Roasting : Removal of the volatile components of a mineral by heating mineral either alone (or) mixed with some other substances to a high temperature in the presence in the presence of air is called Roasting.
`rarr` It is applied to the sulphide ore.
`rarr` `SO_(2)` gas is producted along with metal oxide.
Eg : `2ZnS+3O_(2)overset(Delta)rarr2ZnO+2SO_(2)uarr`
Calcination : Removal of the volatile components of a mineral by heating in the absence of air is called calcination.
`rarr` It is applied to carbontes and bicarbonates.
`rarr` `CO_(2)` gas is produced along with metal oxide.
Eg : `CaCO_(3)overset(Delta)rarrCaO+CO_(2)`
`ZnCO_(3)overset(Delta)rarrZnO+CO_(2)`
