YANG Ya，JI Hongbing^*

( State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China)

Abstract:Chemical forms and leaching characteristics of nine trace elements As, Cd, V, Zn, Co, Cr, Cu, Ni, and Pb in different weathering degree of coal gangue from Xinhua coal mine area in Guizhou Province, China were investigated by using BCR sequential extraction procedures and soaking experiments of contamination releasing regularity of coal gangue. Results of BCR sequential extraction procedures show that As and Cd in coal gangue were mainly in the form of the acid soluble, reducible and oxidizable occurrence, and other trace elements V, Zn, Co, Cr, Cu, Ni, and Pb were mainly in the form of residual occurrence. Except for V, the percentage of chemical forms of other trace elements was affected by the weathering degree of coal gangue. Results of soaking experiments show that soaking time was an important factor to release concentration of trace elements in coal gangue. During the soaking experiment, leaching concentration of most trace elements was influenced by the weathering degree of coal gangue at pre-soaking. Weathering degree of coal gangue can affect leaching concentration of Zn and Cu in whole soaking progress. During different particle size of coal gangue soaking, leaching concentration of trace elements decreased with increasing particle size of coal gangue at pre-soaking and mid-soaking, other than As and Co.

Keywords: coal gangue; trace element; BCR sequential extraction; leaching experiment; weathering; coal gangue

EARTH AND ENVIRONMENT Vol. 44, No.1 Tot No.309, 2016, Page 36-46