Recovery of copper from copper manganese residue by acid leaching and selective sulfide precipitation

In this paper, a systematic study of H₂SO₄ leaching of copper manganese slag and Na₂S₂O₃ selective copper precipitation in acid leaching solution was conducted. The influencing factors of these two processes were explored by single factor experiment. The results showed that the optimal conditions for sulfuric acid leaching of copper manganese slag were H₂SO₄ dosage of 200 g/L, liquid to solid of (mL/g) 7∶1, reaction temperature of 80 ℃ and reaction time of 2 h. Under these conditions, the leaching rates of copper, cobalt, zinc and manganese were 99.81%, 99.54%, 99.07% and 24.10% respectively, and the main phase of leaching residue was MnO₂. The optimal conditions for selective copper precipitation in acid leaching solution were Na₂S₂O₃ dosage multiple of 2.0 and reaction time of 90 min, reaction temperature of 70 ℃. The results indicated that the precipitation rates of copper, cobalt, zinc and manganese were 99.99%, 0.26%, 0.34% and 0.29% respectively, and the main phase of copper slag was CuS. After the above process, the recovery efficiency of copper could reach 99.80%. The leaching residue and copper precipitation residue could be directly used in industrial production, and the liquid after copper precipitation could continue to separate zinc, cobalt and other metal elements.