Method for purification of lithium containing brine

Abstract

Embodiments relate to methods and processes for purification of lithium containing brines by selectively separating boron containing compounds. The method includes passing a feed brine including lithium and at least one boron compound through at least one semi-permeable membrane in which the boron compounds are separated from the lithium by preferentially passing the boron compounds through the membrane stage(s). At least one environmental condition of the feed brine and / or membrane stage(s) may be modified to allow boron compounds to be preferentially passed through the membrane stage(s). The lithium-rich concentrate stream may be further purified and / or converted into lithium products, while the resultant boron-rich permeate stream (including the separated boron containing compounds) may be further processed.

Description

Atty. Ref. No.0036709-000242 METHOD FOR PURIFICATION OF LITHIUM CONTAINING BRINE CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] The present application claims priority to U.S. Provisional Patent Application No.63 / 620,373, filed on January 12, 2024. The entirety of this provisional patent application is incorporated by reference herein. FIELD

[0002] Embodiments relate to methods and processes for purification of lithium containing brines, specifically to methods and processes for purification of lithium containing brines by selectively separating boron containing compounds from the brines. BACKGROUND

[0003] The fundamental properties of lithium make it a widely used industrial material. Industrial uses of lithium include metal refinement, high strength / low weight metal alloy production, high temperature lubricants manufacturing, use as a coolant in nuclear power generating processes, air purification, glass and ceramic manufacturing, rocket propellant and pyrotechnics production, organometallic compound synthesis for applications in the fields of rubber, plastics, and medicines, use as a component in rechargeable and non-rechargeable batteries, etc. Due to its desirable properties, lithium has become a key component in electric vehicle (EV) batteries and is therefore a major element of the clean energy transition. High grade lithium production requires the removal of impurities, such as boron compounds, present in lithium containing fluids to produce a lithium quality suitable for use. It isAtty. Ref. No.0036709-000242 therefore important to effectively and efficiently separate impurities from the lithium containing fluids.

[0004] Existing approaches for removing impurities (e.g., boron compounds) from lithium containing fluids include ion exchange (see FIG.1), precipitation, and solvent extraction. The efficiencies of these approaches in removing impurities are impacted by the concentration of boron compounds and presence of other species in the lithium containing fluids. These approaches are also associated with high costs, including construction and operating costs, as well as potential loss or deterioration of lithium from the boron removal process.

[0005] In existing approaches utilizing lithium, the operating conditions of the membrane often lead to marginal removal of boron compounds, and such approaches do not adequately isolate boron compounds from lithium containing fluids. This can result in multiple or inefficient process steps in an effort to remove boron compounds. SUMMARY

[0006] We have therefore developed methods and processes for purification of lithium containing brines by selectively separating boron containing compounds. The method includes passing a feed brine including lithium and at least one boron compound through at least one semi-permeable membrane in which the boron compounds are separated from the lithium by preferentially passing the boron compounds through the membrane(s). At least one environmental condition of the feed brine and / or membrane(s) may be modified to allow boron compounds to be preferentially passed through the membrane(s). For example, differences in the selectivity of membranes as a function of at least one environmental condition (e.g.,Atty. Ref. No.0036709-000242 pH, oxidation / reduction potential (ORP), temperature, pressure, salinity or other concentration measurement, fluid velocity, percent recovery across the membrane stage, flux of the membrane stage, membrane voltage potential, etc.) to substantially remove boron from the brine. This may allow for the production of a lower volume, more concentrated boron-rich permeate stream while reducing potential dilution or other quality deterioration of the lithium containing fluid produced.

[0007] Additionally, the lithium-rich concentrate stream may be further purified and / or converted into lithium products, while the resultant boron-rich permeate stream (including the separated boron containing compounds) may be further processed.

