In iron and steel industry, the main raw materials for blast furnace ironmaking are iron ore, coke and limestone. What's the use of limestone here?
Calcium oxide absorbs sulfur dioxide and prevents it from polluting the air.
At high temperatures, limestone (calcium carbonate) breaks down into lime (calcium oxide, which is useful) and carbon dioxide.
CaCO3 CaO + CO2 =C = 2CO + CO2Fe2O3
