Impurity removal during Mn recycling stream in Zn electrowinning

Manganese in the electrolyte is of great significance to zinc electrowinning for corrosion protection of Pb-Ag anode and improved current efficiency, and most hydrometallurgical zinc plants recycle electrolyte together with Mn to leaching. In hydrometallurgical production of Cu-Zn oxide mine, solvent extraction followed by electrowinning (SX-EW) of zinc results in Mn recycling stream different from the conventional zinc plant, since Mn cannot be extracted by P204. The recyling of Mn can be achieved by SO ₂ reductive leaching of zinc anode slime and returning to electrowinning. Thermodynamic calculations and experiments were carried out in this work to selectively leach Mn from zinc anode slime, with impurities removed by the leaching residue. Impurities in Mn-bearing electrolyte effluent can be purified by neutralization and DMDTC, an efficient organic chemical to simultaneously remove Cu, Fe, Co, Ni.