Method and process for lithium extraction from lithium manganese oxides (LMOS)

Abstract

A method for extracting lithium from lithium-containing manganese oxides (LMOs) is provided. The disclosed methods are closed cycles in which the energy provided to drive the extraction is provided by heat. The closed cycle is enabled using an acidic ion exchange material (IEX) that undergoes several ion exchange steps in an overall method that converts thermal energy into chemical energy by forming variations in pH.

Description

127861.000003METHOD AND PROCESS FOR LITHIUM EXTRACTION FROM LITHIUM MANGANESE OXIDES (LMOs)CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of United States Provisional Application No. 63 / 681,945, filed August 12, 2024, the entirety of which is incorporated by reference herein.TECHNICAL FIELD

[0002] This application pertains to the field of lithium extraction from lithium manganese oxides.BACKGROUND

[0003] Lithium manganese oxides (LMOs) are finding use and / or being explored in several different technologies. For example, lithium containing manganese oxides are applied in lithium-ion batteries (see X. Ji , et al., “A review on progress of lithium-rich manganese- based cathodes for lithium ion batteries;' J Power Sources, 487 (2021) 229362) and as products from ion sieving lithium cations from brines, wastewater and seawater (manganese oxides can have high ion selectivity for lithium cation (see C. Qiu, et al., “Highly efficient and selective extraction of Li+ from high sodium lithium containing wastewater using manganese series adsorbent,” J Hazardous Material Adv.. 11 (2023) 100347)). See D. Weng, et al., “Introduction of manganese based lithium-ion Sieve-A review,” Progress in Natural Science: Materials International, 30 (2020) 139.

[0004] Extraction of the lithium ions from the manganese oxides has proven to be challenging. As early as 1981, Hunter showed that HC1 can be used to treat LiMmCh to remove lithium. See J. Hunter. “Preparation of a New Crystal Form of Manganese Dioxide: lamba-MnCh”, J Solid State Chem., 39 (1981) 142. Other acids have also been explored. See L. Herrmann, et al., “Lithium recovery' from geothermal brine - an investigation into the desorption of lithium ions using manganese oxide adsorbents.” Energy Adv., 1 (2022) 877. Of interest. Liu et al. reported that the lithium extraction amount was independent of whether HC1 or acetic acid were used provided that the final pH of the solution was the same (see D.F.127861.000003Liu et al., “Li4MnsOi2 Desorption Process with Acetic Acid and Mn Dissolution Mechanism,” J Chem. Eng. Japan, 52 (2019) 274 at Fig. 4).SUMMARY

[0005] The disclosure provides a new method for extracting lithium from LMOs. The disclosed method does not require addition of acids like HC1 etc., but rather is a closed cycle where the energy7provided to drive the extraction is provided by heat. The closed cycle is enabled using an acidic ion exchange material (IEX) that undergoes several ion exchange steps in an overall scheme that converts thermal energy into chemical energy by forming variations in pH.

[0006] Thus, the disclosure provides methods for extracting lithium cations from lithium manganese oxides comprising the steps:(i) contacting a lithium cation-containing manganese oxide with an aqueous solution having a pH less than 3 to liberate the lithium cations into solution and thereby form a lithium cation-containing solution;(ii) contacting the lithium cation-containing solution from step (i) with a protoncontaining zeolite, wherein the contacting results in exchange of the zeolite-bound protons for the lithium cations in solution, thereby producing lithium cationcontaining zeolite and proton-containing solution;(iii) contacting the lithium cation-containing zeolite from step (ii) with an aqueous solution of ammonium hydroxide, wherein the contacting results in exchange of the zeolite-bound lithium cations for the ammonium cations in solution, thereby producing ammonium cation-containing zeolite and lithium cation-containing solution;(iv) heating the ammonium cation-containing zeolite from step (iii) to give off ammonia and thereby produce proton-containing zeolite; and(v) capturing the ammonia produced in step (iv) into an aqueous solution to produce an aqueous solution of ammonium hydroxide.BRIEF DESCRIPTION OF THE DRAWINGS

[0007] FIG 1 illustrates one embodiment of this invention that is provided to guide understanding of the example data provided herein. FIG 1 shows a schematic of a lithium recovery cycle. Comprised of steps i-v: (i) lithium manganese oxide acid treatment, (ii) ion127861.000003 exchange of aqueous lithium to an ion exchanging solid (IEX), (iii) ion exchange of adsorbed Li+ions on the IEX with NH4+from aqueous NH4OH, (iv) gaseous ammonia desorption via thermal treatment, and (v) hydrolysis of produced NHs to form NH4OH.

