The recovery rate of gold in wet mercury depends on the size shape of natural gold, the color of gold particles, the quality of mercury, the temperature of amalgamation, the concentration of pulp, the method of amalgamation and equipment factors.
The size shape of gold and the degree of monomer dissociation are mainly related to the grinding operation, especially the degree of monomer dissociation has a great influence. The recovery rate of amalgamation can be improved by appropriately increasing the grinding fineness. The gold particles suitable for amalgamation are generally 0.2~0.3 mm, and the lower grain size of amalgamation board is 0.015 mm during the grinding cycle, but the fine gold particles are lost with the pulp.
The fineness of ore gold is higher than that of vein gold, and the fineness of gold in oxidation zone is higher than that of primary ore. The gold with high fineness is easy to amalgamate, and the amalgamation ability of gold particle surface polluted will be significantly reduced. Amalgamation can be divided into internal amalgamation and external amalgamation. The external amalgamation is the process of amalgamation for gold extraction outside the grinding operation. The external amalgamation is commonly used in fixed amalgamation plate and vibrating amalgamation plate. Internal amalgamation is the process of amalgamation gold extraction in the grinding operation cycle, gold mines in South Africa and the United States often carry out internal amalgamation in the pound, small and medium-sized gold mines in the former Soviet Union often use rolling machines, and domestic amalgamation barrels are often used. Internal amalgamation has higher efficiency and better quality than external amalgamation. The concentration of the outer mercury slurry should not be too large to form a loose thin slurry flow, and the flow rate should not be too high, so that the gold particles fall to the mercury board. The concentration of the inner mercury slurry should be 30%~50%, and the mercury should be suspended.
The pH of pulp has a great influence on the effect of amalgamation. Amalgamation effect in acidic medium and cyanide solution is good, but in the case of more slime, due to amalgamation of mercury in acidic medium, such as lime as the adjustment agent precipitation soluble salt and eliminate the adverse effects of oil. The effect of amalgamation is better when PH=8~8.5.
The quality of mercury has a great influence on the effect of amalgamation, but the wetting effect of pure mercury is not good, and a small amount of gold, silver and base metals in mercury can reduce the surface tension of mercury and improve the wetting effect. Oil and other organic matter and fine mud can pollute the surface of gold particles, sulfide ore, talc, graphite and arsenide in the ore are easy to adhere to the surface of mercury, and also affect the wetting ability of mercury to gold
When amalgamating mercury, the amount of mercury added should be appropriate, too much will reduce the elasticity and consistency of the mercury paste, and make the mercury paste lose with the pulp. The insufficient amount of mercury makes the mercury paste hard, lose elasticity, and reduce the performance of gold trapping. The initial amount of mercury added after the mercury board is put into production is 15 to 30 grams/meter, and the mercury added is 2 to 5 times the ore content is appropriate, and the mercury consumption is often 3 to 8 grams/ton of ore.
In addition, temperature also affects the effect of amalgamation. Too low temperature will increase the viscosity of mercury and affect the effect of amalgamation. High temperature increases the fluidity of mercury, resulting in partial loss of mercury gold with the loss of mercury. Therefore, amalgamation index is prone to seasonal change, the hybrid temperature should be more than 15℃, and the method of adding mercury and adjusting pulp concentration is used to eliminate the influence of temperature.
