Key Factors Affecting Screening Efficiency

　　Screening equipment is a common and indispensable device in the production processes of basic industries such as coal, chemical, metallurgy, mining, and building materials. These basic industrial fields have renowned domestic academic institutions: China University of Mining and Technology, Liaoning University, Beijing Iron and Steel Research Institute, etc., which have produced a group of screening experts and scholars whose research results represent the country's cutting-edge screening technology.

　　**First, the purpose of screening is particle size classification, and the higher the efficiency, the better. Many factors affect screening efficiency, such as:

　　1: Material characteristics. The geometric shape, moisture content, ash content, muddy phenomena, gangue, iron wires, wood, garbage, woven materials, etc., in the material group all produce different classification results in screening, i.e., the performance of screening efficiency.

　　These material characteristics are the prerequisites for screening and cannot be changed.

　　2: Screening area.

　　Screening area is the main factor to measure screening efficiency. Without this basic rule, no equipment can achieve **rate!

　　3: Screen opening rate. Under a fixed screening area, the higher the opening rate, the better. The screen opening rate is the basic condition for material permeability!

　　4: Material thickness. The thinner the material on the screen surface, the more instantaneous the screening can be, and the higher the screening efficiency. In other words, the wider the screen surface, the better. If it cannot be widened, a multi-layer design is needed to further reduce the material thickness on the screen surface.

　　5: Screen permeability time. During the material's movement on the screen surface, permeability is completed. The thinner the screen, the shorter the material permeability time; conversely, the permeability time is extended. The material that can subsequently pass through will move forward, reducing the chance of permeability. The thinner the screen, the shorter the material permeability time.

　　6: Screening time. The longer the material stays on the screen surface, the higher the relative screening efficiency. The belt conveyor delivers material more concentratedly, feeding the full width of the screen through a coal chute or distributor. While the material moves on the screen surface, permeability is completed. If the material moves too fast, the effect worsens. The permeability effect and screening time have a positive proportional relationship.

　　7: Material layering. To achieve high screening efficiency for wet sticky material groups, fluffiness and layering are essential factors. The material group is a complex mixture of raw coal, coal slime, gangue, and particles of various sizes, bonded together. Without dispersing, fluffing, and layering the material group, fine materials will not actively settle, and fine particles smaller than the screen openings will not have the chance to pass through, severely affecting screening efficiency.

　　8: Screen surface angle. For vibrating screens, the smaller the screen surface angle, the higher the relative screening efficiency because the screen angle and Earth's gravity determine the material running speed. The faster the speed, the shorter the screening time; conversely, the screening time increases relatively, and screening efficiency also improves.

　　9: Feeding effect. The width and length of the screen surface determine the screening area. To achieve higher screen surface utilization, a feeding function needs to be added above the screen to feed the full width of the screen evenly. The material layer becomes thinner, and screening efficiency can be further improved on the original basis.

　　10: Probabilistic screening. Probabilistic screening involves using double or multiple screen layers, with larger openings on the upper layer, smaller on the second, and even smaller on the lower layer. The material group is classified by particle size and layered operation. The screen surface's wear resistance is significant, and efficiency is higher.

　　11: Equal thickness screening. The screen surface of the screening machine is designed with multiple angles. The feed end is large with more material; after screening out some material, the amount decreases, and the screen angle becomes gentler. Theoretically, this achieves a uniform thickness of material on the screen surface, which is more conducive to screening and improving screening efficiency.

　　11: Layered and split-route combined screening. In a screening system, several screening units are divided, decomposing a larger amount of material onto the screen surfaces of each unit. The material layer reaches an extremely thin state, thereby achieving extremely high screening efficiency.

　　For vibrating screens, the relationship between amplitude and vibration frequency must also be considered. The higher the amplitude, the greater the acceleration on the material, the better the material layering effect, and the higher the efficiency. Therefore, wet sticky materials require larger amplitude and lower frequency. Conversely, dry fine materials require smaller amplitude and higher vibration frequency.

　　There are more factors affecting screening efficiency beyond these. This description only covers the basic permeability rules of screening equipment, which are the principles followed internationally and domestically. For screening large amounts of wet sticky fine materials, it is even more necessary to further optimize each factor to maximize screening efficiency.