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 .
Priority
Applicant’s Petition to accept an unintentionally delayed claim to foreign priority was dismissed in the petition decision issued 03/09/2026. Before the remaining requirements of 37 CFR 1.55(e) can be considered, a renewed petition accompanied by the required updated Application Data Sheet must be filed. Applicant is encouraged to follow the guidance and requirements set forth in the Petition Decision when assembling the response.
Response to Amendment
The amendment filed 02/11/2026 has been entered. Claims 1, 5, 9, 15, 17, 20, 26, 33-34, 37, 42, 44, 79, 101, 104, 109, 123, 129, 131, 148-154 are pending in this application and examined herein. Claims 1, 42, 44, and 131 are amended. Claims 2-4, 5-8, 10-14, 16, 18-19, 21-25, 27-32, 35-36, 38-41, 43, 45-78, 80-100, 102-103, 105-108, 110-122, 124-128, 130, and 132-147 are cancelled. Claims 152-154 are new.
The objection to claim 131 is withdrawn in view of the amendments to claim 131.
Continued Examination Under 37 CFR 1.114
A request for continued examination under 37 CFR 1.114, including the fee set forth in 37 CFR 1.17(e), was filed in this application after final rejection. Since this application is eligible for continued examination under 37 CFR 1.114, and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114. Applicant's submission filed on 02/11/2026 has been entered.
Claim Rejections - 35 USC § 103
The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action.
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, 5, 9, 15, 17, 20, 26, 33, 34, 101, 104, 109, 123, 129, 131, and 149 are rejected under 35 U.S.C. 103 as being unpatentable over Snydacker et al. (US 20190256987 A1, cited in Office Action dated 09/11/2025) in view of Xu et al. (CN 114086006 A, original document and machine translation provided herein).
Regarding claim 1, Snydacker teaches a process for extracting lithium from an aqueous solution containing lithium (Abstract, [0003]). Snydacker teaches contacting an aqueous solution containing lithium [0004] with an ion exchange material (i.e., a lithium sorbent) to absorb the lithium to produce a mixture of a lithium loaded sorbent and spent brine (i.e., lithium depleted solution) [0096]. Snydacker teaches separating the lithium loaded sorbent and the lithium depleted solution ([0004, 0327], e.g., Fig. 7), and treating the lithium loaded sorbent to produce a mixture of a lithium rich solution [0004], wherein said lithium ions from said lithium loaded sorbent are exchanged with hydrogen ions [0004], regenerating the sorbent. Snydacker teaches wherein the pH in step (i) is controlled to provide the lithium depleted solution at a pH of 5-7 during adsorption [0380, 0402], which would include the pH of the lithium depleted solution when adsorption has been completed, which is within the claimed range. Snydacker teaches the lithium sorbent has an average size of less than about 0.1, 1, 10, 50, or 100 microns (µm) [0343], such as 3 µm (Fig. 13), teaching wherein the sorbent is in a micronized form.
Snydacker teaches the sorbent may be kept in a permeable compartment where uptake occurs into the permeable compartment in a tank, where the permeable compartment may be moved to another container for elution (i.e., separating the lithium loaded sorbent and lithium depleted solution) [0308], where one of ordinary skill would also recognize the permeable container would be returned to the container for uptaking lithium once lithium has been eluted (i.e., separating the lithium rich solution and the regenerated sorbent), thus the permeable walls of the container comprise a membrane for separating the sorbent and solution according to steps (ii) and (iv). Snydacker does not teach wherein the membrane is an ultrafiltration membrane.
Xu teaches a lithium extraction process using a powdered lithium adsorbent coupled with a hollow fiber membrane (title), where lithium-containing brine is subjected to cyclic adsorption with powdered lithium adsorbent to obtain a solid-liquid mixture which is separated by a liquid membrane to obtain lithium-containing adsorbent and delithiated brine [n0006-n0008], then the adsorbent is rinsed with water [n0009], and desorbed to obtain lithium-rich liquid and regenerated adsorbent, which are then separated by another solid-liquid membrane [n0010], thus Xu and Snydacker are analogous to the instant application as both are directed to lithium extraction processes where lithium-containing brines are contacted with sorbents to load lithium onto the sorbent, separating the sorbent from the lithium depleted solution, treating the lithium loaded sorbent to produce lithium rich solution and regenerated sorbent, and separating the lithium rich solution and regenerated sorbent. Xu teaches the membranes are preferably ultrafiltration membranes [n0029].
