An optimized recovery of cobalt and tungsten carbide WC from 2025 Minerals

Tungsten extraction from scheelite and wolframite ores is a well-established process. However, continuous exploitation has led to more complex ore compositions and lower WO3 concentrations in tungsten concentrates, posing significant challenges for sustainable extraction. Primary and secondary tungsten sources often contain valuable metals such as Sn, Ta, Nb, Mo, Sc, and Co; however, current industrial processes focus predominantly on tungsten recovery, neglecting other metals and compromising sustainability. This study aimed to develop a process for the co-recovery of tungsten carbide (WC), cobalt (Co), and tungsten (W) from cemented carbide scrap using a sulphate-based leaching system. A statistical Design Of Experiments (DOE) approach was employed to screen and optimize process variables, including acid concentration, leaching time, solid-to-liquid ratio, temperature, and agitation rate. Characterization revealed the material contained 85.95 wt% W, 8.77 wt% C, and 5.28 wt% Co. Optimal leaching occurred with 2 M H2SO4, a 1:10 S/L ratio, at 82 ◦C, and 750 rpm agitation, achieving 25.13 % Co extraction in 10 h and 97.6 % after 4.2 days. Increasing the temperature to 92 ◦C improved extraction, reaching 31.7 % in 10 h. Temperature was identified as the primary factor influencing cobalt dissolution kinetics. The recovered WC powder consisted of well-defined, fine particles comparable in quality to ‘virgin’ WC. Electroplated cobalt achieved 91.9 % current efficiency over 3 h, producing metal with 98.0 wt% purity and good morphological integrity. Synthetic tests confirmed that tungsten recovery as scheelite (CaWO4) is highly feasible.