Numerical simulation of a cyclone separator to recycle the active components of waste lithium batteries

In this paper, cyclone separator is proposed for the first time to separate particles according to density, and it is applied to the recovery of lithium iron phosphate (LFP) from spent lithium battery materials for the first time. The effect of the flow field on the motion of injected particles in a cyclone separator is studied by means of computational fluid dynamics (CFD). It is found that there is a classification phenomenon caused by the difference in the particle densities and the separation process is simulated accordingly. The results show that 60% LiFePO4 in the original feed can be separated after 7 separations, and the mass purity is 91%, with 7% Al and 2% Fe under instantaneous surface injection conditions. Compared with the original feed, LFP is effectively recycled. After 15 separations, the efficiency increases to 76%. Under simulated continuous injection conditions, the separation efficiency of LFP is 61.22% after 20 simulated separations, and the mass purities of the separated products are 92.53% LFP, 6.92% Al, 0.44% Fe and 0.11% Cu. Compared with the traditional method, the new method has advantages of low energy consumption, low cost, theoretically no pollution, and great development potential.