What is the role of limestone during the extraction of iron from haematite ore?
What is the role of limestone during the extraction of iron from haematite ore?
Leaching agent
Oxidising agent
Reducing agent
Flux
Solution
During extraction of iron from haematite ore, roasted ore, along with coke and limestone is heated in blast furnance. Here coke behaves as reducing agent and limestone is worked as flux. In this process, in reducing zone $\left(400-900^{\circ} \mathrm{C}\right)$, spongy iron is obtained. In slag zone $\left(900-1200^{\circ}\right)$, limestone reacts with impurity (e.g., silica) to form slag. In the combustion and fusion zone $\left(1200-1600^{\circ} \mathrm{C}\right)$, all the charge melts and pig iron is obtained which purified further.