Treatment of sulphate leach liquors to recover cobalt from waste dusts generated by the glass industry

A hydrometallurgical process has been developed for cobalt recovery from a waste dust formed during the colouring of glass plates. This dust, containing about 33% Co, is highly contaminated by Fe and Cr. The process consists of the following major steps: (1) leaching the dust in H2SO4; (2) purification of leach liquors by hydrolytic precipitation using Na2CO3 and/or K2CO3 as neutralizing agent; (3) precipitation of basic cobalt(II) carbonate; (4) dissolution of basic cobalt(II) carbonate in sulphuric acid and separation of residual chromium; (5) electrowinning of cobalt from refined sulphate solutions. A compact metallic deposit containing =99.5% Co was obtained.