Thickeners are widely used in mining, mineral processing, and water treatment to concentrate slurry and recover water. They come in different types, each suitable for specific applications and operational requirements. Refer to the thickener types in mineral processing, how many do you know? Follow us to get the answer.
Thickeners Types
Classified according to the transmission mode, the thickener can be divided into peripheral and center transmission thickeners.
Classified according to the size, the thickener can be divided into small, medium & large-scale thickeners.
Classified according to the structure, the thickener can be divided into rake, multi-layer, filtration, deep cone, titled plate, and bottom feed thickeners.
Rake Thickener
Rake thickener is mainly composed of a thickening tank, rake frame, transmission mechanism, feeding device, and unloading device, mainly relying on gravity sedimentation to separate suspended solid particles from liquid. Rake thickeners are often used for dewatering fine-grained materials, with a maximum diameter of 150-183 meters. Rake thickener can be divided into two types: center transmission thickener and peripheral transmission thickener.
Center transmission thickener
The center transmission thickener comprises a pool, rake, and transmission mechanism, among other parts. The pool is in its original shape, the bottom is in the shape of a conical funnel, and the horizontal plane is about 6-10 degrees of inclination. The center of the bottom of the pool opens a conical discharge port. The pool is made of concrete, and the smaller size of the pool can also be welded to the steel plate. In the center of the pool on the axle hanging rake mechanism. The rake mechanism by the rake arm, rake teeth, and reinforcement with the composition of the tie, two pairs of rake arms perpendicular to each other in the shape of a cross. The center of the upper part of the pool is installed with a round feeding barrel, and the slurry enters the thickener through the pipeline for concentration and precipitation. The overflow water is discharged from the circular overflow tank around the pool. The advantages are simple structure, easy operation, low power consumption, and high technical index.
Center transmission thickener: the center drive drive device is more complex, but the operation is simple, and suitable for automatic rake lifting when overloaded.
Peripheral transmission thickener
Larger diameter densifiers are of the peripheral transmission type, with the pool constructed of concrete and a reinforced concrete pillar in the center of the pool, which is used to support one end of the rake mechanism and the slurry tanks, etc. The other end of the rake mechanism is driven by the drive mechanism. The other end of the rake mechanism is supported in the periphery of the pool with the help of a transmission device, which is divided into two kinds gear drive and roller drive. Slurry along the slurry tank into the central feed cylinder, and precipitation in the pool, precipitates from the center pillar along the peripheral division equipped with a cast iron funnel discharge port. The clarified overflow flows out from the peripheral annular overflow tank.
Peripheral transmission thickener: The whole transmission system is simple, reliable operation, but need enough friction, easy to slip.
Efficient Thickener
The efficiency thickeners are similar to conventional thickeners in that the structure of the tank, rake, and drive section is more or less the same as that of an ordinary thickener. However, they are designed for faster settling, often with steeper tank walls and optimized feed chutes. The slurry enters the exhaust system, discharges the air brought in, and enters the mixing chamber through the feeding tube, after being fully mixed with the flocculant, it is directly given to the middle and upper part of the sedimentation layer through the radially distributed feeding tube in the lower part of the mixing chamber. The liquid is filtered through the upper layer of the sedimentation sand and rises to the overflow, while the flocculent remains in the sedimentation sand and enters the underflow.
Under the condition of the same processing capacity, the diameter of the high-efficiency concentration pool is only 2/3 to 1/2 of the diameter of the ordinary concentration pool, covering an area of about 1/9 to 1/4 of the ordinary concentration pool, while the processing capacity per unit area can be increased by several times to dozens of times. High-efficiency thickeners are suitable for high throughput operations that require rapid settling, such as iron ore or gold processing.
Tilted Plate Thickener
The tilted plate thickener is a kind of high-efficiency dewatering equipment for fine-grained materials. It is characterized by a small tank, small footprint, and low investment, but it is generally necessary to add flocculant to the slurry. When working, the slurry enters the thickening plate and stabilizes the plate uniformly from the feed pipe through the feed opening. The overflow is discharged from the overflow weir into the manifold. Sedimentation sand is deposited from the thickening plate, deposited into the square cone box through the stabilizing plate, and discharged from the discharge pipe. Since there are several thickening plates about 150 mm apart in the tilted plate thickening box, the sludge settling time and distance are effectively shortened, and the effective thickening area is greatly increased.
Deep Cone Thickener
The barrel of the deep cone thickener is conical, and the lower part of the cone is equipped with a sand discharge valve, which is used for sand discharge and drainage in case of accidents or maintenance. The cone angle is generally 55° or 60°, and 55° is generally used when the slurry contains mud. When the cone angle is less than 55°, the height of the body will be increased with the same settling area.
The functions of deep cone thickener
- Thickening and dewatering of raw slurry before grinding.
- Thickening and desliming of the overflow from the slurry grading box before shaking table operation. Gravity separation, flotation, magnetic separation products, or slime dewatering.
- Thickening and dewatering of ore before feeding in centrifuges, belt chutes, and other sorting operations.
Features of deep cone thickener
Deep cone thickener has a simple structure, no power consumption, and can play the role of ore storage, concentration, and desliming to a certain extent. However, the sedimentation area is small, the desliming efficiency is low, and the configuration height loss is large. Generally, it is only applicable to the dewatering of the ore dressing products for a time, and sometimes it needs to be dewatered again when the overflow is sent to the next operation.
Deep Cone Multi-Layer Thickener
Effective deep cone multi-layer thickener has a conical appearance, which can make the flocculant and material fully contact, and greatly shorten the concentration time. The pool height of the deep cone multi-cone thickener is much larger than the pool diameter, and the whole is a vertical barrel cone, because the pool body is slender, and flocculant is added in the thickening process, which accelerates the thickening process of material settlement and overflow water clarification. And it makes the overall footprint of the thickener smaller and the processing capacity stronger.
Different mining thickeners are suitable for different environments, and the economic benefits produced are also different. Such as: the small thickener is suitable for small-scale production or laboratory use; the medium thickener is suitable for medium-scale industrial production and the larger thickener is applicable to large-scale industrial production. The rake thickener is the common type of thickener, the multi-layer thickener is used for processing multi-layer materials. The filtration thickener combines the characteristics of filtration of slurry layers. Ad the bottom feed thickener is fed from the bottom.