China Nonferrous Metallurgy

The copper to sulfuric acid ratio is a key index to affect normal production of copper electrolysis. The imbalance of copper to sulfuric acid ratio can easily intensify the polarization of concentration, enhance the concentration of impurity ions and thereby affect the cathode copper quality. This paper tracks and investigates the trend in the variation of copper ion concentration, sulfuric acid concentration and concentration of As5+, Sb3+, Bi3+ and Ni2+ in different areas and at different time during the copper electrolysis process as well as corresponding cathode copper quality, analyzes the impact mechanism of copper to sulfuric acid proportion on cathode copper quality, and draws the conclusion as follows. Imbalance of copper to sulfuric acid ratio will intensity the enrichment of impurity ions and facilitate formation of granules on the surface of the cathode copper. A proper ratio of copper to sulfuric acid can improve the appearance quality of cathode copper; insufficient volume of purified electrolyte will accelerate the hydrolysis of various salts in the electrolyte and cause imbalance of copper to sulfuric acid ratio, while increasing the volume of purified electrolyte is beneficial for maintaining normal copper to sulfuric acid ratio. The fine property of electrolyte and uniformity of ion concentration can be improved by the means of enhanced electrolyte convection, which prevents the imbalance of copper to sulfuric acid ratio in the electrolyte; when the size of impurity ions in the electrolyte is large, the copper to sulfuric acid ratio shall maintain in the range from 0.25 to 0.3.