Question

Calcination is used in metallurgy for removal of

• A. water and sulphide
• B. water and CO$_2$
• C. CO$_2$ and H$_2$S
• D. H$_2$O and H$_2$S

Hint:

Calcination → removes water and CO$_2$, roasting → removes sulphur.

Answer 1

The Correct Option is B

In metallurgy, calcination is a thermal treatment process used to decompose and remove certain components from ores or other materials. Specifically, it is used to remove volatile substances, moisture, and to create a solid residue by heating the material at high temperatures in a controlled environment.

Concept of Calcination:

• Calcination involves heating the material in the absence or limited supply of air or oxygen to cause thermal decomposition.
• The primary objective of calcination is to remove volatile components such as water (H₂O) and carbon dioxide (CO₂).
• It is commonly applied to metal carbonates, where the process results in the conversion of carbonates into oxides with the release of carbon dioxide.

Explanation of Removal:

• Water (H₂O) is removed as the material is heated, causing the water to evaporate.
• Carbon Dioxide (CO₂) is removed through thermal decomposition of carbonates into oxides and CO₂.

Justification of the Correct Option:

Let's analyze the options provided:

1. Water and Sulphide
2. Water and CO₂ (Correct Answer)
3. CO₂ and H₂S
4. H₂O and H₂S

From the above analysis, calcination primarily involves the removal of water and carbon dioxide. Hence, the correct answer is Water and CO₂. Other options include the removal of sulphide or hydrogen sulphide (H₂S), which is typically not involved in the process of calcination.

Therefore, the correct answer is: Water and CO₂.