Question -
Answer -
The different steps involved inthe extraction of zinc from zinc blende (ZnS) are given below:
(i) Concentration of ore
First,the gangue from zinc blende is removed by the froth floatation method.
(ii) Conversion to oxide (Roasting)
Sulphideore is converted into oxide by the process of roasting. In this process, ZnS isheated in a regular supply of air in a furnace at a temperature, which is belowthe melting point of Zn.
(iii) Extraction of zinc from zinc oxide (Reduction)
Zinc isextracted from zinc oxide by the process of reduction. The reduction of zincoxide is carried out by mixing it with powdered coke and then, heating it at673 K.
(iv) Electrolytic Refining
Zinc canbe refined by the process of electrolytic refining. In this process, impurezinc is made the anode while a pure copper strip is made the cathode. Theelectrolyte used is an acidified solution of zinc sulphate (ZnSO4). Electrolysis resultsin the transfer of zinc in pure from the anode to the cathode.
