Efficient Dissolution of Tungsten Carbide Using an Oxygen-Containing Molten Salt

Abstract

Efficient electrochemical dissolution of tungsten carbide is crucial to obtain an efficient recovery of cemented carbide via molten salt electrolysis. Based on the interfacial process, the dissolution mechanism of tungsten carbide in oxygen-containing molten salt was investigated via a mass loss test, electrochemical tests, and first principles calculations. Through the mass loss study, it was found that, although the tungsten-carbon bond was extremely stable, an effective electrochemical dissolution of tungsten carbide could also occur in the presence of oxygen ions. The electrochemical tests demonstrated that an increase in oxygen ions leads to a continuous substitution of chloride ions with oxygen ions on the anode surface. These oxygen ions are further converted into oxygen atoms under the action of an electric field. The oxygen atoms on the anode surface can then effectively destroy the tungsten-carbon bond and promote mass loss, as demonstrated by first principles calculations. In addition, the appearance of maximum mass can be related to the saturation of the electrostatic adsorption of oxygen ions.