[0008] FIG 2 is a reproduction of Figure 3 of S.B. Sharma, et al., '‘Characterization of catalyst acidity by microcalorimetry and temperature-programmed desorption,” Appl. Catal. A: General, 102 (1993) 253, 259. The figure shows the TPD spectrum of ammonia desorption from H-mordenite (solid curve) and simulation using AH^ from microcalorimetry (dashed curve).DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

[0001] The present disclosure may be understood more readily by reference to the following detailed description of embodiments and the example that follows.

[0002] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art.

[0003] The singular forms '‘a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise.

[0004] As used in the specification and in the claims, the term "comprising" can include the embodiments "consisting of1and "consisting essentially of.”

[0005] As used herein, the term “about” means that the amount or value in question can be the value indicated ±10% variation. For example, “about 10%” can indicate a range of 9% to 11%, and “about 1” can mean from 0.9-1. 1.

[0006] All ranges disclosed herein are inclusive of the recited endpoint and independently of the endpoints. For example, the expression "from about 2 to about 4” also discloses the range “from 2 to 4.”

[0007] It will be understood that the terms “solution” or “aqueous solution” as used herein, have the meaning commonly understood by one of ordinary skill in the art. It will further be understood that in some embodiments, “solution” or “aqueous solution” refers to the solution (or aqueous solution) phase of multiphase mixture (e.g, a solid / liquid mixture).

[0008] In some aspects, the disclosure provides methods for extracting lithium cations from lithium manganese oxides. Lithium manganese oxides are compounds having the formula LixMnyOz. and include, for example, LiMmCh, LnMnOv Li2MnO3, LiMnCh, and the like.127861.000003Step(i)

[0009] In some aspects, the methods comprise step (i) contacting a lithium cationcontaining manganese oxide with an aqueous solution having a pH less than 3 to liberate the lithium cations into solution and thereby form a lithium cation-containing solution.

[0010] In some embodiments, the aqueous solution used in this step has a pH of less than 3, such as, for example. 2.9, 2.8, 2.7, 2.6. 2.5, 2.4, 2.3, 2.2. 2.1, 2, 1.9, 1.8, 1.7, 1.6, 1.5, 1.4, 1.3, 1.2, 1.1. 1, 0.9, 0.8. 0.7. 0.6, 0.5, 0.4. 0.3. 0.2, or 0.1.

[0011] In some embodiments, the aqueous solution used in this step has a pH of about 2.

[0012] In some embodiments, the aqueous solution used in this step has a pH of about 1.9.

[0013] In some embodiments, the aqueous solution used in this step has a pH of about 1.8.

[0014] In some embodiments, the aqueous solution used in this step has a pH of about 1.7.

[0015] In some embodiments, the aqueous solution used in this step has a pH of about 1.6.

[0016] In some embodiments, the aqueous solution used in this step has a pH of about 1.7.

[0017] In some embodiments, the aqueous solution used in this step has a pH of about 1.6.

[0018] In some embodiments, the aqueous solution used in this step has a pH of about 1.5.

[0019] In some embodiments, the aqueous solution used in this step has a pH of about 1.4.

[0020] In some embodiments, the aqueous solution used in this step has a pH of about 1.3.

[0021] In some embodiments, the aqueous solution used in this step has a pH of about 1.2.

[0022] In some embodiments, the aqueous solution used in this step has a pH of about 1. 1127861.000003

[0023] In some embodiments, the aqueous solution used in this step has a pH of about 1.0.

[0024] In some aspects, the aqueous solution that has a pH of less than 3 used in this step is an aqueous solution of acid. In principle, the acid solution can be comprised of any acid that has an anion that forms a soluble lithium salt and that can be incorporated into an anionic ion exchange zeolite.

[0025] In some embodiments, the aqueous solution of acid is an aqueous mineral acid solution.

