6.14 Giving examples, differentiate between ‘roasting’ and ‘calcination’.
Roasting- The process of converting sulphide ore to oxide. In this process, the ore is heated in the furnace with a regular supply of air, below its melting temperature: example- sulphide ore of zinc, lead, and copper.
Calcination- Process of converting hydroxide and carbonate ore to oxide in a limited supply of air. The temperature should be below the metals melting point in this process volatile matter which escapes, leaving behind the metal oxide.