Lithium-Sodium Separation by a Lithium Composite Membrane Used in Electrodialysis Process: Concept Validation

Abstract

The recent expansion of global Lithium Ion Battery (LIBs) production has generated a significant stress on the lithium demand. One of the means to produce this element is its extraction from different aqueous sources (salars, geothermal water etc.). However, the presence of other mono- and divalent cations makes this extraction relatively complex. Herein, we propose lithium-sodium separation by an electrodialysis (ED) process using a Lithium Composite Membrane (LCM), whose effectiveness was previously demonstrated by a Diffusion Dialysis process (previous work). LCM performances in terms of lithium Recovery Ratio (RR(Li+)) and Selectivity (S(Li/Na)) were investigated using different Li+/Na+ reconstituted solutions and two ED cells: a two-compartment cell was chosen for its simplicity, and a four-compartment one was selected for its potential to isolate the redox reactions at the electrodes. We demonstrated that the four-compartment cell use was advantageous since it provided membrane protection from protons and gases generated by the electrodes but that membrane selectivity was negatively affected. The impact of the applied current density and the concentration ratio of Na+ and Li+ in the feed compartment ([Na+]F/[Li+]F) were tested using the four-compartment cell. We showed that increasing the current density led to an improvement of RR(Li+) but to a reduction in the LCM selectivity towards Li+. Increasing the [Na+]F/[Li+]F ratios to 10 had a positive effect on the membrane performance. However, for high values of this ratio, both RR(Li+) and S(Li/Na) decreased. The optimal results were obtained at [Na+]F/[Li+]F near 10, where we succeeded in extracting more than 10% of the initial Li+ concentration with a selectivity value around 112 after 4 h of ED experiment at 0.5 mA·cm−2. Thus, we can objectively estimate that the concept of this selective extraction of Li+ from a mixture even when concentrated in Na+ using an ED process was validated.

Research on Membranes and Their Associated Processes at the Université Paris-Est Créteil: Progress Report, Perspectives, and National and International Collaborations

“…The application of this LCM5 on electrodialysis was tested using two ED cells: a two-compartment and a four-compartment cell [ 77 ]. The second one was found to be advantageous thanks to its membrane-protection ability, presented in Figure 3 .…”

“… Schematic illustration and operating principle of our four-compartment ED cell. Adapted from [ 77 ]. …”

Li2CO3 Recovery through a Carbon-Negative Electrodialysis of Lithium-Ion Battery Leachates

“…Mass balance of metals showed that 48.4 wt % of Li from the anolyte was recovered in the form of Li 2 CO 3 dried product. A recent literature on membrane-based Li separation and recovery reports Li recoveries in that range of 5.9–99%, but this information only accounts for the Li reported in the catholyte and not as a final solid product. ,, Nevertheless, improvements in Li 2 CO 3 yields are necessary in order to make this technology industrially relevant. Due to the OER and MnO 2 formation, the pH of the anolyte decreased from 2.10 to 1.28, while the pH of the catholyte increased from 8.15 to 9.92.…”

New Trends in Separation Techniques of Lithium Isotopes: A Review of Chemical Separation Methods

“…Nevertheless, 6 Li isotope separation factor was not calculated in the above-mentioned paper and further studies are needed. Furthermore, the lithium solid ceramics can be used to separate lithium ions from sodium and potassium, and Ounissi et al used lithium composite membrane to separate lithium from sodium ions [29] with electrodialysis, but the selectivity coefficient of Li + over Na + was recorded to 112.3, a value which is higher than the selectivity coefficients previously reported in other electrodialysis methodologies [30]. Nevertheless, cation-exchange resins methods are usually preferred as preconcentration steps employed for the separation of lithium from other alkaline ions.…”