Selective dissolution of the cobalt binder from scraps of cemented tungsten carbide in acids containing additives

Scraps of cemented tungsten carbide were electrolyzed to dissolve their cobalt binder and recover tungsten carbide. Anodic passivation retards the acid dissolution of the cobalt. Anodic linear sweep and cyclic voltammetry were conducted for selecting adequate electrolytes, in which the passivation was diminished and thus the cobalt dissolution was enhanced. Anodic passivity of the scrap in acids was minimized in the presence of additives (e.g. 0.1 M citric acid in 1 M HCl). More effective electrolysis was carried out potentiostatically at 0.200-0.600 V (vs. SCE). A flowsheet to recover the tungsten carbide and cobalt from scraps of cemented tungsten carbide is suggested.