Method for regenerating sorbent for direct lithium extraction

Abstract

The present disclosure relates generally to direct lithium extraction (DLE) from brines. More specifically, the present disclosure relates to methods for regenerating layered double hydroxide (LDH) sorbents and methods of using the same in DLE. The present disclosure reports that escalating anionic displacement (EAD) and / or divalent-supported anionic displacement (DSAD), and / or modified brine DSAD (MB-DSAD) can be utilized to override empirically-derived anion incorporation hierarchies to reduce, prevent, or eliminate LDH sorbent fouling. The present disclosure also reports that lithium elution can be suppressed by solutions comprising high concentrations of anions and cations. As set out in the present disclosure, this finding can be leveraged in combination with EAD, DSAD, and / or MB-DSAD to regenerate LDH sorbents in situ. In select methods of the present disclosure, DLE absorption-elution cycles are supplemented with regenerative washes to restore and / or maintain the lithium uptake capacity and / or lithium elution capacity of an LDH sorbent.

Description

METHOD FOR REGENERATING SORBENT FOR DIRECT LITHIUM EXTRACTIONCROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims priority under applicable laws to U.S. Provisional Patent Application No. US 63 / 632,318 filed on April 10, 2024, the content of which is incorporated herein by reference in its entirety for all purposes.TECHNICAL FIELD

[0002] The present disclosure relates generally to direct lithium extraction (DLE) from brines. More specifically, the present disclosure relates to methods for regenerating sorbents and methods of using the same in DLE.BACKGROUND

[0003] Lithium is a critical and technologically important element. It is used in ceramics, glass, lubricants, light-weight alloys, pharmaceuticals, and batteries. The use of lithium-ion batteries in portable electronic devices and electric vehicles has increased global demand for lithium. Projections indicate that between 12 and 20 million metric tons of lithium production will be required to meet global demand through the year 2100.

[0004] Lithium is primarily found in three types of feedstocks: (i) pegmatites; (ii) hydrothermally altered clays; and (iii) continental brines. Continental brines have the potential to be the most economically and environmentally viable, but their lithium contents vary widely. By way of example, select brines from Salar de Atacama have an average lithium concentration of greater than 2,000 mg / L, whereas select brines from California’s Searles Lake have an average lithium concentration of about 65 mg / L. Continental brines also vary with respect to the spectrum and concentrations of other ions they contain. Sodium ions, potassium ions, magnesium ions, calcium ions, chloride ions, sulfate ions, and carbonate ions are ubiquitous in continental brines, and they can form a range of ionic salts. Taken together, the wide range of lithium concentrations and complex profiles of other ions present in continental brines introduce considerable challenges for lithium producers. These challenges are often compounded by remote and / or harsh operating conditions, complex regulatory requirements, restrictions on water use, and / or strict environmental standards.

[0005] Direct lithium extraction (DLE) processes are being developed to address these challenges. DLE processes typically employ sorbent technologies, ion-exchange technologies, and / or solvent exchange technologies to selectively extract lithium from brine. Sorbenttechnologies are particularly promising, and lithium-incorporated-aluminum-hydroxide (LIAH) compositions are a leading class of inorganic sorbents for DLE. LIAH compositions are commonly referred to as layered double hydroxide (LDH) sorbents in view of their common structural forms, and these names are used interchangeably in the present disclosure without limitation to any particular structural form.

[0006] In a typical DLE process employing a sorbent technology, an LDH sorbent is contacted with brine and then eluent, as it is cycled through adsorption and elution sequences. During the sequences, the LDH sorbent is exposed to a spectrum of ions, at least some of which may be incorporated into the LDH sorbent. In the context of the present disclosure, the term “incorporated” is used broadly to include intercalation, coordination, complexation, and other types of surface and / or lattice interactions between ions and sorbents. The relative tendencies of ions to incorporate into LDH sorbents have been shown empirically. For example, chloride ions tend to be readily exchanged for carbonate ions and sulfate ions. Likewise, sulfate ions tend to be readily exchanged for carbonate ions. In the context of the present disclosure, the terms “exchange” and “displace” are used interchangeably to characterize anion-sorbent interactions without limitation to any particular mechanism.

[0007] This hierarchy of anion exchange is problematic for LDH sorbent applications in DLE - chloride ion incorporation is associated with facile absorption and elution of lithium ions, whereas incorporation of multivalent anionic species, such as carbonate ions and / or sulfate ions, tend to attenuate lithium ion absorption and elution. Accordingly, incorporation of carbonate ions and / or sulfate ions is said to foul an LDH sorbent -where "foul" means: (i) to exhibit reduced lithium uptake capacity in the extraction process; and / or (ii) to exhibit reduced lithium elution capacity in the elution process.

[0008] In the context of DLE, there is an unmet need for methods of regenerating fouled sorbents. More specifically, there is an unmet need for methods of treating LDH sorbents to displace carbonate ions and / or sulfate ions and return at least some of their reduced lithium uptake capacity and / or lithium elution capacity. Methods that can be implemented within a cycle of adsorption and elution sequences to provide for in situ regeneration are particularly valuable in the context of DLE.SUM MARY

[0009] In evaluating layered double hydroxide (LDH) sorbent behaviours across an array of elution protocols, the present inventors discovered that the noted hierarchy of anion exchange can be overridden by utilizing solutions comprising high anion and cation concentrations. The presentdisclosure reports a plurality of methods for sorbent regeneration derived from their studies that can be used alone or in combination.

[0010] The first method of sorbent regeneration is referred to herein as “escalating anionic displacement” (EAD). EAD originates from the finding that under select conditions: (i) carbonate ions can be displaced from an LDH sorbent by washing with a solution comprising a high concentration of sulfate ions; and then (ii) sulfate ions can be displaced from the LDH sorbent by washing with a solution comprising a high concentration of chloride ions. Those skilled in the art will appreciate that EAD is counterintuitive, as it requires washing a sorbent with fouling anions, such as sulfate anions. However, as evidenced by the examples reported in the present disclosure, doing so as part of an EAD protocol can provide for LDH sorbent regeneration.

[0011] The second method of sorbent regeneration is referred to herein as “divalent-supported anionic displacement” (DSAD). DSAD originates from the finding that the noted hierarchy of anion exchange can be overridden by utilizing a wash solution comprising a high concentration of at least one divalent cation. For example, under select conditions, carbonate ions can be displaced from an LDH sorbent through washing with a solution having a high concentration of a Ca2+(aq).

[0012] The third method of sorbent regeneration is referred to herein as “modified-brine DSAD” or “MB-DSAD”. MB-DSAD originates from the finding that the effectiveness of DSAD methods may be improved by utilizing a wash solution comprising a depleted brine provided it is modified to spike the concentration of at least one divalent-ion species (e.g., Ca2+(aq), Mg2+(aq)). In the context of the present disclosure, a “depleted brine” or “depleted brine stream” is one which has had lithium extracted therefrom through a DLE process. For example, a depleted brine may have had at least about 50 mg / L extracted therefrom through a DLE process. In the context of the present disclosure, the terms “modified depleted brine” and “modified brine” are used interchangeably to describe a brine that has been mixed with an additive (e.g., a solid or a solution) to spike the concentration of at least one divalent-ion species. For example, a modified depleted brine may have at least 10,000 mg / L magnesium chloride added to increase the divalent cation and chloride content. MB-DSAD may enable DLE operators to reduce: (i) raw material costs; (ii) water usage; (iii) reinjection costs; and / or (iv) chemical waste.

[0013] In researching and developing EAD, DSAD, and MB-DSAD, the present inventors discovered that wash solutions comprising high concentrations of anions and cations can reliably suppress lithium elution. This finding is important, because it enables EAD, DSAD, and / or MB- DSAD methods to be utilized in-situ within a DLE process. Accordingly, the present disclosure provides methods of DLE, where absorption-elution cycles are supplemented with regenerativewashes to restore and / or maintain the lithium uptake capacity and / or lithium elution capacity of a sorbent.

[0014] In the context of DLE, the benefits of in-situ sorbent regeneration may include increased sorbent lifetime, reduced operational down time, reduced water consumption, reduced energy consumption, higher lithium concentrate purity, and / or higher lithium concentrate concentration. The foregoing benefits may engender significant decreases in DLE CAPEX and / or OPEX. They may also engender significant improvements in a DLE operator’s off-take revenue and / or ESG metrics.

[0015] An aspect of the present disclosure relates to a method for regenerating a sorbent that is fouled at least in part by carbonate ion incorporation, sulfate ion incorporation, or a combination thereof, the method comprising contacting the sorbent with a wash solution comprising a brine with a spiked concentration of at least one divalent cation and a spiked concentration of chloride anions.

[0016] In an embodiment of the present disclosure, the brine has a lithium concentration of between about 10 mg / L and about 1 ,000 mg / L.

[0017] In an embodiment of the present disclosure, the brine has a lithium concentration of at least 10 mg / L, at least about 50 mg / L, at least about 200 mg / L, at least about 500 mg / L, or at least about 1 ,000 mg / L.

[0018] In an embodiment of the present disclosure, the spiked concentration of the at least one divalent cation is at least about 30,000 mg / L, at least about 120,000 mg / L, or at least about 200,000 mg / L.

[0019] In an embodiment of the present disclosure, the spiked concentration of the at least one divalent cation of the wash solution is between about 30,000 mg / L and about 35,000 mg / L, between about 120,000 mg / L and about 125,000 mg / L, or between about 200,000 mg / L and about 220,000 mg / L.

[0020] In an embodiment of the present disclosure, the spiked concentration of the chloride anions is at least about 1 ,000 mg / L, at least about 25,000 mg / L, at least about 50,000 mg / L, at least about 200,000 mg / L, or at least about 400,000 mg / L.

[0021] In an embodiment of the present disclosure, the spiked concentration of the chloride anions is between about 1 ,000 mg / L and about 2,500 mg / L, between about 25,000 mg / L and about50,000 mg / L, between about 50,000 mg / L and about 200,000 mg / L, between about 200,000 mg / L and about 300,000 mg / L, or between about 300,000 mg / L and about 400,000 mg / L.

[0022] In an embodiment of the present disclosure, the at least one divalent cation is Mg2+, Ca2+, Sr2+, Ba2+, or a combination thereof.

[0023] In an embodiment of the present disclosure, the sorbent is an LDH sorbent.

[0024] In an embodiment of the present disclosure, sorbent is a lithium-incorporated-aluminum- hydroxide (LIAH) composition as described in Formula 1 :LiaX mAI(OH)3 nH2O Formula 1 in which: a is about 1 ;X is a monovalent anion; m is between about 1 .9 and about 3.6; and n is between about 2.1 and about 4.3.

[0025] An aspect of the present disclosure relates to a method for regenerating a sorbent that is fouled at least in part by carbonate ion incorporation, the method comprising: contacting the sorbent with a first wash solution comprising a high concentration of sulfate ions to displace carbonate ions from the sorbent; and contacting the sorbent with a second solution comprising a high concentration of chloride ions to displace sulfate ions from the sorbent.

[0026] In an embodiment of the present disclosure, the sulfate ion concentration of the first wash solution is at least about 1 ,000 mg / L, at least about 25,000 mg / L, at least about 90,000 mg / L, or at least about 150,000 mg / L.

[0027] In an embodiment of the present disclosure, the sulfate ion concentration of the first wash solution is between about 1 ,000 mg / L and about 2,500 mg / L, between about 25,000 mg / L and about 30,000 mg / L, between about 90,000 mg / L and 100,000 mg / L, or between 150,000 mg / L and about 160,000 mg / L.

[0028] In an embodiment of the present disclosure, the chloride ion concentration of the second wash solution is at least about 1 ,000 mg / L, at least 25,000 mg / L, at least about 50,000 mg / L, at least about 200,000 mg / L, or at least about 400,000 mg / L.

[0029] In an embodiment of the present disclosure, the chloride ion concentration of the second wash solution is between about 1 ,000 mg / L and about 2,500 mg / L, between about 25,000 mg / L and about 50,000 mg / L, between about 50,000 mg / L and about 200,000 mg / L, between about 200,000 mg / L and about 300,000 mg / L, or between about 300,000 mg / L and about 400,000 mg / L.

[0030] In an embodiment of the present disclosure, the first wash solution further comprises a high concentration of at least one divalent cation.

[0031] In an embodiment of the present disclosure, the concentration of the at least one divalent cation in the first wash solution is at least about 30,000 mg / L, at least about 120,000 mg / L, or at least about 200,000 mg / L.

[0032] In an embodiment of the present disclosure, the concentration of the at least one divalent cation in the first wash solution is between about 30,000 mg / L and about 35,000 mg / L, between about 120,000 mg / L and about 125,000 mg / L, or between about 200,000 mg / L and about 220,000 mg / L.

[0033] In an embodiment of the present disclosure, the second wash solution further comprises a high concentration of at least one divalent cation.

