Hydrocyclone is a common classification beneficiation equipment, with unique structure design adopts the composite structure of multi section type column body. It changes the height of column according to the need. If the height increased, overflow fineness increase up to about 10 μm diameter. Each diameter has unique cylinder length and cone angle, which can achieve the maximum tangential velocity at the minimum total cyclone length, so as to increase centrifugal force and improve the classification efficiency.

Structure of the hydrocyclone

The structure of the hydrocyclone is shown in Figure 1, the upper part is a hollow cylinder, and the lower part is an inverted cone connected with the cylinder, and the two constitute the working cylinder of the hydrocyclone. The upper end of the cylindrical cylinder is cut to the ore pipe, and the top is equipped with a overflow pipe and a overflow pipe. At the bottom of the cone, there is a desilting port. Each part is connected with a plate and a screw. The feed, the cylinder and the spigot is usually lined with rubber, polyurethane or diabase, so as to reduce wear and replace the wear. The desilting port can also be adjustable and adjust its size according to the needs. The small hydrocyclone can also be made entirely of polyurethane.



1. feed pipe; 2. cylindrical tube; 3. overflow pipe; 4. cone cylinder; 5. desilting port; 6. overflow pipe

working principle of hydrocyclone

With a certain pressure and speed, the pulp enters the cylindrical tube in the tangent direction from the pipe to the ore pipe, and then revolves around the axis at a high speed and produces a large centrifugal force. Particles of different size and density of the slurry, due to centrifugal force is different, so their movement speed, centrifugal force in the cyclone acceleration and direction are also different from the thick and heavy particles, were thrown into the wall, by the downward spiral line track to the bottom, as the sand discharged from the desilting port. The fine and light particles are subjected to a small centrifugal force, which is taken to the center, and the spiral ore flows upward in the center of the cone, which is discharged from the overflow pipe as a overflow. The separation size range of the hydrocyclone is generally 0.3-0.01mm.

working principle of hydrocyclone

Figure2.working principle of hydrocyclone

Main specifications of hydrocyclone

1. The cylinder diameter and height

The diameter is the main size of the cyclone, and it has a certain relation with the size of other components. As this diameter increases, the processing capacity can be improved, but the overflow size is coarser and vice versa. In order to classify the fine particles and increase the amount of processing, it is usually used by a number of small swirler parallel groups (such as Figure 3). The height of cylindrical cylinder has an effect on the retention time of pulp in cyclone, that is, the grading efficiency. However, it is not very high or too low, usually 0.6-1.0 times its diameter.

hydrocyclone group

Figure3.hydrocyclones group

2.The diameter of feed port

This diameter is usually 0.08-0.25 times of the diameter of the cyclone, which can increase the processing capacity, but the classification efficiency is reduced. The inlet is often made into a rectangle.

3.the diameter of overflow pipe

This diameter is generally 0.1-0.4 times of the diameter of the cyclone, which can be used to regulate the relative yield of overflow and sand. The overflow diameter increases, the overflow flow increases, the overflow granularity becomes coarser, the fine grain decreases and the concentration increases.

4.The diameter of desilting port

Generally, the diameter of the desilting port is increased, the discharge flow is reduced, the size of the overflow is finer, and the amount of the sand is increased, the concentration is lower, and the fines increase, but there is no obvious effect on the amount of treatment. The smaller the diameter of the grit hole, the smaller the sand drain volume. The phenomenon of "rough running" will appear in the overflow. If it is too small, it will make the coarse particles accumulate on the cone top and cause more blockage. The diameter of the sand should be umbeled, with the angle of 40 -70 degrees, and the ratio of the diameter of the desilting port  to the diameter of the overflow pipe is 0.4-0.8.

5.Insertion depth of overflow pipe

If the overflow pipe is inserted too shallow, it will make the coarse grains too late to enter the overflow in the centrifugal force field. If the penetration is too deep, the coarse grains will enter the overflow, which will reduce the classification efficiency. The insertion depth of the overflow tube should generally be 0.7-0.8 times the height of the cylindrical cylinder.

6.The Cone angle of conical cylinder

The increase of the cone angle will reduce the height of the equipment, and increase the average radial velocity of the pulp. At the same time, the upward flow velocity of the pulp increases as the impaction of the cone increases, resulting in the coarser size of the overflow. Therefore, separation of coarse granularity with large cone cyclone (30-60°), the separation of fine particle size with small cone angle cyclone (15-30°), desliming by a cyclone when the smaller cone angle (10-15°).

7.Ore feeding pressure

The commonly used ore feeding pressure is 49-157kPa (0.5-1.6kgf/cm2). The feed pressure is directly related to the amount of treatment and the size of the separation. The increase of feed pressure can reduce the grading size and increase the amount of treatment, but it will significantly increase the power consumption and equipment wear. The ore pressure should be kept stable during normal work.

8.Pulp features

It mainly refers to the density, grain size and pulp concentration of the ore. The larger the density of the ore, the finer the particle size is. When the concentration of pulp is large and the mud content is high, the viscosity and density of the slurry increases, which increases the movement resistance of the particles, and makes the grading size coarser. Vice versa The appropriate concentration of the pulp is usually determined by the test.

polyurethane hydrocyclone

Figure4. polyurethane hydrocyclone

Specification of Hydrocyclone



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      The way of involute feeding through the inlet branch reduces the turbulence of the burst emanative flow when materials entry, makes a smooth movement of  liquid inside cyclone, therefore gives a sharp classification.

      The rational length proportion of column and cone and reasonable insert depth of vortex finder.

      Wear resistant rubber as liners prolongs the service life by 2-4 times.

The working principle of hydrocyclone is centrifugal sedimentation, when two phases or three phases mixed liquid is fed into hydrocyclone by a certain pressure liquid and produces strong three-dimensional-elliptic rotational movement. Due to the different density of particles, the centrifugal force, the centripetal buoyancy and drag force are different.  So most coarse particles or heavy phase are discharged from cyclone underflow outlet, and the fine particles or light phase from the overflow tube, so as to achieve separation.