Selective separation and recovery of cobalt from leach liquor of discarded Li-ion batteries using thiophosphinic extractant

Synergistic Approach for Selective Leaching and Separation of Strategic Metals from Spent Lithium-Ion Batteries

Recycling spent Li-ion batteries (LIBs) is paramount to pursuing resource efficiency and environmental sustainability. This study introduces a synergistic approach for selectively leaching and separating strategic metals from waste LIBs, representing a more efficient alternative to traditional single-acid-based leaching methods. The research also thoroughly analyzes diverse extraction parameters, aiming to achieve clean metal separation through synergistic concepts rather than single-phase extraction. The outcome of this study is developing a comprehensive downstream process, advancing the cause of sustainable waste management in the LIB industry. Under specific conditions with 0.6 mol/L total acid content (0.5 mol/L tartaric acid + 0.1 mol/L ascorbic acid), 99.9% cobalt and 100% lithium were effectively leached. The subsequent extraction process achieved a clean separation, with 48.3% of cobalt extracted using a mixture of 0.1 mol/L Alamine-336-Cyanex-272 (A-336-Cy-272) from the leach liquor with no coextraction of lithium, and this efficiency was improved to 67.3% by adjusting the pH from 2.44 to 7.5. However, it is worth noting that increasing the extractant concentration led to an antagonistic effect. To further enhance cobalt enrichment in the organic phase, the McCabe-Thiele plot method was recommended, employing saponified Cy-272. Moreover, the regeneration of saponified Cy-272 was investigated, and the stripped solution was processed with NaOH to form Co(OH)2, subsequently converting it into cobalt oxide (Co3O4) through calcination.

Selective Recovery of Cathode Materials from Spent Lithium-Ion Battery Material with a Near-Room-Temperature Separation

Effective separation of cathode materials from the current collector is a critical step in recycling a spent lithium-ion battery (LIB). This typically necessitates the decomposition or dissolution of the organic binder, poly(vinylidene fluoride) (PVDF), to achieve efficient recovery of cathode materials. However, this process requires a high decomposition temperature, typically between 400 and 600 °C, and can lead to side reactions, such as current collector oxidation/brittleness, decomposition of cathode materials, and formation of metal fluorides. In this study, we propose that non-thermal plasma (NTP) treatment can be used to achieve an extremely high separation of cathode materials and aluminum current collector at near room temperature. Instead of relying on PVDF decomposition, which requires high temperatures, PVDF can be deactivated by partially breaking down long molecular chains with appropriate NTP conditions. With a total treatment time of around 2000 s and an environmental temperature of approximately 80 °C, minor side reactions can be avoided. The separation rate can reach up to 95.69%, and high-quality cathode materials can be obtained with only 0.02 wt % aluminum impurity content. This research could potentially offer a new approach toward minimizing recycling steps and reducing energy consumption in the recycling of spent LIBs. It could also be extended to the recovery of a broader range of electronic wastes.

Indium extraction from nitrate medium using Cyphos ionic liquid 104 and its mathematical modeling

The treatment and recovery of pollutants in aquatic system is one of the greatest challenges for environmentalists throughout the world. In this study, solvent extraction of indium using phosphonium ionic liquid (Cyphos IL 104) as an extractant and its mathematical model was proposed for prediction of In(III) ion transport across a FSSLM (flat-sheet-supported liquid membrane). Solvent extraction experiments on indium have been carried out under various experimental conditions in order to assert some fundamental parameters using mathematical analysis for mass transfer process. Diffusion is the process which facilitates metal ion transport across liquid membrane, indicating the applicability of Fick's law of diffusion in model formulation. The influence of different parameters like composition of diluent, feed acidity, and ligand concentration on In(III) ion transport rate has been reported. At different extractant concentrations, the modeling outputs and experimental indium extraction were observed to be in reasonably good agreement.

