Question

Haematite , the ore of iron undergo roasting.
How is it removed then ? Explain.

Answer 1

It is removed during metallurgy. At high temperature, $CaC{O}_3$ (limestone) decomposes to form $CaO$ , which is the flux. $CaO$ combines with $Si{O}_2$ and forms $CaSi{O}_3$ (slag).

Reactions taking place in the blast furnace are:

$CaC{O}_3\left(s\right)\to CaO\left(s\right)+C{O}_2\left(g\right)$
$CaO\left(s\right)+Si{O}_2\left(s\right)\to CaSi{O}_3\left(s\right)$