[0026] In some embodiments, the aqueous solution of acid is an aqueous HO solution. In some embodiments, the aqueous HC1 solution has an HC1 concentration of 0.001 M, about 0.005 M, about 0.01 M, about 0.015 M, about 0.02 M, about 0.025 M, about 0.03 M, about 0.035 M. about 0.04 M, about 0.045 M, about 0.05 M, about 0.055 M, about 0.06 M, about 0.065 M, about 0.07 M, about 0.075 M, about 0.08 M, about 0.085 M, about 0.09 M, about 0.095 M, about 0.1 M, about 0.105 M, about 0.11 M, about 0.115 M, about 0. 12 M, about 0.125 M, about 0.13 M, about 0.135 M, about 0.14 M, about 0.145 M, about 0.15 M, about 0. 155 M. about 0. 16 M, about 0. 165 M, about 0. 17 M, about 0. 175 M, about 0. 18 M, about 0.185 M, about 0.19 M, about 0.195 M, or about 0.2 M.

[0027] In some aspects of the step of contacting a lithium cation-containing manganese oxide with an aqueous solution having a pH less than 3 to liberate the lithium cations into solution and thereby form a lithium cation-containing solution, the amount of acid that is used is an amount that results in a mixture having an HCl:Li molar ratio of about 1 : 1 to about 5: 1, such as, for example, 1: 1, 1.1: 1, 1.2: 1, 1.3: 1, 1.4: 1, 1.5: 1, 1.6: 1, 1.7:1, 1.8: 1, 1.9: 1, 2: 1, 2.1 : 1, 2.2:1, 2.3: 1, 2.4: 1, 2.5: 1, 2.6:1, 2.7: 1, 2.8: 1, 2.9: 1, 3: 1, 3.1: 1, 3.2: 1, 3.3:1, 3.4: 1, 3.5: 1, 3.6: 1, 3.7:1, 3.8: 1, 3.9: 1, 4: 1, 4.1:1, 4.2: 1, 4.3: 1, 4.4: 1, 4.5:1. 4.6: 1, 4.7: 1, 4.8: 1, 4.9: 1, or 5: 1.

[0028] In some embodiments, the amount of acid that is used is an amount that results in a mixture having an HCl:Li molar ratio of about 1.5: 1.

[0029] In some embodiments, the amount of acid that is used is an amount that results in a mixture having an HCl:Li molar ratio of about 2: 1.

[0030] In some embodiments, the amount of acid that is used is an amount that results in a mixture having an HCl:Li molar ratio of about 2.5: 1.127861.000003

[0031] In some embodiments, the amount of acid that is used is an amount that results in a mixture having an HCl:Li molar ratio of about 3: 1.

[0032] In some aspects of the step of contacting a lithium cation-containing manganese oxide with an aqueous solution having a pH less than 3 to liberate the lithium cations into solution and thereby form a lithium cation-containing solution, the contacting is conducted as any suitable temperature. In some embodiments, the contacting is conducted at a temperature in the range of about 0°C to about 80°C, such as, for example, at a temperature in the range of from 0°C. about 5°C. about 10°C, about 15°C, about 20°C, about 25°C, about 30°C, about 35°C, about 40°C, about 45°C, about 50°C, about 55°C, about 60°C, about 65°C, about 70°C, about 75°C, or about 80°C.

[0033] In some embodiments, the contacting is conducted at a temperature of about 25°C (z.e., at RT).

[0034] In some embodiments, the contacting is conducted at a temperature of about 60°C.

[0035] In some aspects of the step of contacting a lithium cation-containing manganese oxide with an aqueous solution having a pH less than 3 to liberate the lithium cations into solution and thereby form a lithium cation-containing solution, the contacting is conducted for any suitable amount of time. In some embodiments, the contacting takes place for a length of time of about 0.5 hr to about 24 hours, such as, for example, about 0.5 hr, about 1 hr, about 1.5 hr, about 2 hr, about 2.5 hr, about 3 hr, about 3.5 hr. about 4 hr, about 4.5 hr, about 5 hr, about 5.5 hr, about 6 hr, about 6.5 hr. about 7 hr. about 7.5 hr, about 8 hr, about 8.5 hr, about 9 hr, about 9.5 hr, about 10 hr, about 10.5 hr, about 11 hr, about 11 .5 hr, about 12 hr, about 12.5 hr, about 13 hr, about 13.5 hr, about 14 hr, about 14.5 hr, about 15 hr, about 15.5 hr, about 16 hr, about 16.5 hr, about 17 hr, about 17.5 hr, about 18 hr, about 18.5 hr, about 19 hr, about 19.5 hr, about 20 hr, about 20.5 hr, about 21 hr, about 21.5 hr, about 22 hr, about 22.5 hr, about 23 hr, about 23.5 hr, or about 24 hr.

