The common ore of iron are iron oxides, and we have earlier discussed how these can be reduced to iron by heating them with coke in a blast furnace. The molten iron that is produced contains various non metal impurities that are removed or reduced by mixing it with scrap iron, blowing pure oxygen into the mixture, and adding calcium oxide. The slag that forms is removed, and other elements like chromium, nickel and manganese are added to the steel to produce alloys such as stainless steel.
