Disposal of solutions of copper electrofining processing of non-ferrous metal scrap

Abstract

The results of studies on the utilization of copper electrorefining solutions, zinc-containing sublimation dusts of pyrometallurgical processing of non-ferrous metal scrap are presented. Zinc-containing sublimation dusts for the regeneration of commercial electrolyte by the neutralization method were used for the first time. Contained in dust, zinc oxide, when dissolved in a sulfuric acid electrolyte, binds sulfate ions of free sulfuric acid and increases the pH of the solution. When the pH of the precipitation of non-ferrous metals is reached, they are precipitated in the form of hydroxides, which makes it possible to return to processing a significant amount of copper, nickel, zinc, lead and tin contained in them. Studies of the material composition of the commercial electrolyte of copper and zinc sublimates for the processing of non-ferrous metal scrap have been carried out. The conditions for purification of the electrolyte by the method of staged neutralization are determined. The first stage of neutralization was carried out with zinc sublimates, the second and third stages with potash. As a result of the first stage of neutralization to pH 4.7, lead was obtained - a tin-containing product that can be processed together with lead-containing copper electrorefining sludge. As a result of the second stage of neutralization with potash to pH 7.1, a precipitate was obtained, after treatment of which in a KOH solution, a precipitate of copper oxide was obtained. As a result of the third stage of neutralization to pH 9.5, a nickel-zinc-containing precipitate was obtained. After treating the precipitate with a KOH solution, a zinc-containing solution and a nickel-containing precipitate were obtained, after calcining which a nickel oxide precipitate was obtained.