Question

Calcination is used in metallurgy for the removal of:
(A) ${H_2}O{\rm{ \& }}{{\rm{H}}_2}S$
(B) $C{O_2}{\rm{ \& }}{H_2}S$
(C) Water $\& \,\,C{O_2}$
(D) Water and sulphide

Answer 1

Hint: The science of extracting metals from their ore is known as metallurgy. When the process of metallurgy is carried out at high temperature but in the limited supply of oxygen or air, then the process is termed as calcination.

Complete Step by Step Solution:
The metals are usually obtained through the electrolysis process of their respective oxides in metallurgy. In many cases, metals are not present in the form of oxides; instead , many ores are formed as carbonates or sulphates of the metal. In such cases, the extraction of metals from their ores is done by applying a process known as calcination in which sulphate or carbonate ores thermally decompose to form oxides of the corresponding metals.

An example of the process of calcination is given below:
- Malachite (ore of copper) on heating undergoes calcination and produces copper oxide along with the removal of water and carbon dioxide.

Therefore, Calcination in metallurgy is used in the removal of Water $\& \,\,C{O_2}$.
Thus, option (C) is the correct answer.

Note: It is important to note that in case of calcination, ore of the metals becomes porous after the removal of volatile products like water and carbon dioxide while organic impurities decompose into smaller volatile products. Alternatively, the extraction of metals can be performed by the process known as roasting in which the thermal decomposition of the metal ore takes place in the excess of oxygen or air.