Extracting iron

Iron is used in bridges, buildings and other structures because it is strong.

The blast furnace

Iron is extracted from iron ore in a huge container called a blast furnace. Iron ores such as haematite contain iron(III) oxide, Fe2O3. The oxygen must be removed from the iron(III) oxide to leave the iron behind.

Reactions in which oxygen is removed are called reduction reactions.

Blast furnace. Iron ore, carbon, limestone enter at top. Air enters at side near bottom. Three zones. Air into zone 1, waste gases out above zone 3. Slag out below zone 1, iron out at very bottom.

It is so hot in the blast furnace that carbon monoxide is the reducing agent which reduces the iron(III) oxide. The equation for the reduction of iron(III) oxide in the blast furnace is:

iron(III) oxide + carbon monoxide → iron + carbon dioxide

Fe2O3(s) + 3CO(g) → 2Fe(l) + 3CO2(g)

Molten iron is tapped off at the bottom of the blast furnace.

Raw materials for the reaction

Raw materialContainsFunction
Iron ore (haematite)Iron(III) oxideA compound that contains iron
CokeCarbonBurns in air to produce heat, and reacts to form carbon monoxide (needed to reduce the iron oxide)
LimestoneCalcium carbonateHelps to remove acidic impurities from the iron by reacting with them to form molten slag
AirOxygenAllows the coke to burn, and so produces heat