), isomorphism(<1%) and ion adsorption(0.02%~24%), there is also a fourth occurrence, that is, the nano-minerals(>75%). The rare earth elements are bound in the layer structure of clay minerals in the form of nano-mineral particles. Critical rare earth elements(CREE) of praseodymium(Pr), neodymium (Nd), terbium(Tb) and dysprosium(Dy) accounted for 23.34%. The leaching rate of rare earth elements is more than 90% and the comprehensive recovery rate is more than 80% through the short-flow integrated process technology of separation and smelting. This new type of REE resources has great prospects for development and utilization, and is expected to become a new source of CREE in China.