Crushing, Grinding and Concentration of the Ore Class Notes
The impurities left undissolved are removed by filtration. Leaching method is used for concentrating ores of aluminium, silver, gold etc. For example: a) The ore of aluminium, bauxite, is concentrated by this method. The bauxite ore is contaminated with impurities of silica (SiO 2), iron oxides (Fe 2 O 3), titanium oxide (TiO 2), etc.