Industrial Extraction of Iron in the Blast Furnance

Industrial Extraction of Iron in the Blast Furnace

Iron ore (usually haematite which contains iron(III) oxide – Fe2O3)
Coke (a type of carbon)
Limestone (calcium carbonate - serves to remove sand impurities in the ore by neutralisation)

The coke, or carbon, burns in the blast furnace to produce heat and reacts to form carbon monoxide (CO)
- C + O2 -> CO2
Carbon dioxide then reacts with leftover coke to produce carbon monoxide
- CO2 + C -> 2CO
The carbon monoxide then reduces iron (III) oxide present in the iron ore to form iron and carbon dioxide
- 3CO + Fe2O3 -> 2Fe + 3CO2
The calcium carbonate in limestone decomposes to form calcium oxide and carbon dioxide
- CaCO3 -> CaO + CO2
Calcium oxide, also known as quicklime, reacts with silicon dioxide, the primary impurity in the iron ore, to form calcium silicate or slag
- CaO + SiO2 -> CaSiO3

Pig iron is produced in the blast furnace. It has around 96% iron content but is brittle due to impurities
The slag floats on top of the iron and can be separated and used in the construction industry
Steel is produced by removing further impurities from pig iron. It is an alloy of iron and other elements and is far less brittle than pig iron