High mud content in raw ore affects gold ore flotation efficiency: What to do?

High mud content in raw ore affects gold ore flotation efficiency: What to do?

Flotation is a commonly used method in gold ore beneficiation plants. However, during the gold ore flotation process, some raw gold ores have a high mud content, which affects the flotation effect. Therefore, how to reduce the impact of mud on the flotation separation effect of gold ore with high mud content has become a widely concerned issue.

In studying how to reduce the impact of mud on the gold ore flotation effect, we must first understand the ore properties of gold ores with high mud content. Typically, this type of raw gold ore often contains a large amount of easily floatable and easily mud-forming gangue (talc, serpentine, chlorite, calcite, dolomite, sericite, kaolinite, montmorillonite, feldspar, etc.), characterized by high mud content, fine-grained metallic mineral embedding, poor floatability of metallic minerals, small mass, and large specific surface area, making the ore properties relatively complex.

For gold ore flotation, excessive slime can cause crusher blockage, decreased gold concentrate quality, difficulty in filtration, slower fine-particle flotation speed, and poor selectivity, ultimately leading to reduced gold recovery and deterioration of flotation indicators. To address these issues, we need to adopt appropriate solutions tailored to the different properties of gold ore to mitigate and prevent the harmful effects of slime and enhance fine-particle flotation. This involves using suitable process flows or targeted flotation reagents. Specific measures include:

I. Washing: Washing is an important method to remove slime, which affects flotation efficiency. Adding a vibrating screen after primary crushing removes the slime from the ore. The screened slime is then processed by a spiral classifier, and the returned sand enters the fine ore bin or is directly ground. The classification overflow can be flotated together with the ground product or separately. For classification overflow with very low gold content, it can be discharged directly with the tailings. Simultaneously, waste rock can be manually removed from the washing screen by hand to improve the feed grade.

II. Before flotation, a portion of the slime should be separated using a hydrocyclone. If the slime has a high gold content, the separated slime can be flotated separately. In this case, a longer flotation time should be used for fine slime, maintaining a high-concentration pulp conditioning (60%-70% pulp concentration) and low-concentration flotation (generally below 20%). Simultaneously, staged dosing should be employed, increasing the collector dosage, reducing the frother dosage, maintaining a large aeration rate, small bubbles, and weakening the rising pulp flow. For some easily floatable slime with low gold content, a small amount of frother can be added before pre-flotation to remove it.

III. Adding slime dispersants such as water glass, sodium carbonate, and sodium hexametaphosphate can prevent non-selective agglomeration of fine slime, fully dispersing the slime and reducing its flocculation and covering effect. In this process, staged dosing can be considered to reduce the harmful effects of excessive adsorption of reagents by the slime.

IV. Increase the apparent particle size of particulate minerals by using physical or chemical methods to increase the apparent particle size of particulate minerals in order to improve the flotation rate and selectivity of the minerals to be separated.