China Nonferrous Metallurgy

The content of As, Sb and Bi ions in the copper electrolyte is an important factor affecting the quality of the cathode copper. The existing electrolytic deposition method has high power consumption and large copper loss, and the extraction method and ion exchange method have the defect of large liquid volume. In this paper, using SO₂ as reducing agent to reduce As⁵⁺ and Sb⁵⁺, H2O2 as an oxidant to oxidize As³⁺ and Sb³⁺, adjust the valence of arsenic, antimony and bismuth to form precipitated anode slime. An experimental study was carried out to reduce the impurity ions of arsenic, antimony and bismuth in copper electrolyte by counterflow precipitation of sulfur dioxide and hydrogen peroxide. The experiment results show that under certain conditions, the concentration of Sb ions can be reduced by pumping SO₂ into the copper electrolyte alone, but the concentration of arsenic and bismuth ions does not change much; adding H₂O₂ into the copper electrolyte alone can reduce the concentration of arsenic and antimony ions, but it will also reduce the concentration of copper and bismuth ions, which may lead to anode passivation; the best experimental conditions is H₂O₂ added dropwise, the addition amount 4mL/L, the SO₂ inlet concentration 0.125g/L, the stirring speed 250r/min, and the reaction temperature 50℃, under which counterflow precipitation technology can reduce the concentration of arsenic, antimony, bismuth impurity ions in copper electrolyte, and there will be no anode passivation.