DEM study of compaction of cohesive powders

Roll compaction is widely used in mineral and pharmaceutical in mineral and pharmaceutical industry to increase the bulk density and uniformity of particulate formulations as a tightly compacted ribbon, which is also convenient for later treatments in dry granulation or powder rolling. Generally it is a particle-bonding process where feeding powders undergo four stages: particle rearrangement, particle deformation, particle fragmentation and particle bonding.the knowledge of roll compaction is still limited because of the difficulties in determining important process parameters in experiments. In this work, a numerical models based on the Discrete Element Method is developed to simulate the roll compaction. The Spring-Dashpot-Slider model is used, normal forces including contact force and damping force, tangential forces including contact force and damping force are modeled, as well as torque and friction torque. Cohesive force considered in this model is van der Waals force, which is long-range and noncontact force.A series of controlled numerical experiments are performed to quantify the effects of key variables affecting the process performance. The roll compaction process has been investigated by the DEM, focusing on the effect of some key variables. The findings have improved our understanding of the process, which will be helpful for proper handling of feed particles