Lithium Recovery Research Articles

Solar-enhanced lithium extraction with self-sustaining water recycling from salt-lake brines

Lithium is an emerging strategic resource for modern energy transformation toward electrification and decarbonization. However, current mainstream direct lithium extraction technology via adsorption suffers from sluggish kinetics and intensive water usage, especially in arid/semiarid and cold salt-lake regions (natural land brines). Herein, an efficient proof-of-concept integrated solar microevaporator system is developed to realize synergetic solar-enhanced lithium recovery and water footprint management from hypersaline salt-lake brines. The 98% solar energy harvesting efficiency of the solar microevaporator system, elevating its local temperature, greatly promotes the endothermic Li+ extraction process and solar steam generation. Benefiting from the photothermal effect, enhanced water flux, and enriched local Li+ supply in nanoconfined space, a double-enhanced Li+ recovery capacity was delivered (increase from 12.4 to 28.7 mg g-1) under one sun, and adsorption kinetics rate (saturated within 6 h) also reached twice of that at 280 K (salt-lake temperature). Additionally, the self-assembly rotation feature endows the microevaporator system with distinct self-cleaning desalination ability, achieving near 100% water recovery from hypersaline brines for further self-sufficient Li+ elution. Outdoor comprehensive solar-powered experiment verified the feasibility of basically stable lithium recovery ability (>8 mg g-1) directly from natural hypersaline salt-lake brines with self-sustaining water recycling for Li+ elution (440 m3 water recovery per ton Li2CO3). This work offers an integrated solution for sustainable lithium recovery with near zero water/carbon consumption toward carbon neutrality.

Strategy for Efficient Recovery of NCM Materials by the Reagent-Free Method: Green Recovery of Lithium and High-Value Byproducts through Capacitive Deionization Reverse Applications

Strategy for Efficient Recovery of NCM Materials by the Reagent-Free Method: Green Recovery of Lithium and High-Value Byproducts through Capacitive Deionization Reverse Applications

Engineering Compounds for the Recovery of Critical Elements from Slags: Melt Characteristics of Li5AlO4, LiAlO2, and LiAl5O8.

Engineered artificial minerals (EnAMs) are the core of a new concept of designing scavenger compounds for the recovery of critical elements from slags. It requires a fundamental understanding of solidification from complex oxide melts. Ion diffusivity and viscosity play vital roles in this process. In the melt, phase separations and ion transport give rise to gradients/increments in composition and, with it, to ion diffusivity, temperature, and viscosity. Due to this complexity, solidification phenomena are yet not well understood. If the melt is understood as increments of simple composition on a microscopic level, then the properties of these are more easily accessible from models and experiments. Here, we obtain these data for three stoichiometric lithium aluminum oxides. LiAlO2 is a promising EnAM for the recovery of lithium from lithium-ion battery pyrometallurgical processing. It is obtained through the addition of aluminum to the recycling slag melt. The high temperature properties spanning from below to above the liquidus temperature of three stoichiometric Li-Al-Oxides: Li5AlO4, LiAlO2, and LiAl5O8 are determined using molecular dynamic simulations. The compounds are also synthesized via the sol-gel route. The Li+ ion exhibits the largest diffusivity. They are quite mobile already below the liquidus temperature, i.e., for LiAlO2 at T = 1700 K, the diffusion coefficient of the lithium ion equals D = 3.0 × 10-9 m2 s-1. The other ions Al3+ and O2- do not move considerably at that temperature. The diffusivity of Li+ is largest in the lithium-rich compound Li5AlO4 with D = 32 × 10-9 m2 s-1 at 2500 K. The lower the viscosity, the higher the lithium content. The Li5AlO4 exhibits a viscosity of η = 2.2 mPa s at 1328 K which matches well with the experimentally determined 2.5 mPa s at this temperature. The viscosity of LiAlO2 at 1800 K is more than two times higher. These data sets can help to describe the melts on a microscopic level and understand how the melt properties will change due to gradients in the Li/Al concentration.

