Analysis of particle stratification in vibratory screening: Insights from DEM simulations

Abstract

The screening process involves two key mechanisms: particle stratification and passage of free particles through apertures. Efficient separation relies on high stratification rates, where fine particles percolate to the bottom of the bed, and larger particles rise to the top. These processes vary along the screen length, with fine particles typically passing through the screen earlier. Vibration conditions (motion type, frequency, amplitude), feed rate, and material properties significantly influence this behavior. In this study, particle bed structure and stratification patterns were analyzed under various screening conditions using DEM simulations. The DEM model was validated using a laboratory-scale setup based on partition curves and cut-size (d₅₀). The study examined the effects of three vibration modes (linear, circular, elliptical) along with vibration frequency, amplitude, feed rate, and material characteristics. The results show distinct stratification patterns for each vibration mode. Elliptical and circular motions performed best for near-mesh particles, while linear motion was most effective for fine particle sieving. These findings offer valuable insights for optimizing screening parameters based on feed characteristics. This will help in improved design, and better selection of parameters for screening of bulk materials.