[0034] In an embodiment of the present disclosure, wherein the concentration of the at least one divalent cation in the second wash solution is at least about 30,000 mg / L, at least about 120,000 mg / L, or at least about 200,000 mg / L.

[0035] In an embodiment of the present disclosure, the concentration of the at least one divalent cation in the second wash solution is between about 30,000 mg / L and about 35,000 mg / L, between about 120,000 mg / L and about 125,000 mg / L, or between about 200,000 mg / L and about 220,000 mg / L.

[0036] In an embodiment of the present disclosure, the at least one divalent cation is Mg2+, Ca2+, Sr2+, Ba2+, or a combination thereof.

[0037] In an embodiment of the present disclosure, the sorbent is an LDH sorbent.

[0038] In an embodiment of the present disclosure, the sorbent is a lithium-incorporated- aluminum-hydroxide (LIAH) composition as described in Formula 1LiaX mAI(OH)3 nH2O Formula 1 in which: a is about 1 ;X is a monovalent anion; m is between about 1 .9 and about 3.6; and n is between about 2.1 and about 4.3.

[0039] An aspect of the present disclosure relates to a method for regenerating a sorbent that is fouled at least in part by carbonate ion incorporation, sulfate ion incorporation, or a combination thereof, the method comprising contacting the sorbent with a wash solution comprising a high concentration of at least one divalent cation and a high concentration of chloride anions.

[0040] In an embodiment of the present disclosure, the high concentration of the at least one divalent cation is at least about 30,000 mg / L, at least about 120,000 mg / L, or at least about 200,000 mg / L.

[0041] In an embodiment of the present disclosure, the high concentration of the at least one divalent cation is between about 30,000 mg / L and about 35,000 mg / L, between about 120,000 mg / L and about 125,000 mg / L, or between about 200,000 mg / L and about 220,000 mg / L.

[0042] In an embodiment of the present disclosure, the high concentration ofthe chloride anions is at least about 1 ,000 mg / L, at least 25,000 mg / L, at least about 50,000 mg / L, at least about 200,000 mg / L, or at least about 400,000 mg / L.

[0043] In an embodiment ofthe present disclosure, the high concentration ofthe chloride anions is between about 1 ,000 mg / L to about 2,500 mg / L, between about 25,000 mg / L and about 50,000 mg / L, between about 50,000 mg / L and about 200,000 mg / L, between about 200,000 mg / L and about 300,000 mg / L, or between about 300,000 mg / L and about 400,000 mg / L.

[0044] In an embodiment ofthe present disclosure, the at least one divalent cation is Mg2+, Ca2+, Sr2+, Ba2+, or a combination thereof.

[0045] In an embodiment of the present disclosure, the sorbent is an LDH sorbent.

[0046] In an embodiment of the present disclosure, the sorbent is a lithium-incorporated- aluminum-hydroxide (LIAH) composition as described in Formula 1 :LiaX mAI(OH)3 nH2O Formula 1 in which: a is about 1 ;X is a monovalent anion; m is between about 1 .9 and about 3.6; and n is between about 2.1 and about 4.3.

[0047] An aspect of the present disclosure relates to a method for DLE, the method comprising:(51) contacting a sorbent with a brine to selectively adsorb lithium ions from the brine;(52) contacting the sorbent with a wash solution comprising a modified brine with a spiked concentration of at least one divalent cation and a spiked concentration of chloride anions; and(53) contacting the sorbent with an eluent to elute lithium ions.

[0048] In an embodiment of the present disclosure, the steps are completed in the order (S1),(52), (S3).

[0049] In an embodiment of the present disclosure, the steps are completed in the order (S1),(53), (S2).

[0050] In an embodiment of the present disclosure, the steps (S1) and (S3) are executed sequentially in a cycle that is repeated, and wherein the step (S2) is executed once every 2-4 cycles, 5-10 cycles, 10-20 cycles, 20-40 cycles, 40-100 cycles, or greater than 100 cycles.

[0051] In an embodiment of the present disclosure, the lithium concentration of the modified brine is between about 10 mg / L, and about 1 ,000 mg / L.

[0052] In an embodiment of the present disclosure, the spiked concentration of the at least one divalent cation in the wash solution of step (S2) is at least about 30,000 mg / L, at least about 120,000 mg / L, or at least about 200,000 mg / L.

[0053] In an embodiment of the present disclosure, the spiked concentration of the at least one divalent cation in the wash solution of step (S2) is between about 30,000 mg / L and about 35,000mg / L, between about 120,000 mg / L and about 125,000 mg / L, or between about 200,000 mg / L and about 220,000 mg / L.

[0054] In an embodiment of the present disclosure, the spiked concentration of the chloride anions in step (S2) is at least about 1 ,000 mg / L, at least 25,000 mg / L, at least about 50,000 mg / L, at least about 200,000 mg / L, or at least about 400,000 mg / L.

[0055] In an embodiment of the present disclosure, the spiked concentration of the chloride anions in step (S2) is between about 1 ,000 mg / L to about 2,500 mg / L, between about 25,000 mg / L and about 50,000 mg / L, between about 50,000 mg / L and about 200,000 mg / L, between about 200,000 mg / L and about 300,000 mg / L, or between about 300,000 mg / L and about 400,000 mg / L.

[0056] In an embodiment of the present disclosure, the at least one divalent cation is Mg2+, Ca2+, Sr2+, Ba2+, or a combination thereof.

[0057] In an embodiment of the present disclosure, the sorbent is an LDH sorbent.

[0058] In an embodiment of the present disclosure, the sorbent is a lithium-incorporated- aluminum-hydroxide (LIAH) composition as described in Formula 1 :LiaX mAI(OH)3 nH2O Formula 1 in which: a is about 1 ;X is a monovalent anion; m is between about 1 .9 and about 3.6; and n is between about 2.1 and about 4.3.

[0059] In an embodiment of the present disclosure, the brine is a continental brine comprising: (i) between about 10 ppm and about 3,000 ppm of lithium as determined by elemental analysis; between about 1 ppm and about 1 ,500 ppm of carbonate ions as determined by titrimetry ; and (iii) between about 1 ppm and about 30,000 ppm of sulfate ions as determined by elemental analysis.

[0060] An aspect of the present disclosure relates to a method for DLE, the method comprising the following steps:(S1) contacting a sorbent with a brine to selectively adsorb lithium ions from the brine;(52) contacting the sorbent with a wash solution comprising a high concentration of sulfate ions;(53) contacting the sorbent with a wash solution comprising a high concentration of chloride ions; and(54) contacting the sorbent with an eluent to elute lithium ions.

[0061] In an embodiment of the present disclosure, the steps are completed in the order (S1), (S2), (S3), (S4).

[0062] In an embodiment of the present disclosure, the steps are completed in the order (S1), (S4), (S2), (S3).

[0063] In an embodiment of the present disclosure, the steps (S1) and (S4) are executed sequentially in a cycle that is repeated, and wherein the steps (S2) and (S3) are executed once every 2-4 cycles, 5-10 cycles, 10-20 cycles, 20-40 cycles, 40-100 cycles, or greater than 100 cycles.

[0064] In an embodiment of the present disclosure, the wash solution of step (S2) further comprises a high concentration of at least one divalent cation.

[0065] In an embodiment of the present disclosure, the concentration of the at least one divalent cation in the wash solution of step (S2) is at least about 30,000 mg / L, at least about 120,000 mg / L, or at least about 200,000 mg / L.

[0066] In an embodiment of the present disclosure, the concentration of the at least one divalent cation in the wash solution of step (S2) is between about 30,000 mg / L and about 35,000 mg / L, between about 120,000 mg / L and about 125,000 mg / L, or between about 200,000 mg / L and about 220,000 mg / L.

[0067] In an embodiment of the present disclosure, the wash solution of step (S3) further comprises a high concentration of at least one divalent cation.

[0068] In an embodiment of the present disclosure, the concentration of the at least one divalent cation in the wash solution of step (S3) is at least about 30,000 mg / L, at least about 120,000 mg / L, or at least about 200,000 mg / L.

[0069] In an embodiment of the present disclosure, the concentration of the at least one divalent cation in the wash solution of step (S3) is between about 30,000 mg / L and about 35,000 mg / L,between about 120,000 mg / L and about 125,000 mg / L, or between about 200,000 mg / L and about 220,000 mg / L.

[0070] In an embodiment of the present disclosure, at least one divalent cation is Mg2+, Ca2+, Sr2+, Ba2+, or a combination thereof.

[0071] In an embodiment of the present disclosure, sorbent is an LDH sorbent.

[0072] In an embodiment of the present disclosure, the sorbent is a lithium-incorporated- aluminum-hydroxide (LIAH) composition as described in Formula 1 :LiaX mAI(OH)3 nH2O Formula 1 in which: a is about 1 ;X is a monovalent anion; m is between about 1 .9 and about 3.6; and n is between about 2.1 and about 4.3.

[0073] In an embodiment of the present disclosure, the brine is a continental brine comprising: (i) between about 10 ppm and about 3,000 ppm of lithium as determined by elemental analysis; (ii) between about 1 ppm and about 1 ,500 ppm of carbonate ions as determined by titrimetry ; and (iii) between about 1 ppm and about 30,000 ppm of sulfate ions as determined by elemental analysis.

[0074] In an embodiment of the present disclosure, the sulfate ion concentration of the wash solution of step (S2) is at least about 1 ,000 mg / L, at least about 25,000 mg / L, at least about 90,000 mg / L, or at least about 150,000 mg / L.

[0075] In an embodiment of the present disclosure, the sulfate ion concentration of the wash solution of step (S2) is between about 1 ,000 mg / L and about 2,500 mg / L, between about 25,000 mg / L and about 30,000 mg / L, between about 90,000 mg / L and 100,000 mg / L, or between 150,000 mg / L and about 160,000 mg / L.

[0076] In an embodiment of the present disclosure, the chloride ion concentration of the wash solution of step (S3) is at least about 1 ,000 mg / L, at least 25,000 mg / L, at least about 50,000 mg / L, at least about 200,000 mg / L, or at least about 400,000 mg / L.

[0077] In an embodiment of the present disclosure, the chloride ion concentration of the wash solution of step (S3) is between about 1 ,000 mg / L and about 2,500 mg / L, between about 25,000mg / L and about 50,000 mg / L, between about 50,000 mg / L and about 200,000 mg / L, between about 200,000 mg / L and about 300,000 mg / L, or between about 300,000 mg / L and about 400,000 mg / L.

[0078] An aspect of the present disclosure relates to a method for direct lithium extraction DLE, the method comprising the following steps:(51) contacting a sorbent with a brine to selectively adsorb lithium ions from the brine;(52) contacting the sorbent with a wash solution comprising a high concentration of at least one divalent cation, and a high concentration of chloride anions; and(53) contacting the sorbent with an eluent to elute lithium ions.

[0079] In an embodiment of the present disclosure, the steps are completed in the order (S1),(52), (S3).

[0080] In an embodiment of the present disclosure, the steps are completed in the order (S1),(53), (S2).

[0081] In an embodiment of the present disclosure, the steps (S1) and (S3) are executed sequentially in a cycle that is repeated, and wherein the step (S2) is executed once every 2-4 cycles, 5-10 cycles, 10-20 cycles, 20-40 cycles, 40-100 cycles, or greater than 100 cycles.

[0082] In an embodiment of the present disclosure, the concentration of the at least one divalent cation in the wash solution of step (S2) is at least about 30,000 mg / L, at least about 120,000 mg / L, at least about 200,000 mg / L, or at least about 400,000 mg / L.

[0083] In an embodiment of the present disclosure, the concentration of the at least one divalent cation in the wash solution of step (S2) is between about 30,000 mg / L and about 35,000 mg / L, between about 120,000 mg / L and about 125,000 mg / L, or between about 200,000 mg / L and about 220,000 mg / L.

[0084] In an embodiment of the present disclosure, the at least one divalent cation is Mg2+, Ca2+, Sr2+, Ba2+, or a combination thereof.

[0085] In an embodiment of the present disclosure, the sorbent is an LDH sorbent.

[0086] In an embodiment of the present disclosure, the sorbent is a lithium-incorporated- aluminum-hydroxide (LIAH) composition as described in Formula 1 :LiaX mAI(OH)3 nH2O Formula 1 in which: a is about 1 ;X is a monovalent anion; m is between about 1 .9 and about 3.6; and n is between about 2.1 and about 4.3.

[0087] In an embodiment of the present disclosure, the brine is a continental brine comprising: (i) between about 10 ppm and about 3,000 ppm of lithium as determined by elemental analysis; between about 1 ppm and about 1 ,500 ppm of carbonate ions as determined by titrimetry ; and (iii) between about 1 ppm and about 30,000 ppm of sulfate ions as determined by elemental analysis.BRIEF DESCRIPTION OF THE DRAWINGS

[0088] In the drawings and description provided herein, similar reference numerals may indicate similar components. For sake of simplicity and clarity, not all drawings contain references to all the components and features, and references to some components and features may be found in only one drawing. Components and features of the present disclosure which are illustrated in other drawings can be readily inferred therefrom.

