Enrichment of critical elements (Nb-Ta-Zr-Hf-REE) within coal and host rocks from the Datanhao mine, Daqingshan Coalfield, northern China

摘要

This paper discusses the modes of occurrence of critical elements and their origins in the studied coal and associated rock samples (partings and roof strata) from the Datanhao coal mine, Daqingshan Coalfield, Inner Mongolia, northern China. The studied coals are enriched in trace elements including Zr, Hf, Th, Be, F, Zn, Ga, Nb, Mo, Cd, In, Sn, Ta, Hg, W, Pb, and rare earth elements and Y (REY). Zirconium, Nb, Ta, and Hf are largely associated with anatase in the studied coal and non-coal samples. The main carriers of REY, Th, and U in both coal and non-coal samples are Ca-bearing REE-phosphate minerals, most likely monazite, although U is partly associated with organic matter. Fluorine in the Datanhao coals is mainly associated with kaolinite.