Question

Difference between roasting and calcination.

Answer 1

In both calcination and roasting, an ore is converted into its oxide, albeit through different chemical pathway. Calcination is the process in which the ore is heated below its melting point, either in the absence or in a limited supply of air, in an aim to drive off volatile expunges, moisture, water of hydrates and organic matter from the ore. Carbonate, bicarbonate and hydroxide ores are generally subjected to calcination which produce the metal oxide after expelling CO2 or H2O in the process.

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 !!