A Study on the Effect of Particle Size on Li-Ion Battery Recycling via Flotation and Perspectives on Selective Flocculation

Abstract

The recycling of active materials from Li-ion batteries (LIBs) via froth flotation has gained interest recently. To date, recycled graphite has not been pure enough for direct reuse in LIB manufacturing. The present work studied the effect of particle sizes on the grade of recycled graphite. Furthermore, selective flocculation is proposed as a novel approach to control particle sizes and thus improve graphite grade by preventing the entrainment of cathode components. Zeta potential and particle size measurements were performed to find an optimal pH for electrically selective flocculation and to study the interaction of flocculants, respectively. Batch flotation experiments were performed to investigate the effect of particle size on the purity of the recovered graphite. Results suggested that, in the absence of ultrafine fine particles, battery-grade graphite of 99.4% purity could be recovered. In the presence of ultrafine particles, a grade of 98.2% was observed. Flocculating the ultrafine feed increased the grade to 98.4%, although a drop in recovery was observed. By applying a dispersant in addition to a flocculant, the recovery could be increased while maintaining a 98.4% grade. Branched flocculants provided improved selectivity over linear flocculants. The results suggest that particle size needs to be controlled for battery-grade graphite to be recovered.

Ultra-High-Molecular-Weight, Narrow-Polydispersity Polyacrylamides Synthesized Using Photoiniferter Polymerization to Generate High-Performance Flocculants

“…Flocculants are essential substances to facilitate rapid solid–liquid separation and are crucial in applications such as municipal wastewater treatment, food processing, , paper making, white biotechnology, , palm oil extraction, Li-ion battery recycling, mineral processing, − and oil sands tailings. , For example, although paper-based materials are widely perceived to be “environmentally friendly” and “sustainable” products, paper production is one of the biggest producers of industrial wastewater per unit volume, generating around 3 billion tons of wastewater per year (≈42% of all industrial wastewater production) . Therefore, closed-loop water cycles and improved methods for wastewater treatment can significantly improve the environmental sustainability and CO 2 balance for the paper and card manufacturing industry …”