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 .
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.
Claim Rejections - 35 USC § 103
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 and 4-5 are rejected under 35 U.S.C. 103 as being unpatentable over Ansari et al. (US PG Pub 2020/0231462 A1, hereinafter “Ansari”) in view of Gomaa et al. (J. Mater. Cycles Waste Manag. 2024, 26, 882-893, published online 26 December 2023, hereinafter “Gomaa”), Buonincontri (“Electrolytic Removal of Tin from Tinplated Scraps”, Master’s Thesis, Polytechnic University of Milan, 2021. URL: <https://www.politesi.polimi.it/handle/10589/179197>), Silva et al. (“Production of Iron Pigments (Goethite and Haematite) from Acid Mine Drainage,” International Mine Water Association, 2011, 469-473, <URL: https://www.imwa.info/docs/imwa_2011/IMWA2011_Silva_377.pdf>, hereinafter “Silva”), and Hassanpour et al. (RSC Adv., 2024, 14, 17296-17305”, published online 29 May 2024, hereinafter “Hassanpour”).
Regarding claim 1, Ansari teaches a method of making CuFe2O4 nanoparticles (abstract and paragraph 107, where x=0.0) by mixing an iron nitrate solution with an aqueous copper nitrate solution in a 2:1 molar ratio (a molar ratio or the copper(II) salt to …the iron(III) salt of …about 1:2; paragraph 77; it is again noted, chromium will be zero in this embodiment) to obtain spinel CuFe2O4 (copper ferrite) nanoparticles through co-precipitation (copper ferrite nanoparticles…were prepared by co-precipitation method using copper(II) nitrate pentahydrate [and] iron nitrate, paragraph 107, where x=0.0 no chromium is present), centrifuging the spinel CuFe2O4 nanoparticles (separated, e.g. centrifuged; paragraph 82), and drying and calcining the spinel CuFe2O4 nanoparticles to obtain CuFe2O4 nanoparticles (the method further involves the step of drying the precipitate… to produce the spinel ferrite nanoparticles…and an additional heat treatment; i.e. annealing; paragraph 83). The instant specification likewise uses calcining and annealing interchangeably, for example in paragraphs 7 and 32, where this final step is described as annealing.
Ansari does not teach the use of iron cans coated in tin as starting material, the removal of tin from said cans using H2SO4, cutting the can into pieces, or the dissolving, precipitation with NaOH, centrifuging and redissolving in nitric acid. Ansari also does not teach washing the spinel CuFe2O4 with water and ethanol, as required by the instant claim.
However, Gomaa teaches the upcycling of tin cans to related iron-oxide based nanoparticles (low-cost iron oxide catalysts have been prepared …using tin food can waste, abstract; the nano characteristics are apparent from the sizes in Table 1) and the preparation of ferric (iron) nitrate solutions by first cutting the clean iron can into pieces and dissolving the pieces in nitric acid to obtain an iron nitrate solution (p. 884, column 2, paragraphs 3-4; p. 883, column 2, paragraph 1 describes that the “tin” food packaging cans are composed primarily of iron with a small tin content) and then slowly adding an aqueous NaOH solution to the iron nitrate solution dropwise, the aqueous NaOH solution having a concentration of 2.0 M (p. 885, paragraph 1), which is similar to the instantly claimed concertation of 1.5 M.
Regarding performing the reaction on 4 grams of pieces using 5 mL nitric acid and then adding 25 mL of nitric acid, these particulars are considered an obvious variation of the process taught by Gomaa where 25 g of clean cans were cut to small pieces and immersed in a beaker containing 1000 mL of 1 M HNO3 solution and the mixture stirred to obtain a solution (p. 884,¶ 4), as the courts have held that changing the scale of a reaction as well as the sequence of adding ingredients represent obvious variations in the absence of new or unexpected results. In re Rinehart, 531 F.2d 1048, 189 USPQ 143 (CCPA 1976). Ex parte Rubin, 128 USPQ 440 (Bd. App. 1959). In re Burhans, 154 F.2d 690, 69 USPQ 330 (CCPA 1946). In re Gibson, 39 F.2d 975, 5 USPQ 230 (CCPA 1930). MPEP 2144.04(IV).
Furthermore, Buonincontri teaches the removal of tin from tin plated iron cans by dissolving the tin in H2SO4 (the dissolution and subsequent extraction of tin from scraps is carried out in acidic solutions, such as H2SO4; page 16, lines 10-11). Buonincontri also teaches that hydrometallurgical processes, such as the leaching of tin with H2SO4, are generally preferred due to their relatively simple equipment and low cost procedures (Section 1.5, page 15-16).
