With the help of suitable chemical equations, list the two main differences between roasting and calcination. How is metal reduced from the product obtained after roasting/calcination of the ore ? Write the chemical equation for the reaction involved.

	Roasting	Calcination
$\displaystyle 1$	It is carried out for sulphide ores.	It is carried out for carbonate ores.
$\displaystyle 2$	Ore is heated in excess of air \[ \begin{aligned}	2 \mathrm{ZnS}+3 \mathrm{O}_{2} \longrightarrow 2 \mathrm{ZnO}+2 \mathrm{SO}_{2}
	\mathbf{O R} \end{aligned} \]	Ore is heated in absence or limited supply of air. \[ \mathrm{ZnCO}_{3} \xrightarrow[\mathbf{O R}]{\text { Heat }} \mathrm{ZnO}+\mathrm{CO}_{2} \] \[ \begin{gathered} \mathrm{CaCO}_{3} \xrightarrow{\text { heat }} \mathrm{CaO}+\mathrm{CO}_{2}
\mathbf{O R} \end{gathered} \] \[ \mathrm{PbCO}_{3} \xrightarrow{\text { heat }} \mathrm{PbO}+\mathrm{CO}_{2} \]

Reduction with the help of carbon \[\mathrm{ZnO}+\mathrm{C} \underset{\text { Heat }}{\longrightarrow} \mathrm{Zn}+\mathrm{CO} \] Alternate answer With the help of heat \[2 \mathrm{HgO}(\mathrm{~s}) \xrightarrow{\text { Heat }} \underset{\mathbf{O R}}{2 \mathrm{Hg}(\mathrm{l})}+\mathrm{O}_{2}(\mathrm{~g}) \] Auto reduction / Heating with its ore \[2 \mathrm{Cu}_{2} \mathrm{O}+\mathrm{Cu}_{2} \mathrm{~S} \xrightarrow{\text { Heat }} 6 \mathrm{Cu}(\mathrm{~s})+\mathrm{SO}_{2}(\mathrm{~g}) \]Roasting