[0089] Figure 1 is a plot of lithium elution capacity of a layered double hydroxide (LDH) sorbent as a function of usage ( / .e., absorption-elution cycles over time) in extracting lithium ions from a brine comprising carbonate ions and sulfate ions.

[0090] Figure 2 is a series of X-ray diffraction (XRD) patterns: one generated from pristine sorbent, one generated from sorbent that has been contaminated with sulfate, one generated sorbent that has been contaminated with carbonate, and one generated from sorbent that has been fully regenerated.

[0091] Figure 3 is a schematic illustration of an archetypal sorbent unit that comprises an array of columns, in which embodiments of the methods of the present disclosure may be deployed.

[0092] Figure 4 is a block flow diagram (BFD) of an archetypal direct lithium extraction (DLE) process, in which embodiments of the methods of the present disclosure may be deployed.

[0093] Figure 5 shows a pair of flow diagrams depicting various methods for regenerating a LDH sorbent by utilizing divalent-supported anionic displacement (MB-DSAD) in accordance with embodiments of the present disclosure.

[0094] Figure 6 shows a pair of flow diagrams depicting various methods for regenerating a sorbent by utilizing escalating anionic displacement (EAD) in accordance with embodiments of the present disclosure.

[0095] Figure 7 shows a pair of flow diagrams depicting various methods for regenerating a LDH sorbent by utilizing divalent-supported anionic displacement (DSAD) in accordance with embodiments of the present disclosure.

[0096] Figure 8 shows a plot of a lithium elution capacity of a LDH sorbent as a function of initial usage ( / .e., adsorption cycles) followed by DSAD in accordance with embodiments of the present disclosure.DETAILED DESCRIPTION

[0097] The following detailed description and examples are illustrative and should not be interpreted as further limiting the scope of the present disclosure. On the contrary, the scope is intended to cover all alternatives, modifications, and equivalents that can be included as described, inferred, taught, or suggested by the present description. Objects, advantages, and other features of the methods of the present disclosure will be more apparent and better understood by those skilled in the art upon reading the following non-restrictive description and references made to the accompanying drawings.

[0098] In direct lithium extraction (DLE), sorbent fouling in the presence of carbonate- and / or sulfate ions is a widely recognized problem. In the context of the present disclosure, the terms “fouling”, “foul”, “fouled”, etc. refer to performance attenuation of a sorbent - specifically: (i) reduced lithium uptake capacity in an extraction process; and / or (ii) reduced lithium elution capacity in an elution process. Evidence of fouling may be depicted via a plot of lithium elution capacity as a function of usage, as exemplified by plot 100 in Figure 1 , the details of which are set out in Example 1.

[0099] Current methods for regenerating sorbents are limited. For example, continuous rinsing with dilute aqueous solution has been shown to remove some impurities, but it has also been shown to lead to unintended lithium desorption and / or premature sorbent degradation (e.g., deformation of bonding sites, altered alignment of two-dimensional sheets, and / or distorted tertiary structure). For example, excessive washing of lithium from a layered double hydroxide (LDH) sorbent may cause interlayer collapse, and / or the formation of Gibbsite. Additionally, available methods for physically regenerating such sorbents (e.g., high-temperature calcination) are often not viable or ineffective without significant modifications to process equipment.

[0100] A DLE operator may elect to perform sorbent rinsing, using available DLE solutions including those commonly employed in sorbent processes (e.g., eluent). As those skilled in the art will appreciate, sorbent process solutions may be effective to remove soluble species (e.g., impurity salts) from the surface of sorbent particles, but they may prove ineffective at accessing and / or removing the soluble species from within sorbent particles. For example, anionic impurities within a LDH sorbent interlayer may not be removed by eluent washing under reasonable DLE timelines (e.g., about 5-10 column bed volume rinses) making further rinsing impractical and determinantal to OPEX.

[0101] In the present disclosure, the terms “LDH sorbent” and “lithium-incorporated-aluminum- hydroxide (LIAH) compositions” are used interchangeably without limitation to any particular structural form. As one example, an LDH sorbent may be a LIAH composition as defined in Formula 1 :LiaX mAI(OH)3 nH2O Formula 1 in which: a is about 1 ;X is a monovalent anion; m is between about 1 .9 and about 3.6; and n is between about 2.1 and about 4.3.

[0102] An LDH sorbent may be fouled by carbonate incorporation, sulfate incorporation, or a combination thereof. In the context of the present disclosure, the terms “incorporation”, “incorporated”, “incorporate”, etc. are used broadly to include intercalation, coordination, complexation, and other types of surface and / or lattice interactions between ions and sorbents. In the context of the present disclosure, the term “intercalation” refers to the reversible inclusion or insertion of a molecule and / or ion into a layered material or a material with layered structure. In the context of the present disclosure, the terms “coordination”, “complexation”, “surface interactions”, and “lattice interactions” are used in accordance with their accepted definitions in the field of inorganic chemistry.

[0103] In the context of the present disclosure, carbonate and sulfate incorporation within an LDH sorbent may be determined by X-ray diffraction (XRD) analysis. As those skilled in the art will appreciate, the diffraction peak at Miller index (002) is representative of one of the crystal lattice planes comprising the sorbent backbone (e.g., lithium, aluminum, and hydroxide). In the context of the present disclosure, Miller index (002) may present in an XRD diffractogram at about 11 .5020for an uncontaminated sorbent. Similarly, the diffraction peak at Miller index (004) is representative of the plane of the sorbent interlayer, which may contain stabilizing anions {e.g., chloride), and where brine species may interact with the sorbent {e.g., lithium chloride, and / or calcium carbonate). In the context of the present disclosure, Miller index (004) may present in the XRD diffractogram at about 23.5020 for a nominal sorbent. Analysis of the changes to the peak position of the Miller indices in the diffractogram provides data on the changes within an LDH sorbent of the present disclosure during contamination. For example, carbonate contamination may lead to a higher02© for the diffraction peaks at Miller indices (002) and (004), indicating a contraction of the interlayer spacing. Without being bound to any particular theory, this contraction may be indicative of significant substitutions of chloride anions for a carbonate species anion within the interlayer. Changes to the diffractogram peak shape e.g., relative intensity, and / or peak width) at the Miller indices may indicate changes to the relative crystallinity of the sorbent, whereas a lack of change to peak shape may indicate impurity inclusion without immediate effect on the sorbent crystallinity. Figure 2 depicts an example of these changes individually, as a result of separate carbonate fouling and separate sulfate fouling. Overlay 200 shows four X-ray diffraction patterns: one generated from uncontaminated sorbent (201), one generated from sorbent contaminated with 7,500 ppm sulfate (202), one generated from sorbent contaminated with 4,000 ppm carbonate (203), and one generated from regenerated sorbent (204), in accordance with embodiments of the present disclosure. The Miller index (002) peak position of an uncontaminated sorbent (211) may shift, as noted above, and can be determined to have increased about 0.1 degrees 2-theta during conversion of uncontaminated sorbent to carbonate contaminated sorbent (231). This peak shifting is restored, reducing the Miller index (002) peak back down 0.1 degrees 2-theta following regeneration by wash solutions (241) as described in select embodiments of the present disclosure. Sulfate contamination, as noted above, is shown to have resulted in a loss of crystallinity, observed in the significant drop in intensity of the Miller index (002) diffraction peak (221). Those skilled in the art will appreciate the rigor with which XRD experiments must be conducted to achieve reliable precision and repeatability to ascertain peak position differences for comparison across multiple samples, highlighting the need to avoid extensive XRD analysis. Similarly, a DLE operator may wish to avoid removing a LDH sorbent from an in-use column to ascertain the status of sorbent contamination.

[0104] In the field of inorganic chemistry, the relative exchange / displacement tendencies of anions, including but not limited to carbonate ions, sulfate ions, oxalate anions, phosphate anions, arsenate anions, and chloride ions, have been shown empirically. Without being bound to any particular theory, these hierarchies may correlate with electrostatic factors including valency and charge density - and steric factors relating to lattice and / or interlayer structures of a particularsorbent. For example, with reference to LDH sorbents, the relative exchange / displacement tendencies of carbonate ions, sulfate ions, and chloride ions may be described by the following hierarchy: Ck < SO42-< COs2-. In the context of the present disclosure, the terms “carbonate”, “carbonate ion” and “carbonate anion” are used broadly and may refer to H2CO3, HCOs1-, COs2-, or a combination thereof. As will be appreciated by those skilled in the art, such species may exist in an equilibrium that is dependent on factors such as temperature, concentration, pH, ionic strength, and other types of ions in solution (both cations and anions).

[0105] In the context of the present disclosure, the terms “regenerate”, “regeneration”, “regenerated”, etc. may be used with reference to a sorbent to describe improvement, restoration, and / or maintenance of its lithium absorption capacity and / or lithium elution capacity. For example, a washing protocol may improve the lithium elution capacity, the lithium uptake capacity, or both, of a sorbent by at least about 5%, at least about 10%, at least about 20%, at least about 50%, at least about 100%, or at least about 300%, relative to its fouled state. Likewise, a washing protocol may restore the lithium elution capacity, the lithium update capacity, or both, of a sorbent to at least about 5%, at least about 10%, at least about 20%, at least about 50%, at least about 75%, or at least about 99%, relative to its initial lithium absorption capacity. Further, a washing protocol may retain the lithium elution capacity, the lithium uptake capacity, or both, of a sorbent within an operating window, such as about + / - 20%, about + / - 10%, or about + / - 5%, relative to its initial elution capacity, the initial lithium uptake capacity, or both.

[0106] In the context of the present disclosure, lithium absorption capacity for a sorbent may be defined by Formula 2: Formula 2in which:Li Cap is the lithium capacity of the sorbent, in mg(lithium) / g(sorbent);£ZAis the change in lithium concentration, in mg / L or ppm;LiRis the final brine volume, in mL; and msoris mass of sorbent, in g.

[0107] Those skilled in the art will readily appreciate the equivalent definition of lithium elution capacity. Those skilled in the art will further appreciate that lithium capacity values are time dependent, and that they may be measured after a sorbent has equilibrated. For example, the lithium concentration in solution may vary during an elution phase, as a large amount of lithium ionsdesorb quickly due to the concentration difference between a dilute eluent, at low lithium concentration or in the absence of lithium, and a lithium-loaded sorbent at high lithium concentration. Therefore, it is common to measure lithium capacity relative to a specific extraction sequence (e.g., lithium elution) and for the measurements to occur across a specific timeframe (e.g., measuring capacity for an entire elution cycle). For example, lithium capacity may be assessed during an elution process, and it may be measured relative to the initial lithium concentration, at the beginning of the elution cycle, and relative to the final lithium concentration, once the eluent stream has re-equilibrated following complete elution. In some instances, a lithium elution capacity value for a sorbent may range between 2.0 mg / g and 20 mg / g during a DLE process.

[0108] The present disclosure provides methods to regenerate sorbents for DLE that utilize escalating anionic displacement (EAD), divalent-supported anionic displacement (DSAD), and / or modified brine DSAD (MB-DSAD).

[0109] In the context of the present disclosure, MB-DSAD may comprise contacting a sorbent with a wash solution comprising: (i) depleted brine, the depleted brine comprising its nominal native constituent ion species including, but not limited to, sodium, potassium, calcium, magnesium, iron, boron, carbonate, sulfate, phosphate, silicate, wherein some or all of the lithium cations have been removed, to a maximum of at least about 1 ,000 mg / L; (ii), a high concentration of divalent cations, wherein the divalent cation concentration is at least about 30,000 mg / L, at least about 90,000 mg / L at least about 120,000 mg / L, or at least about 200,000 mg / L; and (iii) a high concentration of chloride ions, wherein the chloride concentration is at least about 1 ,000 mg / L, at least about 25,000 mg / L, at least about 50,000 mg / L, at least about 200,000 mg / L, or at least about 400,000 mg / L. In select embodiments of the present disclosure, the divalent cation concentration of the wash solution is between about 30,000 mg / L and about 35,000 mg / L, between about 90,000 mg / L and about 95,000 mg / L, between about 120,000 mg / L and about 125,000 mg / L, or between about 200,000 mg / L and about 220,000 mg / L. In select embodiments of the present disclosure, the chloride ion concentration is at least about 1 ,000 mg / L, at least 25,000 mg / L, at least about 50,000 mg / L, at least about 200,000 mg / L, or at least about 400,000 mg / L. In select embodiments of the present disclosure, the chloride ion concentration of the wash solution is between about 1 ,000 mg / L and about 2,500 mg / L, between about 25,000 mg / L and about 50,000 mg / L, between about 50,000 mg / L and about 200,000 mg / L, between about 200,000 mg / L and about 300,000 mg / L, or between about 300,000 mg / L and about 400,000 mg / L. In select embodiments of the present disclosure, the divalent cation is Mg2+, Ca2+, Sr2+, Ba2+, or a combination thereof.

