DETAILED ACTION
Notice of Pre-AIA or AIA Status
The present application is being examined under the pre-AIA first to invent provisions.
This is a response to applicant’s amendment filed on January 22, 2026. Claims 31 and 86 have been amended. Claims 54-58 have been cancelled. No claims have been added. Claims 31-32 and 86-92 are pending in the application.
Response to Amendment
Rejections under 35 USC § 112(a) of Claims 31-32 and 86-92 have been withdrawn in view of applicant’s amendments.
Rejections under 35 USC § 112(a) of Claims 54-58 have been withdrawn in view of cancellation of claims 54-58.
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 86-92 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.
Claim 86 recites the limitation: “…remove lithium chloride from a stream of brine, wherein the brine has a reduced concentration of silica and iron, the concentration of silica and the iron having been reduced by oxidizing the brine to precipitate silica and iron, wherein the concentration of the silica is less than about 25ppm and the pH of the flashed Salton Sea geothermal brine is between about 4.5 and 6…” There is no mention of a flashed Salton Sea geothermal brine previously in claim 86. Therefore, there is insufficient antecedent basis for this limitation in the claim.
For purposes of examination, examiner will interpret claim 86 as reciting: “…remove lithium chloride from a stream of flashed Salton Sea geothermal brine, wherein the flashed Salton Sea geothermal brine has a reduced concentration of silica and iron, the concentration of silica and the iron having been reduced by oxidizing the flashed Salton Sea geothermal brine to precipitate silica and iron, wherein the concentration of the silica is less than about 25ppm and the pH of the flashed Salton Sea geothermal brine is between about 4.5 and 6…”
Claims 87-92 have been rejected because they depend on rejected claim 86.
The following is a quotation of 35 U.S.C. 112(d):
(d) REFERENCE IN DEPENDENT FORMS.—Subject to subsection (e), a claim in dependent form shall contain a reference to a claim previously set forth and then specify a further limitation of the subject matter claimed. A claim in dependent form shall be construed to incorporate by reference all the limitations of the claim to which it refers.
The following is a quotation of pre-AIA 35 U.S.C. 112, fourth paragraph:
Subject to the following paragraph [i.e., the fifth paragraph of pre-AIA 35 U.S.C. 112], a claim in dependent form shall contain a reference to a claim previously set forth and then specify a further limitation of the subject matter claimed. A claim in dependent form shall be construed to incorporate by reference all the limitations of the claim to which it refers.
Claims 87-88, 90 and 92 are rejected under 35 U.S.C. 112(d) or pre-AIA 35 U.S.C. 112, 4th paragraph, as being of improper dependent form for failing to further limit the subject matter of the claim upon which it depends, or for failing to include all the limitations of the claim upon which it depends.
Claim 87 recites: “…wherein the brine is a geothermal brine.” This limitation fails to further limit the subject matter of claim 86 because claim 86 (see examiner interpretation above) already discloses that brine is a geothermal brine.
Claim 88 recites: “…wherein the brine is a Salton Sea geothermal brine.” This limitation fails to further limit the subject matter of claim 86 because claim 86 (see examiner interpretation above) already discloses that brine is a Salton Sea geothermal brine.
Claim 90 recites: “… wherein the concentration of the silica is less than about 25ppm.” This limitation fails to further limit the subject matter of claim 86 because claim 86 already discloses that the concentration of the silica is less than about 25ppm.
Claim 92 recites: “…wherein the pH of the brine is between about 4.5 and 6.” This limitation fails to further limit the subject matter of claim 86 because claim 86 already discloses that the pH of the brine is between about 4.5 and 6.”
Applicant may cancel the claims, amend the claims to place the claims in proper dependent form, rewrite the claims in independent form, or present a sufficient showing that the dependent claims comply with the statutory requirements.
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 pre-AIA 35 U.S.C. 103(a) which forms the basis for all obviousness rejections set forth in this Office action:
(a) A patent may not be obtained through the invention is not identically disclosed or described as set forth in section 102, if the differences between the subject matter sought to be patented and the prior art are such that the subject matter as a whole would have been obvious at the time the invention was made to a person having ordinary skill in the art to which said subject matter 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 pre-AIA 35 U.S.C. 103(a) 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.
