Question

Explain the method for obtaining pig iron from magnetite. 

Answer 1

Extraction of iron from Magnetite takes place in following steps:

(i) Concentration of ore: It is done by Gravity separation followed by magnetic separation process. 

(ii) Calcination: It involve heating when the volatile matter escapes leaving behind metal oxide. 

Fe₂O₃. xH₂O→ Fe₂O₃ + xH₂O 

(iii) Roasting: It involves heating of ore in presence of air, thus moisture,CO₂,SO₂, As₂O₃ removed And FeO oxidized to Fe₂O₃. 

(iv) Smelting of roasted ore: A mixture of ore, coke & CaCO₃ is smelted in long BLAST FURNACE. Following reaction takes place at different temperature zones:- 

(i) Zone of reduction: Temperature range 250 °C - 700 °C

(ii) Zone of slag formation: Temperature range 800°C -1000°C

(iii) Zone of fusion:- Temperature range 1150°C-1350°C 

CO₂ + C → 2CO

(iv) Zone of fusion: Temperature range 1450 °C-1950°C 

C + O₂ → CO₂