Question

What are the differences between calcination and roasting?

Answer 1

CALCINATION:

Calcination is the process of heating the ore below it's melting point in the absence of air to remove volatile impurities like arsenic etc...

ROASTING:

Roasting is the process by which ore is heated below melting point in the presence of air to oxidise the impurities.

Answer 2

Hey !!

ROASTING  

It is the process of heating the ore below its melting point with excess of air.

Sulphide ore are converted into oxide form.  

          2Zns + 3O₂ ---(HEAT)--> 2ZnO + 2SO₂↑

Volatile impurities are removed as oxides SO₂ , As₂O₃ etc.

CALCINATION

It is the process of heating the ore below its melting point in the absence or limited supply of air.

Carbonate ores are converted into oxide

         ZnCO₃ ---(Heat)--> ZnO + CO₂↑

Water and organic impurities are removed.

Hope it helps you !!