“Acid + Oxidant” Treatment Enables Selective Extraction of Lithium from Spent NCM523 Positive Electrode

With the rapid development of new energy vehicles and energy storage industries, the demand for lithium-ion batteries has surged, and the number of spent LIBs has also increased. Therefore, a new method for lithium selective extraction from spent lithium-ion battery cathode materials is proposed, aiming at more efficient recovery of valuable metals. The acid + oxidant leaching system was proposed for spent ternary positive electrode materials, which can achieve the selective and efficient extraction of lithium. In this study, 0.1 mol L−1 H2SO4 and 0.2 mol L−1 (NH4)2S2O8 were used as leaching acid and oxidant. The leaching efficiencies of Li, Ni, Co, and Mn were 98.7, 30, 3.5, and 0.1%, respectively. The lithium solution was obtained by adjusting the pH of the solution. Thermodynamic and kinetic studies of the lithium leaching process revealed that the apparent activation energy of the lithium leaching process is 46 kJ mol−1 and the rate step is the chemical reaction process. The leaching residue can be used as a ternary precursor to prepare regenerated positive electrode materials by solid-phase sintering. Electrochemical tests of the regenerated material proved that the material has good electrochemical properties. The highest discharge capacity exceeds 150 mAh g−1 at 0.2 C, and the capacity retention rate after 100 cycles exceeds 90%. The proposed new method can extract lithium from the ternary material with high selectivity and high efficiency, reducing its loss in the lengthy process. Lithium replenishment of the delithiation material can also restore its activity and realize the comprehensive utilization of elements such as nickel, cobalt, and manganese. The method combines the lithium recovery process and the material preparation process, simplifying the process and saving costs, thus providing new ideas for future method development.

Controlling amine monomers via UiO-66-NH2 defect sites to enhance forward osmosis membrane performance for lithium recovery

The excessive thickness of the separation layer and the presence of cracks cause low water flux and poor lithium recovery in conventional forward osmosis (FO) membranes. According to the influence of the diffusion behavior of amine monomers in interfacial polymerization, the use of an interlayer optimizes the separation layer structure of traditional thin-film composite FO membrane. However, it is difficult to accurately control the separation layer structure by simply adjusting the amount of the interlayer material loaded. Herein, FO membranes with defect-containing metal–organic framework (MOF) interlayers were constructed. By adjusting the concentrations of competitive ligands, the MOFs showed different degrees of linker loss, which exposed the metal ions in the MOFs to different extents. The defective sites of the constructed MOFs increased the interaction between the interlayer and m-phenylenediamine (MPD), and density functional theory (DFT) simulations also revealed an increase in the binding energy of the two materials. Therefore, MPD attachment and diffusion were controlled by changing the proportion of defects in the MOFs, thereby finely regulating the separation layer structure. Additionally, tannic acid (TA) was predeposited to improve the stability of the interlayer. The prepared membrane exhibited water fluxes of 33.84 and 65.81 LMH and reverse salt fluxes of 0.58 and 2.38 gMH in the active layer facing feed solution (AL-FS) and active layer facing draw solution (AL-DS) modes, respectively. Excellent lithium ion recovery and fouling resistance was also demonstrated in battery wastewater treatment.

Selective Solid-Liquid Extraction of Lithium Cation Using Tripodal Sulfate-Binding Receptors Driven by Electrostatic Interactions.

Owing to the important role of and increasing demand for lithium resources, lithium extraction is crucial. The use of molecular extractants is a promising strategy for selective lithium recovery, in which the interaction between lithium and the designed extractant can be manipulated at the molecular level. Herein, we demonstrate that anion receptors of tripodal hexaureas can selectively extract Li2SO4 solids into water containing DMSO (0.8% water) compared to other alkali metal sulfates. The hexaurea receptor with terminal hexyl chains displays the best Li+ extraction selectivity at 2-fold over Na+ and 12.5-fold over K+. The driving force underpinning selective lithium extraction is due to the combined interactions of Li+-SO42- electrostatics and the ion-dipole interaction of the lithium-receptor (carbonyl groups and N atoms); the latter was found to be cation size dependent, as supported by computational calculations. This work indicates that anion binding receptors could drive selective cation extraction, thus providing new insights into the design of receptors for ion recognition and separation.