[0110] In the context of the present disclosure, EAD may comprise: (i) contacting a sorbent with a first wash solution comprising a high concentration of sulfate ions to displace carbonate ions from the sorbent; and (ii) contacting the sorbent with a second wash solution comprising a high concentration of chloride ions to displace sulfate ions from the sorbent. Those skilled in the art will appreciate that washing a sorbent with fouling anions, such as sulfate anions, is counterintuitive. However, as evidenced by the examples reported in the present disclosure, doing so as part of an EAD protocol can provide for sorbent regeneration. In the context of the present disclosure, the terms “exchange” and “displace” are used interchangeably to characterize anion-sorbent interactions without limitation to any particular mechanism. In select embodiments of the present disclosure, the sulfate ion concentration of the first wash solution may be at least about 1 ,000 mg / L, at least about 25,000 mg / L, at least about 90,000 mg / L, or at least about 150,000 mg / L. In select embodiments of the present disclosure, the sulfate ion concentration of the first wash solution may be between about 1 ,000 mg / L and about 2,500 mg / L, between about 25,000 mg / L and about 30,000 mg / L, between about 90,000 mg / L and 100,000 mg / L, or between 150,000 mg / L and about 160,000 mg / L. In select embodiments of the present disclosure, the chloride ion concentration of the second wash solution may be at least about 1 ,000 mg / L, at least 25,000 mg / L, at least about 50,000 mg / L, at least about 200,000 mg / L, or at least about 400,000 mg / L. In select embodiments of the present disclosure, the chloride ion concentration of the second wash solution may be between about 1 ,000 mg / L and about 2,500 mg / L, between about 25,000 mg / L and about 50,000 mg / L, between about 50,000 mg / L and about 200,000 mg / L, between about 200,000 mg / L and about 300,000 mg / L, or between about 300,000 mg / L and about 400,000 mg / L. In select embodiments of the present disclosure, the first wash solution and / or the second wash solution further comprises a high concentration of a divalent cation. In select embodiments of the present disclosure, the concentration of the divalent cation in the second wash solution is at least about 30,000 mg / L, at least about 120,000 mg / L, or at least about 200,000 mg / L. In select embodiments of the present disclosure, the concentration of the divalent cation in the second wash solution is between about 30,000 mg / L and about 35,000 mg / L, between about 120,000 mg / L and about 125,000 mg / L, or between about 200,000 mg / L and about 220,000 mg / L. In select embodiments of the present disclosure, the divalent cation is Mg2+, Ca2+Sr2+, Ba2+, or a combination thereof.

[0111] In the context of the present disclosure, DSAD may comprise contacting a sorbent with a wash solution comprising a high concentration of a divalent cation. In select embodiments of the present disclosure, the divalent cation concentration of the wash solution is at least about 30,000 mg / L, at least about 90,000 mg / L at least about 120,000 mg / L, or at least about 200,000 mg / L. In select embodiments of the present disclosure, the divalent cation concentration of the wash solution is between about 30,000 mg / L and about 35,000 mg / L, between about 90,000 mg / L and about95,000 mg / L, between about 120,000 mg / L and about 125,000 mg / L, or between about 200,000 mg / L and about 220,000 mg / L. In select embodiments of the present disclosure, the chloride ion concentration of the wash solution is at least about 1 ,000 mg / L, at least 25,000 mg / L, at least about 50,000 mg / L, at least about 200,000 mg / L, or at least about 400,000 mg / L. In select embodiments of the present disclosure, the chloride ion concentration of the wash solution is between about 1 ,000 mg / L and about 2,500 mg / L, between about 25,000 mg / L and about 50,000 mg / L, between about 50,000 mg / L and about 200,000 mg / L, between about 200,000 mg / L and about 300,000 mg / L, or between about 300,000 mg / L and about 400,000 mg / L. In select embodiments of the present disclosure, the divalent cation is Mg2+, Ca2+, Sr2+, Ba2+, or a combination thereof. Without being bound to any particular theory, the heat of hydration for a given divalent cation may approximate heat of ligation for anionic impurities, such as sulfate and / or carbonate. As those skilled in the art may appreciate, the heat of hydration for magnesium cation is lower than that of calcium cation, which may correlate to the relative propensity of each cation to bind to sulfate and / or carbonate ions in solution. Examples in the present disclosure outline the regenerative performance of both cations such that relative sulfate and / or carbonate exchange / removal tendencies of the cations may be described by the following hierarchy: Mg2+> Ca2+.

[0112] DSAD and / or MB-DSAD may be additionally modified to include a high concentration of dissolved solids (TDS). As those skilled in the art will appreciate, additional dissolved solids allow for increased ion content beyond what may be achieved from a singular salt alone. For example, a saturated solution of calcium chloride may still dissolve sodium chloride. In this manner, chloride ion concentration may be increased beyond that of a solution containing a singular salt. Without being bound to any particular theory, a high TDS solution may also be seen as stabilizing for impurity anions (e.g., carbonate) by providing additional positive charges (e.g., sodium cations, potassium cations) that may associate directly (e.g., proximal electrostatic interactions) or indirectly (e.g., association via solvation cages) before, during, and / or after the removal of the anionic impurity anions.

[0113] Select methods of the present disclosure utilize EAD, DSAD and / or MB-DSAD for in-situ sorbent regeneration within an extraction process that employs an array of columns that are cycled through absorption and elution sequences. In the context of the present disclosure, the term “elution” may refer to contacting a sorbent with an eluent to desorb lithium that has been adsorbed thereto. An eluent may include a known amount of lithium (e.g., 200 ppm) in water, and may include other cations (e.g., sodium, potassium, calcium) and / or anions (e.g., chloride, sulfate). In some instances, an eluent may have a lithium concentration target between about 10 ppm to about 750 ppm, and / or between about 50 ppm to about 250 ppm. As will be appreciated by those skilled inthe art, the lithium concentration target and range for an eluent may be selected for the process in which it is used. The lithium concentration within an eluent may be decreased to allow for greater sorbent lithium capacity per unit volume of eluent. For example, a 50 ppm lithium eluent may be able to remove more adsorbed lithium per unit volume than a 300 ppm lithium eluent, given a sorbent containing about 6000 ppm lithium and a nominal desorption timeframe. Those skilled in the art will appreciate that elution timeframes may be correlated to equipment size and capacity. Conversely, the lithium concentration of an eluent may be increased, relative to the concentration on a loaded sorbent, to prevent unwanted elution of lithium from the sorbent material while providing solution flow through the sorbent material for alternative processes (e.g., removal of surface impurity anions).

[0114] Figure 3 shows an archetypal lead, lag, elution column configuration and an archetypal sorbent flow process 300 in which select methods of the present disclosure may be employed. In Figure 3, the lead column is indicated by cross hatching, the lag column is indicated by horizontal hatching, and the elution column is indicated by vertical hatching. During operation, these columns are rotated through an extraction cycle. The sorbent flow process 300 uses columns 308, 310, and 312, to process brine according to steps 302, 304, and 306 as follows.

[0115] At step 302, column 308 is adsorbing lithium while column 310 acts as a lag column to collect any residual lithium before depleted brine is discharged as a raffinate which may be recycled for further lithium extraction, further treated, stored, or disposed of. Also at step 302, an eluent is flowed through column 312 to desorb lithium adsorbed during a previous cycle. This provides a lithium eluate, which may flow to a water recovery unit as depicted in Figure 2. Between steps 302 and 304, a method in accordance with the present disclosure may employ one or more wash cycles to regenerate sorbent in column 308 and / or column 312 by utilizing EAD, DSAD, and / or MB-DSAD as described herein.

[0116] At step 304, column 310 is reconfigured from lag column to lead column. Column 310 receives brine and adsorbs lithium therefrom. Also at step 304, column 312 is reconfigured from elution column to lag column, and it adsorbs breakthrough lithium. Also at step 304, column 308 is reconfigured from lead column to elution column, and it desorbs lithium retained from step 302. Between steps 304 and 306, a method in accordance with the present disclosure may employ one or more wash cycles to regenerate sorbent in column 310 and / or column 308 by utilizing EAD, DSAD, and / or MB-DSAD as described herein.

[0117] At step 306, column 312 is reconfigured from lag column to lead column. Column 312 receives brine and adsorbs lithium therefrom. Also at step 306, column 308 is reconfigured fromelution column to lag column, and it adsorbs breakthrough lithium. Also at step 306, column 310 is reconfigured from lead column to elution column, and it desorbs lithium retained from step 304. Between steps 306 and 302, a method in accordance with the present disclosure may employ one or more wash cycles to regenerate sorbent in column 312 and / or column 310 by utilizing EAD, DSAD, and / or MB-DSAD as described herein.

[0118] Step 302, step 304, step 306, and the wash cycles interposed between them may be cycled by adjusting a valve manifold (or an alternative means for fluid control) to direct flows of brine, eluent, wash solutions, and the like.

[0119] Select methods of the present disclosure utilize EAD, DSAD, and / or MB-DSAD for in- situ sorbent regeneration in the context of a DLE process. An archetypal DLE process is represented as a block flow diagram (BFD) 400 in Figure 4. The DLE process employs a DLE technology stack that includes a pretreatment unit 401 , a sorbent unit 402, an eluent unit 403, and a water recovery unit 404. In the BFD 400, brine flows into the pretreatment unit 401 via flow path 405 where it is filtered, treated, blended, mixed and / or diluted - thereby providing a pretreated brine. Those skilled in the art will appreciate that such pretreatments are common but not necessarily required in DLE processes. In the BFD 400, the pretreated brine flows from the pretreatment unit 401 to the sorbent unit 402 via flow path 406. Further details relating to sorbent units (such as the sorbent unit 402), and the absorption-elution cycles they employ, are set out above with reference to Figure 3 and further discussed throughout the present application. In the BFD 400, the sorbent unit 402 produces depleted brine, which exits via flow path 414 and may be directed to containment flow path 416 (e.g., directed for further processing and / or reinjection) and / or recycled for further extraction via flow path 415. In the BFD 400, the sorbent unit 402 also produces lithium eluate, which exits via flow path 407 and may be directed to the water recovery unit 404 via flow path 408 and / or to the eluent unit 403 via flow path 410. In the BFD 400, makeup water also flows to the eluent unit 403, via flow path 412. In the BFD 400, eluent flows to the sorbent unit 402 via flow path 413. In the BFD 400, lithium eluate may be at least partially concentrated in the water recovery unit 404, which provides lithium concentrate for further processing downstream via flow path 409. The methods of the present disclosure may be implemented in a sorbent unit (such as sorbent unit 402), and the benefits of the methods of the present disclosure may span a DLE process (such as that embodied by BFD 400) more broadly. The benefits of the methods of the present disclosure may include: (i) reduced pretreatment requirements (e.g., at pretreatment unit 401), (ii) increased sorbent lifetime (e.g., at sorbent unit 402); (iii) reduced operational down time (e.g., across BFD 400); (iv) reduced water consumption (e.g., at pre-treatment unit 401 , sorbent unit 402, and / or eluent unit 403); (v) reduced energy consumption (e.g., at pre-treatment unit 401 , sorbent unit 402, and / or water recovery unit 204); (vi) higher lithium concentrate purity(e.g., at flow path 407, flow path 408, and / or flow path 409); and / or (vii) higher lithium concentrate concentration (e.g., at flow path 407, flow path 408, and / or flow path 209). The foregoing benefits may engender significant decreases in DLE CAPEX and / or OPEX. They may also engender significant improvements in a DLE operator’s off-take revenue and / or ESG metrics.

[0120] A method for DLE utilizing MB-DSAD may comprise the following steps: (S1) contacting a sorbent with a brine to selectively adsorb lithium ions from the brine; (S2) contacting the sorbent with a wash solution comprising depleted brine, a spiked concentration of at least one divalent cation, and a spiked concentration of chloride anions; and (S3) contacting the sorbent with an eluent to elute lithium ions.In select embodiments of the present disclosure, the steps are completed in the order (S1), (S2), (S3). In select embodiments of the present disclosure, the steps are completed in the order (S1), (S3), (S2). For example, as depicted in process flows 501 and 502 of Figure 5, carbonate ions may be displaced from a sorbent by washing with a high concentration divalent cation solution (divalent cation and chloride wash step 504). In process flow 501 , the divalent cation and chloride wash step 504 is positioned after a lithium adsorption step 506 and before a lithium elution step 508. In process flow 502, the divalent cation and chloride wash step 504 is positioned after both the lithium absorption step 506 and the lithium elution step 508.