[0008] In an exemplary embodiment, a method for separating at least one boron compound from a feed brine including lithium and the at least one boron compound includes directing the feed brine to an environmental modification unit, wherein the environmental modification unit is configured to produce a modified brine by modifying at least one environmental condition of the feed brine; directing the modified brine to a semi-permeable membrane unit, wherein the semi-permeable membrane unit is configured to separate the modified brine into a concentrate stream and a permeate stream, wherein the concentrate stream is a lithium-rich stream having a greater lithium to boron ratio than the feed brine, and wherein the permeate stream is a boron-rich stream having a lower lithium to boron ratio than the feed brine.

[0009] In some embodiments, the at least one environmental condition of the feed brine is selected from the group consisting of pH, temperature, oxidation reduction potential, salinity or other concentration measurement, and fluid velocity.Atty. Ref. No.0036709-000242

[0010] In some embodiments, the at least one environmental condition of the feed brine is pH.

[0011] In some embodiments, the pH of the feed brine is modified to between 6.0 and 8.0.

[0012] In some embodiments, the method further includes treating the concentrate stream to produce a treated concentrate stream having a greater lithium to boron ratio than the concentrate stream.

[0013] In some embodiments, treating the concentrate stream includes directing the concentrate stream to at least one treatment unit selected from the group consisting of an ion exchange unit, a chelation unit, a chemical precipitation unit, and a solvent extraction unit.

[0014] In some embodiments, the method further includes processing the concentrate stream to produce of a lithium containing product.

[0015] In some embodiments, the lithium containing product is selected from the group consisting of lithium carbonate, lithium hydroxide monohydrate, lithium sulfate monohydrate, and lithium chloride.

[0016] In some embodiments, the method further includes directing the permeate stream to a second semi-permeable membrane unit, wherein the second semi- permeable membrane unit is configured to separate the permeate stream into a second concentrate stream and a second permeate stream, wherein the second concentrate stream has a greater concentration of boron than the permeate stream, and wherein the second permeate stream has a lower concentration of boron than the permeate stream.Atty. Ref. No.0036709-000242

[0017] In some embodiments, the method further includes, prior to directing the permeate stream to a second membrane unit, directing the permeate stream to a second environmental modification unit, wherein the second environmental modification unit is configured to produce a modified permeate stream by modifying at least one environmental condition of the permeate stream.

[0018] In some embodiments, the at least one environmental condition of the permeate stream is pH.

[0019] In some embodiments, the semi-permeable membrane unit is configured to preferentially pass the at least one boron compound.

[0020] In some embodiments, the semi-permeable membrane unit includes one or more reverse osmosis membrane stage.

[0021] In an exemplary embodiment, a method for separating at least one boron compound from a feed brine comprising lithium and the at least one boron compound includes providing a semi-permeable membrane unit comprising one or more membrane stages; modifying at least one environmental characteristic of at least one membrane stage; directing the feed brine to the semi-permeable membrane unit, wherein the semi-permeable membrane unit is configured to separate the modified brine into a concentrate stream and a permeate stream, wherein the concentrate stream is a lithium-rich stream having a greater lithium to boron ratio than the feed brine, and wherein the permeate stream is a boron-rich stream having a lower lithium to boron ratio than the feed brine.

[0022] In some embodiments, the at least one environmental characteristic of the membrane stage is selected from the group consisting of a pressure applied at theAtty. Ref. No.0036709-000242 membrane stage, a surface potential of the membrane stage, percent recovery across the membrane stage, and flux of the membrane stage.

[0023] In some embodiments, the method further includes treating the concentrate stream to produce a treated concentrate stream having a greater lithium to boron ratio than the concentrate stream.

[0024] In some embodiments, treating the concentrate stream includes directing the concentrate stream to at least one treatment unit selected from the group consisting of an ion exchange unit, a chelation unit, a chemical precipitation unit, and a solvent extraction unit.

[0025] In some embodiments, the method further includes processing the concentrate stream to produce of a lithium containing product.

[0026] In some embodiments, the lithium containing product is selected from the group consisting of lithium carbonate, lithium hydroxide monohydrate, lithium sulfate monohydrate, and lithium chloride.

