Magnetic-flotation: a sustainable solution for the flotation recycling of batteries’ blackmass

Rising interest in lithium-ion batteries as a key energy-storage option underscores the pressing need to develop recycling approaches that are both environmentally responsible and high-performing, especially for black mass rich in recoverable graphite and cathode active materials (CAMs). Froth flotation is the well-known technique for separating ultrafine CAM particles from graphite. Flotation beneficiation operates on the principle of surface properties, while binders in the batteries complicate the separation process. This study introduces magnetic-assisted flotation (MAGFLO) as a novel and environmentally friendly approach to enhance the flotation-based recycling of blackmass for nickel-manganese-cobalt (NMC) batteries. The MAGFLO leverages CAMs' magnetic susceptibility and hydrophilicity to improve their separation from non-magnetic and hydrophobic graphite, thereby reducing dependence on thermal/chemical surface modifications. The MAGFLO system was implemented as a retrofit setup, and experiments were conducted using an electromagnet with different setups (voltage: 10, 20, or 30) across various flotation cells (steel and stainless-steel) and configurations. Flotation results indicated that the magnetic properties of CAM particles could enhance their separation from graphite. SEM analysis revealed that fine CAM particles adhered to graphite particles, potentially influencing process efficiency. However, particle entrapment could be minimized by using magnetic field pulsation (the “on/off interval” mode of the electromagnet). The steel cell generally showed a higher separation efficiency with over 90% CAM recovery. Overall, MAGFLO demonstrated strong potential as a sustainable and scalable approach for future industrial recycling applications. • Magnetic-assisted flotation (MAGFLO) was used for recycling blackmass. • Cathode particles’ magnetic susceptibility can be used for their separation. • Both cathode and anode materials were efficiently recovered using MAGFLO. • MAGFLO-“on/off interval” mode would reduce graphite entrapment.