A novel pulsated pneumatic separation with variable-diameter structure and its application in the recycling spent lithium-ion batteries

In recycling of the spent lithium iron phosphorus (LiFePO4) batteries, the mechanical pretreatment is critical for relieving the pressure of the subsequent recycling process and reducing the cost of whole recycling process. In order to achieve the separation and concentration of the cathode materials, anode materials, copper and aluminum foils from spent LiFePO4 batteries, a novel pneumatic separation combined with froth flotation is designed in this research. A pulsated pneumatic separation with variable-diameter structure separator is used, through which 92.08% of copper and 96.68% of aluminum were recovered. In the pneumatic separation the movement of the copper and aluminum flakes can be described by an improved equivalent diameter method, based on the force analysis of the flaky particles. The froth flotation is utilized to recover the cathode materials and anode materials with the recovery of 92.86% and 83.21%, respectively. A mass balance and a technological route of the recycling process are provided finally. The present work provides a green and high-efficiency recycling process in which copper, aluminum, anode and cathode materials in lithium-ion batteries can be recovered respectively only by physical methods.