[0027] In some embodiments, the semi-permeable membrane unit is configured to preferentially pass the at least one boron compound.

[0028] In some embodiments, the semi-permeable membrane unit includes one or more reverse osmosis membrane stage.

[0029] In some embodiments, the method further includes directing the permeate stream to a second semi-permeable membrane unit, wherein the second semi- permeable membrane unit is configured to separate the permeate stream into a second concentrate stream and a second permeate stream, wherein the second concentrate stream has a greater concentration of boron than the permeate stream,Atty. Ref. No.0036709-000242 and wherein the permeate stream has a lower concentration of boron than the permeate stream.

[0030] Further features, aspects, objects, advantages, and possible applications of the present invention will become apparent from a study of the exemplary embodiments and examples described below, in combination with the Figures, and the appended claims. BRIEF DESCRIPTION OF THE FIGURES

[0031] The above and other objects, aspects, features, advantages, and possible applications of the present invention will be more apparent from the following more particular description thereof, presented in conjunction with the following drawings. It should be understood that like reference numbers used in the drawings may identify like components.

[0032] FIG.1 is a flow diagram of a conventional method for removing boron from a lithium containing brine.

[0033] FIG.2 is a flow diagram of an exemplary method for purifying a lithium containing brine.

[0034] FIG.3 is a flow diagram of an exemplary method for further processing a boron-rich permeate stream produced from a semi-permeable membrane. DETAILED DESCRIPTION OF THE INVENTION

[0035] The following description is of exemplary embodiments presently contemplated for carrying out the present invention. This description is not to be taken in a limiting sense but is made merely for the purpose of describing theAtty. Ref. No.0036709-000242 general principles and features of the present invention. The scope of the present invention should be determined with reference to the claims.

[0036] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the subject matter disclosed herein belongs. Although any methods, devices, and materials similar or equivalent to those described herein can be used in the practice or testing of the presently disclosed subject matter, representative methods, devices, and materials are described herein.

[0037] All references to singular characteristics or limitations of the present disclosure shall include the corresponding plural characteristic(s) or limitation(s) and vice versa, unless otherwise specified or clearly implied to the contrary by the context in which the reference is made.

[0038] As used herein (when used in this application, including the claims), the terms “a,” “an,” and “the” refer to “one or more.” The use of the word “a” or “an” when used in conjunction with the term “comprising” in the claims and / or the specification may mean “one,” but it is also consistent with the meaning of “one or more,” “at least one,” and “one or more than one.”

[0039] All combinations of method or process steps as used herein can be performed in any order, unless otherwise specified or clearly implied to the contrary by the context in which the referenced combination is made.

[0040] Embodiments relate to methods and processes for purification of lithium containing brines. Referring to FIG.2, a feed brine 10 includes lithium and at least one boron containing compound. The feed brine 10 may further include additional components or contaminants, such as but not limited to other dissolved salts (e.g.,Atty. Ref. No.0036709-000242 sodium chloride, calcium chloride, etc.). The feed brine 10 may be directed to semi- permeable membrane unit 200, which is configured to separate brine into a permeate stream 210 and a concentrate (reject) stream 230. The permeate stream 210 may be a boron-rich stream and the concentrate stream 210 may be a lithium- rich stream. For example, the concentrate stream 230 may have a greater lithium to boron ratio (concentration of Li to concentration of B) than the feed brine 10, and the permeate stream 210 may have a lower lithium to boron ratio than the feed brine 10.

[0041] The purpose of the semi-permeable membrane unit 200 is to reduce the volume of a lithium-containing fluid and thereby increase the fluid’s lithium concentration, which may advantageously enable the efficient production of high quality lithium in downstream processing. The semi-permeable membrane unit 200 may therefore include one or more membrane stages configured to preferentially pass boron compounds, thus resulting in the boron-rich permeate stream 210 being passed through the membrane stage(s) and the lithium-rich concentrate stream 230 being rejected by the membrane stage(s). While the vast majority of the lithium may be rejected by the membrane stage(s) and remain in the concentrate stream 230, it is contemplated that a small / minor amount of lithium may pass through the membrane stage(s) into the permeate stream 210. The membrane stage(s) may further reject other dissolved salts (e.g., sodium chloride, calcium chloride, etc.) into the concentrate stream 230. The permeate stream 210 may therefore include low amounts of lithium and dissolved salts and a significant amount (e.g., half or more) of the boron compounds.

