Selective Removal of Copper Ions from Fully Leached Solution of Lithium Iron Phosphate Using Copper Chelating Resin

The wet recovery of spent lithium iron phosphate (LFP) batteries is severely hindered by the low efficiency of copper removal. Here, a new process has been developed using a copper-removing chelating resin with pyridine nitrogen, carboxyl, and hydroxyl groups for the selective separation of copper ions. This copper chelating resin achieved a copper removal efficiency of 96.99% and reduced the residual copper content to below 10 milligrams per liter, significantly outperforming the traditional iron powder method. The adsorption process is highly sensitive to pH, with the highest efficiency at pH 1.75. A concentration of 2.0 moles per liter of H2SO4 can achieve a desorption rate of approximately 95%. The adsorption process follows the Langmuir isothermal equation and the pseudo-second-order kinetic model, corresponding to single-layer chelated chemical adsorption. Mechanism studies have confirmed that the synergistic coordination effect of the multifunctional groups helps in the efficient capture of copper ions. This copper chelating resin exhibits excellent stability, reversibility, and reusability, providing a promising method for efficient copper removal and recovery in the wet metallurgical recycling of LFP.