Combined Flotation Processes for Gold and Silver Ore

Different types of gold ores exhibit significant differences in mineral structure and the occurrence of valuable metals. Therefore, flotation processes must be flexibly selected based on ore characteristics and finished product requirements. The industry's mainstream combined flotation processes for gold ores are divided into five categories, along with mature silver extraction technologies, adaptable to the beneficiation needs of various primary and oxidized gold-bearing ores.

 Five Mainstream Gold Ore Flotation Processes

1. Flotation + Concentrate Cyanidation: For gold-bearing quartz vein sulfide ores, a small amount of gold and silver concentrate is first enriched by flotation, followed by cyanidation leaching. This method is more economical than whole-ore cyanidation. It eliminates the need for overall fine grinding of the ore, significantly reducing grinding energy consumption, plant footprint, and infrastructure investment. It is a commonly used and efficient process in small and medium-sized mines.

2. Flotation + Concentrate Roasting + Roasting Slag Cyanidation: Primarily used for gold-arsenic, gold-antimony, and high-sulfur, refractory gold ores. Arsenic and antimony in the ore inhibit the gold extraction effect of cyanidation. Roasting the flotation concentrate removes harmful impurities and breaks the sulfide minerals' encapsulation of gold and silver, allowing for full recovery of precious metals through cyanidation.

3. Flotation + Concentrate Pyrometallurgical Refining: Widely used in polymetallic gold ores. Using composite collectors for flotation, gold and silver, along with associated sulfide metals, are enriched in the concentrate and sent to a smelter for comprehensive pyrometallurgical recovery of gold, silver, and other valuable metals. Suitable for large-scale polymetallic mines.

4. Concentrate Roasting Cyanidation + Tailings Middlings Cyanidation: Suitable for quartz sulfide gold ores containing pyrrhotite and chalcopyrite. After roasting the flotation concentrate, gold is extracted via cyanidation; gold and silver remain in the flotation tailings and middlings, so a cyanidation process is added for simultaneous recovery, maximizing the overall metal recovery rate.

5. Whole Ore Cyanidation + Tailings Flotation: For complex ores with incomplete gold and silver liberation. The raw ore is first cyanided, and the gold and silver encapsulated in the sulfide ore in the cyanidation tailings are then recovered through a second flotation process, which can increase the total gold and silver output by 5% to 10% and reduce resource waste.