DETAILED ACTION
Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Election Acknowledged
Applicant’s election without traverse of Group I, claims 1-16, in the reply filed on 04/15/2026 is acknowledged.
Status of Claims
Claims 1-17 are pending. Of the pending claims, claims 1-16 are presented for examination on the merits. Claim 17 is withdrawn from further consideration pursuant to 37 CFR 1.142(b) as being drawn to a nonelected invention, there being no allowable generic or linking claim.
Priority
Receipt is acknowledged of certified copies of papers required by 37 CFR 1.55.
Information Disclosure Statement
Four (4) information disclosure statement(s) (IDS) were submitted on 06/19/2024, 01/07/2025, 07/14/2025, and 12/16/2025. The submissions are in compliance with the provisions of 37 CFR 1.97. Accordingly, the IDS are being considered by the examiner.
Claim Rejections - 35 USC § 112
The following is a quotation of 35 U.S.C. 112(b):
(b) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention.
The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph:
The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention.
Claims 1-16 are rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor (or for applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention.
Regarding claim 1, the term “replacing” is indefinite for lack of clarity and lack of consistency with the specification. See MPEP § 2173.03. Specifically, the plain meaning of the term “replacing” is taking the place of, i.e., a substitution. It follows that the claim appears to recite that the lithium adsorbent is replaced with an alkaline high-lithium low-impurity solution and the lithium adsorbent is removed, deleted, or set aside from the process. However, a replacement or substitution is inconsistent with the remainder of the claim, which implies the continued existence and presence of the lithium adsorbent in the process due to the desorption step using acid solution to retrieve lithium ions. Additionally, the examples describe the replacement zone as the flowing of high-lithium low-impurity solution through columns (e.g., instant specification at p. 7 – lines 33-39). Thus, the lack of precision and clarity of the term renders the claim indefinite.
Further regarding claim 1, the term “higher” in the phrase “higher lithium content” is indefinite because it is a relative term without a direct comparison. The claim does not recite what (solution) is being compared to the high-lithium salt solution. Therefore, the scope of the claim cannot be determined.
Regarding claims 2-16, the claims are likewise rejected, as they dependent directly or indirectly on rejected claim 1.
Further regarding claim 3, the claim is indefinite because the scope is ambiguous. The phrase “can be” raises questions as to whether the subsequent limitation is mandatory, i.e., the high-lithium salt solution must be electrolyzed, or whether such limitation is optional, i.e., the high-lithium salt solution may be electrolyzed but is not required to be. Because the scope cannot be readily determined, the claim lacks definiteness.
Further regarding claims 4-6, the phrase “resin provided by a patent CN108421539A” renders the claim indefinite because the scope of the claim cannot be ascertained. Reference to a patent document by identification number is non-standard language for setting forth claim limitations. Given the amount of information in a patent document, one of ordinary skill in the art would not be able to evaluate what portion of the patent document is relevant to defining the boundary of the claimed resin, causing confusion regarding the scope of the claim.
Further regarding claim 5, the term “special” renders the claim indefinite because it is a subjective relative term. The specification provides no objective standard for measuring what makes the functional group “special,” and one of ordinary skill in the art would not be aware which functional groups qualify as special and which ones are considered non-special groups. See MPEP § 2173.05(b)(IV).
Further regarding claim 5, the term “stable” is a relative term which renders the claim indefinite. The term “stable” is not defined by the claim, the specification does not provide a standard for ascertaining the requisite degree, and one of ordinary skill in the art would not be reasonably apprised of the scope of the invention. Without an objective metric or definition, one of ordinary skill in the art would not understand which resins are stable and which ones qualify as unstable. See MPEP § 2173.05(b)(I).
Further regarding claim 7, the claim is indefinite for being dependent on claim 5, which recites the indefinite phrase “resin provided by a patent CN108421539A,” as noted above.
Further regarding claim 7, the phrase "such as" renders the claim indefinite because it is unclear whether the limitations following the phrase are part of the claimed invention. This leads to confusion because it is unclear whether the resins listed following the phrase “such as” are intended to be a required part of the scope of the claim or whether said resins serve merely as optional examples. See MPEP § 2173.05(d).
