Comprehensive recovery of valuable metals from copper smelting open-circuit dust with a clean and economical hydrometallurgical process

Abstract

A clean and efficient hydrometallurgical process was developed to recover Cu, Zn, Cd, Bi and Pb from the hazardous solid waste of copper smelting open-circuit (CSO) dust using the hazardous effluent of waste acid as leaching agent. By waste acid leaching-iron powder cementation, Cu was recovered as sponge copper. After As in the barren solution was removed mainly as thermodynamically stable ferric arsenate by iron salt precipitation, the Zn and Cd were simultaneously precipitated into zinc and cadmium residue through Na2CO3 neutralization. Bi in the waste acid leaching residue was recovered as bismuth oxychloride via chloride leaching-hydrolysis precipitation, and Pb was enriched in the form of PbSO4 in the chloride leaching reside (i.e. lead concentrate). 99.0% of total Cu, 86.8% of total Zn, 81.7% of total Cd, 90.4% of total Bi and 98.9% of total Pb in the CSO dust and waste acid entered their separate products. The input–output analysis demonstrates that a high revenue of 3803.4 CNY is gained for treating one ton of the CSO dust by the developed process. This process can realize waste treatment by waste and comprehensively recover valued metals from both of hazardous wastes simultaneously, and thus has good industrial application prospect.