HIGH CURRENT DENSITY ELECTROLYTIC DECOMPOSITION PROCESS FOR COPPER

摘要

A process for high current density electrolytic decomposition of copper for the electro-refining of copper using a crude copper product as an anode, which comprises maintaining the temperature of an electrolyte solution in an electrolyzer at a temperature of 55 DEG C or higher; rendering an electrolyte solution to flow continuously into an electrolyzer at its upper portion and to flow out continuously from the bottom of the electrolyzer together with slime, removing the slime from the electrolyte solution and recycling the resulting electrolyte solution containing no slime to the electrolyzer; and passing the electrolyte solution through the space between the electrodes at an average flow rate sufficient for the electrolyte solution to flow in downward direction over the whole surface of a cathode, in the defiance of the upward flow of the electrolyte solution being caused on the surface of the cathode when the electrolysis is started in a condition wherein the solution is at rest. The above electrolytic decomposition process is free from the occurrence of passivation of a cathode even when electro-refining of copper is carried out with a high current density, from the deposition of slime on the surface of a cathode and from the formation of irregularities in a knot or wrinkle form on the surface of a cathode, and further can be employed for producing an electro-refined copper product having reduced contents of impurities such as S, As, Sb, and Bi.