DETAILED ACTION
Claims 1-10 were subjected to restriction requirement mailed on 12/31/2025.
Applicants filed a response, and elected Group I, claims 1-6, and canceled claims 7-10, with traverse on 02/25/2026.
Claims 1-6 are pending.
Claims 1-6 are rejected.
Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Election/Restrictions
Applicant's election with traverse of claims 1-6 in the reply filed on 02/25/2026 is acknowledged. This is not found persuasive because the reason set forth below.
Applicants primarily argue:
“The claims in different groups are not patentably distinct because they are not separate and independent inventions, but rather constitute a continuous, indivisible integrated production process.
Steps (S13) and (S14) of Invention I (a method for preparing iron phosphate) produce "precipitation A" and "by-product expressed as a third solution," respectively. Invention II (a method for preparing fertilizer) explicitly requires "mixing and concentrating the precipitate A in step (S13) and the by-product expressed as the third solution in step (S14)" followed by "melting and granulating." This explicitly demonstrates that the starting materials and essential steps for Invention II are entirely dependent on the implementation of Invention I. In other words, separated from Invention I, the Invention II itself cannot be implemented independently. Therefore, what the two describe are not two "distinct" methods that can exist independently with unrelated functions, but rather a continuous, logically sequential integrated process flow aimed at addressing an integrated technical problem of "how to efficiently, in an environmental-friendly manner, co- produce iron phosphate and nitro-phosphorus fertilizer from phosphorus concentrate."”
Remarks, p. 4-5
The examiner respectively traverses as follows:
Claim 7 (now canceled) only requires by-product from the method according to claim 1, does not require all the steps of claim 1. In other words, the “by-product from a method for preparing iron phosphate using ammonium phosphate according to claim 1” is a product-by-process limitation.
Thus, “[E]ven though product-by-process claims are limited by and defined by the process, determination of patentability is based on the product itself.
Applicants primarily argue:
“The specification clearly discloses a complete and coherent technical solution for preparing iron phosphate from phosphorus concentrate and further utilizing its by-products to produce fertilizer. This solution is described as an integrated inventive concept, not as two unrelated inventions. The relevant embodiments (e.g., Examples 1-4 of the specification) clearly demonstrate how the recited sequential steps are implemented as a unified process flow. Therefore, there is no circumstance in this case that necessitates separate search or examination for two distinctly different subjects.”
Remarks, p. 5
The examiner respectively traverses as follows:
Invention I is drawn to a method for preparing iron phosphate using ammonium phosphate, comprising the steps of (S11) decomposing phosphorus concentrate with nitric acid, and meanwhile adding a defoamer to defoam during the decomposition process, and following the decomposition, removing insolubles in acid by filtration to obtain a first solution; (S12) adding sulfuric acid to the first solution in step (S11) for reaction, and following the reaction, performing the filtration to remove calcium sulfate precipitation, to obtain a crude solution of phosphoric acid; (S13) adding ammonia to the crude solution of phosphoric acid in step (S12) for neutralization reaction, and following the neutralization reaction, performing filtration to obtain a precipitation A and a second solution; (S14) adding an iron source to the second solution in step (S13) for reaction, and following the reaction, performing the filtration to obtain iron phosphate expressed as a precipitation B and by-product expressed as a third solution, which are not required in Invention II; while Invention II requires a method for preparing fertilizer comprising the following steps of: mixing and concentrating the precipitate A in step (S13) and the third solution of the by-product in step (S14) and then melting, and granulating the molten material via a granulation device to obtain nitro-phosphorus fertilizer, which are not required in Invention I, as set forth on pages 2-3 in Office Action mailed 12/31/2025.
Applicants primarily argue:
“Although the two claimed inventions are assigned different classifications (C01B 25/375 V.S. C05B 7/00), they are highly related in technical field, the technical problem addressed, and the key technical means employed. When searching for and evaluating prior art for the iron phosphate preparation method (Invention I), one would inevitably consider the nature, treatment, and potential uses of its reaction by-products, which is precisely the subject matter of Invention II, and vice versa. Therefore, the search for one group would significantly overlap with the search scope for the other. The classification difference noted by the Examiner is insufficient to demonstrate a "serious search and/or examination burden."”