[0121] In select embodiments of the present disclosure, the steps (S1) and (S3) are executed sequentially in a cycle that is repeated, and the step (S2) is executed once every 2-4 cycles, 5-10 cycles, 10-20 cycles, 20-40 cycles, 40-100 cycles, or greater than 100 cycles.

[0122] In select embodiments of the present disclosure, the concentration of the divalent cation in the wash solution of step (S2) is at least about 30,000 mg / L, at least about 120,000 mg / L, or at least about 200,000 mg / L. In select embodiments of the present disclosure, the concentration of the divalent cation in the wash solution of step (S2) is between about 30,000 mg / L and about 35,000 mg / L, between about 120,000 mg / L and about 125,000 mg / L, between about 200,000 mg / L and about 220,000 mg / L. In select embodiments of the present disclosure, the chloride ion concentration of the wash solution is at least about 1 ,000 mg / L, at least 25,000 mg / L, at least about 50,000 mg / L, or at least about 350,000 mg / L. In select embodiments of the present disclosure, the chloride ion concentration of the wash solution is between about 1 ,000 mg / L and about 2,500 mg / L, between about 25,000 mg / L and about 50,000 mg / L, between about 50,000 mg / L and about 200,000 mg / L, between about 200,000 mg / L and about 300,000 mg / L, or between about 300,000 mg / L and about 400,000 mg / L .In select embodiments of the present disclosure, the divalent cation is Mg2+, Ca2+, Sr2+, Ba2+, or a combination thereof. In select embodiments of the present disclosure,the brine is a continental brine comprising between about 10 ppm and about 3,000 ppm of lithium ions as determined by elemental analysis.

[0123] In select embodiments of the present disclosure, a method for DLE utilizing EAD may comprise the following steps: (S1) contacting a sorbent with a brine to selectively adsorb lithium ions from the brine; (S2) contacting the sorbent with a wash solution comprising a high concentration of sulfate ions; (S3) contacting the sorbent with a wash solution comprising a high concentration of chloride ions; and (S4) contacting the sorbent with an eluent to elute lithium ions.

[0124] In select embodiments ofthe present disclosure, the steps may be completed in the order (S1), (S2), (S3), (S4). In select embodiments ofthe present disclosure, the steps may be completed in the order (S1), (S4), (S2), (S3). For example, as depicted in process flows 601 and 602 of Figure 6, carbonate ions may be displaced from a sorbent by washing with a high concentration sulfate solution (sulfate wash step 604) followed by a high concentration chloride solution (chloride wash step 606). In process flow 601 , the sulfate wash step 604 and the chloride wash step 606 are positioned after a lithium adsorption step 608 and before a lithium elution step 610. In process flow 602, the sulfate wash step 604 and the chloride wash step 606 are positioned after both the lithium absorption step 608 and the lithium elution step 610.

[0125] In select embodiments of the present disclosure, the steps (S1) and (S4) may be executed sequentially in a cycle that is repeated, and the steps (S2) and (S3) may be executed once every 2-4 cycles, 5-10 cycles, 10-20 cycles, 20-40 cycles, 40-100 cycles, or greater than 100 cycles.

[0126] In select embodiments of the present disclosure, the wash solution of step (S2) further comprises a high concentration of a divalent cation. In select embodiments of the present disclosure, the wash solution of step (S3) further comprises a high concentration of a divalent cation. In select embodiments of the present disclosure, the concentration of the divalent cation in the wash solution of step (S2) and / or (S3) is at least about 30,000 mg / L, at least about 120,000 mg / L, or at least about 200,000 mg / L. In select embodiments of the present disclosure, the concentration of the divalent cation in the wash solution of step (S2) and / or (S3) is between about 30,000 mg / L and about 35,000 mg / L, between about 120,000 mg / L and about 125,000 mg / L, or between about 200,000 mg / L and about 220,000 mg / L. In select embodiments of the present disclosure, the concentration of the divalent cation in the wash solution of step (S2) and / or (S3) is between about 30,000 mg / L and about 35,000 mg / L, between about 120,000 mg / L and about 125,000 mg / L, between about 200,000 mg / L and about 220,000 mg / L, or between about 300,000 mg / L and about 400,000 mg / L. In select embodiments of the present disclosure, the divalent cation is Mg2+, Ca2+, Sr2+, Ba2+, or a combination thereof. In select embodiments of the present disclosure,the brine is a continental brine comprising: (i) between about 10 ppm and about 3,000 ppm of lithium as determined by elemental analysis; (ii) between about 1 ppm and about 1 ,500 ppm of carbonate ions as determined by titri metry ; and (iii) between about 1 ppm and about 30,000 ppm of sulfate ions as determined by elemental analysis. In select embodiments of the present disclosure, the sulfate ion concentration of the wash solution of step (S2) is at least about 1 ,000 mg / L, at least about 25,000 mg / L, at least about 90,000 mg / L, or at least about 150,000 mg / L. In select embodiments of the present disclosure, the sulfate ion concentration of the wash solution of step (S2) is between about 1 ,000 mg / L and about 2,500 mg / L, between about 25,000 mg / L and about 30,000 mg / L, between about 90,000 mg / L and about 100,000 mg / L, or between 150,000 mg / and about 160,000 mg / L. In select embodiments of the present disclosure, the chloride ion concentration of the wash solution of step (S3) is at least about 1 ,000 mg / L, at least 25,000 mg / L, at least about 50,000 mg / L, at least about 300,000 mg / L, or at least about 400,000 mg / L. In select embodiments of the present disclosure, the chloride ion concentration of the wash solution of step (S3) is between about 1 ,000 mg / L and about 2,500 mg / L, between about 25,000 mg / L and about 50,000 mg / L, between about 50,000 mg / L and about 200,000 mg / L, between about 200,000 mg / L and about 300,000 mg / L, or between about 300,000 mg / L and about 400,000 mg / L.

[0127] In select embodiments of the present disclosure, a method for DLE utilizing DSAD may comprise the following steps: (S1) contacting a sorbent with a brine to selectively adsorb lithium ions from the brine; (S2) contacting the sorbent with a wash solution comprising a high concentration of a divalent cation and chloride anions; and (S3) contacting the sorbent with an eluent to elute lithium ions.In select embodiments of the present disclosure, the steps are completed in the order (S1), (S2), (S3). In select embodiments of the present disclosure, the steps are completed in the order (S1), (S3), (S2). For example, as depicted in process flows 701 and 702 of Figure 7, carbonate ions may be displaced from a sorbent by washing with a high concentration divalent cation solution (divalent cation and chloride wash step 704). In process flow 701 , the divalent cation and chloride wash step 704 is positioned after a lithium adsorption step 706 and before a lithium elution step 708. In process flow 702, the divalent cation and chloride wash step 704 is positioned after both the lithium absorption step 706 and the lithium elution step 708.

[0128] In select embodiments of the present disclosure, the steps (S1) and (S3) are executed sequentially in a cycle that is repeated, and wherein the step (S2) is executed once every 2-4 cycles, 5-10 cycles, 10-20 cycles, 20-40 cycles, 40-100 cycles, or greater than 100 cycles.

[0129] In select embodiments of the present disclosure, the concentration of the divalent cation in the wash solution of step (S2) is at least about 30,000 mg / L, at least about 120,000 mg / L, or atleast about 200,000 mg / L. In select embodiments of the present disclosure, the concentration of the divalent cation in the wash solution of step (S2) is between about 30,000 mg / L and about 35,000 mg / L, between about 120,000 mg / L and about 125,000 mg / L, or between about 200,000 mg / L and about 220,000 mg / L. In select embodiments of the present disclosure, the divalent cation is Mg2+, Ca2+, Sr2+, Ba2+, or a combination thereof. In select embodiments of the present disclosure, the brine is a continental brine comprising: (i) between about 10 ppm and about 3,000 ppm of lithium ions as determined by elemental analysis; (ii) between about 1 ppm and about 5,000 ppm of carbonate ions as determined by titrimetry ; and (iii) between about 1 ppm and about 50,000 ppm of sulfate ions as determined by elemental analysis.

[0130] In select embodiments of the present disclosure, wash cycles utilizing EAD, DSAD and / or MB-DSAD may be implemented repeatedly. For example, 1-2 regeneration washes, 2-5 regeneration washes, 5-10 regeneration washes, or greater than 10 regeneration washes may be used. With reference to process flows 501 and 502 in Figure 5, such repetitive washing may comprise repeating the modified depleted brine wash step 504. With reference to process flows 601 and 602 in Figure 6, such repetitive washing may comprise repeating both the sulfate wash step 404 and the chloride wash step 606. With reference to process flows 701 and 702 in Figure 7, such repetitive washing may comprise repeating the divalent cation and chloride wash step 704. In select embodiments of the present disclosure, repeated wash cycles may be implemented using variable concentrations (e.g., wash iteration 1 using 200,000 mg / L calcium chloride, wash iteration 2 using 100,000 mg / L calcium chloride, wash 3 using 50,000 mg / L calcium chloride, etc.) and / or variable compositions (e.g., wash iteration 1 using 100,000 mg / L calcium chloride, wash iteration 2 using 100,000 mg / L magnesium chloride) which may be determined by the specific requirements of the broader DLE process.

[0131] Those skilled in the art will appreciate that regenerative washes may be employed differently depending on operation tolerance and / or CAPEX and OPEX considerations. For example, continual and / or intermittent impurity analysis of carbonate (e.g., mass balance calculations of carbonate in input brine relative to depleted brine, as analyzed by carbonate titration) may provide indications of relative sorbent fouling over time. For example, continual and / or intermittent lithium elution capacity analysis may indicate a loss of sorbent performance. In these and other cases, a DLE operator may elect to employ a method utilizing EAD, DSAD, and / or MB- DSAD to regenerate the sorbent. Alternatively, long-term sorbent material data may indicate a timeframe of effective performance for lithium extraction cycles, and a routine regeneration wash may be scheduled accordingly.

[0132] Figure 8 shows a plot 800 of long-term sorbent performance analysis. The series depicts typical adsorption (801) and elution (802) capacities over time, represented by number sorbent bed volumes of brine processed, for a LDH sorbent. The brine contains a high level of sulfate (about 8,000 mg / L) and carbonate (about 1 ,100 mg / L) impurities, leading to a continual decrease in sorbent lithium capacities with repeated exposure. A regeneration cycle (803) is effected after lithium elution capacity is reduced to about 50% (e.g., 811), which restores the sorbent lithium capacities to at least 90% of original capacity (e.g., 813).

[0133] In some instances, a specific impurity (e.g., sulfate) may be identified and may allow for a specific selection of regeneration wash solution to effectively remove the impurity. For example, in the case of a sorbent fouled by sulfate incorporation, the use of a regeneration wash solution with a weaker binding efficiency (e.g., potassium chloride) may be employed. As those skilled in the art will appreciate, the concentration of a regeneration wash solution will be determined on a case-by-case basis. For example, a potassium chloride regeneration wash solution of 20,000 ppm may be appropriate for a sorbent with 1 ,500 ppm sulfate (mg / L) incorporation, but may not be appropriate for a sorbent with 15,000 ppm sulfate incorporation.

[0134] In some instances, following removal of a fouling ion, a sorbent may be re-equilibrated to operating conditions using an appropriate solution (e.g., lithium eluent, pre-processed brine stream, depleted brine stream) as required for a specific extraction cycle. After the sorbent is returned to nominal conditions, the lithium capacity may be assessed to determine the outcome of the regeneration cycle.

[0135] As those skilled in the art will appreciate, assessment of sorbent performance may be critical to an efficient and effective DLE operation, and may be achieved by common methodologies including, but not limited to: conductivity measurements during extraction, and / or lithium mass balance measurements of unprocessed brine relative to depleted brine, and / or direct elemental analysis of digested sorbent. Selection of the correct assessment technique may be balanced against the operational requirements (e.g. opportunity for sorbent unit downtime), access to analytical equipment and reagents (e.g., DLE from petroleum shale brines in Pennsylvania may have significantly fewer logistical concerns for analysis as compared to DLE from Salar brines in remote locations, such as Salar de Atacama).

[0136] In some instances, the potential fouling ions within a brine may be known from compositional and / or elemental analysis of the brine prior to extraction. Analytical results may allow a DLE operator to proceed with a method of the present disclosure in a selective manner to address the specific contaminant(s). In select embodiments of the present disclosure, methods utilizingEAD, DSAD, and / or MB-DSAD may be employed in concert with conventional wash protocols. For example, borates are known to associate with LDH sorbents under some conditions, and they may be readily displaced through washing with a standard lithium eluent before, during, and / or after a method of the present disclosure. Likewise, silicates and other so called “surface contaminants” may be readily displaced through washing with a standard lithium eluent before, during, and / or after a method of the present disclosure.

