Analysis of the technical scheme of dry tailings discharge

Dry tailings discharge is a new tailings treatment technology that has gradually emerged at home and abroad. After the tailings slurry is concentrated in multiple stages, it is processed by high-efficiency dehydration equipment such as dehydration vibrating screens to form a small water content, easy to precipitate and solidify, and use the site for storage. The slag can be transported to a fixed location for dry storage.

According to different tailings types, particles, concentration, and mud content, reasonable formulation of tailings dry discharge process and selection of tailings dry discharge equipment can minimize the area and save equipment investment on the premise of ensuring dry discharge. Below, I will take you to understand the five common dry tailings process schemes, and help you choose a suitable dry tailings process scheme.

1. Cyclone-thickener scheme

The beneficiation tailings with a concentration of 10%-20% enter the cyclone through the slurry pump, and the cyclone overflows into the thickener, and then the fine-grained particles are concentrated. The overflow of the thickener is clarified water, which is returned to the production cycle water for reuse. After the cyclone sedimentation and the underflow of the thickener are combined, the concentration is 45%-50%.

The dry tailings process plan makes full use of the difference in different particle sizes of tailings. Prioritize the concentration of large particles, which improves the processing capacity of the thickener, reduces the diameter of the thickener, and saves investment. However, the concentration of the discharged tailings is not high, and it is not easy to dry up.

dry tailings discharge

2. Thickener-filtration scheme

Feed the beneficiation tailings into the thickener, and the underflow of the thickener into the filter. The filtered filter cake contains 15%-20% water and can be directly drained. The overflow water and filtered water of the thickener are returned to the production circulating water for reuse.

The dry tailings discharge process can obtain materials with lower water content, to achieve the purpose of direct dry discharge and is convenient for transportation. It is worth noting that the dry tailings process plan requires the use of large-scale thickeners, which occupy a large area and high investment, so it is not suitable for the tailings treatment of large and medium-sized concentrators.

3. Two-stage concentration-filtration scheme

A cyclone is used as first-stage thickening equipment, the tailings slurry is fed into the cyclone, the overflow of the cyclone is fed into the thickener, and the underflow of the cyclone and the underflow of the thickener are combined to the filter. The overflow water and filtered water of the thickener are returned to the production circulating water for reuse. After filtration, the filter cake contains 15-20% water and can be directly drained.

The advantage of this tailings process scheme is that the one-stage dehydration of the cyclone greatly reduces the workload of the thickener. It can clarify the overflow water of the thickener, avoid running muddy, and at the same time reduce the specification of the thickener, occupy a small area, and reduce investment costs. However, the workload of the filter is large, and a large-size filter or multiple filters are required, and the energy consumption is high.

4. Two-stage concentration-dehydration scheme

The beneficiation tailings are fed into the cyclone, the overflow of the cyclone is fed to the thickener, the overflow water of the thickener is returned to the production circulating water for reuse, and the underflow and concentrated underflow of the cyclone is fed into the dewatering screen and on the screen of the dewatering screen, The material contains 20%-25% water for dry discharge, and the under-sieve returns to the thickener.

The tailings dry discharge process scheme uses a dewatering screen to dewater, reducing filter equipment, saving electricity, and reducing investment costs. However, the fine-grained materials under the dewatering screen are returned to the thickener to form an infinite cycle, which affects the concentration effect and makes the concentrated clarified water run out of mud, and finally discharges the dewatering screen into the tailing pond, failing to achieve all dry discharge.

With the release of the “green mine” standard, the dry tailings process has shown advantages in terms of economy, environment, and has become an important choice for tailings treatment in the future. In the actual application of the concentrator, it is recommended to choose the dry tailings process plan suitable for the condition of the concentrator according to the scale and investment of the tailings, and customize the dry tailings equipment.