[0042] The membrane stage(s) of the semi-permeable membrane unit 200 may be reverse osmosis membranes or any other suitable semi-permeable membranes.Atty. Ref. No.0036709-000242

[0043] As used herein, the term “membrane stage” refers to a membrane unit configured to allow for the selective passage of certain substances while rejecting ither substances. More than one membrane stage may work together (e.g., in series), and in such embodiments, the concentrate (reject) stream of a previous stage may serve as a feed for a subsequent stage.

[0044] In exemplary embodiments, environmental modifications may be utilized to provide more favorable conditions for boron separation at the semi-permeable membrane unit 200. In one embodiment, the feed brine 10 may be modified via an environmental modification unit 100 positioned upstream of the semi-permeable membrane unit 200. The environmental modification unit 100 may be configured to produce a modified brine 110 by modifying at least one environmental condition of the feed brine 10. The environmental condition may be selected from the group consisting of pH of the brine, temperature of the brine, oxidation reduction potential (ORP) of the brine, salinity or other concentration measurement of the brine, fluid velocity of the brine, and / or mixtures thereof. An environmental modifier 20 may be added to the feed brine 10 to effectuate modification of the environmental condition.

[0045] In some embodiments, the environmental modifier 20 may be an acid or caustic configured to modify the pH of the brine. For example, the pH may be adjusted to acidic or near neutral conditions (e.g., pH between 6.0 and 8.0) so that the boron compounds may be substantially separated into the permeate stream 210. A modified pH may also have other benefits, such as consistent and reliable operation of the membrane(s) such that formation of scaling compounds may be avoided.Atty. Ref. No.0036709-000242

[0046] In some embodiments, the environmental modification unit 100 may be configured to heat the brine to a predetermined temperature. The predetermined temperature may be a temperature favorable for boron separation.

[0047] In some embodiments, the environmental modification unit 100 may be configured to modify the ORP of the brine. The ORP may be modified by introducing an reducing agent as an environmental modifier 20, modifying pH of the brine, and / or modifying temperature of the brine, or any other suitable technique that may be used to modify the ORP of the brine.

[0048] In some embodiments, the environmental modifier 20 may be a salt or other compound configured to modify the salinity or other concentration measurement of the brine.

[0049] In another embodiment, at least one environmental characteristic of one or more membrane stage(s) of the semi-permeable membrane unit 200 may be modified to provide more favorable conditions for boron separation. The environmental characteristic may be selected from the group consisting of a pressure applied at the membrane stage(s), a surface potential of the membrane stage(s), percent recovery across the membrane stage(s), and flux of the membrane stage(s). For example, the pressure applied at the membrane stage(s) may be a predetermined pressure favorable for boron separation, and / or the surface potential of the membrane stage(s) may be a predetermined surface potential favorable for boron separation.

[0050] In some embodiments, the percent recovery across the membrane stage(s) may be a predetermined percent recovery favorable for boron separation. In someAtty. Ref. No.0036709-000242 embodiments, the operating flux of the membrane stage(s) may be a predetermined flux favorable to membrane separation.

[0051] The lithium-rich concentrate stream 230 may be directed to a treatment unit 300, which is configured to treat and / or refine the concentrate stream 230 to produce a treated concentrate stream having a greater lithium to boron ratio than the concentrate stream. The treatment unit 300 may include an ion exchange unit, a chelation unit, a chemical precipitation unit, a solvent extraction unit, and / or mixtures thereof. The lithium-rich concentrate stream 230 and / or the treated concentrate stream may be processed downstream to produce of a lithium containing product, including but not limited to lithium carbonate, lithium hydroxide monohydrate, lithium sulfate monohydrate, and / or lithium chloride.

