The method of leaching consists of treating the powdered ore with a suitable reagent which can selectively dissolve the ore but not the impurities. The impurities are filtered out and are recovered from the solution. For example, bauxite ore containing SiO₂, iron oxide, and titanium oxides impurities are concentrated by this method.

Leaching is significant as it helps in removing the impurities like SiO₂, FeO₂, TiO₂, etc from the bauxite ore.