What is a blast furnace used for?

According to the American Iron and Steel Institute, the purpose of a blast furnace is to produce enough heat to extract iron from raw ore. Iron ore, coke and limestone are placed into a blast furnace and then heated until liquid iron can be separated from the ore.

Once the blast furnace is heated, there are several chemical reactions that take place. The coke is used to produce carbon monoxide, which is a reducing agent used to extract the molten iron from solid ore. The limestone serves as a fluxing agent that bonds with impurities to produce slag, which is then removed before the liquid iron is poured.