Prosecution Insights
Last updated: April 19, 2026
Application No. 18/971,207

REACTION SCHEMES INVOLVING ACIDS AND BASES; REACTORS COMPRISING SPATIALLY VARYING CHEMICAL COMPOSITION GRADIENTS; AND ASSOCIATED SYSTEMS AND METHODS

Non-Final OA §103§DP
Filed
Dec 06, 2024
Examiner
LI, JUN
Art Unit
1732
Tech Center
1700 — Chemical & Materials Engineering
Assignee
Massachusetts Institute Of Technology
OA Round
3 (Non-Final)
54%
Grant Probability
Moderate
3-4
OA Rounds
3y 7m
To Grant
99%
With Interview

Examiner Intelligence

Grants 54% of resolved cases
54%
Career Allow Rate
462 granted / 857 resolved
-11.1% vs TC avg
Strong +57% interview lift
Without
With
+57.3%
Interview Lift
resolved cases with interview
Typical timeline
3y 7m
Avg Prosecution
70 currently pending
Career history
927
Total Applications
across all art units

Statute-Specific Performance

§101
0.1%
-39.9% vs TC avg
§103
47.8%
+7.8% vs TC avg
§102
9.4%
-30.6% vs TC avg
§112
25.4%
-14.6% vs TC avg
Black line = Tech Center average estimate • Based on career data from 857 resolved cases

