Occurrence of rare earth elements in Huaibei coals, Anhui Province; Abstracts of the 18th annual V. M. Goldschmidt conference

Our previous research indicated that rare earth elements (REEs) enriched in the Permian coals from the Huaibei Coalfield, Anhui Province, China, and the average ΣREE is high up to 141μg/g. Especially in No.5 and 7 coals that influenced by igneous intrusion, REE contents are obviously higher than other coals. Method The six-step sequential extraction procedure was used in this study, and these tests measured the fractional amount of REEs in various density fractions that was soluble in a series of increasingly aggressive solvents and acids. According to the procedures, modes of occurrence of REEs in the Huaibei coals were classified as water-leachable, ion-exchangeable, organicbound, carbonate-bound, silicate-bound, and sulfide-bound. Discussion and Results The results indicated that: (1) water-leachable and ionexchangeable REEs is not abundant in Huaibei coals, and these REEs fractios show a near 1:1 abundance suggesting a common origin; (2) silicate-bound REEs dominated coal seams 3, 4, 5, 7, and 10, respectively accounting 84%, 71%, 94%, 89%, and 77% of the REEs in these seams; (3)a part amount of REE may be in the organic matter of coal, and average organic-bound REEs accounted 7% of the REEs in these coals; (4)carbonate-bound REEs contributed 17% of REEs in coal seam 4, which shown more abundant carbonte minerals.