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), via these steps:
Ore Concentration: Zinc blende is initially concentrated using froth flotation. The ore is crushed and combined with water and frothing agents. Lighter impurities are removed from the heavier zinc ore. 
Roasting: The concentrated zinc ore (ZnS) is heated with oxygen. This roasting process transforms zinc sulfide into zinc oxide, emitting sulfur dioxide: \[ 2{ZnS} + 3{O}_2 \rightarrow 2{ZnO} + 2{SO}_2 \] 
Zinc Oxide Reduction: The zinc oxide produced by roasting is then reduced to zinc metal by heating it with carbon in a furnace: \[ {ZnO} + {C} \rightarrow {Zn} + {CO} \] This reduction occurs at high temperature, and zinc metal is extracted.