Integrated sulfonated poly ether ketone membrane capacitive deionization for lithium recovery from diluted binary solutions

To harness the abundant lithium (Li)-containing aqueous resources and meet the growing demand for Li, membrane-based processes for selective Li recovery have garnered extensive attention. The incorporation of sulfonate groups into membranes is a crucial strategy for fine-tuning ion selectivity, which has been widely used in nanofiltration and electrodialysis for Li separation; however, its potential in the membrane capacitive deionization (MCDI) process for Li recovery remains largely unexplored. This study bridges this research gap by integrating activated carbon (AC) electrodes of capacitive deionization (CDI) with sulfonate poly ether ketone (SPEK) membranes, featuring varying degrees of sulfonation (SPEK-20, SPEK-40, and SPEK-60), and evaluating their Li recovery performance using Li/M (M representing competing cations such as Na, K, Mg, Ca) binary solutions. The synthesized membrane electrodes underwent thorough characterization, confirming the successful formation of sulfonate groups in the SPEK membrane, revealing the SPEK layer with a cross-section thickness below 10 µm, and identifying the hydrophilicity of the AC/SPEK electrode surface. The MCDI results unveiled the significant impact of incorporating SPEK membranes on Li recovery performance in monovalent-cation competing feeds compared to bare AC electrodes, boosting the Li removal rate and Li selectivity in Li/K feed by over 210 % and 120 %, respectively. Meanwhile, SPEK membranes demonstrate a preferable affinity for capturing and releasing divalent ions, with the variations in sulfonation degree exerting a greater influence on cases involving divalent cations.

Oilfield Brine as a Source of Water and Valuable Raw Materials—Proof of Concept on a Laboratory Scale

Oilfield brine is the largest byproduct stream generated during the extraction of crude oil and natural gas and may be considered a resource for the production of potable water and valuable raw materials. The high salinity of such waters limits the application of typical membrane-based techniques. In most oilfields, waste cold energy from the process of the low-temperature separation of natural gas is available and may be used as a source of cold for the freezing desalination (FD) of brine. As a result of the FD process, two streams are obtained: partially desalinated water and concentrated brine. The partially desalinated water may be suitable for non-potable applications or as a feed for membrane desalination. The concentrated brine from the FD could be used as a feed for the recovery of selected chemicals. This paper focuses on verifying the above-described concept of the freezing desalination of oilfield brine on a laboratory scale. The brine from a Polish oilfield located in the Carpathian Foredeep was used as a feed. Four freezing–thawing stages were applied to obtain low-salinity water, which subsequently was treated by reverse osmosis. The obtained permeate meets the criteria recommended for irrigation and livestock watering. The concentrated brine enriched with iodine (48 mg/L) and lithium (14 mg/L) was subjected to recovery tests. Ion exchange resin Diaion NSA100 allowed us to recover 58% of iodine. Lithium recovery using Mn- and Ti-based sorbents varies from 52 to 93%.

In-situ oxidation for selective lithium extraction from spent LiFePO4 cathodes by low acid dosage

Recovery of lithium from spent lithium iron phosphate batteries is crucial to alleviating the storage of lithium. This study proposes a method for the selective recovery of lithium from spent lithium iron phosphate battery cathodes using a leaching system of H2SO4 and H2O2. Efficient and selective lithium recovery was achieved through in-situ oxidation of lithium iron phosphate driven by a low acid dosage, and the mechanism of selective lithium recovery was investigated by precipitation experiments of Fe2+ and PO43−. The shrinking core model was used for the kinetic analysis of the leaching process, and the results suggested that the leaching process was controlled by the internal diffusion of the product layer. Moreover, essential leaching parameters such as acid concentration, H2SO4 dosage, H2O2 dosage, leaching time, and leaching temperature were systematically investigated. The results showed that the leaching rate of Li reached 97.95 % along with a selectivity of 99.60 %, which meets the standard of the battery-grade Li2CO3, while the leaching rate of both Fe and P was less than 1 %.

