Selective desorption strategy for efficient lithium recovery from battery recycling effluents using cationic exchange resin

The recovery of lithium from battery recycling effluents using cationic ion-exchange resins presents a great potential but it is challenged by the inherent non-selectivity of the resins. This study explores an alternative strategy via a selective lithium desorption using Lewatit® TP 308, a weakly acidic resin with chelating functional groups. Batch experiments with synthetic solution containing Li + , Cu 2+ , Ni 2+ , Co 2+ , Mn 2+ show that TP 308 Na exhibits a non-selective sorption but allows efficient and selective lithium desorption using very low acid concentrations such as 0.05 M hydrochloric acid or 0.03 M sulfuric acid. Preferential desorption of lithium is achieved at the equilibrium pH between 4.5 and 5.5; however, it is also influenced by kinetic factors, as lithium desorbs faster than the divalent ions. To improve the pH control and desorption rate, organic acids (oxalic, citric, and acetic) were utilized. The use of 0.1 M acetic acid resulted in high lithium desorption selectivity, evidenced by a separation factor against divalent impurities of 483. Column ion exchange experiments using both synthetic solution and ion-spiked process water from a mechanical treatment of nickel‑manganese‑cobalt (NMC) batteries confirmed the selective desorption using various concentrations of acetic acid, obtaining a solution purity of up to 96.7% and lithium enrichment of up to 4.3. Overall, the inherently low concentrations of competing cations in real battery recycling effluents enabled direct lithium extraction using ion exchange processes with high selectivity in the desorption stage.