Abstract:

The REY(REE+Y) content in the Permian coal seams mined at Xiayukou of Weibei were investigated by inductively coupled plasma mass spectrometry. The content characteristics and distribution patterns of REY were analyzed. Furthermore, the origin and occurrence states of REY were discussed. The results are as follows: compared with mean value of coal in China and North China, the REY are not obviously enriched in this research area with an average of 87.70 μg/g; the mean content of REY in No.2 coal is higher than that of No.3 coal due to the different coalforming microenvironment between them; the ∑REY reduced from top to bottom in the No.3 coal seam and enriched in the floor and roof samples; the light REY is obviously enriched compared with the heavy REY. The weak positive anomaly value of Ce indicates that seawater had little influence on the coal swamps. The negative anomaly value of Eu and the negative correlation between ∑REY and CaO indicate the sediment environments were acidreducing environment. The REY distribution patterns in coal, roof and floor seam samples are similar, indicating that they had the same and stable material supply during the coal formation. Positive but insignificant correlation (R=0.216) of ∑REY vs. ash yields demonstrates the possible coexistence of inorganic and organic states of REY in coals.

Key words: Weibei Coalfield, coal, Permian, rare earth element, geochemistry