Because Snydacker is silent with respect to the construction and type of membrane used for separating sorbent from solution, in order to carry out the invention of Snydacker one of ordinary skill in the art would necessarily look to the art for a reference teaching membranes suitable for use within the process of Snydacker, such as an ultrafiltration membrane as taught by Xu. As Snydacker and Xu both relate to lithium extraction processes with analogous steps as noted above, one of ordinary skill would be motivated to use the permeable ultrafiltration membrane of Xu as the permeable membrane of Snydacker.
Regarding claim 5, Snydacker teaches the lithium sorbent is a metal oxide-based ion exchange sorbent and may be Li2MO3 (M = Ti, Mn), Li4Ti5O12, Li4Mn5O12, LiMn2O4, Li1.6Mn1.6O4, LiTiO2, Li4TiO4, Li7Ti11O24, or Li2MnO3 [0341]. Snydacker teaches contacting the lithium sorbent exchanges hydrogen ions from the ion exchange material with lithium ions from the aqueous solution containing lithium [0003, 0004]. Snydacker then treats the lithium-enriched lithium sorbent with acid solution, where lithium ions in the sorbent are exchanged with hydrogen ions [0004]. For hydrogen to originally be exchanged from the sorbent, the metal oxide-based ion exchange sorbent must contain hydrogen, and be in the hydrogen form of the sorbent material (e.g., H2MnO3). Therefore, the process of Snydacker is one wherein the sorbent is hydrogen manganese oxide or hydrogen titanium oxide.
Regarding claim 9, Snydacker teaches the lithium sorbent has an average size of less than about 100 microns (µm) [0343], such as 3 µm (Fig. 13). Thus, the lithium sorbent has an average particle size D50 of less than about 100 µm.
Regarding claim 15, Snydacker teaches bases such as NaOH, Ca(OH)2, CaO, KOH, or NH3 are optionally added to control to 5-7 during absorption [0097], which is within the claimed pH range.
Regarding claim 17, Snydacker teaches wherein the pH of the aqueous solution containing lithium is maintained at an average pH within the claimed ranges (e.g., about 5 to about 6) when the lithium is being absorbed [0097].
Regarding claim 20, Snydacker teaches wherein the pH of the aqueous solution containing lithium in that process is maintained at an average pH of about 5 to 7 during step (i) and allowed to become more acidic at the end [0380]. This overlaps the claimed range of an average pH of about 6 to 7. The overlap between the ranges taught in the prior art and recited in the claims creates a prima facie case of obviousness, because the prior art indicates substantial utility over the entire range disclosed therein, including that portion of the range which also falls within the claimed range. See MPEP § 2144.05(I).
Regarding claim 26, Snydacker teaches wherein the pH changes to below a pH value of below about pH 2, 3, 4, 5, or 6, base is added at a rate such that the pH does not exceed pH 7 [0402]. Snydacker teaches the pH is low enough to avoid precipitation of metals from the liquid resource (i.e., that localized precipitation is reduced).
Regarding claims 33-34, Snydacker teaches wherein the pH in step (i) is controlled to provide the lithium depleted solution once adsorption is completed in each column at a pH of 3.5 [0444], which is within the claimed ranges.
Regarding claim 101, Snydacker teaches wherein the ratio of an impurity/Li in the lithium rich solution is 0.166 [0466], which is within the claimed range.
Regarding claim 104, Snydacker teaches wherein the ratio of impurities including Ca/Li in the lithium rich solution is less than about 0.166 [0466], which is within the claimed range.
Regarding claim 109, Snydacker teaches the pH of a liquid resource during absorption is maintained below a pH of about 2, 3, 4, 5, 6, or 7 to avoid precipitation of metal [0402], where Mn is a metal that can be precipitated [0396]. As Mn then remains in the brine that is removed (analogous to the lithium depleted solution), less Mn is left on or with the lithium sorbent, and the amount of Mn in the lithium rich solution is decreased relative to an equivalent process in which an aqueous solution containing lithium reaches a maximum pH about 7, 8, 9, or 10 when the lithium is being absorbed.
Regarding claim 123, Snydacker teaches wherein the aqueous solution containing lithium is selected from a geothermal brine, concentrates from processing seawater [0362] sea water, oil well brines, [0012] or other ground waters [0012, 0362].
Regarding claims 129 and 131, Snydacker teaches wherein one or more or all of steps (i)-(iv) are performed in a batch process [0308, 0416] or a continuous process [0310, 0416].
Regarding claim 149, Xu teaches wherein the ultrafiltration membrane is a hollow fiber membrane (Title, [n0006, n0017]).
