Sulfur-bearing gold ore is generally rich in pyrite and arsenopyrite, with low content of gold and relatively small natural gold particles, which are mostly wrapped in pyrite and arsenopyrite. It is easier to achieve the separation of gold and sulfide from this type of ore, while the separation of gold from pyrite and arsenopyrite requires more complex beneficiation and smelting processes.
For refractory sulfur-bearing gold ores, the particle size of gold is small, microscopic and sub-microscopic. Gold mainly occurs in sulfide minerals (pyrite and arsenopyrite). The encapsulation of sulfide blocks the contact of leaching gold reagents with gold. Therefore, the leaching rate of gold is very low.
For refractory gold ores, the process of flotation pre-enrichment - flotation concentrate pretreatment - cyanide leaching is generally used. The pretreatment process includes roasting oxidation method, pressure oxidation method, atmospheric pressure oxidation method, bacterial oxidation method, nitric acid catalytic oxidation method, microwave roasting method, etc. But most of the refractory gold mines have the problem of low flotation recovery rate.
1. Crush and grind the sulfur-containing gold ore to a suitable particle size. The re-crushing stage can be completed with jaw crusher and cone crusher; and different types of ball mills can be used in grinding stage. The medium in the ball mill is used to grind the minerals. When grinding stage finished, the sulfur-bearing gold ore will be sent into separation stage.
2. Magnetic separation equipment such as magnetic separator is used to remove iron minerals, and sulfur in minerals is enriched and removed; then you can adopt gravity separation method to further enrich sulfur and improve the grade of minerals as well as reduce production costs; flotation process by adding chemicals can be used to improve the recovery rate of minerals.
3. Concentrate, filter and dewater the obtained gold concentrate pulp to complete the separation of minerals and obtain relatively pure gold ore.
Although the sulfur contained in the gold ore is difficult to separate, we can still make an appropriate beneficiation plan to effectively improve the mineral quality and gold recovery rate according to the analysis of the properties of the minerals.
