Investigation of effect of particle shape on the screening performance of vibratory screens using the DEM approach

The efficiency of a screening process affects the efficiency of downstream processes, reduces variability in system, improves throughput and quality, reduces waste generation and cost. Among the factors affecting screening efficiency of bulk materials, particle shape is a major one. The particle shape influences particle bed formation and its packing. This in turn decides the porosity and permeability of the bed. It influences two key mechanisms of screening process i.e., particle stratification and passage of fine particles. For obtaining higher screening efficiency, better stratification and higher passage rate is required. Stratification of particles, where larger particles rise to the bed and finer particles migrate down and finally pass through it, depends on vibrating conditions of screen. The effect produced by these vibrations on the particle bed depends on particle characteristics as well as inter-particle and particle-screen interactions. Particle shape is important as different shapes may behave differently under similar vibrating conditions. In this work, a comparative study of behavior of particle shapes for multiple vibrating parameters is done. The varying vibration parameters include different vibration motion types (linear, circular and elliptical). Using DEM methodology, the microscopic parameters like residence time and particle-deck collisions were studied. This microscopic information is used to predict the macroscopic screening performance for different particles’ shape.