Efficient separation and recovery of valuable metals from bismuth sulfide concentrate in methanesulfonic acid medium

Abstract

As the traditional mainstream process for extracting bismuth sulfide concentrate, chloride leaching has operational maturity and strong applicability to raw materials, but it also has significant volatility and severe corrosion. In this paper, the environmentally friendly methanesulfonic acid (MSA) is used as a leaching agent, and the selective oxidative pressure leaching (SOPL) of bismuth sulfide concentrate is proposed. Through precise control of MSA concentration, bismuthinite is transformed to Bi₂O(OH)₂SO₄ and maintained in the pressure leaching residue (PLR), and then high-purity bismuth metal (Bi > 99.96 %) is produced by the alkaline conversion—acid leaching—electrodeposition treatment. Chalcopyrite is dissolved into the pressure leaching solution (PLS) during SOPL, and CuSO₄·5H₂O product is prepared by extraction—stripping—evaporation crystallization. The integrated process achieves 96.34 % bismuth recovery efficiency with 86.04 % copper recuperation as hydrated sulfate. The proposed method realizes efficient separation and recovery of bismuth and copper in bismuth sulfide concentrate, and provides a new solution for sustainable bismuth hydrometallurgy.