Claims 31-32 and 86-92 are rejected under pre-AIA 35 U.S.C. 103(a) as being unpatentable over Wilkins, V. (US Pat. No. 4,016,075, hereinafter Wilkins) in view of Burba, J. (US Pat. No. 4,472,362, hereinafter Burba) and Yan et al. (“Removal of Boron from Refined Brine by Using Selective Ion Exchange Resins”. Journal of Hazardous Materials. ScienceDirect, hereinafter Yan).
In regards to Claims 31-32, 86-90 and 92, Wilkins discloses a system and method for removal of silica and iron from geothermal brine. The system comprises a reaction chamber #13 which receives the geothermal brine with steam produced at a high temperature and pressure from a geothermal well. Ammonium hydroxide #14 is added to the reaction chamber #13 to react with the dissolved aluminum and ferrous ions, i.e. iron, to form a gelatinous sludge precipitate of aluminum and ferrous hydroxides. This precipitated sludge formed in the brine will “sweep” the brine so that dissolved silica will adsorb on the surface of the sludge particles, thereby reducing the concentration of silica from the brine. Enough ammonium hydroxide is added to the brine to increase the pH of the brine sufficiently so that the remaining dissolved silica will be below its saturation level in the brine at the temperature and pressure to which the brine is reduced for subsequent handling. The precipitated sludge is then removed from the brine so that the clarified brine can then be further processed (see column 2, lines 40-58). The reaction of ammonium hydroxide with ferrous ions occurs when a pH of about 5.5 or greater is reached (see column 3, lines 46-48), which falls inside the claimed range of 4.5 and 6, thereby making the claimed range prima facie obvious. See MPEP 2144.05.
The aluminum and ferrous hydroxides will both precipitate out of the brine as a gelatinous sludge which sweeps the brine, causing a major portion of the high concentration of dissolved silica to adsorb onto the surface of the sludge particles and be fixed thereto (see column 3, lines 60-64). After the ammonium hydroxide injection and sludge formation and silica step in the reaction chamber, the steam, brine and suspended sludge passes to a series of connected steam separators #19-#21, which flashes part of the brine to steam, causing cooling of the brine (see figure 1 and column 5, lines 20-41). The brine and precipitate passes from reaction tank to settling tank #35 where the precipitate is removed from the bottom of the tank #35 and the clarified brine from tank #35 is then passed through line #37 to suitable equipment for subsequent recovery of desired elements remaining in solution in the brine (see figure 1 and column 6, lines 12-18).
Examiner notes that although Wilkins is silent in regards to wherein the concentration of silica is less than about 25ppm, Wilkins discloses substantially the same system and method for reducing the concentration of silica and iron, as claimed by the applicant. Therefore, it is reasonably expected, absent evidence to the contrary, that Wilkins system and method is capable of functioning in the same manner as claimed, as it has been held that when the structure recited in the reference is substantially identical to that of the claims, claimed functions are considered prima facie obvious. See MPEP 2112.01.
Examiner notes that although Wilkins does not explicitly disclose wherein the geothermal brine is Salton Sea geothermal brine, using a different feed of geothermal brine is a mere engineering design choice since it is reasonably expected, absent evidence to the contrary, that Wilkins’s system and method will be capable of functioning in the same manner using any type of geothermal brine with a reasonable expectation of success. See MPEP 2144.04.
Wilkins fails to disclose at least one intercalated lithium absorbent column configured to: (1) isolate lithium chloride adapted to remove lithium chloride from a stream of flashed Salton Sea geothermal brine, (2) be regenerated with wash water comprising lithium ions to produce a lithium chloride-rich stream having the removed lithium chloride, and (3) an ion exchange comprising a selective chelating ion exchange resin adapted to reduce the concentration of boron in the lithium chloride-rich stream.
