When smelting assays are done on high sulfide ores, a couple of iron nails are added to the mix. The metal in the nails reacts with the metals in the sulfides reducing the metals to their metallic state.
This iron ore is then converted into various types of iron but first it is processed in a blast furnace to produce pig iron. Used by itself, pig iron has few uses due to its brittle nature. Alloyed with other metals, pig iron takes on new uses.