Question

How is zinc extracted from its ore? Name the processes involved in the extraction and write chemical equations for the reactions that occur during these processes.

Answer 1

Zinc oxide is created by roasting and calcining zinc sulphide (ZnS) and zinc carbonate (ZnCO₃), which are its ores. Metallic zinc is then created by reducing zinc oxide with carbon.

(i) Roasting: Conversion of zinc sulphide into zinc oxide.

\[\ce{2ZnS_{(s)} + 3O2_{(g)} ->[Heat] 2ZnO_{(s)} + 2SO2_{(g)}}\]

(ii) Calcination: Conversion of zinc carbonate into zinc oxide.

\[\ce{ZnCO3_{(s)} ->[Heat] ZnO_{(s)} + CO2_{(g)}}\]

(iii) Reduction: Conversion of zinc oxide into metallic zinc.

\[\ce{ZnO_{(s)} + C_{(s)} -> Zn_{(s)} + CO_{(g)}}\]