Further regarding claim 7, the claim is indefinite because the scope is ambiguous. The phrase “can be used” and “can selectively adsorb” raise questions as to whether the aforementioned resins are part of the scope of the claim and the resins must selectively adsorb lithium ions resulting in separation of lithium from sodium in an alkaline environment or whether such resins and selective adsorption behavior are optional. Because the scope cannot be readily determined, the claim lacks definiteness.
Further regarding claim 8, the claim is indefinite because the scope is ambiguous. The phrase “can also be” could mean that the adsorbent of claim 8 replaces the resin of claim 4 or that the adsorbent of claim 8 is present with (an addition to) the resin of claim 4. Furthermore, the phrase “can also be” raises questions as to whether the adsorbent provided by patent CN102631897B is part of the scope of the claim (mandatory) or whether such adsorbent is optional. Because the scope cannot be readily determined, the claim lacks definiteness.
Further regarding claim 8, the phrase “an adsorbent provided by a patent CN102631897B” renders the claim indefinite because the scope of the claim cannot be ascertained. Reference to a patent document by identification number is non-standard language for setting forth claim limitations. Given the amount of information in a patent document, one of ordinary skill in the art would not be able to evaluate what portion of the patent document is relevant to defining the boundary of the claimed adsorbent, causing confusion regarding the scope of the claim.
Further regarding claim 8, the phrase "especially" renders the claim indefinite because it is unclear whether the limitations following the phrase are part of the claimed invention. This leads to confusion because it is unclear whether the lithium adsorbent prepared from an ionic sieve type lithium adsorbent precursor following the phrase “especially” is intended to be a required part of the scope of the claim or whether said precursor serves merely as an optional example. See MPEP § 2173.05(d).
Further regarding claim 8, the term “type” in the phrase “an ionic sieve type lithium adsorbent precursor” renders the claim indefinite because the term is appended to an otherwise definite expression, and it is unclear to what extent the scope of the phrase is extended. In other words, one would not be apprised of which ionic sieve lithium adsorbents would qualify as an ionic sieve type and which ones would not. See MPEP § 2173.05(b)(III)(E).
Further regarding claim 8, the claim is dependent on rejected claim 4 and is likewise rejected for those reasons presented above.
Further regarding claim 9, the term “type” in the phrase “an ionic sieve type lithium adsorbent” renders the claim indefinite because the term is appended to an otherwise definite expression, and it is unclear to what extent the scope of the phrase is extended. In other words, one would not be apprised of which ionic sieve lithium adsorbents would qualify as an ionic sieve type and which ones would not. See MPEP § 2173.05(b)(III)(E).
Further regarding claim 9, the phrase “using a method provided by the patent CN102631897B” renders the claim indefinite because the scope of the claim cannot be ascertained. Reference to a patent document by identification number is non-standard language for setting forth claim limitations. Given the amount of information in a patent document, one of ordinary skill in the art would not be able to evaluate what portion of the patent document is relevant to defining the method, causing confusion regarding the scope of the claim.
Further regarding claim 9, the claim is dependent on rejected claims 4 and 8 and is likewise rejected for those reasons presented above.
Further regarding claim 11, the claim is indefinite because the scope is ambiguous. The phrase “can reach” raises questions as to whether the subsequent limitation is mandatory, i.e., the lithium concentration in the desorption solution must reach 5 g/L or above, 10 g/L or above, 25 g/L above, or whether such limitation is optional. Because the scope cannot be readily determined, the claim lacks definiteness.
Further regarding claim 11, the claim is indefinite because the scope is ambiguous. The term “when” in the phrases “when the acid concentration reaches [XX value]” raises questions as to whether the subsequent limitation is mandatory, i.e., the acid concentration must become 2-3 mol/L and greater than 3 mol/L, or whether such limitation is optional. Because the scope cannot be readily determined, the claim lacks definiteness.
