LEI Liangqi1, MO Binji2, CHEN Sinai1, MO Jia1, SHI Zhenhuan1
(1.Earth Science Faculty, Guilin University of Technology, Guangxi Guilin 541004,China;
2. Institute of Geology Survey of Guangxi Zhuang Autonomous Region, Guangxi Guilin 541003,China)
Abstract: It should be paid attention to the issues of multi-elements compound pollution, associated with neutral mine drainage (NMD) from siliceous tailings which are rich in SiO2 and poor in sulfide. This paper focuses on the siliceous tailings of Shanhu W-Sn mine, situated in the northeast of Guangxi Province, China. Through studying the fabrics and characteristics of enrichment and migration of Cu, Pb, Zn, Cd, Tl, As and F in the tailings, the paper intends to screen out main elements concerning environmental issues and investigate the influence of cementation layer in the tailings on enrichment and migration of the elements. Results show that (1) In Shanhu tailings, Cd, As, Zn and F are main pollution elements because they have higher enrichment degree and higher exchangeable fraction (i.e. easier migration release fraction), while Pb, Tl and Cu have lesser possibility of environmental pollution; (2) Cementation layer/hardpan has re-enrichment function to heavy metals, but exchangeable Cd, As (Tl) trend to concentrate in the hardpan, while exchangeable Cu, Pb and Zn do not have this concentration tendency. Secondary cements such as illite and gypsum in the hardpan may prefer to adsorb actively exchangeable Cd and As, which are extremely easy to remove, implying that Shanhu tailings may release higher concentrations of Cd and As. Therefore, Shanhu siliceous tailings possess a risk of Cd, As, Zn and F compound pollution, associated with NMD during tailings weathering.
Keywords: siliceous tailing; tailing fabric; elements enrichment; migration; neutral mine drainage; tailing pollution
EARTH AND ENVIRONMENT Vol.46, No.4, Tot No.324, 2018, Page 373-380
