Question

to remove gangue from iron ore a white substance is mixed with it in the blast furnace wha is it? state its one other application

Answer 1

To remove gangue from iron ore a white substance is mixed with it in the blast furnace. This white substance is calcium carbonate.
Calcium carbonate is added as flux to remove the impurities(gangue).
Calcium carbonate decomposes inside the furnace to give CaO and carbondioxide.
The calcium oxide reacts with impurities of silicon as calcium silicate.
The carbondioxide gets reduced to CO by hot coke inside the furnace, which helps in better reduction of iron oxide.