Lithium-ion battery recycling: Recovery of lithium from process water through ion exchange

In Europe, an era of battery recycling is shaping new industries as spent lithium-ion batteries (LIBs) are considered, in addition to mining, as a potential source of battery raw materials with high prospect of environmental and economic incentives. Several recycling routes are being proposed combining hydrometallurgy and pyrometallurgy techniques and with emphasis on the mechanical pre-treatment (i.e., sorting, shredding, sieving) to pre-concentrate the LIBs component into a coarse metal fraction (Fe/plastics, Al, and Cu rich) and a fine electrode powder fraction (graphite and cathode active material - CAM). During LIB recycling, particularly in wet operations, specific LIB components such as Li and F easily dissolve into the water which results to material losses. For instance, immersion of an INR18650 battery in 1L water yielded a 100 mg/L Li and 140 mg/L F concentration. Moreover, the implementation of thermal treatment to liberate the electrode powder from the metal foils causes a carbothermic reduction of CAMs creating a more soluble Li compound that can be recovered by water leaching. Recently, froth flotation of pyrolyzed black mass aiming to separate graphite and CAM revealed a rather high concentration of Li in process water of 1,000 mg/L representing a 45% Li dissolution. A concentration of 2,600 mg/L Li was also reached during water recirculation in the flotation experiment. Hence, this work aims at the recovery of lithium from process water of battery recycling processes through the ion-exchange processes. Using commercial IX resins, the preliminary result shows a recovery of ~80% Li from flotation process water can be achieved after 15-min contact time. Precipitation experiments were also performed which produced a ~94-99% purity Li2CO3 powder.