[0036] In some embodiments, the contacting is conducted for about 0.5 hr.

[0037] In some embodiments, the contacting is conducted for about 4 hr.

[0038] In some embodiments, the contacting is conducted for about 24 hr.

[0039] In some aspects of the step of contacting a lithium cation-containing manganese oxide with an aqueous solution having a pH less than 3 to liberate the lithium cations into solution and thereby form a lithium cation-containing solution, the contacting127861.000003 results in extracting at least about 70% by weight of the Li from the lithium cation-containing manganese oxide, such as, for example, about 70 wt%, about 75 wt%, about 80 wt%, about 85 wt%, about 90 wt%, about 95 wt%, or about 100 wt%.

[0040] In some aspects of the step of contacting a lithium cation-containing manganese oxide with an aqueous solution having a pH less than 3 to liberate the lithium cations into solution and thereby form a lithium cation-containing solution, the step is operated under the conditions set forth in the Example below.Step (ii)

[0041] In some aspects, the methods comprise step (ii) contacting the lithium cation-containing solution from step (i) with a proton-containing zeolite, wherein the contacting results in exchange of the zeolite-bound protons for the lithium cations in solution, thereby producing lithium cation-containing zeolite and proton-containing solution.

[0042] In some aspects, the proton-containing zeolite used in step (ii) may be any zeolite that is capable of exchange of the zeolite-bound protons for the lithium cations in solution. Such zeolites may have any zeolite framework that is capable of the required proton for lithium exchange, including MOR, MFI, or CHA.

[0043] In some embodiments, the proton-containing zeolite used in step (ii) has a Si: Al molar ratio of from about 6 to about 12, such as, for example, about 6, about 6.5, about 7, about 7.5, about 8, about 8.5, about 9, about 9.5, about 10, about 10.5, about 11. about 11.5. or about 12.

[0044] In some embodiments, the proton-containing zeolite used in step (ii) has a Si: Al molar ratio of about 6.5.

[0045] In some embodiments, the proton-containing zeolite used in step (ii) has a Si:Al molar ratio of about 7.5.

[0046] In some embodiments, the proton-containing zeolite used in step (ii) has a Si: Al molar ratio of about 11.5.

[0047] In some embodiments, the zeolite used in step (ii) is subject to a pretreatment such as HC1 treatment or calcination to ensure that the zeolite is in in the proton form.

[0048] In some aspects of step (ii), the contacting of the lithium cation-containing solution from step (i) with a proton-containing zeolite is conducted at a temperature in the127861.000003 range of about 0°C to about 80°C, such as, for example, at a temperature in the range of from 0°C, about 5°C, about 10°C, about 15°C, about 20°C, about 25°C, about 30°C, about 35°C, about 40°C, about 45°C, about 50°C, about 55°C, about 60°C. about 65°C, about 70°C, about 75°C, or about 80°C.

[0049] In some embodiments, the contacting is conducted at a temperature of about 25°C (z.e., at RT).

[0050] In other aspects of step (ii). the contacting of the lithium cation-containing solution from step (i) with a proton-containing zeolite is conducted at any mass ratio of liquid to zeolite that results in the desired ion exchange. In some embodiments, the contacting is conducted at any mass ratio of liquid to zeolite of from about 2:1 to about 200:1, such as, for example, about 2: 1, about 3: 1, about 4: 1, about 5: 1, about 6: 1, about 7: 1, about 8: 1, about 9: 1, about 10: 1, about 20: 1, about 30: 1, about 40: 1, about 50: 1, about 60: 1. about 70: 1. about 80: 1, about 90: 1, about 100: 1, about 1 10: 1, about 120: 1, about 130: 1, about 140: 1, about 150: 1, about 160: 1, about 170:1, about 180: 1, about 190: 1, or about 200: 1. In some embodiments, the contacting is conducted at any mass ratio of liquid to zeolite of 4: 1.

