Basic scheme of copper and zinc waste recycling in metallurgical brass production

Abstract

The article proposes a recycling scheme for dusty waste generated during the metallurgical brass production with the use of two-stage leaching. During the first stage, when the dust is dissolved by a 0,5 mol/l sulfuric acid solution, a product solution containing the major amount of zinc ions (0,46 mol/l) and a small amount of copper ions (less than 0,02 mol/l) is obtained. Copper is sequentially electrochemically isolated from this solution, at a current density of 0,1 A/dm2, and then zinc is isolated at 5,0 A/dm2. The dry residue (cake) is subjected to copper-ammonia leaching, as a result of which all copper passes into the solution, and associated metals remain undissolved. In order to extract copper from the resulting solution, the liquid extraction by a 0,34 mol/l DH-510A solution in kerosene is used. Copper ions are extracted from the organic phase through re-extraction by a 2,0 mol/l sulfuric acid solution. The cathode copper is extracted from the obtained sulfuric acid electrolyte at current density of 1,5–2,0 A/dm2. The advantages of the proposed scheme are the increase in environmental friendliness through the use of solution recirculation at all stages of the process, as well as waste minimization through the entire process of dusty metallurgical sludge recycling.