A Combined Pyro- and Hydrometallurgical Approach to Recycle Pyrolyzed Lithium-Ion Battery Black Mass Part 2: Lithium Recovery from Li Enriched Slag—Thermodynamic Study, Kinetic Study, and Dry Digestion

Abstract

Due to the increasing demand for battery raw materials, such as cobalt, nickel, manganese, and lithium, the extraction of these metals, not only from primary, but also from secondary sources, is becoming increasingly important. Spent lithium-ion batteries (LIBs) represent a potential source of raw materials. One possible approach for an optimized recovery of valuable metals from spent LIBs is a combined pyro- and hydrometallurgical process. The generation of mixed cobalt, nickel, and copper alloy and lithium slag as intermediate products in an electric arc furnace is investigated in part 1. Hydrometallurgical recovery of lithium from the Li slag is investigated in part 2 of this article. Kinetic study has shown that the leaching of slag in H2SO4 takes place according to the 3-dimensional diffusion model and the activation energy is 22–24 kJ/mol. Leaching of the silicon from slag is causing formation of gels, which complicates filtration and further recovery of lithium from solutions. The thermodynamic study presented in the work describes the reasons for the formation of gels and the possibilities of their prevention by SiO2 precipitation. Based on these findings, the Li slag was treated by the dry digestion (DD) method followed by dissolution in water. The silicon leaching efficiency was significantly reduced from 50% in the direct leaching experiment to 5% in the DD experiment followed by dissolution, while the high leaching efficiency of lithium was maintained. The study takes into account the preparation of solutions for the future trouble-free acquisition of marketable products from solutions.

Worth from Waste: Utilizing a Graphite-Rich Fraction from Spent Lithium-Ion Batteries as Alternative Reductant in Nickel Slag Cleaning

“…Recently, Sommerfeld et al and Klimko et al proposed a combined pyro-and hydrometallurgical approach to recycle pyrolyzed LIB black mass [19,21]. In the first step, a Co-Ni-Cu alloy-and lithium-enriched slag was produced in a laboratory-scale electric arc furnace [19].…”

“…In the first step, a Co-Ni-Cu alloy-and lithium-enriched slag was produced in a laboratory-scale electric arc furnace [19]. In the second step, a hydrometallurgical treatment was proposed for lithium recovery from the slag [21]. Holzer et al studied a novel pyrometallurgical method in which they recovered 76-97% of lithium from batteries in a gas stream, from which it could be recovered for further processing [3].…”

“…Holzer et al studied a novel pyrometallurgical method in which they recovered 76-97% of lithium from batteries in a gas stream, from which it could be recovered for further processing [3]. Overall, the recycling approach by Sommerfeld et al and Klimko et al presented studies in which the pyrometallurgical step was used as a treatment method before hydrometallurgical treatment of the intermediate metal alloy/matte and slag products [19,21].…”

Assessment of recycling methods and processes for lithium-ion batteries

“…The most commonly employed industrial methods globally are the conventional pyro- and hydrometallurgical technologies which are combined or used separately ( Klimko et al., 2020 ). The former is a process of thermal treatment employing high temperatures to cause physical and chemical transformations on spent LIBs for the recovery of metals ( Makuza et al., 2021 ) whereby the latter is a chemical treatment method.…”

Tailoring Lithium Aluminate Phases Based on Thermodynamics for an Increased Recycling Efficiency of Li-Ion Batteries

“…However, the recycling efficiency of lithium from the slag phase is still a challenging issue . Also, interesting combinations of pyrometallurgical and hydrometallurgical processes have been investigated to recycle pyrolyzed LIB black mass. , In terms of recycling and energy efficiency, these recent studies also demonstrate the importance of generating high lithium-containing phases by tailored slag composition and solidification to efficiently apply hydrometallurgical approaches to the pyrometallurgically gained slags. In the work of Elwert et al, compositions of phases of lithium-containing slags gained from the Umicore LIB recycling process were investigated.…”