Write chemical reactions taking place in the extraction of zinc from zinc blende.
The steps involved in the extraction of zinc from zinc blende (ZnS) are as followed:-
1) Concentration: the ore is crushed and then concentrated by froth floatation process.
2) Roasting: the concentrated ore is heated in the presence of an excess of air at about 1200K to form zinc oxide.
ZnS + 3 O2→ 2 ZnO + 2 SO2
3) Reduction: ZnO obtained above is mixed with powdered coke and heated to 1673K in a fireclay resort.
4) Electrolytic Refining: Zinc is refined by the process of electrolytic refining. In this process, impure zinc is made the anode and a pure copper strip is made the cathode. The electrode used in an acidified solution of zinc sulphate (ZnSO4). Electrolysis results in the transfer of zinc in pure form from the anode to the cathode.
