Attritor milling mechanisms and optimization for selective separation of aluminum foil from cathode materials recovered by electrical pulsed discharge

This study investigates the quantitative optimization of attritor milling conditions for the selective separation of aluminum (Al) from cathode active materials (CAM) recovered from spent lithium-ion batteries (LiBs) via electrical pulsed-discharge delamination, with the aim of establishing an efficient direct recycling process. Attritor milling experiments were conducted using various media diameters, rotational speeds, and durations to evaluate their effects on Al removal and particle modification. The recovered powders were analyzed for their particle size, composition, and structure. Population balance modeling and discrete element simulations were applied to elucidate comminution mechanisms. The results revealed that 3 mm media promoted surface grinding with controlled fine-particle generation, whereas 10 mm media induced impact-driven volume breakage. The distinct behavior of Al originates from the coexistence of foil fragments and plasma re-solidified particles, which respond differently to milling. Under optimized conditions (3 mm media, 800 rpm, 20 min), 92 wt% of CAM was recovered with Al contamination below 0.3 wt%, while Li(Ni, Mn, Co)O 2 particles was preserved, satisfying the requirements for direct recycling. These findings demonstrate that optimizing attritor milling after electrical pulsed discharge enables the efficient selective separation of Al and high-purity CAM recovery, contributing to the sustainable direct recycling of spent LiBs.