Froth flotation works by exploiting the hydrophobic properties of gold molecules. First, ore is ground into an extremely fine powder. The powdered ore is mixed with water to create a slurry, which is mixed with surfactants to increase the golds hydrophobicity. This mixture is placed into a large tank filled with distilled water.
The discharge from the tube mill is first passed through a 4 mesh screen to separate out coarse material, which is laundered direct to the classifier. The remainder of the pulp, diluted to give a W/S ratio of 1/1, passes to a Denver Sub A Flotation Cell, from which 60% of the gold and silver in the feed is removed as a concentrate.
Another quick view of gold being recovered via froth flotation in a large gold operation. Again, not a great video but... you get the idea.
Our initial investigations in the mechanical flotation cell were with a wide variety of samples, including beach sands and alluvium. The more definitive work with the ASH and the flotation column has been on three samples. Some of the beach sands are cemented and can require vigorous attritioning to achieve liberation of the gold.
Tailing from the cell flows to the classifiers, and the flotation concentrate joins the concentrate stream from .the main flotation circuit. The purpose of the hydraulic attachment is to remove gold that is too coarse to float, thus avoiding an accumulation in the tube mill circuit.
This mixture is placed into a tank or flotation cell filled with distilled water. Air bubbles are pumped into the flotation cell and the water is agitated. 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.