Question

Why we converted ores into oxides give reason why cannot be separate directly?

Answer 1

Answer:

to remove impurities from ore

Answer 2

Answer:

In case of medium reactivity,the ores exist maybe with carbonates and sulphates only and to separate them we use calcination and roasting methods respectively.

In case of low reactivity,the ores exist  with  sulphates only and to separate them we use roasting method.