Further regarding claim 11, a broad range or limitation together with a narrow range or limitation that falls within the broad range or limitation (in the same claim) may be considered indefinite if the resulting claim does not clearly set forth the metes and bounds of the patent protection desired. See MPEP § 2173.05(c). In the present instance, the claim recites the broad recitation “10 g/L or above” and the claim also recites “even 15 g/L or above,” which is the narrower statement of the range/limitation. The claim is considered indefinite because there is a question or doubt as to whether the feature introduced by such narrower language is (a) merely exemplary of the remainder of the claim, and therefore not required, or (b) a required feature of the claims. The term “even” also introduces the same ambiguity because it is unclear whether this is exemplary or merely a preferred concentration.
Further regarding claim 14, the claim is indefinite for lack of clarity. The claim refers to a bipolar membrane as a device that provides an acid and an alkaline high-lithium low-impurity solution for a system. However, the claim does not specify how (or even if) the device is used with the method of claim 1. Additionally, the claim refers to a “a system” without any nexus to a system in the context of the method of claim 1.
Further regarding claim 15, the claim is indefinite for lack of clarity. Step (2) recites that resin or adsorbent are saturated via adsorption. However, step (1) and claim 1 recite that the adsorbent is the entity that adsorbs the lithium ions, not a resin. Additionally, by referring to the resin and adsorbent separately, the claim implies that the adsorbent cannot be a resin, which contradicts claim 4, for example.
Further regarding claim 15, the phrase "such as" renders the claim indefinite because it is unclear whether the limitations following the phrase are part of the claimed invention. This leads to confusion because it is unclear whether the sodium ions and potassium ions listed following the phrase “such as” are intended to be a required part of the scope of the claim (i.e., sodium and potassium are required impurities) or whether said ions serve merely as optional examples. See MPEP § 2173.05(d).
Further regarding claim 15, the claim is indefinite because the scope is ambiguous. The phrase “can be” raises questions as to whether the subsequent limitation is mandatory, i.e., sodium hydroxide and potassium hydroxide are returned and lithium ion concentration are 0.1-20 g/L, or whether such limitations are optional, i.e., the hydroxides may be returned and lithium ion concentration may be 0.1-20 g/L but neither are required to be. Because the scope cannot be readily determined, the claim lacks definiteness.
Further regarding claim 15, the claim is indefinite because the scope is ambiguous. The phrase “can also be” (step (2)) could mean that the alkaline high-lithium low-impurity solution is further defined by being a saturated lithium salt solution or that the alkaline high-lithium low-impurity solution is optionally a saturated lithium salt solution. Because the scope cannot be readily determined, the claim lacks definiteness.
Further regarding claim 15, the term “merely” in the phrase “alkaline high-lithium low-impurity merely means” is indefinite because it is preceded by a limitation already setting forth a definition of the alkaline high-lithium low-impurity solution (“wherein the alkaline high-impurity low impurity solution means”). It is unclear whether the definition following “merely means” supersedes the definition following “means” or whether the definition following “merely means” contains additional requirements that add to the definition of the alkaline high-lithium low-impurity solution.
Further regarding claim 15, the claim is indefinite because the scope is ambiguous. The phrase “can reach” raises questions as to whether the subsequent limitation is mandatory, i.e., the lithium ions in the desorption solution must reach 10 g/L or above, 15 g/L or above, 25 g/L above, or whether such limitation is optional. Because the scope cannot be readily determined, the claim lacks definiteness.
Further regarding claim 15, the claim is indefinite because the scope is ambiguous. The term “when” in the phrase “when the acid concentration is greater than 3 mol/L” raises questions as to whether the subsequent limitation is mandatory, i.e., the acid concentration must exceed 3 mol/L, or whether such limitation is optional. Because the scope cannot be readily determined, the claim lacks definiteness.
Further regarding claim 15, two values for the same parameter is considered indefinite because the claim does not clearly set forth the metes and bounds of the patent protection desired. See, for example, MPEP § 2173.05(c). In the present instance, the claim recites the recitation “10 g/L” and the claim also recites “even 15 g/L or above” for the same parameter of lithium ion content. There is a question or doubt as to whether the feature introduced by the higher value (“even 15 g/L or above”) is (a) merely exemplary of the remainder of the claim, and therefore not required, or (b) a required feature of the claims. The term “even” also introduces the same ambiguity because it is unclear whether this is exemplary or merely a preferred concentration.
