Why is iron pyrite not the ideal choice of ore for the extraction of iron?

The chemical reaction that involves the roasting process is:

The processes of calcination and roasting in metallurgical industries,respectively,can lead to :-

The reaction $2ZnS + 3O_2 \to 2ZnO + 2SO_2$ in the metallurgical process of zinc is called:

In the process of calcination,the ore is heated in.......

Choose the correct code regarding the Roasting process.
$I$. It is the process of heating ore in air to obtain the oxide.
$II$. It is an exothermic process.
$III$. It is used for hydrated oxide and oxysalt ore.
$IV$. It is used after the concentration of ore.