Would the High Slime Content Reduce the Efficiency of Gold Froth Flotation Process in the Concentrator?

Abstract: The froth flotation process is one of the commonly used methods in gold concentrators. When some gold ores contain a large amount of slime, the efficiency of the froth flotation process would be reduced. This article mainly proposes 4 methods to reduce the harmful effects of high slime content on the froth flotation process.

Keywords: Froth Flotation Process

Gold Concentrator/Gold Slime 

Generally, the ore with high slime content often contains a large amount of easy-floating and muddy gangue (talc, serpentine, chlorite, calcite, dolomite, sericite, kaolinite, montmorillonite, feldspar, and so on). This kind of ore has complex properties, including fine particle size, poor metal mineral floatability, small quality, large specific surface area, etc.

Insufficient gold ore slime handling may result in bringing the whole minerals processing plant to a halt or leading to inefficiencies in important processes such as classification, separation, dewatering, and tailings handling. For the gold froth flotation process, too much slime would block the crusher and reduce the quality of the gold concentrate, which leads to a decrease in the recovery rate of the gold ore. In order to solve the above issues on the gold froth flotation process, we need to adopt corresponding solutions. The specific measures are as follows:

Ⅰ.Ore Washing in Gold Froth Flotation Process

After one-stage crushing, the vibrating screen is added to wash the ore and remove the muddy. The sieved sludge is processed by a spiral classifier, and returned to the powder ore bin or directly grounded. The overflow can be floated together with the grinding product or separately. If the gold content in the overflow is very low, it can be directly discharged together with the tailings. 

Ⅱ.Separate Part of Slime by Hydrocyclone before Froth Flotation Process

If the gold content in the sludge is high, the removed sludge can be floated separately. At this time, the separate flotation of fine mud should adopt a longer flotation time, and maintain high-concentration slurry adjustment (60%-70% slurry concentration) and low-concentration flotation (generally less than 20%). At the same time, it is administered in stages, increasing the amount of collector, reducing the amount of foaming agent, maintaining large aeration and small bubbles, and weakening the rising slurry flow. For some sludge that is easy to float with low gold content, a small amount of foaming agent can be added before flotation to remove it.

Ⅲ.Add Sludge Dispersant in Gold Froth Flotation Process

Water glass, sodium carbonate, sodium hexametaphosphate, and other sludge dispersants can be added to prevent non-selective agglomeration of fine sludge, so as to fully disperse sludge and reduce the flocculation and covering effect of sludge. In this process, the stepwise dosing method can be considered to reduce the harmful effects of a large number of adsorbents in the sludge. 

Ⅳ.Increase Particle Size before Gold Froth Flotation Process

Use physical or chemical methods to increase the particle size of the minerals and improve the flotation rate.

◆ Selective flocculation flotation before gold froth flotation process

The flocculant agents are used to selectively flocculate the target mineral or gangue sludge of the particles, and then the flotation method is used for separation.

◆ Carrier flotation before gold froth flotation process

The general particle size is used as the carrier so that the fine particles are covered on the carrier and float out together with the carrier.

◆ Reunion flotation before gold froth flotation process

Also known as emulsification flotation, fine-grained minerals are treated by collectors, and oily foam with minerals is formed under the action of neutral oil.

For most gold concentrators, flotation represents a key component. The mining industry’s continuous drive to ramp up production from existing assets makes it important to view flotation solutions as one part of a much larger picture. Reliable flotation is often referred to as the heart of gold concentrators as it ensures the smooth flow of the process. Even small improvements in flotation efficiency can have a drastic impact on the profitability of mining operations.

Backed by the latest in flotation technology, the series also offers excellent resistance to abrasion and erosion. We ensure that you will always find the correct flotation solution for your process needs.

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