[0052] The boron-rich permeate stream 210 may be directed to a second semi- permeable membrane unit 500 (e.g., a second pass configured to receive the permeate stream of the first semi-permeable unit 200, or first pass), which is configured to separate streams into a second permeate stream 510 and a concentrate (reject) stream 520. The second semi-permeable membrane unit 500 may be configured to reject boron compounds such that the permeate stream 510 may include low amounts of boron, and low amounts of lithium and other dissolved salts.

[0053] The second semi-permeable membrane unit 500 may therefore include one or more membrane stage(s) configured to preferentially reject boron compounds, thus resulting in a boron-light permeate stream 510 being passed through the membrane stage(s) and a boron-rich concentrate stream 520 being rejected by the membrane stage(s). The membrane stage(s) of the second semi-permeable membrane unit 500Atty. Ref. No.0036709-000242 may be reverse osmosis membranes or any other suitable semi-permeable membranes.

[0054] In exemplary embodiments, environmental modifications may be utilized to provide more favorable conditions for boron separation at the second semi- permeable membrane unit 500. In one embodiment, the permeate stream 210 may be modified via an environmental modification unit 400 positioned upstream of the second semi-permeable membrane unit 500. The environmental modification unit 400 may be configured to produce a modified permeate stream 410 by modifying at least one environmental condition of the permeate stream 210. The environmental condition may be selected from the group consisting of pH of the stream, temperature of the stream, fluid velocity of the stream, and / or mixtures thereof. An environmental modifier 220 may be added to the permeate stream 210 to effectuate modification of the environmental condition.

[0055] In some embodiments, the environmental modifier 220 may be an acid or caustic configured to modify the pH of the stream. For example, the pH may be increased so that the boron compounds may be substantially separated into the concentrate stream 520. It is contemplated that the low salt concentration of the permeate stream 210 allows pH to be increased without significant risk of scaling at the second semi-permeable membrane unit 500.

[0056] In some embodiments, the environmental modification unit 400 may be configured to heat the stream to a predetermined temperature. The predetermined temperature may be a temperature favorable for boron rejection.

[0057] In another embodiment, at least one environmental characteristic of one or more membrane stage(s) of the second semi-permeable membrane unit 500 may beAtty. Ref. No.0036709-000242 modified to provide more favorable conditions for boron rejection. The environmental characteristic may be selected from the group consisting of a pressure applied at the membrane stage(s), a surface potential of the membrane stage(s), percent recovery across the membrane stage(s), and flux of the membrane stage(s). For example, the pressure applied at the membrane stage(s) may be a predetermined pressure favorable for boron rejection, and / or the surface potential of the membrane stage(s) may be a predetermined surface potential favorable for boron rejection.

[0058] In some embodiments, the percent recovery across the membrane stage(s) may be a predetermined percent recovery favorable for boron separation. In some embodiments, the operating flux of the membrane stage(s) may be a predetermined flux favorable to membrane separation.

[0059] The boron-rich concentrate stream 520 may be directed to a polishing unit 700, which is configured to remove scale forming constituents from the stream. The polishing unit 700 may include an ion exchange unit, a chemical precipitation unit, and / or mixtures thereof. This may enable the maximization of the recovery of a low salinity permeate to 95% or higher and thus reduce the volume of the boron-rich concentrate stream 520 significantly. This may allow a boron-rich reject stream to be recycled to an upstream lithium extraction process, to be disposed via well injection, etc. In some embodiments, the polishing unit 700 may be followed by one or more filtration steps.

[0060] The boron-light permeate stream 510 may include low amounts of boron, and low amounts of lithium and other dissolved salts. This may allow the stream to be recycled and may enable increased water recovery (e.g., via recovery / or recycling unit 600).Atty. Ref. No.0036709-000242 EXAMPLES

[0061] Below are examples of specific embodiments for carrying out the present application. The examples are offered for illustrative purposes only and are not intended to limit the scope of the present application in any way. Efforts have been made to ensure accuracy with respect to numbers used (e.g., amounts, temperatures, etc.), but some experimental error and deviation should, of course, be allowed for.