Selective lithium extraction employing lithium manganese oxide-loaded polymeric membranes at natural brine pH and room temperature

The current technology for lithium extraction from brines is recognized both for its techno-economic disadvantages and its environmental impacts. We have synthesized, characterized, and evaluated particles based on lithium manganese oxide towards selective lithium recovery from complex media. A solid-state synthesis and a hydrothermal method produced sub-micrometre sized particles that showed diameters of 253 nm and 154 nm, respectively, both with very low polydispersity. 23.7 mgLi/gHMO and 30.7 mgLi/gHMO adsorption capacity values were obtained with solid-state synthetic and hydrothermal oxides. The hydrothermally synthesized sub-micrometre sized particles were incorporated into polymeric membranes aiming at the development of a straightforward technological application. Membranes were prepared from polyacrylonitrile and polyethylene-glycol, and the affinity to lithium was once again evaluated. Membranes showed a high adsorption capacity for lithium (32.7 mgLi/gHMO) with almost identical kinetics and cyclability as the free particles in solution. An excellent selectivity for lithium was confirmed in experiments with a natural lithium-rich brine from the Lithium Triangle. All adsorption experiments were performed at neutral pH and room temperature. An undeniable advantage of membranes vs. sub-micrometre sized particles is that the former do not require centrifugation after successful adsorption/desorption. These three characteristics are fundamental in the perspective of technology scale-up to minimize operational costs.

A comparison of batch and semi-batch reactors for leaching battery cathodes (LiCoO2) under controlled addition of HCl and H2O2

Recovery of cobalt and lithium from end-of-life Li-ion battery wastes have been evaluated in batch and semi-batch leaching systems. In this preliminary study, HCl and H2O2 were used as leaching and reducing agents, respectively. The comparison of batch and semi-batch processes was carried out, obtaining an improvement from 40% to 70% in the metal mass extracted (i.e. Co and Li) for semi-batch experiments under the same experimental conditions. Effects of the initial concentration of reducing and leaching agents were evaluated for a semi-batch system in which the acid was continuously fed to maintain a constant pH value. From experimental results, it was found that the concentration of H2O2 plays an important role in the leaching process in terms of selectivity. For the experiments carried out using 0.1 M of HCl and 1 M of H2O2, the percentage of Li and Co extracted was 90% for a leaching time of 30 min. The double-controlled addition of HCl and H2O2 to the semi-batch system allows the reduction of the H2O2 concentration to 0.5 M. The optimization of reactants entails not only the decrease of their consumption but also maximize the selectivity of the reactions desired, which represents promising results for the environmental sustainability of the process. Further work will examine the fate of chloride ions in the process.

Crystallization of battery-grade lithium carbonate with high recovery rate via solid-liquid reaction

Lithium carbonate (Li2CO3) stands as a pivotal raw material within the lithium-ion battery industry. Hereby, we propose a solid-liquid reaction crystallization method, employing powdered sodium carbonate instead of its solution, which minimizes the water introduction and markedly elevates one-step lithium recovery rate. Through kinetic calculations, the Li2CO3 solid-liquid reaction crystallization process conforms by the Avrami equation rather than shrinking core model, which means the dissolution rate of Na2CO3 is the most important factor affecting the reaction process. The effects of reaction conditions such as temperature and stirring speed on the Li2CO3 precipitation behavior were evaluated. The results indicated that temperature is a most essential parameter than other reaction conditions or stirring speed. The exceptional 93% recovery of Li2CO3 at 90 °C with a remarkable purity of 99.5% was achieved by using 1.2 M ratio of Na2CO3/Li2SO4. This method provides a new idea for the efficient preparation of battery-grade Li2CO3.