[0051] In other aspects of step (ii). the contacting of the lithium cation-containing solution from step (i) with a proton-containing zeolite is conducted for any suitable amount of time. In some embodiments, the contacting takes place for a length of time of about 0.5 hr to about 24 hours, such as, for example, about 0.5 hr, about 1 hr, about 1.5 hr, about 2 hr, about2.5 hr, about 3 hr, about 3.5 hr, about 4 hr, about 4.5 hr, about 5 hr, about 5.5 hr, about 6 hr, about 6.5 hr, about 7 hr, about 7.5 hr, about 8 hr, about 8.5 hr, about 9 hr. about 9.5 hr. about 10 hr, about 10.5 hr, about 11 hr, about 11.5 hr, about 12 hr, about 12.5 hr, about 13 hr, about13.5 hr, about 14 hr, about 14.5 hr, about 15 hr, about 15.5 hr, about 16 hr, about 16.5 hr, about 17 hr, about 17.5 hr, about 18 hr, about 18.5 hr, about 19 hr, about 19.5 hr, about 20 hr, about 20.5 hr, about 21 hr, about 21.5 hr, about 22 hr. about 22.5 hr, about 23 hr. about 23.5 hr, or about 24 hr.

[0052] In some aspects of step (ii), the step results in a lithium cation-containing zeolite and proton-containing solution. In some aspects, the pH of the proton-containing solution has a pH of between about 2.9 and 1, such as, for example. 2.9, 2.8, 2.7, 2.6, 2.5, 2.4, 2.3, 2.2, 2.1, 2. 1.9, 1.8, 1.7, 1.6. 1.5, 1.4, 1.3. 1.2. 1.1, or 1.

[0053] In some embodiments, the pH of the proton-containing solution has a pH of between about 2.1.127861.000003

[0054] In some embodiments, the pH of the proton-containing solution has a pH of between about 2.2.

[0055] In some embodiments, the pH of the proton-containing solution has a pH of between about 2.6.

[0056] In some embodiments, the pH of the proton-containing solution has a pH of between about 2.7.

[0057] In some aspects of the methods of the disclosure, the proton-containing solution formed in step (ii) is used as the aqueous solution having a pH less than 3 in a subsequent performance of step (i).

[0058] In some aspects of the disclosed methods, step (ii) is operated under the conditions set forth in the Example below.Step (iii)

[0059] In some aspects, the methods comprise step (iii) contacting the lithium cation-containing zeolite from step (ii) with an aqueous solution of ammonium hydroxide, wherein the contacting results in exchange of the zeolite-bound lithium cations for the ammonium cations in solution, thereby producing ammonium cation-containing zeolite and lithium cation-containing solution.

[0060] In some aspects, the lithium cation-containing zeolite from step (ii) and the aqueous solution of ammonium hydroxide are contacted at a temperature in the range of about 0°C to about 80°C. such as, for example, at a temperature in the range of from 0°C, about 5°C, about 10°C, about 15°C, about 20°C, about 25°C, about 30°C, about 35°C, about 40°C, about 45°C, about 50°C, about 55°C, about 60°C, about 65°C, about 70°C, about 75°C, or about 80°C.

[0061] In some embodiments, the contacting is conducted at a temperature of about 25°C (z.e., at RT).

[0062] In other aspects of step (iii), the lithium cation-containing zeolite from step (ii) and the aqueous solution of ammonium hydroxide are contacted for any suitable amount of time. In some embodiments, the contacting takes place for a length of time of about 4 hr to about 48 hours, such as. for example, about 4 hr, about 8 hr, about 12 hr. about 16 hr, about 20 hr, about 24 hr, about 28 hr, about 32 hr, about 36 hr, about 40 hr, about 44 hr, or about 48 hr.127861.000003

