Cobalt cementation by zinc dust in presence of copper,cadmium and antimony additives

The cementation of cobalt by zinc dust in the presence of copper,cadmium and antimony additives was investigated experimentally for the purpose of deeply purifying zinc electrolyte.The effects of initial mass concentrations of Cu(II) ions(ρ(Cu2+)0),Cd(II) ions(ρ(Cd2+)0),dosage of zinc dust,temperature and stirring speed on the rate of cobalt removal and the purities of the zinc sulfate solution were examined.The results show that adding a certain amount of Cu(II) ions not only increases the cobalt removal rate together with the purities of zinc sulfate solution,but also saves the dosage of zinc dust used in the purification process.It is also validated that adding Cu(II) and Cd(II) ions at the same time behaves a better effect of cobalt removal than adding Cu(II) ions solely.The optimal conditions for cobalt removal are obtained as follows: ρ(Cu2+)0 15 mg/L,ρ(Cd2+)0 15 mg/L,antimony potassium tartrate 3 mg/L,zinc dust dosage 2 g/L,temperature 85 ℃ and stirring speed 300 r/min.