a) Among the following which metal is extracted from bauxite: i) Zinc ii) Iron iii) Aluminium iv) Copper

Question

Metals are extracted from their ores 

a) Among the following which metal is extracted from bauxite:

i) Zinc

ii) Iron

iii) Aluminium

iv) Copper

b) Suiphide ores are subjected to roasting while carbonate ores are subjected to calcination. Comment on the statement.

Answer 1

a) iii) Aluminium

b) In roasting, the ore is heated in a regular supply of air in a furnace at a temperature below the melting point of the metal. Here, oxygen is consumed. The sulphide ores need to be converted to oxides. Hence these are subjected to roasting.

e.g. 2ZnS + 3O₂ → 2ZnO + 2SO₂

In calcination, the ore ¡s heated in a limited supply fair below its melting point morder to remove he volatile matter. Here, oxygen is not consumed. Hence, the carbonate ores are subjected to calcination.

e.g. ZnCO₃(s) → ZnO(s) + CO₂(g)