Enrichment of rhenium, uranium and tantalum in jurassic coal from yili basin, xinjiang - evidence from mineralogy and geochemistry.

In this study, detailed geochemical and mineralogical investigations were conducted on the No.12 coal from the Early-Middle Jurassic in the Yili Basin. The results indicate the following: (a) The No.12 coal from the southern Yili Basin exhibits super-elevated enrichment (100 < concentration coefficient, CC) of Re(394.02ng/g), U(285.99 µg/g), and Ta(120.51 µg/g); high enrichment (10 < CC < 100) of Mo(29.11 µg/g), Se(28.51 µg/g) and Hf(12.54 µg/g); enrichment (5 < CC < 10) of Zn (7.86 µg/g)and Be (7.62 µg/g); slight enrichment (2 < CC < 5) of Cs (4.78 µg/g), Rb (4.75 µg/g), V (4.64 µg/g), Cr (4.51 µg/g), Co (4.01 µg/g), Ni (3.67 µg/g), W (3.65 µg/g), Pb (3.35 µg/g), Ge (2.96 µg/g), Cd (2.96 µg/g), F (2.70 µg/g), Cu(2.64 µg/g) Tl(2.53 µg/g), In(2.46 µg/g), Ga(2.41 µg/g), Sb(2.32 µg/g), Zr(2.31 µg/g), Sc(2.28 µg/g), and Th(2.18 µg/g); normal abundance (0.5 < CC < 2) of As(1.93 µg/g), Nb(1.75 µg/g), Li(1.42 µg/g), Hg(1.30 µg/g), Ba(1.12 µg/g), Sr(0.84 µg/g), and B(0.67 µg/g); and depletion(CC < 0.5) of Bi (0.40 µg/g). Excluding volatilization during combustion, U, Re, and Ta in the coal ash have certain resource potential to some extent. (b) The most common minerals in the No.12 coal are quartz, kaolinite, and pyrite. Additionally, some uncommon minerals, such as rutile, monazite, barite, clausthalite, ferroselite, pyrrhotite, coffinite, uraninite, sphalerite, and Fe-sulfate, were identified in the coal with super-elevated U content (especially when the U content exceeds 1000 µg/g). Among these minerals, clausthalite, ferroselite, and uraninite can control the enrichment of inorganic U and Se. (c) The enrichment of U-Re-Se-Mo-Ta-Hf in the No.12 coal is probably attributed to the infiltration of U-bearing oxidized solutions and the input of detritus containing critical metal elements from the sedimentary provenance.