Study on the Occurrence of Trace Elements in Low-sulfur Coal Gangue and Their Environmental Effect by Inductively Coupled Plasma-Optical Emission Spectrometry with Sequential Extraction Procedure

Abstract

Coal gangue is the largest industrial solid waste in China. Trace elements in low-sulfur coal gangue samples from the Linhuan coal mining area in the Huaibei coalfield were measured by Inductively Coupled Plasma-Optical Emission Spectrometry(ICP-OES). Sequential extraction procedure and correlation analysis were employed to analyze the occurrence of trace elements in coal gangue. Meanwhile, the environmental effect of trace elements was studied by Risk Assessment Code(RAC). The results showed that trace elements(Ba, Co, Cr, Mn, Ni, Pb and V) were enriched in coal gangue compared with Huaibei coals and Chinese coals, in which the enrichment factors of Mn and V were greater than 1, indicating a certain risk of migration. Trace elements predominantly occur in residual and Fe-Mn oxide bound, the total quality fractions of which range from 68.87% to 92.93%. Cd, Co, Cu, Ni, Pb and Zn are hosted in sulfide minerals, V is hosted in clay minerals, and Mn mainly in carbonate minerals. The environmental hazard of trace elements was in order of Mn >Zn >Ni >Pb >Cd >Cu >Ba >V >Cr >Co, indicating that active Mn most likely pollutes the environment during the outdoor storage of coal gangue and the soil and water pollution induced by Mn should be of concern.

Keywords

• low-sulfur coal gangue
• trace elements
• inductively coupled plasma-optical emission spectrometry
• sequential extraction procedure
• occurrence status
• environmental effects