Concentration and distribution of uranium in Chinese coals

Representative coal uranium concentrations are essential not only to better estimate the environmental and health effects associated with the uranium emissions from coal utilization but also to utilize the potentially valuable uranium in coal combustion by products. The average uranium concentrations of coals in China are estimated based on uranium analyses of 1535 coal samples and coal reserves tonnage. The results showed that the estimated average weighted uranium concentrations of Late Carboniferous and Early Permian (C2–P1), Late Permian (P2), Late Triassic (T3), Early and Middle Jurassic (J1−2), Late Jurassic and Early Cretaceous (J3–K1), and Eogene and Neogene (E–N) coals are 2.91, 5.43, 3.67, 1.18, 1.84, and 3.92 μg/g, respectively. The overall average weighted uranium concentration of coals in China is 2.31 μg/g. The background values of uranium in coals of China were dominated by detrital materials of terrigenous origin, but the anomalous enrichments of uranium were attributed to synsedimentary volcanic ashes and epigenetic low-temperature hydrothermal fluids and magmatic hydrothermal inputs.