Note: metal chromium is a silver white metal, refractory (melting point 1800 ℃), with a specific gravity of 7.1, similar to that of iron. Generally, the chromium produced is hard, brittle, corrosion resistant, and exists only in a combined state. It mainly exists in the form of chromite and is separated from ore by aluminothermic method, silicothermic method or electrolytic method. Chromium metal is mainly used in the production of nickel base and cobalt base superalloys, aluminum alloys, titanium alloys, resistance alloys, corrosion resistant alloys, iron base heat-resistant alloys and stainless steels.