Occurrence and Sequential Chemical Extraction of Rare Earth Element in Coals and Seam Roofs
2002; Elsevier BV; Linguagem: Inglês
ISSN
2212-4578
Autores Tópico(s)Coal and Its By-products
ResumoThe occurrence of rare earth elements (REEs) in coal seams and roofs from Shitanjing, Shizuishan, and Fengfeng coalfields were studied using Sequential Chemical Extraction Experiment (SCEE) in different extraction liquids and conditions. There are 6 types of REEs in coals and seam roofs: water\|soluble state (Ⅰ), ion\|exchangeable state(Ⅱ), carbonate state(Ⅲ), organism\|bonded state(Ⅳ), sialic state(Ⅴ),and sulfide state(Ⅵ). The result shows that REEs mainly distribute in sialic state. The fact that there is less water\|soluble state and ion\|exchangeable state in both coal and seam roof is the reflectance of stable geochemistry characteristics of REEs. The relative high content of carbonate mineral, sulfide mineral and organic matter may play an certain role in REE distribution and occurrence. The content of REEs in sialic state and sulfide state decreases with the increase of atomic numbers, but the REE content in organism\|bonded state increases. The fact that the occurrences of REEs in seam roofs is different from those in coals indicates that the fractional effects of REEs in different sedimentary environment, or of different materials in the same environment, are different.
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