A combined recovery process of metals in spent lithium-ion batteries

This work proposes a new process of recovering Co from spent Li-ion batteries (LIBs) by a combination of crushing, ultrasonic washing, acid leaching and precipitation, in which ultrasonic washing was used for the first time as an alternative process to improve the recovery efficiency of Co and reduce energy consumption and pollution. Spent LIBs were crushed with a 12 mm aperture screen, and the undersize products were put into an ultrasonic washing container to separate electrode materials from their support substrate. The washed materials were filtered through a 2 mm aperture screen to get underflow products, namely recovered electrodes. Ninety two percent of the Co was transferred to the recovered electrodes where Co accounted for 28% of the mass and impurities, including Al, Fe, and Cu, accounted for 2%. The valuable materials left in 2–12 mm products, including Cu, Al, and Fe, were presented as thin sheets, and could be easily separated. The recovered electrodes were leached with 4.0 M HCl for 2.0 h, at 80 °C, along with concurrent agitation. Ninety seven percent of the Li and 99% of the Co in recovered electrodes could be dissolved. The impurities could be removed at pH 4.5–6.0 with little loss of Co by chemical precipitation. This process is feasible for recycling spent LIBs in scale-up.