The effect of interaction between particles on eddy current separation

Solid waste contains a large number of non-ferrous metal resources, which are called “urban mines”. Eddy current separation can achieve the enrichment of non-ferrous metals in solid waste. Under the alternating magnetic field generated by the rotating magnetic roller, due to electromagnetic induction, the non-ferrous metals are subjected to eddy current forces and are thrown into different receiving tanks, thereby achieving the separation between non-ferrous metals and non-metals, as well as between non-ferrous metals. However, the electromagnetic induction can cause interactions between non-ferrous metal particles, change the force states of particles and increase the disorderliness of trajectories during the separation of multiple particles. The interaction between particles affects the effective enrichment of the non-ferrous metals. Therefore, how to control the interactions between particles is one of the key issues in achieving efficient separation of mixed non-ferrous metals. This study proposes methods to control the interaction between particles from two perspectives: utilization and weakening perspectives. The separation experiment and COMSOL Multiphysics were carried out to analyze the changes in the magnetic field, the eddy current, the eddy current force, the motion trajectory, and the particle landing point. The mechanism of interaction between particles caused by electromagnetic induction was revealed, and the implementation method that utilizes the interaction force between particles was proposed. In addition, the effects of magnetic roller speed and particle size on the interaction between non-ferrous metal particles were analyzed, and some suggestions were proposed to weaken the negative impact of interaction.