Claims 37, 150, and 152 are rejected under 35 U.S.C. 103 as being unpatentable over Snydacker in view of Xu as applied to claims 1 and 149 above, and further in view of MSS (“Dead-End Filtration vs. Cross-Flow Filtration — All You Need to Know”, provided herein).
Regarding claim 37, Snydacker in view of Xu teaches wherein separating steps (ii) and (iv) use an ultrafiltration membrane, however Snydacker in view of Xu does not teach wherein the separating steps comprise cross-flow filtration.
MSS teaches cross-flow filtration to benefit from the ability to remove buildup from the membrane’s surface, no need for a filter aid, improved filter media lifespan due to lack of buildup and filter cake, and preventing irreversible fouling of the membrane (pg. 2-3 Advantages of Cross-Flow Filtration over Dead-End Filtration).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have used cross-flow filtration as taught by MSS in the separating steps of Snydacker in view of Xu as doing so would remove buildup from the membrane surface, not require a filter aid, improve the lifespan of the filter media, and prevent irreversible fouling of the membrane as taught by MSS.
Regarding claim 150, Snydacker in view of Xu teaches wherein separating steps (ii) and (iv) use an ultrafiltration membrane, however Snydacker in view of Xu does not teach wherein the separating steps comprise cross-flow filtration.
MSS teaches cross-flow filtration to benefit from the ability to remove buildup from the membrane’s surface, no need for a filter aid, improved filter media lifespan due to lack of buildup and filter cake, and preventing irreversible fouling of the membrane (pg. 2-3 Advantages of Cross-Flow Filtration over Dead-End Filtration).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have used cross-flow filtration as taught by MSS in the separating steps of Snydacker in view of Xu as doing so would remove buildup from the membrane surface, not require a filter aid, improve the lifespan of the filter media, and prevent irreversible fouling of the membrane as taught by MSS.
Regarding claim 152, Snydacker in view of Xu teaches wherein separating steps (ii) and (iv) use an ultrafiltration membrane, however Snydacker in view of Xu does not teach wherein the separating steps comprise cross-flow filtration.
MSS teaches cross-flow filtration to benefit from the ability to remove buildup from the membrane’s surface, no need for a filter aid, improved filter media lifespan due to lack of buildup and filter cake, and preventing irreversible fouling of the membrane (pg. 2-3 Advantages of Cross-Flow Filtration over Dead-End Filtration).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have used cross-flow filtration as taught by MSS in the separating steps of Snydacker in view of Xu as doing so would remove buildup from the membrane surface, not require a filter aid, improve the lifespan of the filter media, and prevent irreversible fouling of the membrane as taught by MSS. Thus, Snydacker in view of Xu and MSS suggests wherein the lithium sorbent separating step (ii) and/or separating step (iv) comprises wherein the lithium sorbent and fluid are cross-flow filtered. As the filtration is used to separate the sorbent and the solution, such intrinsically results in the lithium sorbent being concentrated and the fluid being cross-flow filtered through said ultrafiltration membrane to increase the concentration of the lithium sorbent (i.e., a dewatering step as claimed).
Claim 42 is rejected under 35 U.S.C. 103 as being unpatentable over Snydacker in view of Xu as applied to claim 1 above, and further in view of Wang (CN 108358278 A, machine translation and original document supplied with Office Action dated 09/11/2025).
Regarding claim 42, Snydacker teaches treating the lithium rich solution using osmosis (i.e., a dialysis step) wherein the sorbent is dialyzed with water (e.g., [0466]) with a membrane to concentrate the lithium rich solution [0007] to decrease the amount of a soluble impurity in the sorbent [0239]. Xu teaches wherein the ultrafiltration membrane is a hollow fibre membrane [n0033] made of PVDF [n0029], but Snydacker in view of Xu does not teach wherein the osmosis step is performed using the ultrafiltration membrane.
Wang teaches a method for extracting lithium from salt lake brine using a hollow fiber forward osmosis membrane (Title), where a solution of old salt lake brine, salt lake sun-drying composite salt solution or multi-stage nanofiltration concentrate of salt lake brine lithium extraction process is used as the drawing liquid (analogous to a lithium rich solution) [0013], thus Wang and Snydacker are analogous to the instant application as they both comprise the use of a membrane to treat lithium rich solution to extract lithium from aqueous solution. Wang teaches the membrane is a hollow fiber ultrafiltration made of PVDF [0013-0014].
