Question

Which of the following processes are widely used in the extraction of moderately reactive metals from their sulphide ore?

• A. Electrolytic reduction
• B. Heating with carbon
• C. Roasting
• D. Calcination

Answer 1

Answer: (B), (C)

Roasting

Sulphide ores of medium and low reactive metals, when heated in the presence of oxygen, produces metal oxide and sulphur dioxide. This process is called roasting.
Example:
$\text{ZnS(s)}+{\text{O}}_2\text{(g)}\to \text{ZnO(s)}+{\text{SO}}_2\text{(g)}$

The metal oxides obtained are then heated with carbon to give carbon dioxide and metal.
Example:
$\text{ZnO(s)}+\text{C(s)}\to \text{Zn(s)}+{\text{CO}}_2\text{(g)}$