The first one makes possible to obtain particles no very thick and the second one can creates some problems during the operation of some gravimetric equipments due to there is a tendency of native gold to float on the surface of a slurry in a sluice box and be lost in the tailings. This situation is sometimes called skin flotation.
The common gold extraction processes include gravity separation process, froth flotation process, cyanidation, etc. Froth flotation process is the most widely used in gold extraction, but for different types of gold, we can choose flotation process combined process in order to improve the return on investment.
1. Background. The application of flotation on a reasonable scale within the gold mining industry commenced in the early 1930s following the introduction of water soluble flotation collectors that allowed differential flotation of sulfide minerals .
It was describe by the use of 600 series of flotation reagents which were developed primarily for the purpose of depressing carbonaceous and siliceous slimes in the flotation of gold ores. Carbonaceous material not only greatly increases the bulk and moisture content of a flotation concentrate, but its presence makes cyanidation of the concentrate difficult or impossible owing to reprecipitation of the gold during treatment.
Because of the surfactant, the gold is repelled by the water into the air bubbles, which rise to the top creating a bubbly gold foam. The froth is removed from the top of the cell creating concentrated gold, while the flotation tailings at the bottom of the tank are disposed of.