Optimization of brine leaching of metals from hydrometallurgical residue

An orthogonal array, L16 (45), was used to examine the effects of four parameters, including NaCl concentration, H2SO4 concentration, temperature and pulp density, on the recovery of Cu, In, Pb and Zn from a hydrometallurgical residue via brine leaching. The results show that temperature of leaching solution has a significant effect on the recovery of Cu, In and Zn, while H2SO4 concentration has an obvious influence on these metals extraction. Both pulp density and NaCl concentration significantly affect Pb extraction. Based on the orthogonal array experiments, the optimum conditions for the extraction of Cu, In, Pb and Zn from hydrometallurgical residue are NaCl concentration of 250 g/L, H2SO4 concentration of 1.00 mol/L, temperature of 85 oC, and pulp density of 100 g/L. After 1 h of treatment at these optimum conditions, over 91% of the metals are extracted from the residue. Brine leaching is therefore suitable for the recovery of metals from hydrometallurgical residues.