[0137] In the context of the present disclosure, the term “lithium” may refer to lithium in multiple forms, including but not limited to lithium cations, solvated lithium ions, lithium ion pairs, lithium cations that have been incorporated within a larger structure (e.g., bound or encapsulated within macrocycles or ion cages). Depending on its form, lithium may be in solution, in a colloid, in a slurry, adsorbed to a surface, retained in interstitial sites, and / or in a chemical composition such as a salt (e.g. lithium chloride).

[0138] In the context of the present disclosure, the term “brine” may refer to a natural brine, a synthetic brine, or a combination thereof. In the context of the present disclosure, the term “brine” may refer to a raw brine - i.e. one that has not been treated in a sorbent extraction unit. A brine may be pre-treated, such as via filtration, through removal of a physical contaminant, and / or addition of reagent, such as a flocculant. A brine may contain variable lithium content, for example between 5 ppm and 5000 ppm lithium, and may display variable impurities, including but not limited to, sodium, potassium, strontium, chloride, sulfates, nitrates, carbonates, borates, and arsenates, with the impurities varying across significant concentration ranges (e.g., sodium, 40,000 ppm to 125,000 ppm; total boron, 100 ppm to 5000 ppm). A brine may also be intermixed with physical contaminants (e.g., clays, oils). Depending on the source of a brine, a DLE operation may apply a pretreatment prior to extraction. For example, physical separation may be used to filter out insoluble material or separate aqueous and organic solution phases. Additional consideration may be given to the DLE technology stack, to ensure appropriate compatibility with the brine. For example, a DLE process designed for lithium extraction from a high total dissolved solid (TDS) and high insoluble (e.g. minerals, clays) brine source would likely deploy a comprehensive pretreatment process.

[0139] In the context of the present disclosure, “sorbents” and / or “sorbent materials” may include metal oxides (e.g., titanium oxide, manganese oxide), mixed metal phosphates (e.g., lithium-titanium-iron phosphates), metal organic frameworks (e.g., functionalized zirconium oxide polyhedra), and macrocyclic ligands (e.g., crown ethers, cryptands). In the context of the present disclosure, a sorbent and / or sorbent material may comprise a lithium selective material comprising a cobalt oxide, a manganese oxide, a titanium oxide, a gallium oxide, a tin oxide, a cobalt sulfide, a manganese sulfide, a titanium sulfide, a gallium sulfide, a tin sulfide, a cobalt phosphate, amanganese phosphate, a titanium phosphate, a gallium phosphate, a tin phosphate, a polyether, an immobilized crown ether, an immobilized cryptand, an aluminate, aluminum-based material, aluminum-oxygen-based material, a lithium alumina intercalate prepared from hydrated alumina, a lithium aluminum layered double hydroxide, a layered double hydroxide of modified activated alumina, a layered double hydroxide, or a combination thereof. Such lithium selective materials may be incorporated into, immobilized on, or coordinated with a zeolite, an ion exchange resin, a molecular sieve, a polymer, or a combination thereof.

[0140] The affinity of lithium for a particular sorbent may depend on molecular characteristics of the sorbent, such as its size, shape, and polarity. In the context of the present disclosure, a sorbent may leverage the tendency of solutes in solution to adsorb on the surface of porous materials. Sorbents for DLE may have pore surface areas of at least about 10 m2 / g. In select embodiments of the present disclosure, a sorbent may have pore surface areas ranging from about 10 m2 / g to about 100 m2 / g, about 100 m2 / g to about 1 ,200 m2 / g, about 200 m2 / g to about 1 ,100 m2 / g, about 300 m2 / g to about 1 ,000 m2 / g, about 400 m2 / g to about 900 m2 / g, about 500 m2 / g to about 800 m2 / g, or from about 600 m2 / g to about 700 m2 / g, limits included. In select embodiments of the present disclosure, a sorbent may have pore surface areas of about 50 m2 / g. As those skilled in the art will appreciate, larger surface areas may facilitate higher levels of lithium uptake.

[0141] In some instances, the affinity of lithium for a particular sorbent may also depend on sorbent particle size, sorbent packing density, residence time, brine flow rate (superficial velocity in particular), inlet lithium concentration, brine chemistry, brine pH, and / or brine temperature. The attraction between lithium and the sorbent may be caused by Van der Waals forces and / or hydrophobic interactions. In some instances, bonding energies in lithium adsorption may be at least about 10 kJ / mol. In some instances, bonding energies in lithium adsorption may range from about 10 kJ / mol to about 70 kJ / mol, from about 20 kJ / mol to about 60 kJ / mol, or from about 30 kJ / mol to about 50 kJ / mol, limits included. In some instances, bonding energies in lithium adsorption may be greater than about 70 kJ / mol.

[0142] In the context of the present disclosure, the terms “wash solution” and “regeneration wash solution” may be used interchangeably and may be defined as a solution with a high concentration of cations and anions that is used to elute ionic contaminants from a sorbent. For example, a sulfate-fouled sorbent may be contacted with a 5,000 ppm sodium chloride solution to competitively displace sulfate. As those skilled in the art will appreciate, the selection of such a wash solution may consider both the sorbent composition and the ionic contaminant that has fouled the sorbent. For example, a regeneration wash solution containing chloride may require a high concentration to overcome the binding efficiency of sulfate, such that chloride anions displacesulfate anions from the sorbent. Without being bound to any particular theory, the mechanism for this displacement may be based in competitive binding and / or statistical inhibition.Example 1 - Fouling of an LDH sorbent in the presence of carbonate ions and sulfate ions

[0143] In this example, an LDH sorbent was exposed to a carbonate- and sulfate-containing synthetic brine, and the attenuation of its lithium elution capacity was evaluated over a series of absorption-elution cycles.

[0144] The synthetic brine was prepared by dissolving about 246.7 g NaCI, about 46.7 g KCI, about 1.7 g CaCl2*2H2O, about 40 g MgCh, about 2.86 g H3BO3, about 4.7 g LiCI, about 1 .59 g Na2CO3, and about 38.06 g Na2SO4 in about 1 L of deionized water. The synthetic brine was analyzed by inductively coupled plasma - optical emission spectroscopy (ICP-OES), the results of which are displayed in Table 1 and Figure 1 .

[0145] Table 1. Elemental analysis of a synthetic brine as determined by ICP-OES.

[0146] The carbonate concentration of the brine, measured as calcium carbonate basis by conductivity measurements and titrimetry, was determined to be 1 ,212 mg / L.

[0147] The LDH sorbent was loaded in a column and subjected to sequential adsorption-elution cycles. In each absorption phase, a 100 mL aliquot of the fresh synthetic brine was flowed through the LDH sorbent by peristaltic pump, at about 10 mL / min with 1 / 8” inner diameter (ID) transfer tubing, at 60 °C. In each elution phase, a 100 mL aliquot of fresh eluent comprising 200 mg / L lithium chloride was flowed through the sorbent material by peristaltic pump, at about 1.5 mL / min to 2.0 mL / min with 1 / 8” ID transfer tubing, at about 24 °C. The lithium elution capacity was measured in each elution phase, and the results showed consistent attenuation - leading to a 50% decrease over seven cycles as set out in Table 2.

[0148] Table 2. Lithium elution capacity attenuation over seven cycles of exposure to carbonate ions and sulfate ions.Example 2 - In-situ regeneration of a carbonate-fouled LDH sorbent by EAD

[0149] In this example, a carbonate-fouled LDH sorbent was regenerated through washing with a first wash solution comprising a high concentration of sulfate ions and a second wash solution comprising a high concentration of chloride ions.

[0150] A carbonate solution was prepared by dissolving about 10 g of sodium carbonate and about 3 g of lithium chloride in about 500 mL of deionized water. The carbonate solution was continuously passed through an LDH sorbent material at a circulation rate of about 37.5 mL / min for about 150 minutes at 60 °C to allow for the incorporation of carbonate ions into the LDH sorbent. Prior to the carbonate incorporation, the lithium elution capacity of the LDH sorbent was determined to be about 6.55 mg / g. After the carbonate incorporation, the LDH sorbent was found to have a lithium elution capacity of 1 .3 mg / g.

[0151] The first wash solution, comprising 29,690 mg / L sodium sulfate, was passed through the carbonate-incorporated LDH sorbent at a rate of 37.5 mL / min and circulated for 150 min at 60 °C. The second wash solution, comprising 120,000 mg / L sodium chloride, was then passed through the LDH sorbent at a rate of 37.5 mL / min at 60 °C for about 13 min. The LDH sorbent was then contacted with a 200 mg / L lithium eluent solution. An adsorption phase was then executed using the LDH sorbent and 300 mL of synthetic brine containing about 700 mg / L lithium at a rate of 10 mL / min at 60 °C. Following adsorption, the LDH sorbent was eluted with a 200 mg / L lithium eluate, and was found to have a regenerated lithium capacity of 6.2 mg / L. These results are outlined in Table 3.Table 3: Lithium capacity data for carbonate-fouled LDH sorbent after regeneration by EAD.Example 3 - In situ regeneration of carbonate-fouled LDH sorbent by DSAD

[0152] In this example, a carbonate-fouled LDH sorbent was regenerated in situ through washing with a solution comprising a high concentration of divalent cations and chloride ions.

[0153] A carbonate solution was prepared by dissolving about 10 g of sodium carbonate and about 3 g of lithium chloride in about 500 mL of deionized water. The carbonate solution was continuously passed through an LDH sorbent material at a circulation rate of about 5.5 mL / min for about 90 minutes to allow for the incorporation of carbonate ions into the LDH sorbent. Prior to the carbonate incorporation, the lithium elution capacity of the LDH sorbent was determined to be about 7.16 mg / g. After the carbonate incorporation, the LDH sorbent was found to have a lithium elution capacity of 1 .3 mg / g.

[0154] A high concentration calcium chloride solution was prepared by dissolving about 250 g anhydrous calcium chloride in about 600 mL reverse osmosis-purified water. The calcium chloride solution was continuously passed through the carbonate-incorporated LDH sorbent via recycle flow at a rate of about 20 mL / min at 60 °C to regenerate the LDH sorbent. After the wash, about 100 mL of a lithium eluate comprising about 200 mg / L lithium was passed through the LDH sorbent. This protocol was repeated on duplicate aliquots of the carbonate-incorporated LDH sorbent using varying calcium chloride concentrations. The resulting lithium elution capacities were determined to have improved by about 38% and about 54%, as set out in Table 4.

[0155] Table 4. Lithium capacity data for carbonate-fouled LDH sorbent after regeneration with DSAD.Example 4 - In-Situ regeneration of sulfate-fouled LDH sorbent by DSAD

[0156] In this example, a sulfate-fouled LDH sorbent was regenerated in situ through washing with a solution comprising a high concentration of divalent cations and chloride ions. A related protocol that did not include a high concentration of divalent cations was determined to be ineffective.

[0157] A lithium chloride solution was prepared by dissolving about 500 mg lithium chloride in about 500 mL deionized water. Sodium sulfate was added to this solution until solids remained, after which the solution was decanted and filtered. The mixed lithium chloride-sodium sulfate solution was then continuously passed through an LDH sorbent material at a circulation rate of about 7.5 mL / min for about 60 minutes to allow for the incorporation of sulfate ions into the LDH sorbent.

[0158] A saturated sodium chloride solution was prepared by adding sodium chloride to about 600 mL of reverse osmosis-purified water until solids remained, after which the liquid was decantedand filtered. The saturated sodium chloride solution was continuously passed through the sulfate contaminated at a circulation rate of about 1 .5 mL / min and at about 24 °C for about 180 min.

[0159] After the sodium chloride wash, about 100 mL of a lithium eluate, comprising about 200 mg / L lithium, was passed through the LDH sorbent at a rate of about 10 mL / min, and at about 24 °C. The lithium elution capacity was measured and found to be 0.39 mg / g, from which it was determined that the regeneration was insufficient.

[0160] A calcium chloride solution was prepared by dissolving about 250 mg of anhydrous calcium chloride in 600 mL of deionized water. The sodium chloride treated sorbent material was continuously passed through the sulfate contaminated at a circulation rate of about 1 .5 mL / min and at about 24 °C for about 55 min.

[0161] After the calcium chloride wash, about 100 mL of a lithium eluate, comprising about 200 mg / L lithium, was passed through the LDH sorbent at a rate of about 10 mL / min, and at about 24 °C. The lithium elution capacity was measured and found to be 1.23 mg / g.Example 5 - In-Situ regeneration of carbonate-fouled LDH sorbent by MB-DSAD

[0162] In this example, a sulfate-fouled LDH sorbent was regenerated through washing with a solution comprising depleted brine with a spiked concentration of divalent cations, and a spiked concentration of chloride ions.

