 Several methods exist for the separation of cobalt from copper and nickel . They depend on the concentration of cobalt and the exact composition of the used ore . One separation step involves froth flotation , in which surfactants bind to different ore components , leading to an enrichment of cobalt ores . Subsequent roasting converts the ores to the cobalt sulfate , whereas the copper and the iron are oxidized to the oxide . Leaching with water extracts the sulfate together with the arsenates . The residues are further leached with sulfuric acid , yielding a solution of copper sulfate . Cobalt can also be leached from the slag of copper smelting . 