Claim Rejections - 35 USC § 103
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention.
Claims 1, 2, 10, 12, and 13 are rejected under 35 U.S.C. 103 as being unpatentable over CN 111826524 (A) to Yuan et al. (“Yuan”) (abstract and computer-generated translation are attached) in view of US 2022/005910 (A1) to Jariwala et al. (“Jariwala”) and US 2014/0227154 (A1) to Harrison (“Harrison”).
Regarding claim 1, Yuan is directed to a method for extracting lithium from salt lake brine having a pH of 5-12 (method for extracting lithium from an alkaline solution). Abstract; p. 2 – fourth paragraph; p. 3 – first paragraph. The method includes a step of passing the brine through an adsorbent so that lithium ions in the brine are adsorbed on the adsorbent (adsorbing lithium ions in the alkaline solution by using a lithium adsorbent in an alkaline environment). Page 2 – last paragraph.
The adsorbent is cleaned through exposure to an acidic eluent in order to separate the adsorbed lithium ions and obtain an analytical solution containing eluent and discharged lithium ions (performing desorption by using an acid solution to obtain a high-lithium salt solution). Page 3 – penultimate paragraph; pp. 3-4 – bridging paragraph. The lithium ion concentration in the analysis solution (e.g., 500-5000 ppm) can be higher than the lithium ion concentration in the brine (e.g., greater than or equal to 1 ppm) (high-lithium salt solution with a higher lithium content). Page 2 – fourth and fifth paragraphs.
Yuan teaches a step of cleaning the adsorbent with a cleaning solution after adsorption and before desorption (corresponds to the replacing step). Page 3 – sixth and seventh paragraphs. The cleaning solution is deionized water, distilled water, or filtered river water and does not contain any impurity ions (low-impurity solution). Page 3 – seventh and eighth paragraphs. The cleaning is performed to remove impurity ions, such as sodium ions and iron ions. Page 3 – seventh paragraph.
Yuan does not teach using an alkaline high-lithium low-impurity solution to clean the adsorbent.
Jariwala is drawn to a method for recovering lithium from aqueous sources. Abstract; para. [0002]. The method includes steps of selective adsorption of lithium on a resin and removal of the lithium from resin. Para. [0016], [0019]. The aqueous source of lithium includes salar lakes and surface brines. Para. [0014]. Brine sources include impurities, such as Fe, Ca, and Mg, among others. Para. [0039]. To remove impurities, increasing the pH by adding alkalinity. Para. [0038], [0046].
Jariwala does not specify the agents that can be used to increase the pH. However, Harrison, drawn to a method for preparing lithium carbonate from lithium chloride-containing brines, discloses the addition of bases, such as lithium hydroxide (high-lithium low-impurity solution), for a purification step for removing calcium, magnesium, zinc, manganese, and other divalent ions. Abstract; para. [0003], [0042].
Given the expectation that brines may contain a variety of impurities, such as divalent ions, it would have been obvious to one of ordinary skill in the art to have incorporated the impurity removal step of Jariwala and Harrison as a supplement to the cleaning step in Yuan because the addition of a base, such as lithium hydroxide, would further purify the adsorbent, thereby enhancing the purity of the lithium-containing solution obtained in the subsequent desorption step.
Regarding claim 2, Yuan discloses that the lithium ion concentration in the analysis solution is 500-5000 ppm (0.5-5.0 g/L) (p. 2 – fifth paragraph; pp. 3-4 – bridging paragraph), which overlaps the claimed range. In addition, the analysis solution can be further subjected to a concentration process (p. 4 – seventh full paragraph), which would lead the lithium ion concentration to exceed the lithium ion concentration in the analysis solution (exceed 500-5000 ppm).
Regarding claims 10 and 12, Yuan discloses that the salt lake brine has a pH of 5-12 (p. 2 – fourth paragraph; p. 3 – first paragraph), which overlaps the claimed ranges.
