In the concentrator, the vibrating screen is one of the commonly used grading equipment. The screening effect of the vibrating screen is of great significance to the follow-up operation. Therefore, how to improve the screening effect of the vibrating screen is a problem that needs to be considered. Analyze what factors affect the screening effect and how to improve the screening effect of the vibrating screen by changing these factors.
There are many factors that affect the screening effect of the vibrating screen for mines. Three of the more important factors are the characteristics of the material entering the screen, the parameters of the screen surface of the vibrating screen, and the movement parameters of the vibrating screen. We will analyze these three factors one by one and explore how to improve the effect of mine vibrating screen by changing these factors.
1. The characteristics of the material being screened
Different materials have different characteristics of their own, with differences in density, hardness, and water content. Generally speaking, the screening effect of materials with higher hardness and better brittleness is better than materials with lower hardness and poor brittleness. For the materials that enter the screen, there are two aspects that can directly affect the screening effect: the particle size of the material and the water content of the material.
When the particle size of the material is close to the mesh size, the screening efficiency will be significantly reduced. These particles may block the mesh and reduce the screening area. This is a common phenomenon in the closed-circuit crushing process. This situation can be improved by increasing the vibrating screen. The amplitude can be improved. The increase of the amplitude can promote the fine-grained material to pass through the screen surface and reduce the occurrence of clogging. In addition, it can increase the pass rate of the middle part of the screen to improve the screening effect. It can also be improved by changing the feeding method The utilization rate of the screen surface of the vibrating screen can be multi-channel feeding, which reduces the time and distance of the material on the screen moving on the screen surface and improves the screening effect.
When the material has a large water content, the material is prone to adhesion, which reduces the screening efficiency. Generally speaking, the wet material with a large water content can be improved by increasing the screen hole. However, if the material contains mud ,when the amount is greater than 8%, wet screening or pre-washing methods should be used for treatment.
2. Vibrating screen surface parameters
The screen surface parameters of the vibrating screen include the shape of the vibrating screen mesh, the opening rate of the vibrating screen surface, the material of the screen surface and so on. Generally speaking, a long screen surface has a long material residence time, more chances to penetrate the screen, and high efficiency, while a wide screen surface has better processing capacity. Practice has proved that the appropriate ratio of screen surface aspect ratio is 2:1~3:1.
The opening rate of the screen surface of the vibrating screen here refers to the screening area of the vibrating screen, which is the ratio of the screen area to the total area of the screen surface. The larger the screen area, the higher the productivity per screen surface and the higher the screening efficiency. As for the shape of the sieve holes, the choice is made according to the particle shape of the material. Generally, it is better to use square sieve holes for sieving round particles.
In terms of materials, different screen surface materials will also have an impact on the screening effect, which can directly affect the adhesion coefficient of minerals and screens. For viscous minerals, rubber and polyurethane should be used for screen materials with greater elasticity. Ensure that the material on the screen is loose. However, this type of material usually has the disadvantage of a small open porosity.
After combining the above aspects, we can know that when selecting the vibrating screen surface, different materials and opening rates should be considered comprehensively.
3. Motion parameters of vibrating screen
The motion parameters of the vibrating screen include two factors: the vibration frequency of the vibrating screen and the direction angle of the vibrating screen. Vibration enables the material on the screen surface to be thrown away from the screen surface, so that the coarse material reaches the upper layer of the material layer, and the fine material reaches the lower layer of the material layer, close to the screen surface, the screen layer is evenly distributed, and the passing rate of fine materials increases accordingly. For materials with large particle size, generally the higher the frequency, the higher the number of bounces on the screen surface, the increased chance of contact between the material and the screen surface, and the reduction of the occurrence of clogging of the screen holes. Therefore, an appropriate increase in the vibration frequency can effectively improve the screening effect.
The vibration direction angle is the angle between the vibration direction line and the screen surface. The larger the value of this angle, the smaller the horizontal movement distance of the material during the screening process, and the lower the movement speed on the screen. It is obtained through practice. For materials that are easy to screen, the direction angle should be small, and for materials that are difficult to screen, the direction angle should be large. In general, the direction angle of the linear vibrating screen is between 30 degrees and 60 degrees, and the direction angle of the circular vibrating screen is 90 degrees.
After the above analysis, we understand some of the factors that affect the screening effect of the mine vibrating screen and how to improve the efficiency of the vibrating screen. In short, we must choose the vibrating screen according to the actual needs, and choose the appropriate screen surface material as much as possible to improve the motor adjustment excitation. Vibration force, and try to ensure the lower water content of the material, and improve the screening effect under the premise of ensuring the processing capacity.