Electrochemical separation and extraction of cobalt and tungsten from cemented scrap

Molten salt electrolysis was utilized for the separation of cobalt and tungsten from cemented carbide scrap in the NaCl-KCl melt at 1023 K (750 °C). The WC-15 Co sacrificial anode was dissolved to cobalt and tungsten ions and consequently discharged on the cathode to deposit cobalt and tungsten during electrolysis. The carbon remained at the anode with a porous structure. The oxidation potential of the cobalt and the tungsten carbide in the cemented carbide were analyzed through the electrochemical method. The effects of anode potential, current and duration on the dissolution were investigated. The anodic dissolution processes under different conditions were characterized through SEM and EDX. Subsequently to the two-step electrolysis, the cobalt powders of 100 nm in diameter, the tungsten powders of below 200 nm in diameter and a porous structure of carbon were obtained.