Selective recovery of lithium from used lithium-ion batteries spent via grain boundary reconstruction reaction

Abstract

The demand for lithium resources on the market has increased significantly as a result of the emergence and advancement of the new energy industry. However, improper handling leads to the generation of large amounts of hazardous waste, including spent lithium batteries. The recovery of lithium from these batteries has dual importance in protecting the environment and effectively recycling secondary resources. Herein, a green process for selective extraction of lithium from discarded lithium batteries was proposed. Sodium thiosulfate mixed with waste lithium battery powder was calcined at 600 °C for 90 min, when the molar ratio of sodium thiosulfate to lithium in the raw material was 0.5, and over 99 % lithium can be selectively preferentially extracted. During the roasting process, lithium in the raw materials was converted into water-soluble LiNaSO4, and transition metal oxides after calcination existed as water-insoluble oxides or sulfides, and the goal of preferential lithium extraction can be achieved by simple immersion in water. Lithium-containing leachate was purified by cerium carbonate and NaOH. After removing a small amount of Ni, Co, Mn, Al, Ca, and F impurities, the prepared lithium carbonate had a purity greater than 99.50 %, which met the standard of battery-grade lithium carbonate. This study introduces an approach to the selective extraction of lithium from lithium-containing solid waste, which effectively simplifies the recycling separation procedure and provides support for resource utilization of lithium-containing solid waste.