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

1) Zinc blende is heated in air to get rid of the Sulphur and to convert it into ZnO which is more reactive. This way, it will be easier to obtain the zinc metal.

Reaction when Zinc Blende is heated in the air: 2 ZnS + 3O2→ 2 ZnO + 2SO2

(2)The Zinc Oxide is then mixed with crushed coke (carbon) and heated at 1673 K in fire clay retorts (Belgian Process) when ZnO gets reduced to metallic zinc. In this reaction, carbon acts as the reducing agent as Zinc's oxidation state is reduced from +2 to 0 and carbon itself is reduced.

Reaction when Zinc Oxide is heated in fire clay retorts: 2 ZnO + C → 2 Zn + CO2

(3)Being volatile at this temperature, the metal distils over and is condensed leaving behind Cd, Pb and Fe as impurities. The crude metal is called spelter. This metal may be purified either by electrolysis or by fractional distillation.