This method mainly concentrates sulfide ores. When sulfide ores are added to the oil and water mixture. Sulfide ores are then drenched by oil faster than impurities present in them and impurities present in sulfide ores are drenched by water faster than sulfide ores. This method is very common in Metallurgy.
In this way, when the air flows in suspension of sulfide ore made in oil and water, the particles of sulfide ore become foamy and come to the upper surface and the impurities settle down. This method is also called froth buoyancy method.
In this method, sulfide ore is grinded very finely and put in a pond filled with water. It contains small amounts of pine oil, turpentine oil, eucalyptus oil, or sodium xanthate oil to flow a strong stream of air and the oil-soaked sulphide ores get deposited as foam.
And other impurities present in the ore, such as soil, are deposited on the bottom of the pond. Concentrated ore is thus obtained.