[0163] A contaminant brine solution was prepared using by adding 14 g sodium sulfate, 2.3 g sodium carbonate, 115 g sodium chloride, and 12.3 g lithium chloride to 2 L of deionized water, pH adjusted to about 7 using concentrated hydrochloric acid. Analysis by ICP-OES determined the amounts of key components to be about 1 ,000 ppm lithium, about 25,000 ppm sodium, and about 1 ,500 ppm sulfur. The contaminant brine solution was flowed through an LDH sorbent material at a circulation rate of about 37 mL / min for about 120 minutes to allow for the incorporation of sulfate ions into the LDH sorbent.

[0164] Following contamination, 500 mL of a rinse solution comprised 200 ppm lithium chloride (lithium basis) was flowed through the contaminated sorbent at a rate of 8.3 mL / min.

[0165] A secondary contaminant brine solution was prepared by adding 6 g sodium carbonate and 6 g lithium chloride to 2 L of deionized water, pH adjusted to about 7 using concentrated hydrochloric acid. The secondary contaminant brine solution was then continuously flowed through the previously sulfate contaminated sorbent at a circulation rate of about 37 mL / min for about 120 minutes to allow for the incorporation of carbonate ions into the LDH sorbent.

[0166] Following contamination, 500 mL of a rinse solution comprised of 200 pm lithium chloride (lithium basis) was flowed through the contaminated sorbent at a rate of 8.3 mL / min.

[0167] A natural brine, previously depleted by LIAH sorbent extraction to contain less than about 100 ppm lithium, was analyzed by ICP-OES, the results of which are displayed in Table 5.Table 5 - Elemental analysis of a natural brine as determined by ICP-OES.

[0168] The depleted brine solution was used to prepare three separate regeneration solutions: (1) an unmodified depleted brine; (2) a first modified depleted brine solution, prepared by the addition of 4 g magnesium chloride to 100 mL of depleted brine, analyzed by ICP-OES to contain about 30,000 ppm magnesium cations; and (3) a second modified depleted brine solution, prepared by the addition of 10 g magnesium chloride to 100 mL of depleted brine, analyzed by ICP-OES to contain about 45,000 ppm magnesium cations.

[0169] Separate aliquots of about 3 g sulfur and carbonate contaminated sorbent were rinsed with 100 mL of one of solutions (1) to (3) by continuous flow through at a rate of about 37 mL / min for 30min. After regeneration, each sorbent aliquot was rinsed with 300 mL of a rinse solution comprised of 200 pm lithium chloride (lithium basis) was flowed through the contaminated sorbent at a rate of 37 mL / min for about 60 min. Each rinse solution was then analyzed by titrimetry to determine carbonate content, the results of which are shown below in Table 6, reported in milligrams of bicarbonate per gram sorbent basis.Table 6 - Carbonate removed by MB-DSAD.Example 6 - In-Situ regeneration of sulfate- and carbonate-fouled LDH sorbent by DSAD across multiple fouling cycles

[0170] In this example, an LDH sorbent was contaminated and regenerated continuously, over multiple extraction cycles.

[0171] A synthetic brine containing sulfate and carbonate contaminants was prepared by adding 9.5 g lithium chloride, 71 .1 g sodium sulfate, 4.6g sodium carbonate, and 300 g sodium chloride to 2 L of deionized water, pH adjusted to about 7 using concentrated hydrochloric acid.

[0172] About 4 g of LDH sorbent was then set through continuous adsorption and desorption cycles. Each adsorption cycle was executed by continuous flow using 200 mL of the synthetic brine at a circulation rate of about 37 mL / min for about 60 minutes. Each elution cycle was executed by continuous flow using 300 mL of 200 ppm lithium chloride eluent (lithium basis) at a circulation rate of about 37 mL / min for about 60 minutes.

[0173] After four pairs of adsorption-desorption cycles, the sorbent had been contaminated such that a significant contamination had been achieved (e.g., about 50% reduction in initial lithium capacities). A regeneration solution was prepared using 195 g magnesium chloride in 500 mL deionized water, pH adjusted to about 7 using concentrated hydrochloric acid. 100 mL of the regeneration solution was applied to the sorbent through continuous flow at a rate of about 37 mL / min for about 60 minutes. Regeneration was repeated two additional times with a fresh aliquot of 100 mL of the regeneration solution.

[0174] Following regeneration, 300 mL of 200 ppm lithium chloride (lithium basis) was rinsed through the sorbent at a rate of about 37 mL / min for about 60 min. The sorbent was then subjected to a new round of adsorption-desorption cycles with the synthetic brine. The measured capacities for each adsorption cycle and each desorption cycle are listed below in Table 7.Table 7 - Continuous lithium extraction of sulfate- and carbonate-contaminated brine with continuous sorbent regeneration.

[0175] While particular aspects of the subject matter described herein have been shown and described, it will be apparent to those skilled in the art that, based upon the teachings herein, changes and modifications may be made without departing from the subject matter described herein and its broader aspects and, therefore, the appended claims are to encompass within their scope all such changes and modifications as are within the true spirit and scope of the subject matter described herein.

[0176] All technical and scientific terms and expressions used herein have the same definitions as those commonly understood by the person skilled in the art when relating to the present technology. The definition of some terms and expressions used herein is nevertheless provided below for the purpose of clarity.

[0177] It will be understood by those within the art that, in general, terms used herein, and especially in the appended claims are generally intended as “open” terms (e.g., the term “comprising” should be interpreted as “including but not limited to”,” the term “having” should be interpreted as “having at least,” the term “has” should be interpreted as “has at least,” etc.). For the purposes of the present disclosure, the expression “consisting of’ is considered to be a preferred embodiment of the term “comprising”. If a group is defined hereinafter to include at least a certain number of implementations, it is also to be understood to disclose a group, which preferably consists only of these implementations. As used herein, the term “and / or” includes any and all combinations of one or more of the associated listed items.

[0178] It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases “at least one” and “one or more” to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles “a” or “an” limits any particular claim containing such introduced claim recitation to claims containing only one such recitation, even when the same claim includes the introductory phrases “one or more “or “at least one” and indefinite articles such as “a” or “an” (e.g., “a” and / or “an” should typically be interpreted to mean “at least one” or “one or more”); the same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should typically beinterpreted to mean at least the recited number (e.g., the bare recitation of “two recitations,” without other modifiers, typically means at least two recitations, or two or more recitations).

[0179] Furthermore, in those instances where a convention analogous to “at least one of A, B, and C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B, and C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and / or A, B, and C together, etc.). In those instances where a convention analogous to “at least one of A, B, or C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B, or C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and / or A, B, and C together, etc.).

[0180] It will be further understood by those within the art that typically a disjunctive word and / or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms unless context dictates otherwise. For example, the phrase “A or B” will be typically understood to include the possibilities of “A” or “B” or “A and B.”

[0181] With respect to the appended claims, those skilled in the art will appreciate that recited operations therein may generally be performed in any order. Also, although various operational flows are presented in a sequence(s), it should be understood that the various operations may be performed in other orders than those which are illustrated or may be performed concurrently. Examples of such alternate orderings may include overlapping, interleaved, interrupted, reordered, incremental, preparatory, supplemental, simultaneous, reverse, or other variant orderings, unless context dictates otherwise.

[0182] Throughout this application, the terms “in an embodiment”, “in one embodiment”, “in an embodiment”, “in several embodiments”, “in at least one embodiment”, “in various embodiments,” “in select embodiments”, and the like may be used. Each of these terms, and all such similar terms should be construed as “in at least one embodiment, and possibly but not necessarily all embodiments,” unless explicitly stated otherwise. Specifically, unless explicitly stated otherwise, the intent of phrases like these is to provide non-exclusive and non-limiting examples of implementations of the subject matter.

[0183] The term of degree “substantially”, as used herein means a reasonable amount of dev / ation of the modified term such that the end result is not significantly changed. The term “substantially” should be construed as including a dev / ation of ±5% of the modified term if this dev / ation would not negate the meaning of the term it modifies. The terms of degree “about” and “approximately” should be construed as including a dev / ation of ±20%. Other terms of degrees should be construed as including a dev / ation of ±5% of the modified term.

[0184] The mere statement that one, some, or may embodiments include one or more things or have one or more features, does not imply that all embodiments include one or more things or have one or more features, but also does not imply that such embodiments must exist. It is a mere indicator of an example and should not be interpreted otherwise, unless explicitly stated as such.

[0185] When trade names are used herein, it is intended to independently include the tradename product and the active ingredient(s) of the tradename product.

[0186] Those skilled in the art will appreciate that the foregoing specific exemplary membranes and / or devices and / or methods are representative of more general processes and / or devices and / or technologies taught elsewhere herein, such as in the claims filed herewith and / or elsewhere in the present application.

Claims

CLAIMS1. A method for regenerating a sorbent that is fouled at least in part by carbonate ion incorporation, sulfate ion incorporation, or a combination thereof, the method comprising contacting the sorbent with a wash solution comprising a brine with a spiked concentration of at least one divalent cation and a spiked concentration of chloride anions.

2. The method of claim 1 , wherein the brine has a lithium concentration of between about 10 mg / L and about 1 ,000 mg / L.

3. The method of claim 1 , wherein the brine has a lithium concentration of at least 10 mg / L, at least about 50 mg / L, at least about 200 mg / L, at least about 500 mg / L, or at least about 1 ,000 mg / L.

4. The method of any one of claims 1 to 3, wherein the spiked concentration of the at least one divalent cation is at least about 30,000 mg / L, at least about 120,000 mg / L, or at least about 200,000 mg / L.

5. The method of any one of claims 1 to 3, wherein the spiked concentration of the at least one divalent cation of the wash solution is between about 30,000 mg / L and about 35,000 mg / L, between about 120,000 mg / L and about 125,000 mg / L, or between about 200,000 mg / L and about 220,000 mg / L.

6. The method of any one of claims 1 to 5, wherein the spiked concentration of the chloride anions is at least about 1 ,000 mg / L, at least about 25,000 mg / L, at least about 50,000 mg / L, at least about 200,000 mg / L, or at least about 400,000 mg / L.

7. The method of any one of claims 1 to 5, wherein the spiked concentration of the chloride anions is between about 1 ,000 mg / L and about 2,500 mg / L, between about 25,000 mg / L and about 50,000 mg / L, between about 50,000 mg / L and about 200,000 mg / L, between about 200,000 mg / L and about 300,000 mg / L, or between about 300,000 mg / L and about 400,000 mg / L.

8. The method of any one of claims 1 to 7, wherein the at least one divalent cation is Mg2+, Ca2+, Sr2+, Ba2+, or a combination thereof.

9. The method of any one of claims 1 to 8, wherein the sorbent is a layered double hydroxide (LDH) sorbent.

10. The method of any one of claims 1 to 9, wherein the sorbent is a lithium-incorporated- aluminum-hydroxide (LIAH) composition as described in Formula 1 :LiaX mAI(OH)3 nH2O Formula 1 in which: a is about 1 ;X is a monovalent anion; m is between about 1 .9 and about 3.6; and n is between about 2.1 and about 4.3.

11. A method for regenerating a sorbent that is fouled at least in part by carbonate ion incorporation, the method comprising: contacting the sorbent with a first wash solution comprising a high concentration of sulfate ions to displace carbonate ions from the sorbent; and contacting the sorbent with a second solution comprising a high concentration of chloride ions to displace sulfate ions from the sorbent.

12. The method of claim 11 , wherein the sulfate ion concentration of the first wash solution is at least about 1 ,000 mg / L, at least about 25,000 mg / L, at least about 90,000 mg / L, or at least about 150,000 mg / L.

13. The method of claim 11 , wherein the sulfate ion concentration of the first wash solution is between about 1 ,000 mg / L and about 2,500 mg / L, between about 25,000 mg / L and about 30,000 mg / L, between about 90,000 mg / L and 100,000 mg / L, or between 150,000 mg / L and about 160,000 mg / L.

14. The method of any one of claims 11 to 13, wherein the chloride ion concentration of the second wash solution is at least about 1 ,000 mg / L, at least 25,000 mg / L, at least about 50,000 mg / L, at least about 200,000 mg / L, or at least about 400,000 mg / L.

15. The method of any one of claims 11 to 13, wherein the chloride ion concentration of the second wash solution is between about 1 ,000 mg / L and about 2,500 mg / L, between about 25,000 mg / L and about 50,000 mg / L, between about 50,000 mg / L and about 200,000 mg / L, between about 200,000 mg / L and about 300,000 mg / L, or between about 300,000 mg / L and about 400,000 mg / L.

16. The method of claim 15, wherein the first wash solution further comprises a high concentration of at least one divalent cation.

17. The method of claim 15, wherein the concentration of the at least one divalent cation in the first wash solution is at least about 30,000 mg / L, at least about 120,000 mg / L, or at least about 200,000 mg / L.

18. The method of any one of claims 15, wherein the concentration of the at least one divalent cation in the first wash solution is between about 30,000 mg / L and about 35,000 mg / L, between about 120,000 mg / L and about 125,000 mg / L, or between about 200,000 mg / L and about 220,000 mg / L.

