Optimization of Cobalt Reductive Leaching from Zinc Plant Residue (ZPR) Using Taguchi Experimental Design Method

Hydrometallurgy is a flexible and efficient process for recovering heavy and valuable metals from industrial residues. In this study, various parameters of cobalt reductive leaching were investigated using the Taguchi experiment design (DOE) method to determine the best conditions for dissolving cobalt from zinc plant residue. The experiment parameters included: initial sulfuric acid concentration (0.1 M, 0.316 M and 1 M), reaction temperature (70, 80 and 90°C), reaction time (15, 30 and 60 min), and solid/liquid ratio (1:5, 1:6 and 1:7 g/L). The iron sulfate was used as a reducing agent, and the sulfuric acid was used as the solvent. The experiment results showed that the optimal conditions for dissolving cobalt were initial sulfuric acid concentration 1 M, temperature 90°C, time 60 min, and solid/liquid ratio 1:7. Under these conditions, there was good agreement between predicted (97.5%) and experimental results (97.2%) in terms of cobalt dissolution.