(N/A) Roasting is the process of converting sulphide ores to oxides by heating the ores in a regular supply of air at a temperature below the melting point of the metal. For example,sulphide ores of $Zn$,$Pb$,and $Cu$ are converted to their respective oxides by this process.
$2ZnS + 3O_2 \xrightarrow{\Delta} 2ZnO + 2SO_2$
$2PbS + 3O_2 \xrightarrow{\Delta} 2PbO + 2SO_2$
$2Cu_2S + 3O_2 \xrightarrow{\Delta} 2Cu_2O + 2SO_2$
On the other hand,calcination is the process of converting hydroxide and carbonate ores to oxides by heating the ores either in the absence or in a limited supply of air at a temperature below the melting point of the metal. This process causes the escaping of volatile matter leaving behind the metal oxide. For example,hydroxide of $Fe$,carbonates of $Zn$,$Ca$,and $Mg$ are converted to their respective oxides by this process.
$Fe_2O_3 \cdot 3H_2O \xrightarrow{\Delta} Fe_2O_3 + 3H_2O$
$ZnCO_3(s) \xrightarrow{\Delta} ZnO(s) + CO_2(g)$
$CaMg(CO_3)_2 \xrightarrow{\Delta} CaO(s) + MgO(s) + 2CO_2(g)$