Optimization of flip-flow screen plate based on DEM-FEM coupling model and screening performance of fine minerals

Flip-flow screen has unique advantages in dry deep screening of sticky and wet fine minerals. However, during the flip-flow screening process, the continuous collision of mineral materials causes the actual motion state of the screen plate to differ significantly from the ideal state. Clarifying the actual motion changes and stress characteristics of the flip-flow screen plate under the combined action of its own relaxation and tension motions and particle swarm collision is the basis for optimizing the structure of the flip-flow screen plate and the prerequisite for improving screening efficiency. Therefore, this study constructed a coupling simulation calculation model for the flip-flow screening system and explored the kinematic changes and stress distribution characteristics of the flip-flow screen plate under continuous impact of particle swarm. Furthermore, the influence of particle mass flow rate on the displacement and impact stress of the flip-flow screen plate was elucidated. Regarding the mesh structure, the stress changes of various parts of the mesh were revealed, and an optimization plan for the mesh structure was proposed through comparative experiments. Finally, the 1 mm dry screening experiment of fine coal was conducted on a semi-industrial flip-flow screen to verify the screening effect of the optimized screen plate. The results showed that when the processing capacity was 4.5 t/(h·m2) and the screen plate length was 1.8 m, the screening efficiency could reach 81.73 %, which is about 15 % higher than before the optimizing the screen plate.