Question

Write down two differences between roasting and calcination.

Answer 1

1.In roasting,the ore is heated in excess of air whereas;in calcination the ore is heated in absence or in limited supply of air.
2. Roasting is used for sulphide ores while calcination is used for carbonate ores.

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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 !!