Abstract: Deep purification of zinc ammoniacal leaching solution by cementation using zinc dust was studied. The effects of relative amount of metallic impurities, dosage of zinc dust, purification time, temperature, pH value and total ammonia concentration in the solution on the purification of the solution were investigated. The results indicate that total ammonia concentration in the solution had no effect on the purification, but relative amount of metallic impurities, dosage of zinc dust, purification time, temperature and pH value of the solution were the main factors influencing the purification. Keeping appropriate molar ratio of copper to cadmium or nickel to cadmium was beneficial to the cementation of cadmium. Nevertheless, the presence of cobalt went against the cementation of cadmium and cobalt. All metallic impurities could be decreased to acceptable levels under the optimized conditions of 2 g/L of zinc dust dosage, 1 h of purification time, 35℃, pH value 9.03 of zinc ammoniacal leaching solution. The deeply purified zinc ammoniacal solution obtained by one-stage purification meets the requirements of zinc electrowinning.

Key words: zinc ammoniacal leaching solution, zinc dust, deep purification, relative amount of metallic impurities

摘要： Deep purification of zinc ammoniacal leaching solution by cementation using zinc dust was studied. The effects of relative amount of metallic impurities, dosage of zinc dust, purification time, temperature, pH value and total ammonia concentration in the solution on the purification of the solution were investigated. The results indicate that total ammonia concentration in the solution had no effect on the purification, but relative amount of metallic impurities, dosage of zinc dust, purification time, temperature and pH value of the solution were the main factors influencing the purification. Keeping appropriate molar ratio of copper to cadmium or nickel to cadmium was beneficial to the cementation of cadmium. Nevertheless, the presence of cobalt went against the cementation of cadmium and cobalt. All metallic impurities could be decreased to acceptable levels under the optimized conditions of 2 g/L of zinc dust dosage, 1 h of purification time, 35℃, pH value 9.03 of zinc ammoniacal leaching solution. The deeply purified zinc ammoniacal solution obtained by one-stage purification meets the requirements of zinc electrowinning.

关键词: zinc ammoniacal leaching solution, zinc dust, deep purification, relative amount of metallic impurities