[0063] In some aspects of step (iii), the solution of ammonium hydroxide has a concentration of from about 0. 1 wt% to about 30 wt% ammonia, such as, for example, about 0. 1 wt%, about 0.2 wt%. about 0.3 wt%, about 0.4 wt%, about 0.5 wt%, about 0.6 wt%, about 0.7 wt%, about 0.8 wt%, about 0.9 wt%, about 1 wt%, about 2 wt%, about 3 wt%, about 4 wt%, about 5 wt%, about 6 wt%, about 7 wt%, about 8 wt%, about 9 wt%, about 10 wt%, about 11 wt%, about 12 wt%, about 13 v %, about 14 wt%, about 15 wt%, about 16 wt%, about 17 wt%, about 18 wt%, about 19 wt%, about 20 wt%, about 21 wt%, about 22 wt%, about 23 wt%, about 24 wt%, about 25 wt%, about 26 wt%, about 27 wt%, about 28 wt%. about 29 wt%, or about 30 \\t% ammonia.

[0064] In some embodiments of step (iii), the solution of ammonium hydroxide has a concentration of 1 wt% ammonia.

[0065] In some aspects of step (iii), the amount of Li+extracted from the lithium cation-containing zeolite ranges from about 10 to about 300 pmol of Li7gram of zeolite, such as, for example, about 10, about 15, about 20, about 25, about 30, about 35, about 40, about 45, about 50, about 55, about 60, about 65, about 70, about 75, about 80, about 85, about 90, about 95. about 100, about 105, about 110, about 115. about 120, about 125, about 130, about 135, about 140, about 145, about 150, about 155, about 160, about 165, about 170, about 175, about 180, about 185, about 190, about 195, about 200, about 205, about 210, about 215, about 220, about 225, about 230, about 235, about 240, about 245, about 250, about 255, about 260, about 265, about 270, about 275, about 280, about 285, about 290, about 295. or about 300 pmol of Li / gram of zeolite.

[0066] In some aspects of step (iii), contacting the lithium cation-containing zeolite from step (ii) with the aqueous solution of ammonium hydroxide results in extraction of about 50% to about 100% of the Li+in the lithium cation-containing zeolite into the ammonium hydroxide solution, such as, for example, about 50%. about 55%, about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, about 90%, about 95%, or about 100%.

[0067] In some aspects of the disclosed methods, the lithium cation-containing solution produced in this step contains lithium hydroxide that can be collected or exposed to carbon dioxide to prepare lithium carbonate. In some embodiments, the lithium hydroxide is collected. In other embodiments, the lithium-cation containing solution is exposed to carbon dioxide to prepare lithium carbonate.127861.000003

[0068] In some aspects of the disclosed methods, step (iii) is operated under the conditions set forth in the Example below.Step (iv)

[0069] In some aspects, the methods comprise step (iv) heating the ammonium cation-containing zeolite from step (iii) to give off ammonia and thereby produce protoncontaining zeolite. Methods of desorption of gaseous ammonia from ammonium ion containing zeolites are known in the art. and include those set forth in S.B. Sharma, et al., “Characterization of catalyst acidity by microcalorimetry and temperature-programmed desorption,” Appl. Catal. A: General, 102 (1993) 253, which is incorporated by reference herein.Step (v)

[0070] In some aspects, the methods of the disclosure comprise step (v), capturing the ammonia produced in step (iv) into an aqueous solution to produce an aqueous solution of ammonium hydroxide. Methods of capturing desorbed ammonia into an aqueous solutions to produce aqueous solutions of ammonium hydroxide are known in the art.

[0071] In some embodiments, the ammonium hydroxide solution formed in step (v) is used in a subsequent performance of step (iii).Example

[0072] LMO materials were prepared experimentally via several standard methods. LMO i was synthesized by solid state reaction between LizCCh and M113O4 at a Li:Mn molar ratio of 0.5 at 850 °C under flowing air for 20 hours. LMO ii was synthesized by solid state reaction of Li2CO3 and M113O4 at a molar ratio of Li:Mn of 1.0 under a mixture of nitrogen and steam at 850 °C. LMO iii was synthesized by calcining LMO ii at 450 °C for 24 hours under flowing air.