Regarding claim 13, Jariwala teaches that the alkalinity raises the pH to about 8 or 9. Para. [0046]. Lithium hydroxide is a base (pH > 7, corresponds to a high-lithium solution). Harrison at para. [0042]. The cleaning solution in Yuan does not contain any impurity ions (low-impurity solution). Page 3 – seventh and eighth paragraphs. Since the goal is to remove impurities, it would have been obvious to one of ordinary skill in the art to have provided a purified cleaning solution, as suggested by Yuan, like a pure form of lithium hydroxide such that lithium ions in the solution is higher than that of other ions in order to minimize the introduction of additional impurities to the solution from which lithium is extracted.
Claims 3, 14, and 16 are rejected under 35 U.S.C. 103 as being unpatentable over Yuan in view of Jariwala and Harrison, as applied to claim 1 above, and further in view of CN 112593094 (A) to Zhang et al. (“Zhang”) (abstract and computer-generated translation are attached).
Regarding claims 3 and 14, Yuan, Jariwala, and Harrison do not teach electrolyzing the desorbed solution (high-lithium salt solution) in a bipolar membrane to prepare the lithium hydroxide (alkaline high-lithium low-impurity solution) and acidic eluent (acidic solution) for the replacement and desorption steps.
Zhang is drawn to a method for extracting lithium from salt lake brine. Abstract. Once a purified lithium-rich solution is obtained from adsorption and desorption steps, the purified lithium-rich solution is electrolytically treated with a bipolar membrane to obtain an acid solution and an alkali solution containing lithium hydroxide. Page 2 – fifth full paragraph; p. 3 – ninth paragraph. The by-product acid solution obtained in the bipolar membrane device is used for desorption for saving raw material costs (acid used for the desorption step). Page 3 – last paragraph; p. 4 – fifth full paragraph.
Zhang does not teach returning the alkali solution to the process. But given the utility of lithium hydroxide as a base for removing impurities, as taught by Jariwala and Harrison, above, it would have been obvious to one of ordinary skill in the art to have returned at least some of the lithium hydroxide-containing alkali solution from the bipolar membrane to the process of Yuan because it reduce the need to rely upon the introduction of new raw material into the system, saving costs and material.
Regarding claim 16, Yuan teaches ion exchange in which adsorption, desorption (separation), and concentration occurs (p. 3 – seventh paragraph (S02), (S03); p. 4 – seventh paragraph (S05), but does not teach a continuous ion exchange device that concentrates lithium to 15 g/L or above and paired with a bipolar membrane device.
Jariwala teaches a method comprising steps of selective adsorption of lithium on a resin and removal of the lithium from resin. Para. [0016], [0019]. The method further comprises a concentrating step for concentrating lithium. Para. [0029]; FIG. 1. The process is operated continuously. Para. [0042].
Jariwala teaches that dilute brine sources containing a relatively low concentration of lithium can be processed in an extractor in an acidic environment to yield a stream having 40,000 ppm (40 g/L). Para. [0017], [0026]. Therefore, when subjected to a subjected to the concentrator, the lithium concentration would have to exceed 40,000 pm (exceed 40 g/L), which falls within the claimed range.
Zhang is drawn to a method for extracting lithium from salt lake brine. Abstract. Once a purified lithium-rich solution is obtained from adsorption and desorption steps, the purified lithium-rich solution is electrolytically treated with a bipolar membrane to obtain an acid solution and an alkali solution containing lithium hydroxide. Page 2 – fifth full paragraph; p. 3 – ninth paragraph. The by-product acid solution obtained in the bipolar membrane device is used for desorption for saving raw material costs. Page 3 – last paragraph; p. 4 – fifth full paragraph.
It would have been obvious to one of ordinary skill in the art to have added a bipolar membrane device to the device of Yuan in view of Jariwala and Harrison because it is capable of regenerating the acid used in the desorption step, reducing the need to rely upon the introduction of new raw material into the system, saving costs and material.
