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.
|Original language||English (US)|
|Title of host publication||Geochimica et Cosmochimica Acta|
|Place of Publication||New York, NY|
|State||Published - 2008|