Copper and Zinc Recovery from Brass and Zinc or Zn-Fe Alloy Plated Steel Sheet with Cupric Ammine Solutions

Abstract

Dissolution of brass was examined in aqueous cupric ammine solutions. Copper and zinc were dissolved easily fromαandα+βbrass at a diffusion-limiting rate. However, the presence of Sn, Fe and Pb in the alloys inhibited the dissolution of copper and zinc. Applicability of selective dissolution of zinc from zinc or Zn-Fe alloy plated steel sheet using aqueous cupric ammine solutions has been investigated for zinc recovery. After 15 min immersion of the steel in an aqueous 0.5 mol dm^-3CuSO₄^-1mol dm^-3 (NH₄) ₂S0₄-5 mol dm_-3NH₃solution at ambient temperature, zinc on zinc plated steel was found to be eliminated completely without dissolution of iron. On the other hand, zinc recovery from the Zn-Fe alloy plated steel decreased slightly to be 90% and the residual amount of zinc corresponded to 1.3 mg per 1 g of steel.