Office Action

§103 §DP
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 . 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and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114.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 01/20/2026 has been entered. 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 text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action. Claim(s) 1-5 and 15-19 are rejected under 35 U.S.C. 103 as obvious over Burba (JP2013/528696) (for applicant’s convenience, English equivalent US 20110182786 has been used for citations) in view of Matsubayashi et al. (JP2016020296) (for applicant’s convenience, machine translation has been used for citations). Burba teaches a process for recovering a valuable metal from a valuable metal-containing material using a mineral acid produced by an electrochemical acid generation process, such as a chloralkali cell or bipolar membrane electrodialysis system (i.e. electrolysis) (item 116, 280, Fig. 2), the process comprising (Fig. 2, para. [0016]-[0021], [0056], [0075], [0090]-[0094]): (a) contacting a valuable metal-containing material with a leaching solution to form a pregnant leach solution comprising a dissolved valuable metal (equivalent to dissolving a first substance in a first solution), wherein once dissolved, the valuable metal solution can be optionally isolated from impurities, such as iron, by suitable technique, such as precipitation (para. [0054], [0105]-[0108], Fig. 2-3); (b) recovering the dissolved valuable metal to form a valuable metal product and a byproduct salt solution, wherein typically at least most of the byproduct salt solution is derived from a reaction of an acid with a base in one or both of the contacting and recovering steps; wherein the byproduct salt solution (item 224, Fig. 2) and salt solution (item 216, Fig .2) including a variety of polyvalent impurities (e.g. Ca, Mg, iron) (para. [0105]) and such polyvalent impurity can be optionally removed from the byproduct salt solution by precipitation induced by a pH change from contact of the base with the byproduct salt solution (Fig. 2-3, para. [0105]-[0108], [0128]-[0130]); (c) converting, by one or more of a chloralkai and bipolar membrane electrodialysis cell (i.e. an eletrolyzer), the byproduct salt solution into the acid and base; and (d) recycling at least most of the acid and base to the contacting and/or recovering steps (para. [0105]-[0108], Fig. 2-3). Barbu further discloses: recycling at least most of the acid and base to the contacting and/or recovering steps (para [0011], lixiviant used for leaching may include other inorganic and organic acids. Once dissolved, the valuable metal is isolated from impurities, such iron, by a suitable recovery technique, such as precipitation (para. [00 54]). Barbu teaches an example A: a determination of a multi-stage precipitation of combined solution (item 208) and ion exchange process for removing divalent and trivalent cations prior to a salt splitting process. M2 is the second precipitation stage (FIG. 3) where the metal carbonate slurry was contacted with a sodium hydroxide solution having about 8 wt.% NaOH to further raise the pH to a pH of from about pH 11 to about pH 12 and to further precipitate as hydroxides any of the metals identified above (such as magnesium and calcium, iron etc.) remaining in solution (para. [0128]-[0130]). Since Barbu disclosed combined solution comprising calcium ions and such calcium ions and calcium hydroxide being produced from such calcium ions, therefore, precipitating calcium hydroxide directly from the ions comprising calcium using the base being performed in a region of the plant (i.e. a reactor) with PH of 10 or higher is expected (item 122 Fig. 2). Furthermore, selection of any order of adding ingredients or prior art process steps is prima facie obvious (See §MPEP 2144.04 IV). It would have been obvious for one of ordinary skill in the art to precipitating calcium hydroxide directly from the ions comprising calcium using the base being performed in a region of the plant (i.e. a reactor) with PH of 10 or higher for help obtaining desired calcium hydroxide product as suggested by Barbu. Regarding claim 1and 15, Barbu does not expressly teach dissolving a material comprising Ca to produce ion comprising Ca. However, Barbu already teaches add acid during the process of dissolution in a region of the plant (para. [0054], Fig. 2) and adding base to precipitate out magnesium hydroxide and calcium hydroxide in a region of the plant ([0105], [0106], [0128]-[0130], Fig. 2-3). Barbu also teaches the valuable metal-containing feed material (item 104) may comprise a mined ore, concentrate, tailings, metallurgical residue or a mixture thereof, such as minerals comprising valuable metals (para. [0049]). Matsubayashi et al. teaches a method comprising dissolving steel stag (containing Ca, Fe etc. metal) in a hydrochloric acid to produce dissolved material containing calcium ions (CaCl2) and then such CaCl2 being directly precipitated as Ca(OH)2 when treated at pH of 13 or higher (claim 1, Fig. 1 , para. [0015]-[0017], [0020], [0038]). It would have been obvious for one of ordinary skill in the art to adopt such well-known calcium containing slag as shown by Matsubayashi et al.to modify the valuable metal-containing feeding material in the process of Burba because applying a known technique of dissolving a calcium containing material as valuable metal feeding material to modify a known method of recovering valuable metal for improvement would yield predictable result (See MPEP § 2143 KSR). It would have been obvious for one of ordinary skill in the art to dissolving a material comprising calcium using the acid produced by the electrolysis as a routine operation for obtaining Ca ions in solution because