Blast furnace formula basics
Coke = Carbon (C)
Iron ore (haematite) = Iron oxide = Fe2O3 (Press here to remember this formula)
Iron ore + Carbon monoxide → Iron + Carbon dioxide
Fe2O3 + CO → Fe + CO2
This is not balanced. Can we balance it?
Putting a 3 in front of the carbon monoxide and carbon dioxide will balance both the carbon and oxygen on each side of the equation.
Fe2O3 + 3CO → Fe + 3CO2
Then, we need to balance the iron by adding a 2.
Fe2O3 + 3CO → 2Fe + 3CO2