Claims 4-7 are rejected under 35 U.S.C. 103 as being unpatentable over Yuan in view of Jariwala and Harrison, as applied to claim 1 above, and further in view of CN 108421539 (A) to Li et al. (“Li”) (abstract and computer-generated translation are attached).
Regarding claims 4-7, Yuan discloses an adsorbent that is a manganese-based lithium ion sieve adsorbent (p. 3 – second paragraph), but does not teach a resin adsorbent.
Li is directed to a material capable of adsorbing lithium from a solution that contains both lithium, sodium, and other monovalent ions. Abstract; p. 2 – fourth full paragraph. The material is a polymerized material that has been crosslinked and comprise the functional groups depicted in claim 1 (resin and organic macromolecular crosslinked polymer with special functional group and stable structure, the resin provided by patent CN108421539A). Page 3 – top half of page – item (A). The functional groups are depicted in the original document. Claim 1; para. [0012].
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The material improves lithium ion recovery by the easy separation of lithium from monovalent metal ions. Page 3 – last paragraph; pp. 3-4 – birding paragraph. Therefore, it would have been obvious to one of ordinary skill in the art to have utilized the adsorbent material of Li in conjunction with or as a substitution of the adsorbent in Yuan’s process because it improves the selective removal of monovalent ions like sodium, producing a purer lithium-containing solution and facilitating the removal of other non-lithium metal ions that can be recovered for separate utility.
Claims 8 and 9 are rejected under 35 U.S.C. 103 as being unpatentable over Yuan in view of Jariwala, Harrison, and Li, as applied to claim 4 above, and further in view of CN 102631897 (A) to Xiaokang et al. (“Xiaokang”) (abstract and computer-generated translation are attached).
Regarding claims 8 and 9, Yuan discloses an adsorbent that is a manganese-based lithium ion sieve adsorbent (p. 3 – second paragraph), but does not teach an adsorbent provided by CN102631897B.
Xiaokang is directed to a method for preparing a lithium adsorbent resin for extracting lithium from ha salt lake brine. Abstract; p. 1 – Technical Field. The preparation method is simple and the prepared resin produces zero pollution, has high efficiency and adsorbent capacity, long service life, and recyclability. Abstract. The resin is produced by preparing a precursor of molecular sieve or ion sieve and calcining oxides, nitrates, and hydroxides of manganese and titanium. Page 2 – item (1); p. 3 – first paragraph.
It would have been obvious to one of ordinary skill in the art to have adopted the method of making an adsorbent disclosed by Xiaokang for the method of making the adsorbent of Yuan because of the simplicity of the method of manufacture. Additionally, using an adsorbent material like the adsorbent of Xiaokang together with or as a replacement of the adsorbent of Yuan would facilitate the separation of lithium from brines containing large amounts of magnesium.
Claims 11 and 15 are rejected under 35 U.S.C. 103 as being unpatentable over Yuan in view of Jariwala and Harrison, as applied to claim 1 above, and further in view of US 2019/0044126 (A1) to Snydacker et al. (“Snydacker”).
Regarding claim 11, Yuan discloses that the lithium ion concentration in the analysis solution is 500-5000 ppm (0.5-5.0 g/L) (p. 2 – fifth paragraph; pp. 3-4 – bridging paragraph), which overlaps at the endpoint of the claimed range of 5 g/L or above. The acid concentration may be up to 2 mol/L but is not limited thereto. Pages 3-4 – bridging paragraph.
Yuan does not explicitly state that the lithium ion concentration in the desorption solution differs according to different acid concentrations. However, such a relationship is known in the art.
Snydacker is drawn to an ion exchange system for lithium extraction from sources, such as synthetic brines and leachate solutions from minerals and recycled products. Title; abstract; para. [0002]. An ionic exchange material absorbs lithium ions from the liquid source while releasing hydrogen and the lithium is eluted in acid while absorbing hydrogen. Para. [0003], [0050]. When the lithium is treated with acid having a concentration of, for example, greater than about 0.1 M (greater than about 0.1 mol/L) and greater than about 10 M (greater than about 10 mol/L), hydrogen is absorbed while the lithium is released. Para. [0131].