19. The method of any one of claims 11 to 18, wherein the second wash solution further comprises a high concentration of at least one divalent cation.

20. The method of claim 19, wherein the concentration of the at least one divalent cation in the second wash solution is at least about 30,000 mg / L, at least about 120,000 mg / L, or at least about 200,000 mg / L.21 . The method of claim 19, wherein the concentration of the at least one divalent cation in the second wash solution is between about 30,000 mg / L and about 35,000 mg / L, between about 120,000 mg / L and about 125,000 mg / L, or between about 200,000 mg / L and about 220,000 mg / L.

22. The method of any one of claims 16 to 21 , wherein the at least one divalent cation is Mg2+, Ca2+, Sr2+, Ba2+, or a combination thereof.

23. The method of any one of claims 11 to 22, wherein the sorbent is a layered double hydroxide (LDH) sorbent.

24. The method of any one of claims 11 to 23, wherein the sorbent is a lithium-incorporated- aluminum-hydroxide (LIAH) composition as described in Formula 1LiaX mAI(OH)3 nH2O Formula 1 in which: a is about 1 ;X is a monovalent anion; m is between about 1 .9 and about 3.6; and n is between about 2.1 and about 4.3.

25. A method for regenerating a sorbent that is fouled at least in part by carbonate ion incorporation, sulfate ion incorporation, or a combination thereof, the method comprising contacting the sorbent with a wash solution comprising a high concentration of at least one divalent cation and a high concentration of chloride anions.

26. The method of claim 25, wherein the high concentration of the at least one divalent cation is at least about 30,000 mg / L, at least about 120,000 mg / L, or at least about 200,000 mg / L.

27. The method of claim 25, wherein the high concentration of the at least one divalent cation is between about 30,000 mg / L and about 35,000 mg / L, between about 120,000 mg / L and about 125,000 mg / L, or between about 200,000 mg / L and about 220,000 mg / L.

28. The method of any one of claims 25 to 27, wherein the high concentration of the chloride anions is at least about 1 ,000 mg / L, at least 25,000 mg / L, at least about 50,000 mg / L, at least about 200,000 mg / L, or at least about 400,000 mg / L.

29. The method of any one of claims 25 to 27, wherein the high concentration of the chloride anions is between about 1 ,000 mg / L to about 2,500 mg / L, between about 25,000 mg / L and about 50,000 mg / L, between about 50,000 mg / L and about 200,000 mg / L, between about 200,000 mg / L and about 300,000 mg / L, or between about 300,000 mg / L and about 400,000 mg / L.

30. The method of any one of claims 25 to 29, wherein the at least one divalent cation is Mg2+, Ca2+, Sr2+, Ba2+, or a combination thereof.31 . The method of any one of claims 25 to 30, wherein the sorbent is a layered double hydroxide (LDH) sorbent.

32. The method of any one of claims 25 to 31 , wherein the sorbent is a lithium-incorporated- aluminum-hydroxide (LIAH) composition as described in Formula 1 :LiaX mAI(OH)3 nH2O Formula 1 in which: a is about 1 ;X is a monovalent anion; m is between about 1 .9 and about 3.6; and n is between about 2.1 and about 4.3.

33. A method for direct lithium extraction (DLE), the method comprising:(51) contacting a sorbent with a brine to selectively adsorb lithium ions from the brine;(52) contacting the sorbent with a wash solution comprising a modified brine with a spiked concentration of at least one divalent cation and a spiked concentration of chloride anions; and(53) contacting the sorbent with an eluent to elute lithium ions.

34. The method of claim 33, wherein the steps are completed in the order (S 1 ), (S2), (S3).

35. The method of claim 33, wherein the steps are completed in the order (S 1 ), (S3), (S2).

36. The method of claim 35, wherein the steps (S1) and (S3) are executed sequentially in a cycle that is repeated, and wherein the step (S2) is executed once every 2-4 cycles, 5-10 cycles, 10-20 cycles, 20-40 cycles, 40-100 cycles, or greater than 100 cycles.

37. The method of any one of claims 33 to 36, wherein the lithium concentration of the modified brine is between about 10 mg / L, and about 1 ,000 mg / L.

38. The method of any one of claims 33 to 37, wherein the spiked concentration of the at least one divalent cation in the wash solution of step (S2) is at least about 30,000 mg / L, at least about 120,000 mg / L, or at least about 200,000 mg / L.

39. The method of any one of claims 33 to 37, wherein the spiked concentration of the at least one divalent cation in the wash solution of step (S2) is between about 30,000 mg / L and about 35,000 mg / L, between about 120,000 mg / L and about 125,000 mg / L, or between about 200,000 mg / L and about 220,000 mg / L.

40. The method of any one of claims 33 to 39, wherein the spiked concentration of the chloride anions in step (S2) is at least about 1 ,000 mg / L, at least 25,000 mg / L, at least about 50,000 mg / L, at least about 200,000 mg / L, or at least about 400,000 mg / L.41 . The method of any one of claims 33 to 39, wherein the spiked concentration of the chloride anions in step (S2) is between about 1 ,000 mg / L to about 2,500 mg / L, between about 25,000 mg / L and about 50,000 mg / L, between about 50,000 mg / L and about 200,000 mg / L, between about 200,000 mg / L and about 300,000 mg / L, or between about 300,000 mg / L and about 400,000 mg / L.

42. The method of any one of claims 33 to 41 wherein the at least one divalent cation is Mg2+, Ca2+, Sr2+, Ba2+, or a combination thereof.

43. The method of any one of claims 33 to 42, wherein the sorbent is a layered double hydroxide (LDH) sorbent.

44. The method of any one of claims 33 to 43, wherein the sorbent is a lithium-incorporated- aluminum-hydroxide (LIAH) composition as described in Formula 1 :LiaX mAI(OH)3 nH2O Formula 1 in which: a is about 1 ;X is a monovalent anion; m is between about 1 .9 and about 3.6; and n is between about 2.1 and about 4.3.

45. The method of any one of claims 33 to 44, wherein the brine is a continental brine comprising: (i) between about 10 ppm and about 3,000 ppm of lithium as determined by elemental analysis; between about 1 ppm and about 1 ,500 ppm of carbonate ions as determined by titrimetry; and (iii) between about 1 ppm and about 30,000 ppm of sulfate ions as determined by elemental analysis.

46. A method for direct lithium extraction (DLE), the method comprising the following steps:(51) contacting a sorbent with a brine to selectively adsorb lithium ions from the brine;(52) contacting the sorbent with a wash solution comprising a high concentration of sulfate ions;(53) contacting the sorbent with a wash solution comprising a high concentration of chloride ions; and(54) contacting the sorbent with an eluent to elute lithium ions.

47. The method of claim 46, wherein the steps are completed in the order (S1), (S2), (S3), (S4).

48. The method of claim 46, wherein the steps are completed in the order (S1), (S4), (S2), (S3).

49. The method of claim 48, wherein the steps (S1) and (S4) are executed sequentially in a cycle that is repeated, and wherein the steps (S2) and (S3) are executed once every 2-4 cycles, 5- 10 cycles, 10-20 cycles, 20-40 cycles, 40-100 cycles, or greater than 100 cycles.

50. The method of any one of claims 46 to 49, wherein the wash solution of step (S2) further comprises a high concentration of at least one divalent cation.51 . The method of claim 50, wherein the concentration of the at least one divalent cation in the wash solution of step (S2) is at least about 30,000 mg / L, at least about 120,000 mg / L, or at least about 200,000 mg / L.

52. The method of claim 50, wherein the concentration at least one divalent cation in the wash solution of step (S2) is between about 30,000 mg / L and about 35,000 mg / L, between about 120,000 mg / L and about 125,000 mg / L, or between about 200,000 mg / L and about 220,000 mg / L.

53. The method of any one of claims 46 to 52, wherein the wash solution of step (S3) further comprises a high concentration of at least one divalent cation.

54. The method of claim 53, wherein the concentration of the at least one divalent cation in the wash solution of step (S3) is at least about 30,000 mg / L, at least about 120,000 mg / L, or at least about 200,000 mg / L.

55. The method of claim 53, wherein the concentration of the at least one divalent cation in the wash solution of step (S3) is between about 30,000 mg / L and about 35,000 mg / L, between about 120,000 mg / L and about 125,000 mg / L, or between about 200,000 mg / L and about 220,000 mg / L.

56. The method of any one of claims 53 to 55, wherein the at least one divalent cation is Mg2+, Ca2+, Sr2+, Ba2+, or a combination thereof.

57. The method of any one of claims 46 to 56, wherein the sorbent is a layered double hydroxide (LDH) sorbent.

58. The method of any one of claims 46 to 57, wherein the sorbent is a lithium-incorporated- aluminum-hydroxide (LIAH) composition as described in Formula 1 :LiaX mAI(OH)3 nH2O Formula 1 in which: a is about 1 ;X is a monovalent anion; m is between about 1 .9 and about 3.6; and n is between about 2.1 and about 4.3.

59. The method of any one of claims 46 to 58, wherein the brine is a continental brine comprising: (i) between about 10 ppm and about 3,000 ppm of lithium as determined by elemental analysis; (ii) between about 1 ppm and about 1 ,500 ppm of carbonate ions as determined by titrimetry; and (iii) between about 1 ppm and about 30,000 ppm of sulfate ions as determined by elemental analysis.

60. The method of any one of claims 46 to 59, wherein the sulfate ion concentration of the wash solution of step (S2) is at least about 1 ,000 mg / L, at least about 25,000 mg / L, at least about 90,000 mg / L, or at least about 150,000 mg / L.

61. The method of any one of claims 46 to 59, wherein the sulfate ion concentration of the wash solution of step (S2) is between about 1 ,000 mg / L and about 2,500 mg / L, between about 25,000 mg / L and about 30,000 mg / L, between about 90,000 mg / L and 100,000 mg / L, or between 150,000 mg / L and about 160,000 mg / L.

62. The method of any one of claims 46 to 61 , wherein the chloride ion concentration of the wash solution of step (S3) is at least about 1 ,000 mg / L, at least 25,000 mg / L, at least about 50,000 mg / L, at least about 200,000 mg / L, or at least about 400,000 mg / L.

63. The method of any one of claims 46 to 61 , wherein the chloride ion concentration of the wash solution of step (S3) is between about 1 ,000 mg / L and about 2,500 mg / L, between about 25,000 mg / L and about 50,000 mg / L, between about 50,000 mg / L and about 200,000 mg / L, between about 200,000 mg / L and about 300,000 mg / L, or between about 300,000 mg / L and about 400,000 mg / L.

64. A method for direct lithium extraction (DLE), the method comprising the following steps:(51) contacting a sorbent with a brine to selectively adsorb lithium ions from the brine;(52) contacting the sorbent with a wash solution comprising a high concentration of at least one divalent cation, and a high concentration of chloride anions; and(53) contacting the sorbent with an eluent to elute lithium ions.

65. The method of claim 64, wherein the steps are completed in the order (S 1 ), (S2), (S3).

66. The method of claim 64, wherein the steps are completed in the order (S 1 ), (S3), (S2).

67. The method of claim 66, wherein the steps (S1) and (S3) are executed sequentially in a cycle that is repeated, and wherein the step (S2) is executed once every 2-4 cycles, 5-10 cycles,10-20 cycles, 20-40 cycles, 40-100 cycles, or greater than 100 cycles.

68. The method of any one of claims 64 to 67, wherein the concentration of the at least one divalent cation in the wash solution of step (S2) is at least about 30,000 mg / L, at least about 120,000 mg / L, at least about 200,000 mg / L, or at least about 400,000 mg / L.

69. The method of any one of claims 64 to 67, wherein the concentration of the at least one divalent cation in the wash solution of step (S2) is between about 30,000 mg / L and about 35,000 mg / L, between about 120,000 mg / L and about 125,000 mg / L, or between about 200,000 mg / L and about 220,000 mg / L.

70. The method of any one of claims 64 to 69, wherein the at least one divalent cation is Mg2+, Ca2+, Sr2+, Ba2+, or a combination thereof.

71. The method of any one of claims 64 to 70, wherein the sorbent is a layered double hydroxide (LDH) sorbent.

72. The method of any one of claims 64 to 71 , wherein the sorbent is a lithium-incorporated- aluminum-hydroxide (LIAH) composition as described in Formula 1 :LiaX mAI(OH)3 nH2O Formula 1 in which: a is about 1 ;X is a monovalent anion; m is between about 1 .9 and about 3.6; and n is between about 2.1 and about 4.3.

73. The method of any one of claims 64 to 72, wherein the brine is a continental brine comprising: (i) between about 10 ppm and about 3,000 ppm of lithium as determined by elemental analysis; between about 1 ppm and about 1 ,500 ppm of carbonate ions as determined by titrimetry; and (iii) between about 1 ppm and about 30,000 ppm of sulfate ions as determined by elemental analysis.

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