Question

diff between calcinnation and roasting

Answer 1

Calcination: Process of heating concentrated ore in the absence of air at a temperature below its melting point....
Roasting : Process of heating concentrated ore in the presence of air to a high temperature before it is reduced to metal

Answer 2

Roasting-:
The process of converting sulphide ores into oxides by heating strongly in the presence of excess of air.
Ex. 2Zn +3O2 -----> 2ZnO + 2SO2
Calcination-:
The process of converting carbonate ores into oxides by heating them strongly in the limited supply of air.
Ex. ZnCO3 ---->ZnO + CO2