Potential environmental geochemical hazards of the slag from Dazhai Ge extraction plant in Lincang, western Yunnan, China

The Dazhai Coal Mine in Lincang, western Yunnan, China, one major coal-hosted Ge deposits around the world, is of special environmental interest due to the open storage of slags after Ge extraction. To investigate the... [ view full abstract ]

The Dazhai Coal Mine in Lincang, western Yunnan, China, one major coal-hosted Ge deposits around the world, is of special environmental interest due to the open storage of slags after Ge extraction. To investigate the environmental geochemical characteristics of the slag, 6 bump slag samples were collected from the pile, and the trace elements were determined by ICP-MS and ICP-CCT-MS (As and Se).
These slags commonly preserved the geochemical features of its raw coals with exception of Ge, i.e., unusually enriched in Be and W; and significantly enriched in As, Sb, Cs, and U. Moreover, the slags samples are significantly more enriched in Cr, Cu, Mo, In, and Th than raw coals. The Upper Continental Crust-normalized REY patterns indicated that all the extraction procedures did not changed the REY distribution pattern of its raw coals.
Compared to the world soils, Be (178 mg/kg, 59×), Ge (33.4 mg/kg, 16×), As (172 mg/kg, 34×), Mo (49.8 mg/kg, 42×), In (2.08 mg/kg, 30×), Sb (123 mg/kg, 245×), Cs (9.3 mg/kg, 33×), W (310 mg/kg, 207×), and U (148 mg/kg, 55×) are significantly concentrated in the slags. Therefore, the open storage of these slags might endanger the supergene media (soil, surface and ground water) around the Ge extraction plants.