The electrochemical dissolution mechanism and treatment process in the molten-salt electrolytic recovery of WC-Co two-phase scraps

Abstract

The use and scrap of cemented carbide, especially WC-Co series cemented carbide, are increasing every year. Recycle of cemented carbide scrap is paid attention to more and more by researchers. In this paper, the molten salt electrolysis method was employed to extract tungsten and cobalt. The focal points of this study were the electrochemical dissolution mechanism of WC-Co two-phase scraps and the treatment process of multiple pieces of WC-Co scrap. Electrochemical impedance spectroscopy indicated that the dissolution mechanism of WC-Co composite had the anodic potential dependence. The equivalent circuit model of WC-Co two-phase composite can adopt the “Rct parallel model” of cobalt and tungsten carbide. At the case of surface area evolution or multiple anodes electrolysis, the equivalent circuit model can also adopt the “Rct parallel model”, which built a bridge between single WC-Co anode and multiple WC-Co anodes. Consequently, we designed and achieved the recovery process of multiple WC-Co anodes. The XRD analysis and elemental analysis showed that the products were pure cobalt and pure tungsten, respectively.