Electroleaching of industrial zinc leach residues

Abstract

A room temperature electrolytic process to recover Zn from industrial leach residues was attempted. Slurry electrolysis in acidic electrolytes was carried out to explore the dissolution tendency of Zn from the leach residues. The relative significance of the various factors, namely current density, concentration of electrolyte, time and pulp density, affecting the process was studied using a statistically designed experiment. Mathematical models for both percentage Zn and Fe extraction were arrived at and response surfaces were plotted. It has been concluded from the results that reductive dissolution and creation of anion vacancies are responsible for the dissolution of zinc ferrite present in the leach residue. Based on the laboratory investigations, a process flow-sheet for the electrolytic recovery of Zn from industrial leach residues was developed.