Question

From which of the following ores, metals cannot be extracted using calcination process?

• A. ${\mathrm{CaCO}}_3$
• B. ${\mathrm{Al}}_2{O}_3.2H_{2}O$
• C. ${\mathrm{CaCO}}_3.\mathrm{Ca}(\mathrm{OH}{)}_2$
• D. $\mathrm{ZnS}$

Answer 1

The correct option is D

$\mathrm{ZnS}$

Calcination is the process of converting an ore into an oxide by heating it strongly. The ore is heated below its melting point in absence of oxygen and is commonly used for converting carbonates and hydroxides to their respective oxides. This process is applicable to ${\mathrm{CaCO}}_3.\mathrm{Ca}(\mathrm{OH}{)}_2$ ,${\mathrm{Al}}_2{O}_3.2H_{2}O$ and ${\mathrm{CaCO}}_3$.

Roasting is a method which is used for converting sulphide ores to oxides. $\mathrm{ZnS}$is roasted to get oxide.
$2\mathrm{ZnS}\left(s\right)+3O_2\left(g\right)\to 2\mathrm{ZnO}\left(s\right)+2{\mathrm{SO}}_2\left(g\right)$