(a) What is calcination ?
(b) What is roasting?

Explanation

Calcination. The process of converting carbonates and hydroxide ores of metals to their respective oxides by heating them strongly below their melting points either in absence or limited supply of air is called calcination. For example,
`underset("Limonite")(Fe_(2)O_(3)*3H_(2)O) overset(Delta)to underset("Ferri oxide")(Fe_(2)O_(3))+3H_(2)O`
`underset("Dolomite")(CaCO_(3)*MgCO_(3)) overset(Delta)to CaO+MgO+2CO_(2)`
`underset ("Malachite")(CuCO_(3)*Cu(OH)_(2)) overset(Delta)to 2CuO+H_(2)O+CO_(2)`
`underset("Calaminc")(ZnCO_(3)) overset(Delta)to ZnO+CO_(2)`
Roasting. The process of converting a sulphide ore into its metallic oxide by heating strongly below its melting point in excess of air is called roasting. For example,
`underset("Zinc blende")(2ZnS)+3O_(2)to underset("Zinc oxide") (2ZnO)+2SO_(2) uarr`
`underset("Galena")(PbS)+3O_(2) to underset("Lead oxide")(PbO)+2SO_(2) uarr`