Question

How is zinc extracted from its ore? Name the processes involved in the extraction and write chemical equations for the reactions that occur during these processes.

Hint:

Zinc is extracted from zinc blende by roasting to form zinc oxide, followed by reduction using carbon to obtain pure zinc metal.

Answer 1

Zinc is extracted from its ore, zinc blende (ZnS), through the following processes: 
Concentration of Ore: Zinc blende is first concentrated by the process of frost flotation. In this method, the ore is crushed and mixed with water and frothing agents. The lighter impurities are separated from the heavier zinc ore. 
Roasting: The concentrated zinc ore (ZnS) is heated in the presence of oxygen. This process is called roasting, and it converts zinc sulfide into zinc oxide, releasing sulfur dioxide: \[ 2{ZnS} + 3{O}_2 \rightarrow 2{ZnO} + 2{SO}_2 \] 
Reduction of Zinc Oxide: The zinc oxide obtained from roasting is then reduced to zinc metal by heating it with carbon in a furnace: \[ {ZnO} + {C} \rightarrow {Zn} + {CO} \] This reduction process takes place at a high temperature, and zinc metal is extracted.