Jariwala teaches that dilute brine sources containing a relatively low concentration of lithium can be processed in an extractor in an acidic environment to yield a stream having 40,000 ppm (40 g/L). Para. [0017], [0026].
Given that the hydrogen and lithium are exchanged, it therefore follows that the concentration of acid is directly related to desorbed lithium ion concentration. Therefore, it would have been obvious to one of ordinary skill in the art to have varied the acid concentration in the desorption step in order to collect a desired concentration of lithium ion from the lithium adsorbent.
Regarding claim 15, Yuan discloses a step of passing the brine having a pH of 5-12 at a velocity through an adsorbent so that lithium ions in the brine are adsorbed on the adsorbent (adsorption: allowing an alkaline solution containing lithium ions to flow through an adsorbent at a certain flow rate for adsorption). Page 2 – last paragraph; p. 3 – fourth paragraph.
Yuan, Jariwala, and Harrison disclose a step of cleaning (corresponds to replacement) by flowing a basic solution on the adsorbent after the adsorption step in order to remove a number of non-lithium ions (pushing out impurities), as noted above in the discussion of instant claim 1. The cleaning removes impurity ions, such as sodium ions and iron ions. Yuan at p. 3 – seventh paragraph.
With respect to the cleaning solution, Jariwala teaches that the alkalinity raises the pH to about 8 or 9. Para. [0046]. Lithium hydroxide is a base (corresponds to an alkaline high-lithium solution). Harrison at para. [0042]. The cleaning solution in Yuan does not contain any impurity ions (low-impurity solution). Page 3 – seventh and eighth paragraphs. Since the goal is to remove impurities, it would have been obvious to one of ordinary skill in the art to have provided a purified cleaning solution, as suggested by Yuan, like a pure form of lithium hydroxide such that lithium ions in the solution is higher than that of other ions in order to minimize the introduction of additional impurities to the solution from which lithium is extracted (alkaline high-lithium low-impurity solution where the concentration of lithium ions is higher than that of other ions).
Jariwala teaches that a detector detects changes in impurity levels and is configured to adjust by implementing actions, such as increasing addition of alkalinity, increasing flow of eluent, and intensifying permeation of the concentrator to increase impurity removal. Para. [0038]. Impurity removal occurs by the precipitation of the impurity ions as salts. Jariwala at para. [0046]; Harrison at para. [0042]. Although Jariwala does not specify a numerical concentration of lithium ions in the base (lithium hydroxide, for example) for impurity removal, it would have been obvious to one of ordinary skill in the art to have optimized the concentration value of lithium ions in the lithium hydroxide solution because that concentration determines the level precipitated.
Yuan teaches that the adsorbent is cleaned through exposure to an acidic eluent at a predetermined concentration in order to separate the adsorbed lithium ions and obtain an analytical solution containing eluent and discharged lithium ions (desorption: performing desorption by using an acid solution with a certain concentration and controlling the amount of acid provided). Page 3 – penultimate paragraph; pp. 3-4 – bridging paragraph. The adsorbent material can then be cleaned with water (washing the adsorbent with water to remove acid left thereupon). Page 4 – third through fifth full paragraphs.
Yuan does not teach placing the adsorbent in a resin exchange column, collecting desorption solutions in stages, allowing solution flowing out from a previous stage to enter a previous step, and entering a first step of a next cycle for re-adsorption.
Jariwala teaches that a lithium extraction process may be performed in stages, where the number of stages may be one, two, three, or more. Para. [0043]. For each stage, the lithium-depleted stream can be routed to a prior stage as eluent, and the stages may be operated in a counter-current manner through a backward flow from downstream stages to upstream stages. Para. [0043].
Snydacker is drawn to an ion exchange system for lithium extraction from sources, such as synthetic brines and leachate solutions from minerals and recycled products. Title; abstract; para. [0002]. The extraction can be continuous and take place over columns having various column heights, ion exchange resin, beads, and residence times. Para. [0038], [0066], [0120], [0234]; FIG. 12. Flow can be counter-flow or counter-current. Para. [0137], [0247]. The cycle can be repeated. Para. [0022], [0214], [0215].
