Tailings Dewatering Technology And Equipment

The tailings dewatering equipment carries out a series of treatments on the tailings to form slag with low water content, easy to precipitate and solidify, and stackable for dry storage. This not only relieves the pressure on the tailings pond, but also allows tailings to be reused. Following is the tailings dehydration equipment used in the dry tailings discharge process, and the combination of commonly used tailings dehydration equipment.

Common tailings dehydration equipment

The commonly used tailings dewatering equipment mainly includes dewatering hydrocyclones, high-efficiency deep cone thickeners, high-frequency dewatering screens, and filters.

1. The dewatering hydrocyclones

In the process of tailings dewatering operation, the dewatering hydrocyclone can be used to pre-concentrate the tailings, which can achieve a higher yield of sedimentation. In this way, a better tailings dewatering effect is achieved, the operating load of the filtration and concentration equipment is reduced, and the processing capacity of the equipment is improved.

2. High-efficiency deep cone thickeners

The high-efficiency deep cone thickener adopts a large cone angle setting, which greatly increases the compression area of the thickener. Even if the tailings are fine in particle size and low in concentration, the underflow concentration can still be very high. In the tailings dehydration process, the use of flocculant concentration technology also greatly increases the sedimentation rate and solid flux of fine tailings, thereby obtaining a higher underflow concentration. The high-efficiency deep cone thickener has a small footprint and high efficiency, and can concentrate the tailings slurry concentration to 60%-70% with less equipment and investment cost.

3. High-frequency dewatering screens

High-frequency dewatering screens are widely used in tailings dewatering operations because of their large processing capacity, good dewatering effect, simple structure, convenient maintenance, and simple operation. The dewatering screen has a unique screen plate structure and high-frequency vibration, the particles are not easy to pass through the sieve holes, and the dewatering efficiency is higher. Dry pile tailings with a moisture content of less than 15% can be obtained.

4. Filter press

Commonly used filters for dewatering of tailings mainly include belt filters and chamber filter presses. The belt filter adopts ultra-long filtration and strong double-roll pressing and integrated dewatering method, which is very adaptable to coarse-grained tailings, and the moisture content of the filter cake can be controlled within 20%. However, the concentration and particle size of the tailings have a great influence on the filtering effect.
The Chamber filter press is a kind of filtering equipment widely used in tailings dewatering operations at present. Its superiority lies in high pressure and strong dewatering, low water content of filter cake, and low energy consumption. After filtration, the moisture content of the dry slag is below 8%, which greatly reduces the tailings transportation cost and the risk of dry tailings piles.

Common tailings dehydration equipment combination

1. The dewatering hydrocyclones + High-efficiency deep cone thickeners

This tailings dehydration equipment combination makes full use of the difference in different particle sizes of tailings, and preferentially concentrates large particles. The processing capacity of the thickener is improved, the diameter of the thickener is reduced, and the investment is saved. However, the concentration of the discharged tailings is not too high and it is not easy to dry up.

2. High-efficiency deep cone thickeners + Filter press

The tailings dehydration equipment combination can obtain finished products with lower water content, so as to achieve the purpose of direct dry discharge and is convenient for transportation. However, a large-scale thickener is required, which covers a large area and high investment.

3. The dewatering hydrocyclones + deep cone thickeners + Filter press

The cyclone greatly reduces the workload of the thickener, can clarify the overflow water of the thickener, and avoid running muddy. The specification of the thickener is also reduced, the floor space is small, and the investment cost is reduced. However, the workload of the filter is large, and a large-size filter or multiple filters are required.

4. The dewatering hydrocyclones + deep cone thickeners + dewatering screens

The dewatering screen dewaters, reducing the filter equipment. However, the fine-grained materials under the dewatering screen are returned to the thickener to form an infinite loop, which affects the concentration effect.

5. The dewatering hydrocyclones + deep cone thickeners + dewatering screens + Filter press

The cyclone and dewatering screen is used to sort and dehydrate coarse and heavy particles before dry discharge, which reduces the workload and specifications of the thickener and filter, and reduces the investment cost. The under-sieve of the dewatering screen is fed into the filter to ensure solid-liquid separation, which is convenient for all dry discharges, so as to realize the long-distance transportation of tailings. The cleaning water of the filter is returned to the thickener, which can be reused and the content of solid particles in the reused water is also guaranteed.