Question

a) Calcination and roasting are pre-treatments in metallurgy before metal extraction. Differentiate between calcination and roasting.

b) Match the items of Column I with items of Column II.

Column I	Column II
i) Distillation	a) Ge
ii) Liquation	b) Ni
iii) Zone refining	c) Cu
iv) Vapour phase refining	d) Zn
	e) Sn

Answer 1

a) Calcination is the process of heating the ore in the absence or limited supply of air when the volatile matter escapes leaving behind the metal oxide. Here oxygen ¡s not consumed, It is applied to hydrated oxides, hydroxides and carbonates.

Roasting is the process of heating the ore in a regular supply of air in a furnace at a temperature below the melting point of the metal. Here oxygen is consumed. it is applied to suiphide ores.

b)

Column I	Column II
i) Distillation	d) Zn
ii) Liquation	e) Sn
iii) Zone refining	a) Ge
iv) Vapour phase refining	b) Ni