It would have been obvious to one of ordinary skill in the art to have carried out the process of Yuan, as modified by Jariwala and Harrison, continuously in an apparatus comprising a system of columns because the brine can be treated without interruption and more volume can be processed.
Yuan discloses that the lithium ion concentration in the analysis solution is 500-5000 ppm (0.5-5.0 g/L) and an acid concentration may be up to 2 mol/L but is not limited thereto. Page 2 – fifth paragraph; pp. 3-4 – bridging paragraph).
Yuan does not teach collecting the desorption solution in a middle stage for the purpose of concentrating the solution. Yuan also does not explicitly state that the lithium ion concentration in the desorption solution differs according to different acid concentrations. However, such a relationship is known in the art.
Snydacker is drawn to an ion exchange system for lithium extraction from sources, such as synthetic brines and leachate solutions from minerals and recycled products. Title; abstract; para. [0002]. An ionic exchange material absorbs lithium ions from the liquid source while releasing hydrogen and the lithium is eluted in acid while absorbing hydrogen. Para. [0003], [0050]. When the lithium is treated with acid having a concentration of, for example, greater than about 0.1 M (greater than about 0.1 mol/L) and greater than about 10 M (greater than about 10 mol/L), hydrogen is absorbed while the lithium is released. Para. [0131].
Before or after the liquid resource (source material, e.g., brine) flows through the column, the liquid resource is optionally subjected to other processes including other ion exchange processes, solvent extraction, evaporation, chemical treatment, or precipitation to remove lithium, to remove other chemical species, or to otherwise treat the brine. Harrison at para. [0137]; FIG. 11.
Jariwala teaches that dilute brine sources containing a relatively low concentration of lithium can be processed in an extractor in an acidic environment to yield a stream having 40,000 ppm (40 g/L). Para. [0017], [0026].
Given that the hydrogen and lithium are exchanged, it therefore follows that the concentration of acid is directly related to desorbed lithium ion concentration. Therefore, it would have been obvious to one of ordinary skill in the art to have varied the acid concentration in the desorption step in order to collect a desired concentration of lithium ion from the lithium adsorbent. Furthermore, it would have been obvious to one of ordinary skill in the art to have removed desorbed solution at any point of the desorption stages because it would enable the user to further subject the solution to additional treatment, thereby facilitating customized processing of the solution for valuable solids and liquids.
Yuan discloses the presence of sodium ion impurities (page 3 – seventh paragraph), but does not teach potassium impurity. Yuan does not teach the creation of sodium hydroxide and potassium hydroxide to be returned to the raw materials for removing calcium and magnesium.
Snydacker discloses that K (potassium) is a known impurity in natural brine. Para. [0281]. Jariwala discloses that brines include impurities, such as Fe, Ca, and Mg, among others. Para. [0039]. To remove impurities, increasing the pH by adding alkalinity. Para. [0038], [0046]. Jariwala does not specify the agents that can be used to increase the pH. However, Harrison, drawn to a method for preparing lithium carbonate from lithium chloride-containing brines, discloses the addition of bases, such as sodium hydroxide and lithium hydroxide, for a purification step for removing calcium, magnesium, zinc, manganese, and other divalent ions. Abstract; para. [0003], [0042]. NaOH (sodium hydroxide) and KOH (potassium hydroxide) are known bases for causing precipitation of MgOH2 and CaOH2 solids. Snydacker at para. [0052].
Given the expectation that brines may contain a variety of impurities, such as sodium and potassium, it would have been obvious to one of ordinary skill in the art to have incorporated the impurity removal step of Jariwala and Harrison as a supplement to the cleaning step in Yuan because the addition of base would enhance the purity of the lithium-containing solution obtained in the subsequent desorption step. It would further have been obvious to have used any NaOH and KOH obtained from the impurity removal step as a raw material for the additional step of removing Mg, Ca, and divalent ions because reusing formed hydroxides would decrease reliance on new raw material, thereby reducing costs to perform the process.
Conclusion
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/VANESSA T. LUK/Primary Examiner, Art Unit 1733
July 18, 2026
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