Additionally, Silva teaches that iron-containing solutions can be purified and iron separated from other metals by precipitation with hydroxide (selective precipitation to recover iron…allows the separation of iron from other metals present; p. 469, column 1, paragraph 4; col. 2, ¶ 2; and Eq. 1) followed by centrifuging of the precipitate ([precipitated ferric hydroxide/oxyhydroxide] was further separated … by centrifugation; p. 470, ¶ 3), and subsequent dissolution in nitric acid to give solutions of iron nitrate (hydroxide/oxyhydroxide precipitate …was resolubilized with nitric acid to obtain a ferric nitrate solution; p. 471, column 1, paragraph 3 and Eq. 2). Though Silva teaches precipitation of the ferric iron at pH 3.6, Gomaa teaches that ferric iron can also be precipitated at pH 8.8 and 11.2 (p. 885, ¶ 1).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to generate the iron nitrate solution used in the method of Ansari by:
providing an iron can coated in tin, as taught by Gomaa;
removing the tin by dissolving the tin in H2SO4, as taught by Buonincontri;
cutting the iron can into pieces, and dissolving 4 grams of the pieces in 5 mL nitric acid until the pieces start to etch and then adding 25 mL of nitric acid to obtain an iron nitrate solution, as taught by Gomaa;
adding an aqueous NaOH solution to the iron nitrate solution dropwise until a mixture having a pH in the range 3.6 to 11.2 is obtained, the NaOH solution having a concentration of 2 M, as taught by Gomaa and Silva;
centrifuging the obtained precipitate and adding nitric acid to the centrifuges precipitate to obtain a pure iron nitrate solution, as taught by Silva;
One of ordinary skill in the art would have been motivated to prepare the iron nitrate to be used in the method of Ansari using these steps because Gomaa teaches that the use of tin cans takes advantage of a valuable resource and is in alignment with the principles of sustainability and environmental preservation (page 883, column 1) and because of the low-cost of tin-coated iron cans.
One of ordinary skill in the art would have been further motivated to add the purification steps taught by Silva because Silva teaches that this method produces purified iron nitrate from impure iron-containing sources. This combination would have been obvious because it represents the use of a known technique (the precipitation and redissolution of iron nitrate for purification) to improve similar methods (the recovery of iron from impure sources) in the same way. MPEP 2143(I)(C).
One of ordinary skill in the art would have been additionally motivated to add the tin removal taught by Buonincontri because Buonincontri teaches that the H2SO4 leaching technique can remove tin with simple equipment and at low-cost with (Section 1.5, page 15-16).
Additionally, Hassanpour teaches the washing of copper ferrite nanoparticles with water and ethanol, following a centrifugation and before drying (the precipitate was centrifuged, washed with deionized water and ethanol several times, and dried; Section 2.4), in a synthesis largely similar to that described by Ansari. Hassanpour also teaches calcining the spinel CuFe2O4 precipitate to obtain CuFe2O4 nanoparticles (in order to calcine the product, it was placed in a furnace … and the CuFe2O4 nanoparticles were formed; Section 2.4).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to use the wash the spinel CuFe2O4 nanoparticles obtained by the method of modified Ansari with water and ethanol, as taught by Hassanpour. One of ordinary skill in the art would have been motivated to do so in order to remove impurities and give a purer product. This washing represents the use of a known technique (washing) to improve a similar method (the synthesis of spinel copper ferrite nanoparticles) in the same way. MPEP 2143(I)(C).
Regarding the differences between the 2 M NaOH solution taught by Gomaa and the 1.5 M NaOH required by the instant claim, it is noted the courts have found that “where the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation.” In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955). See MPEP 2144.05 II.
Therefore, it would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to use any concentration of NaOH in this general range of 2.0 M, including 1.5 M. One of ordinary skill in the art would have been motivated to do so because this change represents the substitution of one concentration of solution with another with the same predictable result of adjusting the pH of the reaction mixture to a desired range.
Generally, differences in concentration or temperature will not support the patentability of subject matter encompassed by the prior art unless there is evidence indicating such concentration or temperature is critical. "[W]here the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation." See MPEP 2144.05 and In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955).
It is also noted that the courts have stated where the claimed ranges “overlap or lie inside the ranges disclosed by the prior art” a prima facie case of obviousness exists (see In re Wertheim, 541 F.2d 257, 191 USPQ 90 (CCPA 1976); In re Woodruff, 919 F.2d 1575, 16 USPQ2d 1934 (Fed. Cir. 1990); Titanium Metals Corp. of America v. Banner, 778 F2d 775. 227 USPQ 773 (Fed. Cir. 1985) (see MPEP 2144.05.01). Therefore, the claimed pH for precipitation from the initial iron nitrate solution merely represents an obvious variant and/or routine optimization of the values of the cited prior art.
Regarding claim 4, while modified Ansari does not teach the color of the nanoparticles produced by their methods, the nanoparticles taught by both Ansari and Hassanpour each have the same composition as those of the instantly claimed invention and are produced by a substantially identical processes. As such the color of the nanoparticles disclosed by modified Ansari would be the same as or substantially identical to that of the claimed invention.
