Lithium ion battery active material dissolution kinetics in Fe(II)/Fe(III) catalyzed Cu-H2SO4 leaching system

Leaching of NMC industrial black mass in the presence of LFP

This study focuses on the effect of an emerging source of waste, lithium iron phosphate (LFP) cathode materials, on the hydrometallurgical recycling of the currently dominant industrial battery waste that is rich in transition metals (Ni, Co, Mn, and Li). The effects of the dosage of LFP, initial acidity, and timing of LFP reductant addition were investigated in sulfuric acid (H2SO4) leaching (t = 3 h, T = 60 °C, ω = 300 rpm). The results showed that addition of LFP increased both transition metal extraction and acid consumption. Further, the redox potential was lowered due to the increased presence of Fe2+. An initial acidity of 2.0 mol/L H2SO4 with acid consumption of 1.3 kg H2SO4/kg black mass provided optimal conditions for achieving a high leaching yield (Co = 100%, Ni = 87.6%, Mn = 91.1%, Li = 100%) and creating process solutions (Co 8.8 g/L, Ni 13.8 g/L, Li 6.7 g/L, Mn 7.6 g/L, P 12.1 g/L) favorable for subsequent hydrometallurgical processing. Additionally, the overall efficiency of H2O2 decreased due to its decomposition by high concentrations of Fe2+ and Mn2+ when H2O2 was added after t = 2 h, leading to only a minor increase in final battery metals extraction levels.

A comprehensive review of emerging technologies for recycling spent lithium-ion batteries

Along with the increasing demand for lithium-ion batteries (LIB), the need for recycling major components such as graphite and different critical materials contained in LIB is also reaching a peak in the research community. Several authors review the different LIB recycling methodologies, including pyro- and hydrometallurgy processes. However, the characteristics, main stages, and achievements of LIB emerging recycling are still missing. This study reviews the diverse emerging approaches for recycling critical materials from spent LIB in the last five years. A classification for emerging recycling technologies is provided, including terms like development stage and eco-friendly status. The main stages of recycling LIB are opening, phase separation, and materials recovery. Among the emerging proposals with the highest industrialization potential are direct recycling techniques due to low costs and simple procedures. Concerning phase separation, froth flotation and ultrasound-assisted methods are discussed. The former divides black mass into pure anodic and cathodic materials, while ultrasonication is employed to physically detach active materials from foils or enhance binder degradation. As to materials recovery, several recent approaches show high recovery efficiency for different elements, mainly in leaching. The use of new organic acids, deep eutectic acids, and some salts are worth noting as leaching agents due to their low environmental impact. In addition, leaching methods assisted by ultrasound and microwave irradiation increase valuable metal recovery, reducing time consumption and the number of leaching reactants. As a part of the hydrometallurgy process, metallic ion purification is performed by solvent extraction and ion exchange, while selective precipitation can be achieved by specific chemical agents or electrochemical processes.

Recovery of critical metals from EV batteries via thermal treatment and leaching with sulphuric acid at ambient temperature

In the upcoming years, todaýs e-mobility will challenge the capacity of sustainable recycling. Due to the presence of organic components (electrolyte, separator, casings, etc.), future recycling technologies will combine thermal pre-treatment followed by hydrometallurgical processing. Despite the ongoing application of such treatment, there is still a lack of information on how applied parameters affect subsequent metal recovery. In this study, both oxidative and reductive conditions in dependence on temperature and time were studied. Qualitative and quantitative characterizations of the samples after treatment were performed followed by leaching with 2 M sulphuric acid at ambient temperature to determine the leachability of valuable metals such as Co, Mn, Ni and Li. Moreover, the negative or positive effect of treatment on the leachability of the main impurities (Cu and Al) was determined. Since the presence of carbon affects the degree of active material reduction, it's content after each thermal treatment was determined as well. If all variables, temperature and time of thermal processing are taken into account, pyrolysis at 700 °C for 30 min is the optimal treatment. Under these conditions, full recovery is reached after 2 min for Li, 5 min for Mn and 10 min for both Co and Ni. In the case of the incineration, only processing at 400 and 500 °C promoted higher recovery of metals, while the treatment at 600 and 700 °C led to the formation of less leachable species.

Acid leaching of LiCoO2 enhanced by reducing agent. Model formulation and validation

In this work, a model has been formulated to describe the complex process of LiCoO₂ leaching through the participation of competing reactions in acid media including the effect of H₂O₂ as reducing agent. The model presented here describes the extraction of Li and Co in the presence and absence of H₂O₂, and it takes into account the different phenomena affecting the controlling mechanisms. In this context, the model predicts the swift from kinetic control to diffusion control. The model has been implemented and solved to simulate the leaching process. To validate the model and to estimate the model parameters, a set of 12 (in triplicate) extraction experiments were carried out varying the concentration of hydrochloric acid (within the range of 0.5-2.5 M) and hydrogen peroxide (range 0-0.6%v/v). The simulation results match fairly well with the experimental data for a wide range of conditions. Furthermore, the model can be used to predict results with different solid-liquid ratios as well as different acid and oxygen peroxide concentrations. This model could be used to design or optimize a LiCoO₂ extraction process facilitating the corresponding economical balance of the treatment.

