Leaching of Metals from Hydrometallurgical Residue by Sulfuric Acid

Abstract

A direct leaching on the hydrometallurgical residue with sulfuric acid was developed in this work. The influence of leaching temperature, the leaching time, the particle size and the sulfuric acid concentration was examined. Results of leaching studies that the recovery extraction of Zn, Fe and Cu for hydrometallurgical residue increases with increasing acid concentration and temperature; while it decreases with particle size. The optimum conditions for the extraction Zn, Fe and Cu are: leaching temperature 85 °C; sulfuric acid concentration 2 mol.L-1; the smaller particle size 63µm and the solid-to-liquid ratio 1:10. After 2 h of leaching treatment at these optimum conditions, over 80% of metals are extracted from the residues. The shrinking core model for the diffusion was established to control the mechanism with surface chemical reaction as the rate controlling step for the dissolution process.