It is noted that where the claimed and prior art products are identical or substantially identical in structure or composition, or are produced by identical or substantially identical processes, a prima facie case of either anticipation or obviousness has been established. In re Best, 562 F.2d 1252, 1255, 195 USPQ 430, 433 (CCPA 1977). MPEP 2112 .01(I). Furthermore, once a reference teaching a product appearing to be substantially identical is made the basis of a rejection, and the examiner presents evidence or reasoning tending to show inherency, the burden shifts to the applicant to show an unobvious difference. "[T]he PTO can require an applicant to prove that the prior art products do not necessarily or inherently possess the characteristics of [their] claimed product. Whether the rejection is based on inherency’ under 35 U.S.C. 102, on prima facie obviousness’ under 35 U.S.C. 103, jointly or alternatively, the burden of proof is the same, and its fairness is evidenced by the PTO’s inability to manufacture products or to obtain and compare prior art products." In re Best, 562 F.2d 1252, 1255, 195 USPQ 4380, 483-34 (CCPA 1977)), see MPEP 2112. Applicant has not clearly shown an unobvious difference between the instant invention and the prior art’s product.
Regarding claim 5, modified Ansari teaches the method of claim 1, where Ansari teaches the nanoparticles having an average size in a range of 20 nm-99 nm (paragraph 69), which overlaps with the claimed range of about 20 nm to about 30 nm (claim 5).
It is noted that the courts have stated where the claimed ranges “overlap or lie inside the ranges disclosed by the prior art” a prima facie case of obviousness exists (see In re Wertheim, 541 F.2d 257, 191 USPQ 90 (CCPA 1976); In re Woodruff, 919 F.2d 1575, 16 USPQ2d 1934 (Fed. Cir. 1990); Titanium Metals Corp. of America v. Banner, 778 F2d 775. 227 USPQ 773 (Fed. Cir. 1985) (see MPEP 2144.05.01).
Response to Arguments
The declaration filed 5 January 2026 has been re-considered in light of the amended claims. However, it is unclear how the data and arguments presented therein relate to the concentration of NaOH used to precipitate iron hydroxides in the amended claims. The experiments and data described in this declaration seem to be related only to the concentration of NaOH used to precipitate CuFe2O4, and not the concentration of NaOH that is added to the first iron nitrate solution.
The declaration filed 4 May 2026 references application 17/070,758, and not the instant application. Nevertheless, the contents of the declaration have been considered to the extent that they may be relevant to the instant claims.
The experiments described in this declaration compare a method lacking the newly claimed precipitate[Wingdings font/0xE0]wash/centrifuge[Wingdings font/0xE0]re-dissolution sequence to a method having these steps. However, these steps were introduced upon amendment and these comparisons are now moot in view of the teachings of Silva that have been incorporated into the rejections outlined above. The additional data presented in Table 1 is duplicative of that considered from the declaration filed 5 January 2026.
Applicant’s arguments, pages 6-7 of the reply file 4 May 2026, with respect to the lack of teaching in Ansari and Gomaa of the precipitate[Wingdings font/0xE0]wash/centrifuge[Wingdings font/0xE0] re-dissolution sequence, have been fully considered and are persuasive. Therefore, the prior rejection has been withdrawn. However, upon further consideration, a new ground(s) of rejection is made further in view of Silva, as analyzed above.
Applicant's arguments, pages 7-8 of the reply, with respect to criticality of the 1.5 M NaOH, have been fully considered but they are not persuasive.
For this argument Applicant references the concurrently filed declaration. However, it is noted that most of the declaration filed on 4 May 2026 concerns a comparison between a method lacking the precipitate[Wingdings font/0xE0]wash/centrifuge[Wingdings font/0xE0]re-dissolution sequence and one having these steps. These steps were introduced upon amendment and are now taught by Silva and so these comparisons are not relevant to the rejections outlined above.
Furthermore, the data presented in Table 1 of the declaration seem to be comparing results obtained using different NaOH concentrations to precipitate CuFe2O4 and the phase purity and crystallite size of this material, and do not appear relevant to the criticality of the NaOH used to precipitate the iron hydroxide which is later dissolved in nitric acid. Therefore, these data lack probative value in assessing criticality of the concentration of the NaOH used to precipitate iron hydroxide in the precipitate[Wingdings font/0xE0]wash/centrifuge[Wingdings font/0xE0]re-dissolution sequence of the instant claim, and the concentration used in the instant claim is still considered an obvious variation of that taught in the prior art.
Conclusion
Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). 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 Nicholas A Piro whose telephone number is (571)272-6344. The examiner can normally be reached Mon-Fri, 8:00 am-5:00 pm.
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/NICHOLAS A. PIRO/Assistant Examiner, Art Unit 1738 /PAUL A WARTALOWICZ/Primary Examiner, Art Unit 1735
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