Iron is extracted from haematite by reduction in blast furnace.

The blast furnace is narrow in upper part, wide in middle and narrow at bottom part. The inner side of blast furnace has brick which are fire proof.

Most of the impurities present in ore are removed and then the concentrated ore is added to blast furnace with the help of hooper.

Due to the high temperature following reactions takes place and molten iron is obtained.

i) Coke combines with oxygen and forms carbon dioxide, due to exothermic reaction the temp of furnace becomes 1773K to 1993 K.

C(s) + O₂(g) → CO₂(g) + Heat

ii) Calcium oxide and carbon dioxide are formed due to decomposition of lime stone due to high temperature.

CaCO₃(s) → CaO(s) + CO₂

iii) When hot carbon dioxide goes up in the furnace it combines with coke and forms carbon monoxide, due to the endothermic reaction temperature comes down.

CO₂ (s) + C(s) → CO(g)

iv) When the temp. of furnace is 673K to 973K, the iron oxide present in haematite is reduced to liquid form.

3Fe₂O₃ + CO → 2Fe₃O₄ + CO₂

Fe₃O₄ + CO → 3FeO + CO₂

FeO + CO → Fe + CO₂

Calcium oxide formed during the reaction combines with impurity silica present in haematite and forms calcium silicate i.e. slag.

CaO + SiO₂→ CaSiO₃

Slag is lighter than iron so it floats and separated afterwards.