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have used the hollow fiber membrane of PVDF used by Snydacker in view of Xu to separate sorbent from solution, also as the osmosis membrane as taught by Wang as Wang teaches a lithium osmosis membrane also should be a PVDF hollow fiber membrane, where doing so would have been recognized by one of ordinary skill to simplify the construction of the process equipment used by eliminating the need for e.g., an additional membrane.
Claim 44 is rejected under 35 U.S.C. 103 as being unpatentable over Snydacker in view of Xu as applied to claim 1 above, and further in view of Wang and MSS.
Snydacker teaches treating the lithium rich solution using osmosis (i.e., a dialysis step) wherein the sorbent is dialyzed with water (e.g., [0466]) with a membrane to concentrate the lithium rich solution [0007] to decrease the amount of a soluble impurity in the sorbent [0239]. Xu teaches wherein the ultrafiltration membrane is a hollow fibre membrane [n0033] made of PVDF [n0029], but Snydacker in view of Xu does not teach wherein the osmosis step is performed using the ultrafiltration membrane.
Wang teaches a method for extracting lithium from salt lake brine using a hollow fiber forward osmosis membrane (Title), where a solution of old salt lake brine, salt lake sun-drying composite salt solution or multi-stage nanofiltration concentrate of salt lake brine lithium extraction process is used as the drawing liquid (analogous to a lithium rich solution) [0013], thus Wang and Snydacker are analogous to the instant application as they both comprise the use of a membrane to treat lithium rich solution to extract lithium from aqueous solution. Wang teaches the membrane is a hollow fiber ultrafiltration made of PVDF [0013-0014].
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have used the hollow fiber membrane of PVDF used by Snydacker in view of Xu to separate sorbent from solution, also as the osmosis membrane as taught by Wang as Wang teaches a lithium osmosis membrane also should be a PVDF hollow fiber membrane, where doing so would have been recognized by one of ordinary skill to simplify the construction of the process equipment used by eliminating the need for e.g., an additional membrane.
Snydacker in view of Xu and Wang teaches wherein separating steps (ii) and (iv) use an ultrafiltration membrane, however Snydacker in view of Xu does not teach wherein the separating steps comprise cross-flow filtration
MSS teaches cross-flow filtration to benefit from the ability to remove buildup from the membrane’s surface, no need for a filter aid, improved filter media lifespan due to lack of buildup and filter cake, and preventing irreversible fouling of the membrane (pg. 2-3 Advantages of Cross-Flow Filtration over Dead-End Filtration).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have used cross-flow filtration as taught by MSS in the separating steps of Snydacker in view of Xu as doing so would remove buildup from the membrane surface, not require a filter aid, improve the lifespan of the filter media, and prevent irreversible fouling of the membrane as taught by MSS.
Claim 79 is rejected under 35 U.S.C. 103 as being unpatentable over Snydacker in view of Xu as applied to claim 1 above, and further in view of Chung et al. (US 20210188652 A1, cited in Office Action dated 02/18/2025).
Snydacker, discussed above, does not teach wherein the mixture of the lithium depleted solution and lithium loaded sorbent in steps (i) has a concentration of up to about 30 wt% solids.
Chung teaches a method for recovering lithium where aqueous solution containing lithium is contacted with lithium sorbent to absorb the lithium (Title, Abstract, [0006]), therefore Snydacker and Chung are analogous as both are directed to extracting lithium from aqueous solution using a sorbent. Chung teaches the mixture of the lithium depleted solution and lithium loaded sorbent are in a ratio of 2 g of adsorbent to 1 L of solution [0038]. Whereas the solution is aqueous, 1 L is approximately equivalent to 1000 g of solution (i.e., a concentration in step (i) of about 0.25 wt% solids), which is within the claimed range of “up to about 30 wt% solids”.
Because Snydacker is silent with respect to a solids concentration for the mixture of lithium depleted solution and lithium loaded sorbent, in order to carry out the invention of Snydacker one of ordinary skill in the art would necessarily look to the art for a reference teaching solids concentration known to be suitable for the process of Snydacker, such as that taught by Chung. Therefore, the combined disclosures of Snydacker and Chung would have suggested a process as presently claimed to one of ordinary skill in the art.
Claims 148 and 153-154 are rejected under 35 U.S.C. 103 as being unpatentable over Snydacker in view of Xu as applied to claim 1 above, and further in view of Cheng et al. (US 20180245180 A1, cited in Office Action dated 09/11/2025).
Regarding claim 148 and 154, Snydacker, discussed above, does not teach wherein the mixture of a regenerated sorbent and lithium rich solution separated in step (iv) has a concentration of about 10 to 55 wt% solids.