Study on valuable metal incorporation in the Fe-Al precipitate during neutralization of LIB leach solution

The role of aluminum concentration and pH in the purification of waste Li-ion battery leach solution was investigated using NaOH and LiOH as neutralization agents ([H2SO4] = 0.313 M, t = 6 h). Solution was prepared from synthetic chemicals to mimic real battery leach solution. Results demonstrate that pH (3.5-5.5) has a significant effect on the precipitation of metals (Fe, Al, Ni, Cu, Co, Mn, and Li), whereas higher temperature (T = 30 and 60 °C) decreases the precipitation pH of metals. Iron and aluminum were both found to precipitate at ca. pH 4 and the presence of aluminum in PLS clearly decreased the separation efficiency of Fe vs. active material metals (Ni, Co, Li). In the absence of dissolved aluminum, Fe precipitated already at pH 3.5 and did not result in the co-precipitation of other metals. Additionally, the Al-free slurry had a superior filtration performance. However, aluminum concentrations of 2 and 4 g/L were found to cause loss of Ni (2-10%), Co (1-2%) and Li (2-10%) to the Fe-Al hydroxide cake at pH 4. The use of LiOH (vs. NaOH) resulted in 50% lower co-precipitation of Ni, Co and Li. Overall, these results demonstrate that hydroxide precipitation can be an effective method to remove iron from battery waste leach solutions at aluminum concentrations of < 2 g/L only. Although the highest level of lithium loss in the cake was found at pH 4, the loss was shown to decrease with increasing pH.

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

One possible way of recovering metals from spent lithium-ion batteries is to integrate the recycling with already existing metallurgical processes. This study continues our effort on integrating froth flotation and nickel-slag cleaning process for metal recovery from spent batteries (SBs), using anodic graphite as the main reductant. The SBs used in this study was a froth fraction from flotation of industrially prepared black mass. The effect of different ratios of Ni-slag to SBs on the time-dependent phase formation and metal behavior was investigated. The possible influence of graphite and sulfur contents in the system on the metal alloy/matte formation was described. The trace element (Co, Cu, Ni, and Mn) concentrations in the slag were analyzed using the laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) technique. The distribution coefficients of cobalt and nickel between the metallic or sulfidic phase (metal alloy/matte) and the coexisting slag increased with the increasing amount of SBs in the starting mixture. However, with the increasing concentrations of graphite in the starting mixture (from 0.99 wt.% to 3.97 wt.%), the Fe concentration in both metal alloy and matte also increased (from 29 wt.% to 68 wt.% and from 7 wt.% to 49 wt.%, respectively), which may be challenging if further hydrometallurgical treatment is expected. Therefore, the composition of metal alloy/matte must be adjusted depending on the further steps for metal recovery.

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

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.

Hydrometallurgical Extraction of Li and Co from LiCoO2 Particles–Experimental and Modeling

The use of lithium-ion batteries as energy storage in portable electronics and electric vehicles is increasing rapidly, which involves the consequent increase of battery waste. Hence, the development of reusing and recycling techniques is important to minimize the environmental impact of these residues and favor the circular economy goal. This paper presents experimental and modeling results for the hydrometallurgical treatment for recycling LiCoO2 cathodes from lithium-ion batteries. Previous experimental results for hydrometallurgical extraction showed that acidic leaching of LiCoO2 particles produced a non-stoichiometric extraction of lithium and cobalt. Furthermore, the maximum lithium extraction obtained experimentally seemed to be limited, reaching values of approximately 65–70%. In this paper, a physicochemical model is presented aiming to increase the understanding of the leaching process and the aforementioned limitations. The model describes the heterogeneous solid–liquid extraction mechanism and kinetics of LiCoO2 particles under a weakly reducing environment. The model presented here sets the basis for a more general theoretical framework that would describe the process under different acidic and reducing conditions. The model is validated with two sets of experiments at different conditions of acid concentration (0.1 and 2.5 M HCl) and solid to liquid ratio (5 and 50 g L−1). The COMSOL Multiphysics program was used to adjust the parameters in the kinetic model with the experimental results.

A Combined Pyro- and Hydrometallurgical Approach to Recycle Pyrolyzed Lithium-Ion Battery Black Mass Part 1: Production of Lithium Concentrates in an Electric Arc Furnace

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 like spent lithium-ion batteries (LIBs) is becoming increasingly important. One possible approach for an optimized recovery of valuable metals from spent LIBs is a combined pyro- and hydrometallurgical process. According to the pyrometallurgical process route, in this paper, a suitable slag design for the generation of slag enriched by lithium and mixed cobalt, nickel, and copper alloy as intermediate products in a laboratory electric arc furnace was investigated. Smelting experiments were carried out using pyrolyzed pelletized black mass, copper(II) oxide, and different quartz additions as a flux to investigate the influence on lithium-slagging. With the proposed smelting operation, lithium could be enriched with a maximum yield of 82.4% in the slag, whereas the yield for cobalt, nickel, and copper in the metal alloy was 81.6%, 93.3%, and 90.7% respectively. The slag obtained from the melting process is investigated by chemical and mineralogical characterization techniques. Hydrometallurgical treatment to recover lithium is carried out with the slag and presented in part 2.