Abstract
This article mainly focuses on the mixed material of waste lithium iron phosphate batteries after crushing, and uses vertical pneumatic separation method to separate and recover positive and negative electrode materials and plastic films. Simulation study using CFD-DEM coupling method, which uses sheet-like cylindrical particles and Holzer drag model to improve the accuracy of the simulation experiment of sheet-like cylindrical particles. Before exploring the motion state of particles in vertical pneumatic separation, the accuracy of the resistance model was verified through comparison with other experiments. In addition, the influence of parameters such as inlet air velocity, inlet air angle, separation zone height and initial particle velocity on the separation results during the separation process was analyzed in order to optimize these parameters. Finally, a simple vertical pneumatic separation device was constructed for experiments, and the accuracy of the experimental results was improved through mutual verification between simulation and experiments. Comparing the results of simulation and experiment, it was found that they were basically consistent, which further proves the reliability of the results. Based on the comprehensive simulation and experimental results, we have come to the conclusion that, when the sheet-like cylindrical particle size is around 5mm, The optimal separation speed between plastic film and mixed positive and negative electrode materials is about 2.0m/s, and the optimal separation speed between positive and negative electrode materials copper foil and aluminum foil is about 3.4m/s.
Keywords: Recycling of lithium iron phosphate batteries; vertical pneumatic separation; CFD-DEM; Holzer drag model; Optimize the parameters