Study on impact mechanical characteristics and screening performance of fine coal during flip-flow screening process

Abstract

ABSTRACT Screening is a key link in the coal preparation, and flip-flow screening is the important method for achieving efficient classification of fine coal. During screening, the mechanical response of the screen plate caused by materials collisions not only changes its impact mechanical behavior, but also affects the final screening effect. It is urgent to clarify the mechanism of interaction between particle swarm and flip-flow screen plate. Therefore, in this study, based on the coupling of Discrete Element Method and Finite Element Method (DEM-FEM), the impact mechanical characteristics of the screen plate was explored during the collision process between the coal particle swarm and the screen plate. Conduct specific research on collision process, the relationship between the motion position of the screen plate and the distribution of impact stress was clarified. The trend of impact stress changes near the collision point was studied, and the optimized design of the flip-flow plate was carried out. On this basis, the influences of the processing capacity on the distribution of the screening products and screening efficiency were clarified. With an increase in the processing capacity of the flip-flow screen, the distribution coefficients of particles with approximate screen mesh size in the oversize gradually increased, resulting in an increase in distribution size and equal error size. Furthermore, the screening efficiency decreased from 84.91% to 81.36%. The study results provided a theoretical basis for the development of efficient screening technology for fine coal.