[0062] Example 1: Consider a prophetic example of an embodiment in which a system includes: a Primary Reverse Osmosis (RO) Unit, an Environmental Modification Unit, and a Second Reverse Osmosis (RO) Unit.

[0063] The lithium containing brine has a flow rate of 272,520 kg / hr and the following composition: Table 1: Feed Brine QualityAtty. Ref. No.0036709-000242

[0064] Hydrochloric acid is introduced to the stream as an environmental modifier to reduce the brine pH from 8.5 to 6.8. This brine is treated through RO at the pH of 6.8. Recovery of 92% is considered across this RO unit. A specific combination of reverse osmosis membranes is used in this unit. The feed boron mass flow is 40.88 kg / hr so the boron in permeate is 30.38 kg / hr while 10.50 kg / hr is in the reject (concentrate) stream. About 74% of the feed boron is separated by passing to the permeate and 26% is rejected by the membranes and remains with the lithium concentrate. Table 2: Primary RO Feed, Reject & Permeate Water QualityAtty. Ref. No.0036709-000242

[0065] Caustic is added to increase the Primary RO permeate pH to 9.5, and the pH adjusted permeate is then treated through a Second Pass RO unit.93% recovery is achieved across this RO unit. Approximately 87% of the feed boron is rejected while 13% passes in the permeate. The Second Pass RO feed boron mass flow is 30.38 kg / hr so the boron in permeate is 4.06 kg / hr while 26.32 kg / hr is in the reject stream. Table 3: Second Pass 1st Stage RO Feed, Reject & Permeate Water QualityAtty. Ref. No.0036709-000242

[0066] The reject from this 2nd Pass RO is treated through an ion exchanger softener for hardness removal and treated through another RO to minimize the reject flow.81.6% recovery is considered across this RO unit. Approximately 93% of the feed boron is rejected while 7% passes in the permeate. The feed boron mass flow is ~26.32 kg / hr so the boron in permeate is 1.72 kg / hr while 24.6 kg / hr is in the reject stream. Table 4: Second Pass 2nd Stage RO Feed, Reject & Permeate Water Quality

[0067] The permeate from this RO is blended with the Second Pass RO permeate. Thus the 17579 kg / hr of 2nd Pass RO reject is reduced to 3233.5 kg / hr resulting in an improved water recovery.Atty. Ref. No.0036709-000242

[0068] Example 2: A pilot study was conducted in which the system included a Brackish Water Reverse Osmosis (BWRO) System and Second Pass Sea Water Reverse Osmosis (SWRO) System to validate the claims. The lithium containing brine with the following composition was processed through the pilot skid. Table 5: Pilot System Feed Water Quality

[0069] The brine was treated through the BWRO pilot unit at the pH of 6.5. The pilot skid consisted of three 28 ft2BWRO membrane elements in series. The concentrate was recycled to the feed until a recovery of 80% was reached. The feed contained approximately 0.42 kg of boron. About 71% of the feed boron was separated byAtty. Ref. No.0036709-000242 passing to the permeate and 29% was rejected by the membranes. This corresponds to 0.31 kg boron in the permeate and 0.12 kg boron that remained with the lithium concentrate. Table 6: Pilot BWRO Reject & Permeate Water Quality

[0070] Caustic was added as an environmental modifier to increase the BWRO permeate to a pH of 9.6. The modified permeate was then processed through a Second Pass RO unit. The concentrate was recycled until 95% recovery was reached. The Second Pass RO utilized the same pilot skid setup as BWRO but with SWRO membranes. The Second Pass RO feed began with approximately 0.31 kg ofAtty. Ref. No.0036709-000242 boron. Of the feed to the Second Pass RO, 0.25 kg of boron was rejected while 0.06 kg of boron was in the permeate. This corresponds to 81% of the inlet boron being rejected into the concentrate stream and 19% passing through to the permeate. Table 7: Pilot Second Pass RO Feed, Reject & Permeate Water Quality

