The reduction of iron oxide

The blast furnace

At high temperature, the oxygen of the air reacts with the coke (impure carbon) to produce carbon monoxide (a colourless and toxic gas): $2C$ $ +$ $ O_2$ $ \longrightarrow $ $2CO$ The carbon monoxide reduces iron oxide to iron: $Fe_2O_3 $ $+ $ $3CO $ $ \longrightarrow$ $ 2Fe$ $ +$ $3 CO_2$ The molten iron (cast iron = impure iron) comes together at the bottom of the blast furnace. The liquid blast furnace slag consists of the impurities of the iron ore and the coke. It floats on top of the liquid iron.