recycling such acid material is economical and reducing cost. It would have been obvious for one of ordinary skill in the art to precipitate calcium hydroxide directly from the solution containing calcium as shown by Matsubayashi et al. to modify the precipitation process because by adopting such well-known technique to improve a well-known method for improvement would have predictable results (See MPEP § 2143 KSR). It would have been obvious for one of ordinary skill in the art to collect such precipitated Ca(OH)2 for intended application, such as for forming cement as discussed below. Regarding claim 2-4, Barbu already teaches such limitation as discussed above. Regarding claim 5, Barbu already teaches using acid to dissolve valuable metal containing material with impurities of Ca, Mg etc. in a region of the plant (item 122, Fig. 2, para. [0092], [0105]) wherein apparently such acid having pH value less than 7, therefore, the solution has an overlapping pH range with that of instantly claimed thus renders a prima facie case of obviousness (see MPEP § 2144.05 I). Regarding claim 16-19, Barbu already teaches such limitation as discussed above. Claim(s) 6-14 and 20 are rejected under 35 U.S.C. 103 as obvious over Burba (JP2013/528696) (for applicant’s convenience, English equivalent US 20110182786 has been used for citations) in view of Matsubayashi et al. (JP2016020296) as applied above, and further in view of Bullerjahn et al. (US9718731). Regarding claim 6-8 and 20, Burba in view of Matsubayashi et al. does not expressly teaches using Ca(OH)2 in a downstream process of forming cement (noted cement is a construction material). Bullerjahn et al. teaches Ca(OH)2 can be used as raw materials for forming cement material (claim 1, 3, col. 2 line 65-col. 3 line 5, col. 3 lines 42-46). It would have been obvious to adopt Barbu disclosed Ca(OH)2 as raw material to practice the raw material of Bullerjahn et al. because by doing so can help providing high CaO content forming desired cement composition as suggested by Bullerjahn et al. (col. 2 49-53, col. 3 lines 42-46). Furthermore utilizing such generated Ca(OH)2 obtained from impurity for generating cement material can help efficiently reutilizing materials and save cost for producing valuable cement materials. Regarding claim 9-11 and 14, Bullerjahn et al. also teaches fly ash (pozzolanic material) (col. 3 lines 32, 43-47, col. 6 lines 49-51) and Portland (cement) clinker (col. 4 lines 22-25) can be used as raw material, wherein such fly ash and Portland cement reads onto the instantly claimed Pozzolan cement. Bullerjahn et al. further teaches additional elements and /or oxides can be added during the cement formation process (col. 3 lines 14-16). Bullerjahn et al. also teaches seed crystal such as Portland clinker (containing calcium silicate), calcium silicate hydrate, granulated blast furnace slag (noted such material containing silica and alumina), magnesium silicate, sodium silicate, glass powder can be added during cement forming (col. 4 lines 22-32). It would have been obvious for one of ordinary skill in the art to adopt add such seed crystal of silicate material or material containing silica (e.g. glass powder), alumina (e.g. granulated blast furnace slag), pozzolan cement as shown by Bullerjahn et al. as additive into the raw material mixture containing Ca(OH)2 for forming cement material because by doing so can help accelerate the cement forming reaction as suggested by Bullerjahn et al. (col. 4 lines 22-32). Regarding claim 12, such limitation has been met as discussed above. Regarding claim 13, Bullerjahn et al. further such cement material and additives being mixed with water to form a concrete material being used as building material (i.e. construction material) (col. 1 lines 14-18, Fig. 1, example 1-2. Table 2, claim 26). It would have been obvious for one of ordinary skill in the art to adopt such conventional mixing cement with water and additives as shown by Bullerjahn et al. for help obtaining a desired concrete material as suggested by Bullerjahn et al. because adopting a known technique of mixing cement with water and additive in a known method of producing concrete would have predictable results (see MPEP§ 2143 KSR). Double Patenting The nonstatutory double patenting rejection is based on a judicially created doctrine grounded in public policy (a policy reflected in the statute) so as to prevent the unjustified or improper timewise extension of the “right to exclude” granted by a patent and to prevent possible harassment by multiple assignees. A nonstatutory double patenting rejection is appropriate where the conflicting claims are not identical, but at least one examined application claim is not patentably distinct from the reference claim(s) because the examined application claim is either anticipated by, or would have been obvious over, the reference claim(s). See, e.g., In re Berg, 140 F.3d 1428, 46 USPQ2d 1226 (Fed. Cir. 1998); In re Goodman, 11 F.3d 1046, 29 USPQ2d 2010 (Fed. Cir. 1993); In re Longi, 759 F.2d 887, 225 USPQ 645 (Fed. Cir. 1985); In re Van Ornum, 686 F.2d 937, 214 USPQ 761 (CCPA 1982); In re Vogel, 422 F.2d 438, 164 USPQ 619 (CCPA 1970); In re Thorington, 418 F.2d 528, 163 USPQ 644 (CCPA 1969). A timely filed terminal disclaimer in compliance with 37 CFR 1.321(c) or 1.321(d) may be used to overcome an actual or provisional rejection based on nonstatutory double patenting provided the reference application or patent either is shown to be commonly owned with the examined application, or claims an invention made as a result of activities undertaken within the scope of a joint research agreement. See MPEP § 717.02 for applications subject to examination under the first inventor to file provisions of the AIA as explained in MPEP § 2159. See MPEP § 2146 