[0071] The pilot values were compared to projected values for the same system to ensure operation matched expectations. Pilot values closely aligned with the projections and support the claim of boron reduction through environmental modification.Atty. Ref. No.0036709-000242 Table 8: Boron Pilot Mass and Concentration vs. RO Program Projected ValuesTable 9: Pilot vs. RO Program Projected Boron Rejection

[0072] Example 3: Consider a comparison between the inventive process and the conventional treatment method in terms of the amount of chemical required for regeneration of resin in the boron-removal ion exchange. In the first column, the conventional treatment method treats the full boron load in the lithium containing brine. In the invented art, the boron load is substantially reduced prior to treatment with the boron-removal ion exchange. [Boron IX in the Feed of lithium containing brine having composition as per Table 1 Vs. Boron IX in Primary RO Reject having composition as per Table 2].Atty. Ref. No.0036709-000242 Table 10 Comparison of Prior Art vs. Invented Art

[0073] Based on the above data, HCl consumption in case of the conventional method is 3 times the chemical consumption in case of the invented art. NaOH consumption in case of the conventional method is 1.8 times the chemical consumption in case of the invented art. The regeneration waste produced in the case of the conventional method is feed is 3.7 times more than in case of theAtty. Ref. No.0036709-000242 invented art. Thus, by substantially reducing the mass of boron in the lithium stream using the invented art, the downstream boron impurity removal step of ion exchange is completed in a much more efficient manner, with much lower chemical consumptions and less wastewater generated.

[0074] It should be understood that the disclosure of a range of values is a disclosure of every numerical value within that range, including the end points. It should also be appreciated that some components, features, and / or configurations may be described in connection with only one particular embodiment, but these same components, features, and / or configurations can be applied or used with many other embodiments and should be considered applicable to the other embodiments, unless stated otherwise or unless such a component, feature, and / or configuration is technically impossible to use with the other embodiment. Thus, the components, features, and / or configurations of the various embodiments can be combined together in any manner and such combinations are expressly contemplated and disclosed by this statement.

[0075] It will be apparent to those skilled in the art that numerous modifications and variations of the described examples and embodiments are possible considering the above teachings of the disclosure. The disclosed examples and embodiments are presented for purposes of illustration only. Other alternate embodiments may include some or all of the features disclosed herein. Therefore, it is the intent to cover all such modifications and alternate embodiments as may come within the true scope of this invention, which is to be given the full breadth thereof.

[0076] It should be understood that modifications to the embodiments disclosed herein can be made to meet a particular set of design criteria. Therefore, whileAtty. Ref. No.0036709-000242 certain exemplary embodiments of the apparatus and methods of using and making the same disclosed herein have been discussed and illustrated, it is to be distinctly understood that the invention is not limited thereto but may be otherwise variously embodied and practiced within the scope of the following claims.

Claims

Atty. Ref. No.0036709-000242 WHAT IS CLAIMED IS:

1. A method for separating at least one boron compound from a feed brine comprising lithium and the at least one boron compound, the method comprising: directing the feed brine to an environmental modification unit, wherein the environmental modification unit is configured to produce a modified brine by modifying at least one environmental condition of the feed brine; directing the modified brine to a semi-permeable membrane unit, wherein the semi-permeable membrane unit is configured to separate the modified brine into a concentrate stream and a permeate stream, wherein the concentrate stream is a lithium-rich stream having a greater lithium to boron ratio than the feed brine, and wherein the permeate stream is a boron-rich stream having a lower lithium to boron ratio than the feed brine.

2. The method of claim 1, wherein the at least one environmental condition of the feed brine is selected from the group consisting of pH, temperature, oxidation reduction potential, salinity or other concentration measurement, and fluid velocity.

