Question

What is the purpose of roasting an ore?

Answer 1

Purpose of roasting an ore:

• Roasting is a process of strongly heating the ore to a high temperature in excess of air.
• Roasting is used for converting sulphide ores into oxides for the purification of metals.
• Volatile impurities along with moisture get removed.

Roasting of zinc sulphide:

$2\mathrm{ZnS}\left(\mathrm{s}\right)+3{\mathrm{O}}_2\left(\mathrm{g}\right)\stackrel{∆}{\to }2\mathrm{ZnO}\left(\mathrm{s}\right)+2{\mathrm{SO}}_2\left(\mathrm{g}\right)$