Speciation Characterization and Environmental Stability of Arsenic in Arsenic-Containing Copper Slag Tailing

Abstract

Increasing amounts of arsenic-containing impurities in Cu ores may deteriorate the smelting process and aggravate the environmental impact of slag tailing. Geochemical, mineralogical and chemical speciation characteristics were investigated to elucidate the association and environmental stability of metal(loid)s in copper slag tailing. Results shown that the bulk chemical compositions of the selected slag tailing are Fe2O3 (54.8%) and SiO2 (28.1%). The selected slag tailing may lead to multi-elemental contamination potential for the elevated concentrations of environmental sensitively elements. The mineral phases in slag tailing are silicate (fayalite), oxides (magnetite and hematite), sulfides (galena, sphalerite, arsenopyrite and chalcopyrite). The invariably overlap of silicate, iron, arsenic and oxygen in the elemental distribution suggested that arsenic is existed silicate minerals as Si-Fe-As-O phases. Meanwhile, arsenic is also associated with sulfide minerals and oxides. The percentages of arsenite (As(III)) and arsenate (As(V)) are 59.4% and 40.6% in the selected slag tailing, respectively. The slag tailing is regarded non-hazardous waste for the tiny amounts of toxic elements in leachates. Nevertheless, the slag tailing should be property disposed for the elevated carbonate bound of As and Cu in the slag tailing.