Eco-Friendly Recycling of Lithium Batteries for Extraction of High-Purity Metals

The significant increase in lithium batteries consumption produces a significant quantity of discarded lithium-ion batteries (LIBs). On the one hand, the shortage of high-grade ores leads to the necessity of processing low-grade ores, which contain a low percentage of valuable metals in comparison to the discarded LIBs that contain a high percentage of these metals, which enhances the processing of the discarded LIBs. On the other hand, the processing of discarded LIBs reduces the negative environmental effects that result from their storage and the harmful elements contained in their composition. Hence, the current study aims at developing cost-effective and ecofriendly technology for cobalt and lithium metal ion recovery based on discarded LIBs. A novel synthesized solid-phase adsorbent (TZAB) was utilized for the selective removal of cobalt from synthetic solutions and spent LIBs. The synthesized TZAB adsorbent was characterized by using 13C-NMR, GC-MS, FT-IR, 1H-NMR, and TGA. The factors affecting the adsorption of cobalt and lithium ions from synthetic solutions and spent LIBs, including the sorbent dose, pH, contact time, temperature, and cobalt concentration were investigated. The conditions surrounding the recovery of cobalt and lithium from processing discarded LIBs, were investigated to optimize the maximum recovery. The Langmuir, Freundlich, and Dubinin-Radushkevich (D-R) isotherm models were used to study the kinetics of the adsorption process. The obtained results showed that high-purity CoC₂O₄ and Li₃PO₄ were obtained with a purity of 95% and 98.3% and a percent recovery of 93.48% and 95.76%, respectively. The maximum recovery of Co(II) from synthetic solutions was obtained at C₀ = 500 mg·L^-1, dose of 0.08 g, pH 7.5, T = 25 °C, and reaction time = 90 min. The collected data from Langmuir's isotherm and the adsorption processes of Co agree with the data predicted by the D-R isotherm models, which shows that the adsorption of Co(II) onto the TZAB seems to be chemisorption, and the results agree with the Langmuir and D-R isotherm models.

Deep eutectic solvent for spent lithium-ion battery recycling: comparison with inorganic acid leaching

Deep eutectic solvents (DESs) as novel green solvents are potential options to replace inorganic acids for hydrometallurgy. Compared with inorganic acids, the physicochemical properties of DESs and their applications in recycling of spent lithium-ion batteries were summarized. The viscosity, metal solubility, toxicological properties and biodegradation of DESs depend on the hydrogen bond donor (HBD) and acceptor (HBA). The viscosity of ChCl-based DESs increased according to the HBD in the following order: alcohols < carboxylic acids < sugars < inorganic salts. The strongly coordinating HBDs increased the solubility of metal oxide via surface complexation reactions followed by ligand exchange for chloride in the bulk solvent. Interestingly, the safety and degradability of DESs reported in the literature are superior to those of inorganic acids. Both DESs and inorganic acids have excellent metal leaching efficiencies (>99%). However, the reaction kinetics of DESs are 2-3 orders of magnitude slower than those of inorganic acids. A significant advantage of DESs is that they can be regenerated and recycled multiple times after recovering metals by electrochemical deposition or precipitation. In the future, the development of efficient and selective DESs still requires a lot of attention.

Solvent extraction for recycling of spent lithium-ion batteries

Up to now, solvent extraction not only recycle valuable metals (i.e., Ni, Co, Mn and Li) from the leach liquor of spent cathode materials, but also apply to treat spent electrolyte. This paper summarizes the development of solvent extraction in the field of recycling spent lithium-ion batteries (LIBs) from the aspects of principle, technology and industrialization. Meanwhile, the paper also comments on the challenges and opportunities for the solvent extraction facing in the recycling of spent LIBs.

Selective extraction and separation of Li, Co and Mn from leach liquor of discarded lithium ion batteries (LIBs)

Novel route has been developed to selectively extract lithium (Li), cobalt (Co) and manganese (Mn) from the leach liquor of discarded lithium ion batteries (LIBs) containing 1.4 g/L Cu, 1.1 g/L Ni, 11.9 g/L Co, 6.9 g/L Mn and 1.2 g/L Li. Initially, Cu and Ni were extracted by solvent extraction techniques using 10% LIX 84-IC at equilibrium (Eq.) pH 3 and 4.6, respectively. Subsequently, precipitation studies were carried out at different conditions such as pH, reaction time, precipitant concentration etc., to optimize the parameters for selective precipitation of Co from the leach liquor. Result showed that 99.2% Co was precipitated from the leach liquor (11.9 g/L Co, 6.9 g/L Mn and 1.2 g/L Li) after extraction of Cu and Ni in a range of pH 2.9 to 3.1 using un-diluted ammonium sulfide solution (10% v/v) as a precipitant at 30 °C, while only 0.89% Mn and 0.62% Li were co-precipitated. After Co precipitation, 98.9% Mn was extracted from the filtrate using 10% D2EHPA at equilibrium pH 4.5, and Li remained in raffinate. From the obtained purified solution, metals could be recovered either in a form of salt/metals by precipitation/ evaporation/ electrolysis method.

