Write chemical reactions taking place in the extraction of zinc from zinc blende.
Open in App
Solution
During extraction of Zn from zinc blende (ZnS), following reactions occur: (i) ZnS is roasted in excess air at 1200 K to form ZnO.
2ZnS+2O2Δ−→2ZnO+2SO2 (ii) ZnO is heated with crushed coke at 1673 K, where it is reduced to Zn. ZnO+C1676K−−−−→Zn+CO (iii) Electrorefining is carried out for refining of impure zinc. Anode is impure zinc and cathode is pure zinc. Electrolyte is a mixture of zinc sulphate and dilute sulphuric acid (small amount). When current is passed, zinc is deposited on cathode and is collected. At anode : Zn→Zn2++2e− At cathode: Zn2++2e−→Zn