Question

How is zinc extracted from its carbonate ore (calamine)? Explain with equations.

Answer 1

Calcination is the process in which a carbonate ore is heated strongly in the absence of air to convert it into metal oxide.

Zinc occurs as zinc carbonate in calamine ore, ZnCO₃. So, in order to extract zinc metal from zinc carbonate, this zinc carbonate should first be converted into zinc oxide. This is done by calcination. Thus, when calamine ore (zinc carbonate) is heated strongly in the absence of air, that is, when calamine is calcined, it decomposes to form zinc oxide and carbon dioxide.

\[\ce{\underset{(Calamine ore)}{\underset{Zinc carbonate}{2ZnCO3_{(s)}}} ->[Calcination] \underset{Zinc oxide}{ZnO_{(s)}} + \underset{Carbon dioxide}{CO2_{(g)}}}\]

Thus, calcination converts zinc carbonate into zinc oxide.