Optimization of zinc recovery from sphalerite using response surface methodology and particle swarm optimization

Abstract

Hydrometallurgical leaching process has been identified as a viable procedure for recovering metals of value from their matrices. The optimization of zinc recovery from sphalerite in nitric acid solution was carried out in this study. The Central Composite Rotatable Design (CCRD) of Response Surface Methodology (RSM) and Particle Swarm Optimization (PSO) tool in matlab were deployed for the optimization studies. RSM modeling gave optimum conditions of 73.0 °C leaching temperature, 3.48 M acid concentration, 0.027 g/mL solid/liquid ratio, 411.02 rpm stirring rate, and 82.82 minutes leaching time; with a zinc yield of 87.67 %. With PSO, about 86.9 % zinc was recovered at a leaching temperature of 69.1 °C, acid concentration of 1.8 M, solid/liquid ratio of 0.031 g/mL, stirring rate of 270 rpm and leaching time of 85 minutes. Thus, PSO and RSM proved to be good optimization tools.