Write chemical reactions taking place in the extraction of zinc from zinc blende.

Explanation

The various steps involved in the process are :
i) Concentration of ore
Ore is crushed and concentrated by froth-floatation process.
ii) Roasting
Concentrated ore is roasted in the presence of excess of air at 1200 K.
`2ZnS + 3O_2 underset(1200K)overset(Delta)tounderset ("Zinc oxide")(2ZnO + 2SO_2)`
iii) Reduction
Zinc oxide is heated with powdered coke at 1673 K in a fire clay retort.
`ZnOa + C underset(1673K)overset(Delta)to Zn + CO`
Electrolytic refining
lmpure zinc is made anode and a sheet of pure zinc is cathode. A solution of `ZnSO_4` and dilute `H_2SO_4` act as electrolyte. When current is passed. pure zinc is deposited on the cathode.