Flotation is one of the commonly used beneficiation methods in gold beneficiation plants. But some gold raw ore has a large mud content, which affects the flotation effect. Therefore, in the flotation separation of gold ore with high mud content, how to reduce the influence of ore slime on gold ore flotation effect has become a widely concerned issue.
When studying how to reduce the effect of slime on gold ore flotation, we must first understand the ore properties of gold ore with high slime content. Usually, this kind of gold ore often contains a large amount of gangue that is easy to float and muddy (talc, serpentine, chlorite, calcite, dolomite, sericite, kaolinite, montmorillonite, feldspar, etc.). It has the characteristics of high mud content, fine metal mineral inlaid particle size, poor metal mineral floatability, small quality, large specific surface area, etc., and the ore properties are more complex. For gold ore flotation, too much sludge will cause the crusher to block and the quality of gold concentrate will decrease. Besides, it will be difficult to filter, the fine particle flotation speed will be slow, and the selectivity will be deteriorated, which will lead to the reduction of gold ore recovery rate and deteriorated flotation indicator.
In order to solve the above problems, we need to take corresponding solutions according to the properties of different gold ore to reduce and prevent the harmful effects of ore slime, and strengthen fine-grain flotation. To be specific, to adopt suitable technological processes or use targeted flotation. The specific measures are as follows:
Ore washing can be described as an important method to eradicate the effect of sludge on flotation effect. After the first stage of crushing, the vibrating screen is added to wash the ore. The ore is washed to remove the muddy part, and the screened mud is processed by the spiral classifier, and the sand is returned to the powder ore bin or directly ground. The classification overflow can be combined with the grinding products for flotation or individual flotation. For the classification overflow with very low gold grade, it can be discharged directly with the tailings. At the same time, the ore blocks on the washing screen can also be manually selected to remove the waste rock to improve the selected grade.
If the gold content in the slime is high, the removed slime can be treated by flotation alone. At this time, it is advisable to use a longer flotation time for the flotation of fine mud alone, maintain high-concentration pulping (60%-70% pulp concentration), low-concentration flotation (generally below 20%), and at the same time dosing in stages, Increase the amount of collector, reduce the amount of foaming agent, maintain a large amount of air, small bubbles, and weaken the rising slurry flow. For some slimes that are easy to float and have low gold content, a small amount of foaming agent can also be added before flotation to remove them by flotation.
Slime dispersants such as water glass, sodium carbonate and sodium hexametaphosphate can be added to prevent non-selective agglomeration of fine slime, so as to fully disperse the slime and reduce the flocculation cover effect of the slime. In this process, it is possible to consider the use of staged dosing to reduce the harmful effects of a large amount of adsorbents in the sludge.
Use physical or chemical methods to increase the apparent particle size of particulate minerals to improve the flotation rate and selectivity of the minerals to be sorted.
Select flocculation flotation:
Use flocculant to selectively flocculate the target mineral or gangue slime, and then separate by flotation method.
Carrier flotation:
Using the ore particles of general flotation grade as the carrier, the fine particles are covered on the carrier, and then floated together with the carrier.
Reunion flotation:
Also known as emulsification flotation, fine-grained minerals are treated with collectors, and then under the action of neutral oil, oily foam with minerals is formed.
When using flotation beneficiation method to process ore with high mud content, if the crusher is blocked, the recovery rate of gold ore decreases, and the flotation index becomes worse, it should be noticed whether it is caused by the high mud content of raw ore. Flotation method is a relatively complex gold beneficiation method. It is recommended to conduct a beneficiation test before determining the process flow and process parameters to fully grasp the properties of the ore and improve total ROI.