Recovery of valuable metals from mixed spent lithium-ion batteries by multi-step directional precipitation

The novel strategy of multi-step directional precipitation is proposed for recovering valuable metals from the leachate of cathode material obtained by mechanical disassembly from mixed spent lithium-ion batteries. Based on thermodynamics and directional precipitation, Mn²⁺ is selectively precipitated under conditions of MRNM (molar ratio of (NH₄)₂S₂O₈ to Mn²⁺) = 3, pH = 5.5 and 80 °C for 90 min. Ni²⁺ was then selectively precipitated using C₄H₈N₂O₂ under conditions of pH = 6, MRCN (molar ratio of C₄H₈N₂O₂ to Ni²⁺) = 2, 30 °C and 20 min. Then, the pH was adjusted to 10 to precipitate Co²⁺ as Co(OH)₂. Finally, Li⁺ was recovered by Na₂CO₃ at 90 °C. The precipitation rates of Mn, Ni, Co, and Li reached 99.5%, 99.6%, 99.2% and 90%, respectively. The precipitation products with high purity can be used as raw materials for industrial production based on characterization. The economical and efficient recovery process can be applied in industrialized large-scale recycling of spent lithium-ion batteries.

Investigation of the Physico-Chemical Properties of the Products Obtained after Mixed Organic-Inorganic Leaching of Spent Li-Ion Batteries

Lithium-ion batteries are currently one of the most important mobile energy storage units for portable electronics such as laptops, tablets, smartphones, etc. Their widespread application leads to the generation of large amounts of waste, so their recycling plays an important role in environmental policy. In this work, the process of leaching with sulfuric acid for the recovery of metals from spent Li-ion batteries in the presence of glutaric acid and hydrogen peroxide as reducing agents is presented. Experimental results indicate that glutaric-acid application improves the leaching performance compared to the use of just hydrogen peroxide under the same conditions. Obtained samples of leaching residues after mixed inorganic-organic leaching were characterized with Scanning Electron Microscopy, Fourier Transform Infrared Spectroscopy, and X-ray diffraction.

Toward sustainable and systematic recycling of spent rechargeable batteries

A comprehensive and novel view on battery recycling is provided in terms of the science and technology, engineering, and policy.

Hydrometallurgical recycling of lithium-ion batteries by reductive leaching with sodium metabisulphite

The hydrometallurgical extraction of metals from spent lithium-ion batteries (LIBs) was investigated. LIBs were first dismantled and a fraction rich in the active material was obtained by physical separation, containing 95% of the initial electrode, 2% of the initial steel and 22% of plastic materials. Several reducers were tested to improve metals dissolution in the leaching step using sulphuric acid. Sodium metabisulphite led to the best results and was studied in more detail. The best concentration of Na₂S₂O₅ was 0.1 M. The metals dissolution increased with acid concentration, however, concentrations higher than 1.25 M are unnecessary. Best results were reached using a stirring speed of 400 min^-1. The metals leaching efficiency from the active material (Li, Mn, Ni, Co) increased with the temperature and was above 80% for temperatures higher than 60 °C. The dissolution of metals also rose with the increase in the liquid/solid ratio (L/S), however, extractions above 85% can be reached at L/S as lower as 4.5 L/kg, which is favourable for further purification and recovery operations. About 90% of metals extraction can be achieved after only 0.5 h of leaching. Sodium metabisulphite can be an alternative reducer to increase the leaching of Li, Mn, Co, and Ni from spent LIBs.

Recovery of valuable metals from waste cathode materials of spent lithium-ion batteries using mild phosphoric acid

Sustainable recycling of valuable metals from spent lithium-ion batteries (LIBs) may be necessary to alleviate the depletion of strategic metal resources and potential risk of environmental pollution. Herein a hydrometallurgical process was proposed to explore the possibility for the recovery of valuable metals from the cathode materials (LiCoO₂) of spent LIBs using phosphoric acid as both leaching and precipitating agent under mild leaching conditions. According to the leaching results, over 99% Co can be separated and recovered as Co₃(PO₄)₂ in a short-cut process involved merely with leaching and filtrating, under the optimized leaching conditions of 40°C (T), 60min (t), 4 vol.% H₂O₂, 20mLg^-1 (L/S) and 0.7mol/L H₃PO₄. Then leaching kinetics was investigated based on the logarithmic rate kinetics model and the obtained results indicate that the leaching of Co and Li fits well with this model and the activation energies (Ea) for Co and Li are 7.3 and 10.2kJ/mol, respectively. Finally, it can be discovered from characterization results that the obtained product is 97.1% pure cobalt phosphate (Co₃(PO4)₂).

