Novel application of pneumatic flotation cell for efficient graphite recovery from black mass: advancing critical raw material recycling

Black mass, the fine fraction from spent Li-ion batteries, needs to be recycled both for its valuable metal oxides and spheroidized graphite particles. Still, current recycling techniques show less preference for graphite, despite being a critical raw material, due to lower economic incentives. Flotation is a suitable and cost-efficient process for graphite recovery before downstream processing, however its effective separation from the black mass is hindered by the (ultra)fine particles. To address this challenge, a pneumatic ImhoflotTM cell is employed in this study. The cell utilizes high-shear turbulence to generate fine bubbles, facilitating dispersion/de-agglomeration of particles and removal of adhered slimes, enhancing reagent selectivity, and reducing dosing requirements. ImhoflotTM cell offers advantages over mechanical and column flotation, including increased recovery of fine particles, rapid flotation kinetics, and high attachment rates and reducing the fine entrained metal oxides particles into the concentrate. This research presents a promising approach for efficient graphite recovery from spent Li-ion batteries, securing the sustainable recycling of critical raw materials.