The tailings dry stacking process is a new tailings processing method in recent years, that is, the tailings become stackable slag with low moisture content and easy to precipitate after the treatment of a series of mine tailings dewatering machine, which not only alleviates the pressure capacity of the tailings, reduce the potential risk of the tailings pond, but also increase the tailings recycling means. It is a tailings processing technology that realizes the green and environmentally friendly mine.
Below, we will explain to you the mine tailings dewatering machine used in the tailings dry stacking and give the common tailings dewatering machine combination.
Use the table of contents below to navigate through the guide:
At present, the commonly used tailings dewatering machine mainly includes dewatering hydrocyclone, efficient deep cone thickener, efficient improved thickener, high frequency dewatering screen, filter.
In the mine tailings dewatering process, the dewatering hydrocyclone is used to the pre-concentration of tailings, which can obtain a higher yield of settling sand, achieve a better tailings dewatering effect, and greatly reduce the operating load of filter and thickener, improve the processing capacity of the equipment.
The dewatering hydrocyclone has a specially designed fishtail device at the settling nozzle and syphoning installation, so it has the excellent characteristics incomparable to other hydrocyclones. Adjusting the pipe valve of syphoning installation, the concentration of tailings bottom flow can be adjusted to 78%.
The efficient deep cone thickener is a kind of thickening equipment commonly used in tailings dewatering operation, which is featured with small occupied area and high efficiency. The pulp concentration of the tailings can be up to 60%-70% with less equipment and civil construction investment cost.
The efficient deep cone thickener adopts large cone angle and deep cone setting, which greatly increases the compression area of the thickener. Even if the tailings have fine particle size and low concentration, the bottom flow concentration can still be high. At the same time, the multi-cone structure can transform the compression zone, so that the concentration of tailings bottom flow can be higher. Besides, the inclined plate is installed in the middle settlement area of the efficient deep cone thickener, which increases the settlement area of the thickener by more than 8 times, effectively prevents the fine particles from floating, improves the concentration of tailings bottom flow and makes the overflow water clearer.
The efficient improved thickener is mainly used to deal with the fine and micro-fine materials, and its processing capacity is much greater than that of the conventional thickener. In the tailings dewatering process, the flocculant concentration technology can greatly increase the settling velocity and solid flux of fine-grained tailings, so as to obtain the higher bottom flow concentration.
High frequency dewatering screen is a new type of highly efficient dehydration equipment with simple structure, convenient maintenance, simple operation. And it is widely used in tailings dehydration operation due to its large capacity and good dehydration effect.
In the tailings dewatering process, the unique structure of screen plate and the high frequency vibration of the motor can not only make the pulp particles not easy to pass through the screen hole, but also has the higher dewatering efficiency, and finally get the dry heap tailings with water content less than 15%.
At present, the filter commonly used for mine tailings dewatering treatment mainly includes belt filter and filter press.
The belt filter adopts the dehydration method of ultra-long filtration and strong roller pressing, which has a strong adaptability to the coarse-grained tailings. The moisture of the filter cake can be controlled within 20%, but the feeding concentration and particle size of the tailings have a great influence on the final filtration effect.
The filter press is a kind of filtration equipment widely used in tailings dewatering process at present. It adopts the strong dehydration under the positive pressure and high pressure, so it has the advantages of low moisture content of filter cake and less energy consumption. The filtrate treated by the filter press is clear and transparent, which can meet the requirements of direct discharge of environmental wastewater. The moisture content of the dry slag after filtration can reach less than 8%, which greatly reduces the cost of tailings transportation and the risk of dry tailings pile.
In the practice, different tailings have the different mineral composition, particle size, concentration, density, so it is necessary to determine the type, model and equipment combination of mine tailings dewatering equipment according to different tailings characteristics, so as to achieve the ideal tailings dewatering effect.
The common tailings dewatering machine combination mainly includes:
The tailings dewatering machine combination makes full use of the difference of different particle sizes of tailings, giving priority to concentrating large particles, which improves the processing capacity of the thickener, reduces the diameter of the thickener and saves the investment. However, the concentration of the discharged tailings is not too high and is not easy to dry heap.
The tailings dewatering machine combination can obtain materials with lower water content, so as to achieve the purpose of direct tailings dry stacking, and easy to transport. It is worth noting that this tailings dewatering machine combination needs to choose the thickener of large specifications, which covers a large area and has a high investment, so it is not suitable for the mine tailings dewatering treatment in the large and medium-sized concentrators.
The advantage of this tailings dewatering machine combination is that one-stage dehydration of the hydrocyclone greatly reduces the workload of the thickener, which can clarify the overflow water of the thickener and avoid muddy running. Meanwhile, the thickener's specifications are reduced and the area of occupation is small, thus reducing the investment cost. However, the workload of the filter is large. So, this tailings dewatering machine combination needs to the filter large specifications of or several filters, the energy consumption is high.
The mine tailings dewatering machine combination uses the dewatering screen to dehydrate, and reduces the number of filter equipment, which not only saves the electricity, but also reduces the investment cost. However, the fine-grained materials of the dewatering screen are back to the thickener, forming an infinite cycle, which affects the concentration effect and makes the concentrated clarified water muddy. Finally, the screen underflow is discharged into the tailings pond, the total dry stacking cannot be achieved.
The mine tailings dewatering machine combination uses the hydrocyclone and dewatering screens to separate the coarse and heavy particles and then achieve the dry stacking, which reduces the workload of thickener and filter, accordingly decreases the specifications of thickener and filter, and saves the investment cost. The screen underflow of the dewatering screen is fed into the filter, which ensures the solid-liquid separation and easy to realize the long-distance transportation of tailings. The flowing of the filter and the washing water return to the concentrator, which ensures the content of solid particles in the recycled water, satisfies the quality of production water.
When selecting the mine tailings dewatering machine, it is necessary to make reasonable selection according to the characteristics of tailings mineral composition, pulp concentration, ore density and particle size. It is suggested that the tailing settlement test should be carried out first to determine the tailing settlement velocity and the bottom-flow concentration that can be achieved, so as to provide a scientific basis for the selection of mine tailings dewatering machine.