Mechanistic Understanding of Sieving Lithium Ions Using a Biobased Sorbent Technology for Sustainable Lithium Reclamation and Cleansing Brines.

Low-cost environmentally benign materials that can be produced in a large scale to extract lithium from brine resources could drive the lithium market toward a clean technology with high lithium recovery and production. Herein, we have investigated the utilization of a novel, environmentally benign, and low-cost biobased sorbent for the extraction of lithium from lithium-rich solutions. This biobased molecular sieving sorbent, iron(III)-tannate (Fe(III)-TA), belongs to a novel class of coordination polymer frameworks derived from a natural polyphenol-tannic acid (TA)-coordinated with iron(III) metal cations. Its lithium adsorption and kinetic isotherm studies conducted using lithium-rich aqueous solutions confirm the sorbent's dual function for lithium sieving via physisorption, chemisorption, and mass transfer diffusion processes. The adsorption equilibrium and kinetic isotherm models combined with the external and internal mass transfer diffusion models reveal a mechanistic pathway for lithium-ion adsorption. Aiding by forming a fluid film for external mass transfer diffusion of lithium ions, analytes adsorb onto the sorbent surface via physisorption and chemisorption followed by the internal mass transfer diffusion, occupying lithium ions in the sorbent's pores. The lithium adsorption efficiency studies conducted for brines with different concentrations of interference alkali and alkaline cations evidence that the sorbent's affinity for lithium ions strongly depends on the analyte concentration. The results evidence that the sorbent has the ability to lower the brine's salinity and significantly reduces the ratios of Mg/Li and Ca/Li by 4-fold and 10-fold, respectively, yielding lithium-rich solutions. Thus, implementing this innovative biobased sorbent technology as an add-in step into traditional lithium extraction and refining processes, one can design a cost-effective pathway to yield lithium-rich leachate by reducing the Mg/Li and Ca/Li ratio. Nonetheless, the present work demonstrates that Fe(III)-tannate is an effective multifunctional sorbent for sieving lithium from lithium-rich aqueous solutions as well as for desalinating brine resources to recover usable water. Thus, this biobased sorbent offers the possibility of effective application of lithium reclamation and remediation of brine, mitigating the environmental impact of brine discharge and large volume of freshwater usage for lithium extraction and refining.

Recovery of lithium and copper from anode electrode materials of spent LIBs by acidic leaching.

In view of the importance of environmental protection and resource recovery, recycling of spent lithium ion batteries (LIBs) is quite necessary. In the present study, lithium and copper are recycled to lithium carbonate and copper oxide from anode electrode material of the spent LIBs. The anode electrode material is firstly treated with hydrochloric acid to leach lithium (96.6%) and then with nitric acid to leach copper (97.6%). Furthermore, lithium and copper are recovered as lithium carbonate and copper oxide from their respective solutions using precipitation and calcinations. These synthesized products are further characterized using XRD, FE-SEM, and EDX analysis. Finally, a simple process is proposed for the recovery of lithium and copper from anode electrode material of spent LIBs.

Evaluation of hydrometallurgical black mass recycling with simulation-based life cycle assessment

