Flotation Separation of Licoo2 from Waste Lithium-Ion Batteries Using Catechol and Sodium Periodate

Abstract

Flotation is a cost-effective method for separating and recovering lithium cobalt oxide (LiCoO2) from waste lithium-ion batteries (LIBs). In this study, A novel flotation depressant was synthesized by dissolving catechol and sodium periodate (CA-SP) in an acetate acid buffer solution. This depressant was used to selectively depress the flotation of cathode material, enabling the successful separation of the cathode and anode materials through reverse flotation. A cobalt-rich concentrate was achieved by flotation when using dodecane and CA-SP as collector and depressant, respectively, indicating the potential for this method to be scaled up for industrial recycling of waste LIBs electrode materials. XPS tests showed that CA-SP could be adsorbed on PVDF and graphite surfaces, and the contact angle measurements manifest that the adsorption of CA-SP could turn their surface into hydrophilic. UV and FTIR tests demonstrate that CA-SP adsorbed more on PVDF and LiCoO2 surfaces than graphite, the adsorption mechanisms was further revealed by QCM-D and AFM measurements. After the adsorption of CA-SP, dodecane exhibited weaker adsorption on the cathode material (LiCoO2&PVDF), resulting in selective depression of the cathode material during flotation.

Keywords: waste lithium-ion batteries, catechol, sodium periodate, flotation depressant