Extraction of Zinc from Zinc Blende

Zinc is commonly extracted from its ore, zinc blende (ZnS), using a combination of roasting and reduction processes. The correct answer to the question is option B, which states that the extraction is achieved by roasting followed by reduction with carbon. Let's explore this process in detail:

Roasting of Zinc Blende (ZnS)
1. The first step in the extraction of zinc from zinc blende is the conversion of the ore into its oxide form through the process of roasting.
2. In the roasting process, the concentrated ore is heated strongly in the presence of excess air, causing the sulfur in the zinc sulfide to react with oxygen and form sulfur dioxide gas (SO2).
3. The chemical equation for the roasting of zinc blende is:
2ZnS(s) + 3O2(g) → 2ZnO(s) + 2SO2(g)

Reduction of Zinc Oxide (ZnO)
4. After the roasting process, the resulting zinc oxide (ZnO) is subjected to reduction to obtain pure zinc metal.
5. The reduction of zinc oxide is usually carried out by heating it with carbon (in the form of coke) in a furnace.
6. The carbon acts as a reducing agent, meaning it donates electrons to the zinc oxide, causing it to be reduced to zinc metal while carbon itself gets oxidized to carbon dioxide.
7. The chemical equation for the reduction of zinc oxide using carbon is:
ZnO(s) + C(s) → Zn(g) + CO(g)
The zinc vaporizes and is collected and cooled to form solid zinc.

Summary of the Process
1. Zinc blende (ZnS) is roasted to convert it into zinc oxide (ZnO) and sulfur dioxide (SO2) gas.
2. Zinc oxide is then reduced by heating it with carbon (C) to obtain pure zinc metal and carbon dioxide (CO2) gas.
3. The zinc metal is collected and cooled for further processing and use.

Overall, the extraction of zinc from zinc blende involves the steps of roasting the ore to convert it into zinc oxide, followed by reduction with carbon to obtain pure zinc metal. This process allows for the extraction of zinc from its ore and is commonly used in the industry.