As suggested by its name, a blast furnace uses intense heat to cause the chemical changes that result in the production of iron and its associated byproducts. Blast furnaces process iron ore, most frequently mined in the form of hematite, into pig iron, which can be further processed to make steel.
When highly heated air blasts the raw material of iron oxide, carbon monoxide and heat are produced. The carbon monoxide reacts with the iron oxide to produce molten iron and carbon dioxide after repeated steps of heat application. The overall summary statement of the chemical reaction process is Fe2O3 + 3CO → 2Fe + 3CO2.