An investigation of trends in precious metal and copper content of RAM modules in WEEE: Implications for long term recycling potential

Precious metal (PM) and copper content of dynamic-RAM modules placed on the market during 1991-2008 has been analysed by AAS following comminution and acid digestion. Linear regression analysis of compositional data ordered according to sample chronology was used to identify historic temporal trends in module composition resulting from changes in manufacturing practices, and to project future trends for use in more accurate assessment of future recycling potential. DRAM was found to be 'high grade' waste with: stable levels of gold and silver over time; 80% reduction in palladium content during 1991-2008; and 0.23g/module/year increase in copper content with a 75% projected increase from 2008 by 2020. The accuracy of future recycling potential projections for WEEE using current methods based on static compositional data from current devices is questionable due to likely changes in future device composition. The impact on recycling potential projections of waste laptops, smart phones, cell phones and tablets arising in Europe in 2020 resulting from a 75% increase in copper content is considered against existing projections using static compositional data. The results highlight that failing to consider temporal variations in PM content may result in significant discrepancies between projections and future recycling potential.

Use of mild organic acid reagents to recover the Co and Li from spent Li-ion batteries

New organic acid mixtures have been investigated to recover the valuable metal ions from the cathode material of spent Li-ion batteries. The cathodic active material (LiCoO2) collected from spent Li-ion batteries (LIBs) is dissolved in mild organic acids, iminodiacetic acid (IDA) and maleic acid (MA), to recover the metals. Almost complete dissolution occurred in slightly excess (than the stoichiometric requirement) of IDA or MA at 80°C for 6h, based on the Co and Li released. The reducing agent, ascorbic acid (AA), converts the dissolved Co(III)- to Co(II)-L (L=IDA or MA) thereby selective recovery of Co as Co(II)-oxalate is possible. The formation of Co(III)- and Co(II)-L is evident from the UV-Vis spectra of the dissolved solution as a function of dissolution time. Thus, the reductive-complexing dissolution mechanism is proposed here. These mild organic acids are environmentally benign unlike the mineral acids.

Recovery of cobalt from spent lithium-ion batteries using supercritical carbon dioxide extraction

Continuing technological development decreases the useful lifetime of electronic equipment, resulting in the generation of waste and the need for new and more efficient recycling processes. The objective of this work is to study the effectiveness of supercritical fluids for the leaching of cobalt contained in lithium-ion batteries (LIBs). For comparative purposes, leaching tests are performed with supercritical CO2 and co-solvents, as well as under conventional conditions. In both cases, sulfuric acid and H2O2 are used as reagents. The solution obtained from the supercritical leaching is processed using electrowinning in order to recover the cobalt. The results show that at atmospheric pressure, cobalt leaching is favored by increasing the amount of H2O2 (from 0 to 8% v/v). The use of supercritical conditions enable extraction of more than 95wt% of the cobalt, with reduction of the reaction time from 60min (the time employed in leaching at atmospheric pressure) to 5min, and a reduction in the concentration of H2O2 required from 8 to 4% (v/v). Electrowinning using a leach solution achieve a current efficiency of 96% and a deposit with cobalt concentration of 99.5wt%.

Environmentally-friendly lithium recycling from a spent organic li-ion battery

A simple and straightforward method using non-polluting solvents and a single thermal treatment step at moderate temperature was investigated as an environmentally-friendly process to recycle lithium from organic electrode materials for secondary lithium batteries. This method, highly dependent on the choice of electrolyte, gives up to 99% of sustained capacity for the recycled materials used in a second life-cycle battery when compared with the original. The best results were obtained using a dimethyl carbonate/lithium bis(trifluoromethane sulfonyl) imide electrolyte that does not decompose in presence of water. The process implies a thermal decomposition step at a moderate temperature of the extracted organic material into lithium carbonate, which is then used as a lithiation agent for the preparation of fresh electrode material without loss of lithium.