Question

Draw labelled diagram and reaction of blast furnace in metallurgy of iron.

Answer 1

Main reactions which take place in the blast furnace are:

(i) Reduction zone:
(approx 673 – 978 K) At 673 K
3Fe₂O₃ + CO → 2Fe₃O₄ + CO₂↓
Fe₃O₄ + CO → 2FeO + CO₂↓
Fe₂O₃ + CO → 2FeO + CO₂↓
This iron is porous and solid. It is known as spongy iron.

(ii) Central zone (Endothermic Region):
(approx 1173-1473 K)
CaCO₃ \(\overset{1273k}{\longrightarrow}\) CaO + CO₂↓
FeO + CO → Fe + CO₂ ↓

(iii) Fusion zone:
(approx 1373 – 1573K)
In this zone, spongy iron melts and absorbs C, P, Si, etc.
CO₂ + C → 2CO, ∆H = + 163kJ

(iv) Combustion zone:
(approx 1773K–2173K)

FeO + C → Fe + CO