Gravity Concentration and
Froth Flotation

Gravity concentration or froth flotation procedures might be done in order to concentrate the gold. In certain circumstances, principally when the gold is found in the ore as isolated coarse particles, a gravity concentrate can be directly smelted so as to shape gold bars. In some other circumstances, especially when the gold can be found in the ore as fine particles or is not liberated enough from the rock, the concentrates are put through a cyanidation leaching, and are then placed to the recovery from the leach solution. Recovery from solution in general has to do with adsorption on activated carbon and is then followed by solution concentration or stripping and or electro winning.

Froth flotation is habitually put to practice when the gold that is in an ore is directly associated with sulfide minerals like those of pyrite or arsenopyrite, and when those kind of sulfides can be seen in great amounts in the ore. In this case, concentration of the sulfides ends up in concentration of gold values. In the main, recovery of the gold from the sulfide concentrates has the need of more processing and this is in most cases carried out through roasting or wet pressure oxidation. These pyrometallurgical or hydrometallurgical treatments are in most cases followed by cyanidation and carbon adsorption procedures for concluding recovery of the gold. In certain cases gold can be found as a small constituent in a base metal concentrate, and is recovered as a by-product throughout production of the base metal.