Efficient Separation and Recovery of Manganese, Zinc, and Copper from the Manganese-Rich Wastes by Two-Stage Acid Leaching Followed by Precipitation

Abstract

Recovery of heavy metals (manganese, zinc, and copper) from manganese-bearing wastes has been mentioned in this work. The leaching route was divided into two stages. For the solid waste mixed with Mn (II) compounds and Mn (IV) compounds, a dilute sulfuric acid solution and ferrous sulfate were used for the first-stage reductive acid leaching. The dissolved Cu ion was reduced into metallic copper by adding the reduced iron powder to realize the separation with Mn and Zn. Metallic copper of the first-stage leaching residue was dissolved during the second-stage acid leaching, which was converted to copper sulfate by adding hydrogen peroxide to a sulfuric acid solution. Heavy metals were recovered from first-stage leachate by selective precipitation. The second-stage leachate was concentrated to obtain copper sulfate crystals, and only gypsum was left in the final residue. In this hydrometallurgical work, no solid wastes harmful to the environment are produced.

Keywords: Metal recovery, Reductive leaching, Chemical precipitation, Effective separation, Environmental management