9 Ways to Improve Thickener's Concentrating Efficiency
Jéssica Zhang
Xinhai Mining - Mine EPCM+O Mining & Processing Solutions - Email: [email protected], Phone:+86 185 0316 1314, Portuguese & English & Chinese
As one of the common equipment in a beneficiation plant, thickeners are used for the dewatering operation in the middle process of concentration and tailings in the wet beneficiation operation. With the help of solid particles' gravity, a clarified liquid and high-concentration sediment are divided into two parts. The concentrating efficiency of thickeners plays a vital role in obtaining a qualified concentrate. Here we will discuss how to improve thickeners' concentrating effect from two aspects: force increasing of material and feeding way of ore.
I Force Increasing of Material
Usually, the material in thickeners has its certain weight. By improving the structure equipment or adding chemical agents, the thickening effect will be improved.
1. Degassing by Degassing Tank
Before the pulp entering thickener, it should pass through the degassing tank for degassing. A defoaming cylinder can be added to accelerate the explosion of bubbles, so as to prevent the mineral particles from sticking to the bubbles. During installation, try to keep the upper edge of the overflow baffle be horizontal in the degassing tank, so that the slurry can pass through the baffle evenly in a state of thin film to facilitate gas overflow.
Flocculants can make materials colliding with each other to form flocs, increasing the volume of materials, thereby increasing the settling speed. The method is suitable for fine materials. It is very important to determine the mixing speed according to the time when the ore particles form flocs. In the beginning, the stirring speed should be moderate so that the polyacrylamide flocculant can be fully and evenly dissolved in the slurry. After the particle flocs formed, the stirring speed should be appropriately reduced to avoid the newly formed flocs being destroyed due to the high speed. When adding a flocculant, the addition amount can be automatically controlled to keep the stability of dosage and concentration constant, thereby accelerating the sedimentation rate and ensuring the coagulation effect.
3. Transformation of Hydraulic Transmission
A hydraulic motor can be used instead of a motor transmission. Under the condition of the same output power, the volume and size of the transmission device can be greatly reduced, and it is easy to realize automatic control, thus reducing operating costs.
4. Deepening the Slope of Sedimentation Tank
The height of the sedimentation tank does not affect its production capacity, it mainly depends on the sedimentation speed and the sedimentation area of the tank body. In fact, the solid particles in the concentration tank are not free in the static liquid settled. When the particles are falling, the sedimentation speed will gradually slow down as the density of slurry increases. When the cross-section in the tank reaches the critical speed, if the tank top is too shallow, the concentration effect is difficult to control. Therefore, without affecting the clarity, appropriately increasing the tank height can not only help to increase the sedimentation speed of the clarified liquid, but also the underflow concentration.
Change the rake tooth from a diagonal line to a curved line. When the transmission device drives the rake to rotate, the material deposited in the trough is scraped and transported by the rake to the discharge port in the center of the trough. When the rake scrapes and transports the grit, the sediment is pressured, which is beneficial to squeeze more water out.
For tilted-plate thickeners, multiple inclined plates can be installed in the upper part of the machine along the circumferential direction. When the material enters the inclined plate assembly device, the flocculation group can quickly settle on the inclined plate and slide down to the cone area, under the action of the inclined plate. The thickener is subjected to the stirring action of the internal stirring device and the vibrating action of the external vibration device, which can produce a large amount of water and discharge it quickly, and at the same time, the solid materials are denser under the action of vibration.
II Changing Feeding Way of Ore
Changing the feeding way of ore can improve the thickening effect of thickener from the feeding position, vertical design of the feeding barrel and adding receiving plate.
It is adopted for the traditional thickener in the upper feeding method, and the slurry is easy to affect the deposited slurry during the descending process, thus it is necessary to improve the feeding method. When it comes to the design of the feeding port, the position of the feeding port can be moved down. When the slurry enters the settlement area through the lower feeder barrel at the center of thickeners, the degassed slurry directly enters the tank body under the liquid surface, which can prevent gas from being carried into the slurry.
2. Vertical Design of the Feeding Barrel
The slurry enters the feeding device, reaches the lower part of the settlement zone, and then flows around without destroying the clear water area. At the same time, the fine particles that are difficult to settle in the rising water flow collide, squeeze, stay, and be caught, which can prevent the slurry mixing and improve concentration efficiency.
In order to ensure uniform and stable feeding, a receiving plate can be added to the ore sleeve to prevent the feeding slurry from impacting the precipitated ore particles and avoid the phenomenon of "rolling".
These are 9 ways to improve the concentrating effect of thickener. In the actual operation, it is necessary to adjust the improvement plan according to the existed problem, in order to effectively increase the production capacity of thickeners.
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