However, Burba teaches a system for producing a lithium-chloride rich stream comprising at least one intercalated lithium absorbent column configured to isolate lithium chloride from a stream of geothermal brine. The system comprises a lithium aluminate absorbent formed by heating a mixture of crystalline hydrous alumina and lithium salt ions. The combination of high temperature and high concentration is effective in forcing the lithium salt into the layers of hydrous alumina crystals, which in some cases gives a crystallographic unit cell having two layers of lithium salt and two layers of hydrous alumina. The expression 2-layer refer to the number of layers bounded on both sides by the aluminate layers into which the subject Li compounds are intercalated, i.e. intercalated lithium aluminum intercalate absorbent column (see column 2, lines 39-58) (encompasses the limitation of claims 32 and 89, respectively). The lithium salts for reaction with the hydrous alumina can be lithium chloride (see column 3, lines 34-36). The porous substrate into which the crystalline hydrous alumina can be loaded may be a microporous resin such as an ion exchange resin (see column 4, lines 1-6).
Burba further teaches in example 7, a crystalline 2-layer LiCl2Al(OH)3.nH2O is prepared within microporous beads of DOWEX-MWA-1-Cl ion exchange resin by reacting gibbsite-containing resin with a 20% aqueous solution of LiCl, thereby forming a composite. About 120ml of the composite is placed in an exchange column, i.e. intercalated lithium absorbent column, and is washed with about 150ml of Li+ solution to remove some, but not all, of the Li+ values from the composite. Brine containing about 250ppm of Li+ is passed through the composite until equilibrium is reached, indicating the aluminate crystal is loaded with Li+. The composite is regenerated by passing 150ml 1000ppm Li+ solution and catching the effluent in 5ml cuts. The LiCl concentration of the cuts peaks at 3.93% LiCl; ¼ bed volume of product cuts yields 3.02% LiCl (see column 5, lines 38-61, example 7). This is considered equivalent to at least one intercalated lithium absorbent column configured to isolate lithium chloride adapted to remove lithium chloride from a stream of geothermal brine and be regenerated by wash water comprising lithium ions to produce a lithium chloride-rich stream having the removed lithium chloride, as claimed by the applicant.
Since Wilkins clearly discloses that the clarified brine from tank #35 is then passed through line #37 to suitable equipment for subsequent recovery of desired elements remaining in solution in the brine, it would have been obvious by one of ordinary skill in the art before the effective filing date of the applicant’s invention to modify the system as disclosed by Wilkin by taking the clarified brine to a suitable equipment for subsequent recovery of desired elements remaining in solution in the brine, such as taking the clarified brine and pass it through at least one intercalated lithium absorbent column configured to isolate lithium chloride adapted to remove lithium chloride from a stream of flashed Salton Sea geothermal brine and be regenerated with wash water comprising lithium ions to produce a lithium chloride-rich stream having the removed lithium chloride, as claimed by the applicant, with a reasonable expectation of success, as Burba teaches crystalline lithium aluminates of 2-layer variety are regenerated by using an aqueous wash containing lithium ions, wherein the regenerated crystals deficient with respect to Li+ values are particularly suitable for extracting Li+ values from Li-containing brines, whereby a crystalline 2-layer LiCl2Al(OH)3.nH2O is prepared within microporous beads of DOWEX-MWA-1-Cl ion exchange resin by reacting gibbsite-containing resin with a 20% aqueous solution of LiCl, thereby forming a composite, wherein about 120ml of the composite is placed in an exchange column, i.e. intercalated lithium absorbent column, and is washed with about 150ml of Li+ solution to remove some, but not all, of the Li+ values from the composite, and brine containing about 250ppm of Li+ is passed through the composite until equilibrium is reached, indicating the aluminate crystal is loaded with Li+, wherein the composite is regenerated by passing 150ml 1000ppm Li+ solution and catching the effluent in 5ml cuts and the LiCl concentration of the cuts peaks at 3.93% LiCl; ¼ bed volume of product cuts yields 3.02% LiCl, thereby obtaining a system which efficiently produces a lithium chloride-rich stream from brine (see column 5, lines 38-61, example 7).
Wilkins, in view of Burba, fails to disclose an ion exchange adapted to reduce the concentration of boron in the lithium chloride-rich stream.
