Question

limestone is used in the extraction of iron from its ore.why?

Answer 1

Dear student!
Limestone is basically the calcium carbonate (CaCO₃) which is used as the flux and when it is added to molten iron, it quickly decomposes into carbon dioxide(CO₂) and quick lime i.e. calcium oxide(CaO). Sometimes, calcium oxide (lime or quicklime) is used instead of limestone.
The CaO combines with impurities in the molten iron to form both light and heavy slag like calcium silicates (CaSiO₃), which float to the top or sink to the bottom of the molten iron.