Question

Write down the reaction taking place in blast furnace related to the metallurgy of iron in the temperature rnge 500 K – 800 K. What is the role of limestone in the metallurgy of iron? 

Answer 1

Reaction in blast firnace during metallurgy of Fe at 500 K – 800 K involves.
3Fe₂O₃ + CO → 2Fe₃O₄ + CO₂
3Fe2O₄ + 4CO → 3Fe + 4CO₂
Fe₂O₄ + CO → 2FeO + CO₂ 
Reduction of iron oxides takes place. Limestone is added, during metallurgy as it decomposes to CaO at high temperature in funace. 
\[\ce{ CaCO3{(s)}  ->[\Delta]} CaO(s) + CO{2(g)}\]
Calcium oxide removes silicate impurity of ore as slag. Slag in molten state floats on molten iron metal, hence can be easily removed.