The more advanced way to smelt iron is in a blast furnace. A blast furnace is charged with iron ore, charcoal or coke (coke is charcoal made from coal) and limestone (CaCO 3 ). Huge quantities of air blast in at the bottom of the furnace, and the calcium in the limestone combines with the silicates to form slag.
Iron ore is the raw material used to make pig iron, which is one of the main raw materials to make steel. 98% of the mined iron ore is used to make steel. Minnesota's iron ore was actually discovered while prospectors were searching for gold. Since the object of their search was gold, the iron was ignored.