PurposeThe recycling of lithium-ion batteries is an emerging field faced with the challenge of recovering more than the most valuable elements from the batteries. While the literature presents many innovative approaches to the problem, an overview of the technical and environmental prospects of hydrometallurgical black mass recycling remains crucial. The goal was to analyze the impacts of a black mass process flowsheet and suggest ways to further reduce the impacts of battery recycling.MethodsThe flowsheet was drafted from the literature by combining both state-of-the-art and experimentally demonstrated unit processes by starting with the leaching system, where reductive leaching is performed using only the copper and iron impurities already present in the black mass. The process targeted copper, manganese, cobalt, nickel, and lithium recovery, and three scenarios for manganese recovery were investigated. The flowsheet was simulated using HSC Sim software, and the mass and energy balances were adapted into internally consistent life cycle inventories. The scope was “gate-to-gate” in Europe and CML methodology was used for impact assessment.Results and discussionAssuming that mechanical pre-treatment carries more environmental benefits than burdens, the results indicated that hydrometallurgical black mass recycling had a tentatively lower environmental footprint compared to virgin raw materials in all impact categories except ozone depletion, the results indicated that hydrometallurgical black mass recycling had a tentatively lower environmental footprint compared to virgin raw materials in all impact categories except ozone depletion. Sulfuric acid and neutralizing chemicals were among the most significant contributors to the impacts, and therefore further analysis was conducted based on an experimental study on low acid leaching with a low (< 0.5 M) initial sulfuric acid concentration instead of the baseline 2 M. This reduced the impacts by approximately 30–40% in all categories by decreasing downstream chemical consumption, and more significantly decreased ozone depletion. The challenges and opportunities for further process improvement were also considered.ConclusionsThe study highlights the importance of process optimization to improve the environmental sustainability of battery chemical production, but also revealed critical research gaps in the experimental literature. Rather than focusing on a single unit process, experimental black mass recycling research should aim at finding solutions that are optimal for the up- and downstream units, such as minimization of aluminum in the black mass and acid consumption.

A contribution to understanding ion-exchange mechanisms for lithium recovery from industrial effluents of lithium-ion battery recycling operations

Industrial effluents or process waters generated from spent lithium-ion battery recycling operations often contain high concentrations of lithium ions (Li+). This study characterizes the composition of process water obtained from pre-treatment and concentration operations of LIBs recycling. Ion-exchange experiments are conducted using synthetic lithium solutions (1 g/L) and industrial waters to understand Li+ recovery. Employing four commercial cationic resins, fast Li+ exchange kinetics are observed fitting the pseudo-second order model. The equilibrium isotherm data corresponds to the Langmuir adsorption model and reveals a Li capacity of 30–32 mg/g using Amberlite™ IRC 120 H, 70 mg/g using Lewatit® TP 308 H, 37–40 mg/g using Lewatit® TP 208 Na, and 37–41 mg/g using Lewatit® TP 260 Na. While the resins initially demonstrate moderate affinity for Li+, this can be significantly enhanced by increasing the Li+ concentration. Notably, as LIBs recycling operation effluents typically contain minimal competing ions, these results underscore the potential of employing ion exchange as a viable method to recover and concentrate lithium before precipitation into lithium salts.

Extraction of organic solvents and preferential recovery of lithium from spent lithium-ion batteries by in-situ carbothermal reduction

The sorting of spent lithium-ion batteries is not complete, and the types of black powder obtained by crushing are complex, and it is difficult to recycle. In this study, dimethyl carbonate was used to extract the organic solvent cured in the black powder, and then the carbon in the black powder was combined with complex sulfate for in-situ thermal reduction and water leaching to extract Li preferentially from the black powder. The effects of extraction factors on the recovery of organic solvents and the variables on the preferential leaching of Li were systematically studied. The changes of mineral phase during roasting were analyzed by TG-DTG, XRD, XPS and SEM-EDS. After black powder was roasted at 550°C for 3 h under air atmosphere with the synergistic effect of C and inorganic salts, 85.87 % of lithium can be selectively leached at 25°C for 2 h. Li2CO3 with high purity can be obtained. This method provides a new idea for the recovery of spent lithium-ion batteries with complex components.