Cheng teaches processes for recovering lithium values from lithium-containing brines (Title), where lithium is recovered by passing lithium-containing solution through sorbent to extract lithium from the solution (abstract), thus Cheng and Snydacker are analogous to the instant application as both are directed to processes for recovering lithium from liquid resources by sorption. Cheng teaches that a total of 725 g [0099-103] of sorbent may be used with 5.3 liters (5300 g) of water to unload Li [0103], which would result in regeneration of the sorbent and a lithium rich solution as the lithium is unloaded into the water. Cheng thus teaches a solids ratio of 13.7 wt% solids, which is within the claimed range.
Because Snydacker is silent with respect to a solids concentration for the mixture of lithium rich solution and regenerated sorbent, in order to carry out the invention of Snydacker one of ordinary skill in the art would necessarily look to the art for a reference teaching solids concentration known to be suitable for the process of Snydacker, such as that taught by Cheng. Therefore, the combined disclosures of Snydacker and Cheng would have suggested a process as presently claimed to one of ordinary skill in the art.
Regarding claim 153, Snydacker, discussed above, does not teach wherein the mixture of a regenerated sorbent and lithium rich solution separated in step (iv) has a concentration of about 1 to 55 wt% solids.
Cheng teaches processes for recovering lithium values from lithium-containing brines (Title), where lithium is recovered by passing lithium-containing solution through sorbent to extract lithium from the solution (abstract), thus Cheng and Snydacker are analogous to the instant application as both are directed to processes for recovering lithium from liquid resources by sorption. Cheng teaches that a total of 725 g [0099-103] of sorbent may be used with 5.3 liters (5300 g) of water to unload Li [0103], which would result in regeneration of the sorbent and a lithium rich solution as the lithium is unloaded into the water. Cheng thus teaches a solids ratio of 13.7 wt% solids, which is within the claimed range.
Because Snydacker is silent with respect to a solids concentration for the mixture of lithium rich solution and regenerated sorbent, in order to carry out the invention of Snydacker one of ordinary skill in the art would necessarily look to the art for a reference teaching solids concentration known to be suitable for the process of Snydacker, such as that taught by Cheng. Therefore, the combined disclosures of Snydacker and Cheng would have suggested a process as presently claimed to one of ordinary skill in the art.
Claim 151 is rejected under 35 U.S.C. 103 as being unpatentable over Snydacker in view of Xu as applied to claim 1 above, and further in view of Theway Scholar (“Out-In Membrane or an In-Out Membrane?”, supplied with Office Action dated 09/11/2025).
Regarding claim 151, Xu teaches wherein the ultrafiltration membrane is a hollow fibre membrane [n0033] made of PVDF [n0029]. Xu does not teach wherein the membrane is an outside-in membrane.
Theway Scholar discloses outside-in and inside-out flows through fiber membranes (i.e., a hollow fiber membrane) (Title, paragraph 1), thus Theway Scholar and Xu are analogous to the instant application as both use hollow fiber filters. Theway Scholar teaches the inside-out flow regime has an increased probability of a clogged fiber, which can block the fiber and cause it to burst or immensely slow movement (paragraph 1) and can render the fiber useless (paragraph 3), while the outside-in flow regime results in a thinner thickness of suspended solids on the membrane and lower filtration times (paragraph 2).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have used an outside-in flow membrane as taught by Theway Scholar as the hollow fiber membrane of Xu as doing so would reduce the probability of a clogged fiber, and reduce buildup of suspended solids on the membrane and filtration times.
Response to Arguments
In response to applicant's argument that Snydacker in view of Wang does not teach wherein the separating steps (ii) or (iv) comprise separating sorbent and solution through an ultrafiltration membrane, the Examiner agrees. Therefore, the rejections of claims over 5, 9, 15, 17, 20, 26, 33-34, 37, 42, 44, 79, 101, 104, 109, 123, 129, 131, 148-151 over Snydacker and Wang alone or in view of additional art are withdrawn. The Examiner notes that these claims are now rejected under a new ground of rejection as obvious over Snydacker in view of Xu, and applicant’s arguments are now moot with regard to Wang in view of Snydacker as applied in the previous office action.
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to Nikolas T Pullen whose telephone number is (571)272-1995. The examiner can normally be reached Monday - Thursday: 10:00 AM - 6:00 PM EST.
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/Keith D. Hendricks/Supervisory Patent Examiner, Art Unit 1733
/NIKOLAS TAKUYA PULLEN/Examiner, Art Unit 1733