Electrochemical preparation of tungsten and cobalt from cemented carbide scrap in NaF-KF molten salts

In this study, WC-10Co was used as a consumable anode for the direct preparation of cobalt and tungsten from NaF-KF molten salt at 1023 K. Electrochemical analysis was performed via cyclic and square wave voltammetry. Results showed that cobalt and tungsten ions possess different precipitation potentials in the molten salt, thus theoretically proving the feasibility of preparing separating metallic cobalt and tungsten respectively. Tungsten and cobalt ions exist as W2+ and Co2+, and the reaction is reversible and controlled by diffusion. The effects of electrolytic current, duration, and temperature on anodic dissolution mass, dissolution rate, and cathode composition and morphology were studied via electrochemical analysis. The cathode product was analyzed by XRD and SEM. The results further showed that cobalt powder can be obtained when the electrolytic current was 12 mA for a short period of time. Tungsten powder can be obtained by increasing electrolytic current and duration. Furthermore, tungsten powder with a particle diameter of less than 1 inn can be obtained under the following electrolysis conditions: current of 88 mA, duration of 7 h, and temperature of 1023 K.