Evaluating the possibilities and limitations of the pyrometallurgical recycling of waste Li-ion batteries using simulation and life cycle assessment

Abstract

Pyrometallurgical recycling of Li-ion batteries has been deemed energy-intensive and thought to result in poor recoveries, and it is typically considered disadvantageous in environmental terms in comparison to hydrometallurgical and direct recycling in the state-of-the-art literature. The process pathways for Li-ion batteries are constantly evolving, however, and such assumptions warrant re-evaluation when new technologies emerge, such as for the recovery of lithium by volatilization. The potential benefits and limitations of pyrometallurgical Li-ion battery recycling were evaluated with process simulation and life cycle assessment with and without pre-treatment stage for dismantled end-of-life batteries to demonstrate how the current processes should be developed to reach the EU's battery regulation goals. The analysis showed that the recovery of lithium by novel volatilization method followed by leaching-carbonation is environmentally viable, and that the pyrometallurgical recycling of nickel and cobalt-bearing NMC111 and NMC811 batteries results in significant impact reductions vs. primary raw materials especially when pre-treatment is conducted. The processing of NMC cells or black mass does not necessarily require external reducing agents or fuels due to the presence of graphite on the anode. The recycling of lithium iron phosphate (LFP) batteries, however, is more challenging. The results show that the pyrometallurgical processing of NMC batteries can satisfy both EU Battery Regulation targets assuming that the slagging of cobalt and nickel can be optimized.