Question

Describe calcination and roasting

Answer 1

Difference between Roasting and Calcination. Roasting is the process in which the ore is heated below its melting point in presence of air to oxidise the impurities.  Calcination is the process of heating the ore below its melting point an absence of air to remove volatile impurities like arsenic etc.

Answer 2

The metals in the middle of the reactivity series such as iron, zinc, lead, copper,are moderately reactive. Usually the occur in the form of their sulphide salts or carbonate. It is easier to obtain metals from their oxides rather than sulphide or carbonates. Therefore the sulphide ores are strongly heated in air to transform them into oxides. This process is Called roasting. Carbonate ores are strongly heated in limited supply of air to transform the into oxides. This process is called Calcination.