[0073] Step (i): An aqueous solution containing an acid with a pH below 3 is contacted with a hthium-containing manganese oxide. The lithium in the solid is removed into solution by the uptake of protons, e.g.:[H++ Cl + excess H O| (liquid) + LixMnyO (solid) = [Li++ Cl' + excess HzO] (liquid) + HxMtiyO (solid)

[0074] The solution from this step can be used in step (ii).127861.000003

[0075] The removal of lithium from LMOs (solid-bound Li+and aqueous H+) was investigated by contacting them with a variety of HC1 solutions. The reaction conditions (HC1 concentration, liquid: solids ratio, time and temperature) were varied in a set of experiments shown in Table 1. After reaction the solid and liquid products were separated via filtration and the lithium concentrations in the liquid phases were quantified with a lithium selective ion probe. The amount of Li+extracted from the LMO solid w as then compared to the nominal amount of Li+introduced to the solid in synthesis.Table 1. LMO - acid extraction data

[0076] The near complete Li+extraction from the LMO materials at pHs equal to or less than 3 demonstrates that the cycle schematically represented in Figure 1 will operate if acidic streams with pHs lower than 3 can be produced by an IEX ion exchange process.

[0077] Step(ii): The aqueous solution containing the lithium ions is contacted with a proton form of a zeolite to exchange the Li+for H+:[Li++ Cl + excess H2O] (liquid) + H-IEX (solid) — [H++ O' + excess H2O] (liquid) + Li- IEX (solid)

[0078] The solution from this step can be used in step (i).

[0079] Several zeolite IEX materials were tested for the ion exchange of lithium salts to produce acidic streams. Experiments were performed by mixing each zeolite sample for 1 hour, with a 0.01 M LiCl solution, at a 4: 1 mass ratio of liquid to zeolite, at room temperature. Pretreatments w ere performed on several materials to ensure that all tested materials were present as the proton form of the IEX, e.g., calcination was performed at 450127861.000003°C in flowing air for 24 hours. HC1 pretreatment was accomplished by exposing the solid material to an excess of 0.1 M HC1 overnight at room temperature followed by filtration and rinsing. Post-mixing the liquid and solid phases were separated via centrifugation and the pH of the liquid measured (shown in Table 2).Table 2. Zeolite IEX ion exchange data for 0.01 M LiCl solutions

[0080] Each zeolite IEX tested yields chloride solutions with pHs below 3, demonstrating the applicability of these materials to produce sufficiently acidic liquid streams to be used in the extraction of Li+from LMO materials (step i).

[0081] Step(iii): The Li+containing zeolite is contacted with an ammonium hydroxide aqueous solution to ion exchange the Li+on the zeolite to NHL on the zeolite and releasing Li1into the aqueous solution:[NHL + OH' + excess H2O] (liquid) + Li-IEX (solid) = [Li++ OH' + excess H2O] (liquid) + NHi-IEX (solid)

[0082] The solution from this step contains lithium hydroxide that can be collected or exposed to carbon dioxide to prepare lithium carbonate.

[0083] To evaluate the ability of zeolite lEXs to exchange Li+for NHT from NH4OH solutions, H+form IEX materials were first exchanged with Li+by treatment with LiCl solutions at room temperatures followed by treatment in NH3 - H2O solutions to exchange this Li with NHL. LiCl treatments were performed in two different regimes. Tests w ere performed at low concentrations of LiCl (0.01 M) with small amounts of liquid relative to IEX solids (1 :4 or 1 :9 of a mass basis) and at high concentration LiCl (0. 1 M) with large amounts of liquids relative to IEX solids (1 :200 of a mass basis). In the high concentration127861.000003 cases, materials were then separated from the liquid phase via centrifugation and LiCl treatment was repeated twice. The pHs of the acidified liquid solutions were measured to establish the degree of ion exchange in this step (see Table 3). The lithium containing IEX materials were then mixed for at least 24 hours with 1 wt% NH3 - H2O solutions at room temperature. After mixing, the materials were removed from the mixed phase by settling and decanting and the lithium content of the decanted liquid phases were determined by measurement with a lithium-ion selective electrode. By quantifying both the H+(aq) produced via step ii and Li+(aq) produced via step iii the fraction of Li+adsorbed by the IEX materials which is then desorbed during NH4OH treatment was determined (Table 3). Table 3. Lithium containing IEX ion exchange data for 1 wt% NHsOH solutions

[0084] These results show that removing Li+from a zeolite IEX material via NH4OH treatment (step iii) is feasible. NH4+Li+exchange is observed for materials with both high (>200 timol / g) and low (<20 pmol / g) degrees of Li1exchange.

