Question

Identify \(X\) and \(Y\) involved in the extraction of zinc from sphalerite in the sequence given below \[ \text{Sphalerite} \longrightarrow \text{Froth flotation} \longrightarrow X \longrightarrow \text{Reduction with coke} \longrightarrow Y \longrightarrow \text{Pure zinc} \]

• A. \(X\)- Calcination; \(Y\)- Electrolysis
• B. \(X\)- Roasting; \(Y\)- Fractional distillation
• C. \(X\)- Roasting; \(Y\)- Liquation
• D. \(X\)- Calcination; \(Y\)- Fractional distillation \bigskip

Hint:

Extraction of zinc from sphalerite: \[ \boxed{\text{Froth flotation}\rightarrow \text{Roasting}\rightarrow \text{Reduction with coke}\rightarrow \text{Fractional distillation}} \] Sulphide ores are generally roasted before reduction.

Answer 1

The Correct Option is B

Step 1: Concentration of the ore. Sphalerite (\(\mathrm{ZnS}\)) is first concentrated by the froth flotation process.

Step 2: Conversion into oxide. Since sphalerite is a sulphide ore, it is converted into zinc oxide by roasting. \[ 2\mathrm{ZnS}+3\mathrm{O_2} \rightarrow 2\mathrm{ZnO}+2\mathrm{SO_2} \] Hence, \[ X=\text{Roasting} \]

Step 3: Reduction and purification. The zinc oxide is reduced with coke. \[ \mathrm{ZnO+C} \rightarrow \mathrm{Zn+CO} \] The crude zinc obtained is purified by fractional distillation. Hence, \[ Y=\text{Fractional distillation} \]

Step 4: Final conclusion. Therefore, \[ \boxed{X=\text{Roasting},\qquad Y=\text{Fractional distillation}} \] Hence, the correct option is \(\boxed{(B)}\).