Highly selective granulation adsorbents for lithium recovery from gas field brine: Selectivity, kinetics and mechanism

Polyvinyl chloride (PVC)-based granulated adsorbents with high mechanical stability have proven effective for extracting lithium from salt lake brine on a commercial scale. However, granular materials with high adsorption selectivity for Na+/Li+ separation and long service life still remain a great challenge. Here, we prepared granulated spherical adsorbents by a phase conversion method using PVC as a binder; PEG, PMMA, PAN, and PAA as hydrophilic co-binders; and Li1.33Mn1.67O4 (LMO) as a powder adsorbent. Among these materials, P-PAA exhibited excellent hydrophilicity and excellent binder compatibility, facilitating the dispersion of LMO powders and ensuring high adsorption. Moreover, the mechanism of action of the PVC/PAA binders was first explored via experiments and simulations, which revealed that Li+ migration was promoted and occurred primarily on LMO rather than on binders, so nonselective adsorption decreased. Therefore, P-PAA demonstrated exceptional Li+ adsorption capacity (12.9 mg/g) and selectivity for Li+ (distribution factor of 1391.3 mL/g) over other coexisting cations and a separation factor of αNaLi= 718, which are greater than those of other adsorbents reported in the literature. Furthermore, the unique structure of P-PAA, which was obtained by interconnecting larger core pores (5–10 μm) and abundant smaller pores (0.5–1 μm), accelerated the water/ion transfer kinetics without causing powder leakage. Hence, the lifespan of these materials has been extended, as salt crystals or internal cracks did not form during long-term cyclic use, unlike in the case of other granules. All of the above factors made P-PAA effectively recover Li+ from Puguang gas brine, which contains a high sodium salt content and organic pollutants, with an efficiency of 98.4 %. All these properties demonstrate that P-PAA could be used in an appealing and competitive manner for industrial processes.

Maximizing resource recovery: A green and economic strategy for lithium extraction from spent ternary batteries

Spent ternary lithium-ion batteries contain abundant lithium resource, and their proper disposal is conducive to environmental protection and the comprehensive utilization of resources. Separating valuable metals in the ternary leaching solution is the key to ensuring resource recovery. However, the traditional post-lithium extraction strategies, which heavily rely on ion exchange to remove transition metal ions in the leachate, encounter challenges in achieving satisfactory lithium yields and purities. Based on this, this paper proposed a new strategy to prioritize lithium extraction from ternary leachate using “(+) LiFePO4/FePO4 (-)” lithium extraction system. The preferential recovery of lithium can be realized by controlling the potential over 0.1 V versus Standard Hydrogen Electrode (SHE) without introducing any impurity ions. The lithium recovery rate reaches 98.91%, while the rejection rate of transition ions exceeds 99%, and the separation coefficients of lithium to transition metal ions can reach 126. Notably, the resulting lithium-rich liquid can directly prepare lithium carbonate with a purity of 99.36%. It provides a green and efficient strategy for the preferential recovery of lithium from the spent ternary leachate.

Facets regulation of Li1.6Mn1.6O4 by B-doping to enable high stability and adsorption capacity for lithium extraction

Spinel lithium manganese oxide Li1.6Mn1.6O4 (LMO) is a promising ion sieve material with high adsorption capacity and selectivity for lithium recovery from salt lake brines. However, manganese dissolution seriously hinders its application. In this work, B-doping is used to promote the growth of (100) facets and inhibit the growth of (110) facets of Li1.6Mn1.6O4, which could effectively inhibit dissolution and enhance the stability of LMO. For 8 % B-doped Li1.6Mn1.6O4 (LBMO-0.08), the Mn dissolution decreases from 2.13 % to 1.93 %, the adsorption capacity achieves 42.6 mg·g−1. The DFT calculations provide further evidence that the structure stability of Li1.6Mn1.6O4 is enhanced by B-doping. Additionally, LBMO-0.08 exhibits fast adsorption kinetics, and the equilibrium time is 6 h, which is lower than most reported literatures. After granulation, particles containing 75 wt% LBMO-0.08 represent high adsorption capacity for lithium (16.35 mg·g−1) and considerable selectivity in Qarhan salt lake brine, which have great superiority to separate lithium from salt lake brine in practical applications.