Zinc isolation begins with the mining of sphalerite minerals which contain zinc sulfides. The froth flotation method is used to gather these minerals. During this process, surfactants and wetting agents are used to separate the sulfides from carbonates and oxides. After the froth flotation procedure, the zinc sulfide is roasted using the process of pyrometallurgy; this process oxideses the zinc sulfide into zinc oxide. Pryometallurgy is the process in which metal ores undergo thermal treatment.
After pyrometallurgy, the zinc oxide produced undergoes under goes a leaching process using sulfuric acid to produce zinc sulfate. During the leaching process, iron and other impurities are removed. The last step of zinc isolation removes such elements as copper, cadmium, and cobalt. Zinc metal is removed from a purified zinc sulfate solution in the form of cathodic deposits that are extracted using electro-winning with aluminum sheets. The electro-winning process is carried out using either a low current density process, or a high currently density process.
