What Are The Factors That Affect Coal Screening Efficiency?

Factors that affect coal screening efficiency include coal moisture, coal particle size composition, the shape of the screen plate and screen holes, the length and width of the screen surface, the inclination of the screen surface, amplitude and frequency, and processing capacity. Screening tests can determine the yield of each particle size grade in coal and various quality indicators such as ash content, moisture content, sulfur content, calorific value, etc. Screening test data is the main reference when determining the screening level and its quality indicators.

Factors affecting coal screening efficiency

1. Moisture content of coal

The humidity of the coal entering the screen is one of the important factors affecting the screening process, especially for dry screening. During the screening process, the external moisture of the coal is the basic form that affects the coal screening, but the water in the pores and cracks of the material and the water combined with the material have no effect on the screening process. When the material is screened on a fine-mesh screen, the influence of moisture is particularly obvious.

2. Coal particle size composition

The particle size composition of the coal entering the screen affects the processing capacity and screening efficiency of the vibrating screen. The fine particle content in the raw material, especially the particles close to the size of the screen hole, will affect the difficulty of screening. Generally, flat and rectangular materials are easier to screen than spherical and square materials.

3. The shape of the mesh

The screening effect of the screen surface is determined by the effective area of the screen surface, that is, the ratio of the screen hole area to the total screen surface area. The screening performance of the screen surface increases with the increase of the effective area of the screen surface. When the spacing between the screen holes is reduced, a larger effective screening area can be obtained, but it will affect the life of the screen.

4. Length and width of screen surface

The length of the screen determines the screening efficiency of the vibrating screen. The longer the screen, the higher the screening efficiency. But after reaching a certain value, the screening efficiency will be close to a constant. The width of the screen determines the processing capacity of the vibrating screen. When the thickness of the material layer at the feeding end is given, the width of the screen will directly affect the productivity of the vibrating screen.

5. Amplitude and frequency

The screen box must have a high enough speed to move the material on the screen surface. Experimental research shows that the acceleration of the coal vibrating screen box does not exceed 70~80m/s2, the amplitude is roughly 2~5mm, and the speed is 800~1500r/min.

6. Processing capacity

Increasing the processing capacity too much will seriously affect the screening efficiency and increase the number of particles smaller than the sieve hole in the screen material.