However, Yan teaches boron removal by ion exchange resin from refined brine used to produce low-boron lithium salts (see abstract). Ion exchange technique, which is now most extensively used has been proven to be an effective method for removing micro-amounts of boron from aqueous solutions. It is very necessary to use specific resins for boron removal, due to boron’s low affinity to resin (see introduction). The resin XSC-800 is a chelating ion exchange resin used to remove micro-amounts of boron from refined brine comprising lithium ions and boron. A glass ion exchange column containing the resin XSC-800 was prepared and refined brine was delivered to the column. From the outlet of the column, samples were taken and breakthrough curves of boron were obtained by analysis of each sample (see figure 1 and page 565, 2.2 Column-made sorption elution-studies). Under optimal conditions, boron can be removed much completely by selective ion exchange resin XSC-800 (see page 568, 3.1.7 Column-mode recycle test).
It would have been obvious by one of ordinary skill in the art before the effective filing date of the applicant’s invention to modify the system as disclosed by Wilkins, in view of Burba, by further having an ion exchange comprising a selective chelating ion exchange resin adapted to reduce the concentration of boron in the lithium chloride-rich stream, as claimed by the applicant, with a reasonable expectation of success, as Yan teaches boron removal by ion exchange resin from refined brine used to produce low-boron lithium salts, wherein ion exchange technique, which is now most extensively used has been proven to be an effective method for removing micro-amounts of boron from aqueous solutions, whereby it is very necessary to use specific resins for boron removal, due to boron’s low affinity to resin, and the resin XSC-800 is a selective chelating ion exchange resin used to remove micro-amounts of boron from refined brine comprising lithium ions and boron, wherein a glass ion exchange column containing the resin XSC-800 was prepared and refined brine was delivered to the column and from the outlet of the column, samples were taken and breakthrough curves of boron were obtained by analysis of each sample and, under optimal conditions, boron can be removed much completely by selective ion exchange resin XSC-800, thereby obtaining a system which efficiently removes boron from refined brine and hence, providing a further improved purified lithium salts-rich stream (see page 564, abstract and introduction).
In regards to Claim 91, Wilkins, in view of Burba and Yan, discloses the system as recited in claim 86. Although Wilkins, as modified above, is silent in regards to wherein the concentration of silica is less than about 5ppm, Wilkins, as modified above, discloses substantially the same system, as claimed by the applicant. Therefore, the system as disclosed by Wilkins will be capable of operating in the same manner as claimed, including removing lithium chloride from a stream of Salton Sea geothermal brine with a reduced concentration of silica of less than 5ppm, since the claimed invention is directed to a system and not to a process. The prior art only has to provide a structure that is capable of performing in the manner claimed. If the prior art structure is capable of performing the claimed use, then it meets the claim. See MPEP 2114.
Response to Arguments
Applicant's arguments filed have been fully considered but they are not persuasive.
Applicant argues that: “Wilkins is directed to the addition of ammonium hydroxide to geothermal brine. The addition of ammonium hydroxide raises the pH of the brine to a range between 6.0 and 7.0 (moving it toward a neutral state). This change in pH reacts with aluminum and iron ions already present in the brine, creating a gelatinous "sludge" made of aluminum and iron hydroxides. Wilkins discloses the following:
“As will be noted, the concentration of dissolved silica in the brine decreases very rapidly at first as the pH is increased to a level wherein the sludge-forming reactions begin, and then decreases at a lower rate with a further increase in pH. It has been found that the lower practical limit for pH is about 6.0. At this pH level the silica concentration has been reduced sufficiently such that although supersaturation and silica scale formation may occur when the temperature of the brine is later reduced, the amount of scale formed will be within tolerable limits whereby such scale can be removed by conventional treatments, such as acidifying with hydrofluoric acid, dissolution with an extremely high pH caustic or mechanical scraping. At a pH below 6.0 the brine can still cause considerable corrosion problems. Additionally, as can be seen from FIG. 2, at low pH levels, the slope of curves 16 and 17 is quite steep, making it difficult to control the process, since slight changes in pH result in large variations in the concentration of silica remaining dissolved in the brine. (Emphases added).”
