Study on the Enrichment of Rare Earth Elements in the Stratum Containing Sandstone Uranium Deposits in the Yili Basin
The Yili Basin is located in the western part of Xinjiang Uygur Autonomous Region,in the west Tianshan tectonic belt,which belongs to the intermountain superimposed basin and is rich in mineral resources.The cycle Ⅴ of the Jurassic Shuixigou Group is developed in sandstone uranium deposits in the Yili Basin,with high enrichment of rare earth elements in carbonaceous sandstone and coal seams.After measurement,the highest rare earth element content in the sandstone sample of the coal seam floor is 1 589.0 μg/g,and the highest rare earth element content in the coal sample is 430.3 μg/g.The rare earth element distribution pattern is mainly characterized by a right skewed light rare earth enrichment type,showing a negative anomaly of Eu.In coal samples,the content of rare earth elements is positively correlated with uranium content,and rare earth minerals are mainly composed of yttrium phosphate ore,hydrous cerium phosphate,and aluminum phosphate cerium ore.Research has shown that rare earth elements originate from the weathering and alteration of acidic rocks around the basin,the rare earth elements and uranium elements released by acidic rocks flow together with groundwater and precipitate in organic matter enriched layers.