et seq. for applications not subject to examination under the first inventor to file provisions of the AIA . A terminal disclaimer must be signed in compliance with 37 CFR 1.321(b). The filing of a terminal disclaimer by itself is not a complete reply to a nonstatutory double patenting (NSDP) rejection. A complete reply requires that the terminal disclaimer be accompanied by a reply requesting reconsideration of the prior Office action. Even where the NSDP rejection is provisional the reply must be complete. See MPEP § 804, subsection I.B.1. For a reply to a non-final Office action, see 37 CFR 1.111(a). For a reply to final Office action, see 37 CFR 1.113(c). A request for reconsideration while not provided for in 37 CFR 1.113(c) may be filed after final for consideration. See MPEP §§ 706.07(e) and 714.13. The USPTO Internet website contains terminal disclaimer forms which may be used. Please visit www.uspto.gov/patent/patents-forms. The actual filing date of the application in which the form is filed determines what form (e.g., PTO/SB/25, PTO/SB/26, PTO/AIA /25, or PTO/AIA /26) should be used. A web-based eTerminal Disclaimer may be filled out completely online using web-screens. An eTerminal Disclaimer that meets all requirements is auto-processed and approved immediately upon submission. For more information about eTerminal Disclaimers, refer to www.uspto.gov/patents/apply/applying-online/eterminal-disclaimer. Claims 1-20 are provisionally rejected on the ground of nonstatutory double patenting as being unpatentable over claim 165-176 and 181-184 of co-pending Application No. 17/438,888 (reference application) in view of Burba. Co-pending application’888 teaches a substantially the same method as that of instantly claimed involving dissolving material comprising calcium except precipitating calcium as calcium hydroxide with pH greater than 10 in a region of reactor, but such limitation is taught by Burba. It would have been obvious for one of ordinary skill in the art to adopt such pH value to precipitate out calcium as calcium hydroxide in a region of a reactor as shown by Burba for help obtaining desired calcium hydroxide product (see also MPEP §2143 KSR). This is a provisional nonstatutory double patenting rejection because the patentably indistinct claims have not in fact been patented. Claims 1-20 are provisionally rejected on the ground of nonstatutory double patenting as being unpatentable over claim 1 and 63-80 of co-pending Application No. 17/922,126 (reference application) in view of Burba. Although the claims at issue are not identical, they are not patentably distinct from each other because co-pending application’126 teaches a same or substantially the same method as that of instantly claimed involving dissolving material comprising calcium except precipitating calcium as calcium hydroxide with pH greater than 10 in a region of reactor, but such limitation is taught by Burba. It would have been obvious for one of ordinary skill in the art to adopt such pH value to precipitate out calcium as calcium hydroxide in a region of a reactor as shown by Burba for help obtaining desired calcium hydroxide product (see also MPEP §2143 KSR). This is a provisional nonstatutory double patenting rejection because the patentably indistinct claims have not in fact been patented. Terminal Disclaimer The terminal disclaimer filed on 01/22/2026 disclaiming the terminal portion of any patent granted on this application which would extend beyond the expiration date of U.S. Patent No. 12330989 has been reviewed and is accepted. The terminal disclaimer has been recorded. Response to Arguments Applicant's arguments filed on 01/22/2026 have been fully considered but they are moot in view of current rejections. In response to applicant’s arguments about Barba not teaching dissolving calcium using the acid, Barbu already teaches add acid during the process of dissolution in a region of the plant (para. [0054], Fig. 2) and adding base to precipitate out magnesium hydroxide and calcium hydroxide in a region of the plant ([0105], [0106], [0128]-[0130], Fig. 2-3). Furthermore, dissolving calcium using the acid is well-known in the art for one of ordinary skill in the art as shown by Matsubayashi et al. In response to applicant’s arguments about later-patenting filing date about co-pending application, it is noted that such double patenting rejections are provisional and this co-pending applications teach a substantially the same process as that of instantly claimed. Conclusion Any inquiry concerning this communication or earlier communications from the examiner should be directed to JUN LI whose telephone number is (571)270-5858. The examiner can normally be reached IFP. 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, Ching-Yiu (Coris) Fung can be reached at 571-270-5713. 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. /JUN LI/Primary Examiner, Art Unit 1732
Read full office action

Prosecution Timeline

Dec 06, 2024
Application Filed
Apr 24, 2025
Non-Final Rejection — §103, §DP
Jun 03, 2025
Applicant Interview (Telephonic)
Jun 03, 2025
Examiner Interview Summary
Jul 15, 2025
Response Filed
Jul 22, 2025
Final Rejection — §103, §DP
Jan 20, 2026
Request for Continued Examination
Jan 26, 2026
Response after Non-Final Action
Feb 19, 2026
Non-Final Rejection — §103, §DP (current)

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Study what changed to get past this examiner. Based on 5 most recent grants.

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Prosecution Projections

3-4
Expected OA Rounds
54%
Grant Probability
99%
With Interview (+57.3%)
3y 7m
Median Time to Grant
High
PTA Risk
Based on 857 resolved cases by this examiner. Grant probability derived from career allow rate.

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