The Office alleges that Wilkins teaches a pH range greater than 5.5 for the geothermal brine to precipitate aluminum and iron. However, Wilkins explicitly teaches away from a pH below 6. The present claims recite that the pH of the flashed Salton Sea geothermal brine is between about 4.5 and 6. In this regard, the present discloses that "the pH is adjusted to above at least about 4.5 to induce precipitation of silica and iron ... it is preferred the pH is not increased above about 6, to prevent the precipitation of other ionic species present in the lithium containing brine." This is because the claimed process can potentially recover other valuable ion species and uses an oxidant to selectively precipitate certain compounds. For example, contacting silica present in the lithium chloride containing solution with the iron (III) compound (produced from oxidation) forms a precipitate when the pH is adjusted to between about 4.5 and 6 with the addition of lime or similar base. Wilkins fails to disclose or teach the claimed process in which the pH of the flashed Salton Sea geothermal brine is between about 4.5 and 6. Moreover, Wilkins has no disclosure at all regarding the flashed brine having the claimed pH-at most, Wilkins only teaches adjusting the pH of the initial brine. Wilkins does not mention or teach pH adjustment of the flashed brine. (see Wilkins stating "[a]fter the ammonium hydroxide injection and sludge formation and silica removal step in the reaction chamber 13, the steam, brine and suspended sludge passes, for example, to a series of connected steam separators 19, 20 and 21, where the temperature and pressure of the brine is sequentially reduced and the steam is separated therefrom for beneficial use of for exhaust to atmosphere.”
Examiner respectfully disagrees and points out that even if, assuming arguendo, Wilkins does not disclose or teach the claimed process in which the pH of the flashed Salton Sea geothermal brine is between about 4.5 and 6, the claimed invention is directed to a system and structural limitations related to the system, and not to processes within the system claims. The claimed invention is directed to a system for producing lithium chloride-rich stream having reduced concentration of boron, wherein the system comprises: (1) at least one intercalated lithium absorbent column configured to isolate lithium chloride adapted to (a) remove lithium chloride from a stream of flashed Salton Sea geothermal brine, and (b) be regenerated with wash water comprising lithium ions to produce a lithium chloride-rich stream having the removed lithium chloride, and (2) an ion exchange adapted to reduce the concentration of boron in the lithium chloride-rich stream. The claimed invention is not directed to a process. Therefore, the process and/or way the flashed Salton Sea geothermal brine is produced to have a reduced concentration of silica and iron and a pH of between 4.5 and 6 has no significant patentable weight, as long as the intercalated lithium absorbent column is capable of isolating lithium chloride from the brine. Since Wilkins, in view of Burba and Yan, discloses substantially the same intercalated lithium absorbent column as claimed by the applicant, it is considered reasonably obvious, absent evidence to the contrary, that Wilkins’s system, as modified above, is capable of functioning in the same manner as claimed, such as being capable of removing lithium chloride from the stream of flashed Salton Sea geothermal brine, as claimed by the applicant, as it has been held that when the structure recited in the reference is substantially identical to that of the claims, claimed functions are considered prima facie obvious. See MPEP 2112.01. In view of this, the argument is not considered persuasive and the rejection is thereby maintained.
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure.
Jost et al. (US PAT. No. 4,405,463)- Processes for removing dissolved silica from geothermal brine to prevent silica scaling. The silica removal process can be used for recovery of salts or mineral species contained in geothermal aqueous liquids and which precipitate or are carried along with the iron-rich siliceous material precipitated by the process. The process is used to continuously remove silica from a flow of silica-rich flashed geothermal brine effluent from a geothermal brine. Air is injected from an oxidizing source to flashed brine effluent in a clarifier tank and the brine effluent is found to have a pH between 3 and 5 and a reduced silica content (see example and column 11, line 32 to column 12, line 16).
THIS ACTION IS MADE FINAL. Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to JELITZA M PEREZ whose telephone number is (571)272-8139. The examiner can normally be reached Monday-Friday 9:00am-6:00pm.
Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice.
If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Claire Wang can be reached at (571) 270-1051. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
Information regarding the status of published or unpublished applications may be obtained from Patent Center. Unpublished application information in Patent Center is available to registered users. To file and manage patent submissions in Patent Center, visit: https://patentcenter.uspto.gov. Visit https://www.uspto.gov/patents/apply/patent-center for more information about Patent Center and https://www.uspto.gov/patents/docx for information about filing in DOCX format. For additional questions, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000.
/JELITZA M PEREZ/ Primary Examiner, Art Unit 1774
Prosecution Insights