[0085] Steps (iv) and (v): There is a large literature base on the desorption of gaseous ammonia from ammonium ion containing zeolites. For example, see [7] for the ammonia desorption from a mordenite zeolite (see Fig. 2, which is a reproduction of Fig. 3 from [7]).

[0086] The evolved gaseous ammonia is then contacted with an aqueous solution: NH3(gas) + excess H2O (liquid) = [NH4++ OH + excess H2O] (liquid)127861.000003

[0087] NH3is highly soluble in aqueous solutions and its hydrolysis to form NH4OH is well established. This NH4OH solution can be used in step (iii).

Claims

127861.000003What is claimed:

1. A method for extracting lithium cations from lithium manganese oxides comprising the steps:(i) contacting a lithium cation-containing manganese oxide with an aqueous solution having a pH less than 3 to liberate the lithium cations into solution and thereby form a lithium cation-containing solution;(ii) contacting the lithium cation-containing solution from step (i) with a protoncontaining zeolite, wherein the contacting results in exchange of the zeolite-bound protons for the lithium cations in solution, thereby producing lithium cationcontaining zeolite and proton-containing solution;(iii) contacting the lithium cation-containing zeolite from step (ii) with an aqueous solution of ammonium hydroxide, wherein the contacting results in exchange of the zeolite-bound lithium cations for the ammonium cations in solution, thereby producing ammonium cation-containing zeolite and lithium cation-containing solution;(iv) heating the ammonium cation-containing zeolite from step (iii) to give off ammonia and thereby produce proton-containing zeolite; and(v) capturing the ammonia produced in step (iv) into an aqueous solution to produce an aqueous solution of ammonium hydroxide.

2. The method of claim 1, wherein the aqueous solution having a pH less than 3 has a pH of from about 1 to about 2.

3. The method of claim 1 or claim 2, wherein the aqueous solution having a pH less than 3 is an aqueous mineral acid solution.

4. The method of claim 3, wherein the aqueous solution having a pH less than 3 is an aqueous HC1 solution.

5. The method of claim 4, wherein the aqueous HC1 solution is 0.001M to 0.2 M HC1.

6. The method of any preceding claim, wherein step (i) is conducted at a temperature of from about 0°C to about 80°C.127861.0000037. The method of any preceding claim, wherein the contacting in step (i) is conducted for a length of time of about 0.5 hr to about 24 hours.

8. The method of any preceding claim, wherein step (i) results in extracting at least about 70% by weight of the Li+from the lithium cation-containing manganese oxide.

9. The method of any preceding claim, wherein the aqueous solution having a pH less than 3 used in step (i) is made from a proton-containing solution as produced in step (ii).

10. The method of any preceding claim, wherein the proton-containing zeolite has a MOR, MFI, or CHA framework.

11. The method of any preceding claim, wherein the proton-containing zeolite has a Si: Al molar ratio of from about 6 to about 12.

12. The method of any preceding claim, wherein step (ii) is conducted at a temperature of from about 0°C to about 80°C.

13. The method of any preceding claim, wherein the contacting in step (ii) is conducted for a length of time of about 0.5 hr to about 24 hours.

14. The method of any preceding claim, wherein the proton-containing zeolite used in step (ii) is produced as in step (iv).

15. The method of any preceding claim, wherein the solution of ammonium hydroxide used in step (iii) has a concentration of from about 0.1 wt% to about 30 wt% ammonia.

16. The method of any preceding claim, wherein step (iii) is conducted at a temperature of from about 0°C to about 80°C.

17. The method of any preceding claim, wherein the contacting in step (iii) is conducted for a length of time of about 0.5 hr to about 24 hours.

18. The method of any preceding claim, wherein step (iii) results in extraction of about 10 - 300 pmol of Li+ / gram of zeolite from the lithium cation-containing zeolite.127861.00000319. The method of any preceding claim, wherein step (iii) results in extraction of about 50% to about 100% of the Li+in the lithium cation-containing zeolite into the ammonium hydroxide solution.

20. The method of any preceding claim, wherein the aqueous solution of ammonium hydroxide used in step (iii) is produced as in step (v).

21. A process that employs the method of any preceding claim to recover lithium from a lithium-containing manganese oxide.

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