3. The method of claim 2, wherein the at least one environmental condition of the feed brine is pH.

4. The method of claim 3, wherein the pH of the feed brine is modified to between 6.0 and 8.0.Atty. Ref. No.0036709-000242 5. The method of claim 1, further comprising: treating the concentrate stream to produce a treated concentrate stream having a greater lithium to boron ratio than the concentrate stream.

6. The method of claim 5, wherein treating the concentrate stream comprises directing the concentrate stream to at least one treatment unit selected from the group consisting of an ion exchange unit, a chelation unit, a chemical precipitation unit, and a solvent extraction unit.

7. The method of claim 1, further comprising: processing the concentrate stream to produce of a lithium containing product.

8. The method of claim 7, wherein the lithium containing product is selected from the group consisting of lithium carbonate, lithium hydroxide monohydrate, lithium sulfate monohydrate, and lithium chloride.

9. The method of claim 1, further comprising: directing the permeate stream to a second semi-permeable membrane unit, wherein the second semi-permeable membrane unit is configured to separate the permeate stream into a second concentrate stream and a second permeate stream, wherein the second concentrate stream has a greater concentration of boron than the permeate stream, andAtty. Ref. No.0036709-000242 wherein the second permeate stream has a lower concentration of boron than the permeate stream.

10. The method of claim 9, further comprising, prior to directing the permeate stream to a second membrane unit: directing the permeate stream to a second environmental modification unit, wherein the second environmental modification unit is configured to produce a modified permeate stream by modifying at least one environmental condition of the permeate stream.

11. The method of claim 10, wherein the at least one environmental condition of the permeate stream is pH.

12. The method of claim 1, wherein the semi-permeable membrane unit is configured to preferentially pass the at least one boron compound.

13. The method of claim 1, wherein the semi-permeable membrane unit comprises one or more reverse osmosis membrane stage.

14. A method for separating at least one boron compound from a feed brine comprising lithium and the at least one boron compound, the method comprising: providing a semi-permeable membrane unit comprising one or more membrane stages;Atty. Ref. No.0036709-000242 modifying at least one environmental characteristic of at least one membrane stage; directing the feed brine to the semi-permeable membrane unit, wherein the semi-permeable membrane unit is configured to separate the modified brine into a concentrate stream and a permeate stream, wherein the concentrate stream is a lithium-rich stream having a greater lithium to boron ratio than the feed brine, and wherein the permeate stream is a boron-rich stream having a lower lithium to boron ratio than the feed brine.

15. The method of claim 14, wherein the at least one environmental characteristic of the membrane stage is selected from the group consisting of a pressure applied at the membrane stage, a surface potential of the membrane stage, percent recovery across the membrane stage, and flux of the membrane stage.

16. The method of claim 14, further comprising: treating the concentrate stream to produce a treated concentrate stream having a greater lithium to boron ratio than the concentrate stream.

17. The method of claim 16, wherein treating the concentrate stream comprises directing the concentrate stream to at least one treatment unit selected from the group consisting of an ion exchange unit, a chelation unit, a chemical precipitation unit, and a solvent extraction unit.Atty. Ref. No.0036709-000242 18. The method of claim 14, further comprising: processing the concentrate stream to produce of a lithium containing product.

19. The method of claim 18, wherein the lithium containing product is selected from the group consisting of lithium carbonate, lithium hydroxide monohydrate, lithium sulfate monohydrate, and lithium chloride.

20. The method of claim 14, wherein the semi-permeable membrane unit is configured to preferentially pass the at least one boron compound.

21. The method of claim 14, wherein the semi-permeable membrane unit comprises one or more reverse osmosis membrane stage.

22. The method of claim 14, further comprising: directing the permeate stream to a second semi-permeable membrane unit, wherein the second semi-permeable membrane unit is configured to separate the permeate stream into a second concentrate stream and a second permeate stream, wherein the second concentrate stream has a greater concentration of boron than the permeate stream, and wherein the permeate stream has a lower concentration of boron than the permeate stream.

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