Remarks, p. 5
The examiner respectively traverses as follows:
While applicant argues that
“The classification difference noted by the Examiner is insufficient to demonstrate a "serious search and/or examination burden”,
applicants have provided no evidence to support this position. Therefore, the examiner’s position remains that Group I and Group II have a separate status in the art for the reasons set forth on pages 2-3 of the Office Action mailed on 12/31/2025. Further, as set forth on page 2 of the Office Action mailed on 12/31/2025, the examiner has established that the two groups have a different classification. Specifically, Group I, drawn to a method for preparing iron phosphate, classified in C01B 25/375, and Group II, drawn to a method for preparing fertilizer, classified in C05B 7/00.
The requirement is still deemed proper and is therefore made FINAL.
Claims 7-10 are withdrawn from further consideration pursuant to 37 CFR 1.142(b), as being drawn to a nonelected Group, there being no allowable generic or linking claim. Applicant timely traversed the restriction (election) requirement in the reply filed on 02/25/2026.
Claim Objections
Claims 1 and 5 are objected to because of the following informalities:
Claim 1, lines 6-7, amend “the reaction” to “the reaction with the sulfuric acid”, to ensure proper antecedent basis and clarity.
Claim 1, line 13, amend “the reaction” to “the reaction with the iron source”, to ensure proper antecedent basis and clarity.
Claim 5, line 4, amend “the reaction pH” to “pH of the neutralization reaction”, to ensure proper antecedent basis and clarity.
Appropriate correction is required.
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 2 and 4-5 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 2, line 2, recites a phrase “a concentration of 55-65%”. However, it is unclear what the phrase refers to, as it is unclear what % is based on, i.e., a concentration of 55-65% based on mass, a concentration of 55-65% based on molar content, etc.
The examiner interprets that the phrase refers to a concentration of 55-65% based on mass.
Claim 4, line 2, recites a phrase “a concentration of 98%”. However, it is unclear what the phrase refers to, as it is unclear what % is based on, i.e., a concentration of 98% based on mass, a concentration of 98% based on molar content, etc.
The examiner interprets that the phrase refers to a concentration of 98% based on mass.
Claim 5, line 3, recites a phrase “the ammonium phosphate”, which lacks antecedent basis. Examiner requests to amend the phrase to “ammonium phosphate” to ensure proper antecedent basis.
Claim Rejections - 35 USC § 103
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention.
Claim(s) 1-6 are rejected under 35 U.S.C. 103 as being unpatentable over Huang et al., CN 114455562A (Huang’562) in view of Huang et al., CN 114572948A (Huang’948).
The examiner has provided a machine translation of Huang et al., CN 114455562A (Huang’562) and machine translation of Huang et al., CN 114572948A (Huang’948). The citation of the prior art set forth below refers to the machine translation.
Regarding claim 1, Huang’562 teaches a method for preparation iron phosphate, the method comprises the following steps:
S1: performing acidolysis on the phosphorus concentrate by nitric acid, and filtering the acid insoluble substance to obtain the first solution;
S2: adding sulphuric acid to the first solution in the S1, fully mixing uniformly, filtering to remove calcium sulphate to obtain the second solution;
S3: adding iron source to the second solution in S2, after fully reacting, filtering to obtain precipitate, namely iron phosphate; the concentration of the nitric acid solution in the S1 is 55-65 %, and the mass ratio of the mass of the nitric acid to the phosphorus concentrate is 1.2-1.4: 1; the concentration of the sulphuric acid in the S2 is 98 %, and the amount of the sulphuric acid is 90-98 % of the theoretical amount of calcium in the frozen mother liquid; the S1 iron source is iron powder, ferric oxide, ferrous oxide or ferric nitrate in the one kind of or several; the adding amount of the iron source is 90-95 % of the theoretical amount of the complete reaction of the iron source and the phosphoric acid in the second solution (Huang, Abstract);
preferably, the second solution is neutralized by ammonia before adding iron source (Huang’562, 4th paragraph from bottom);
In the acidolysis process (i.e., with nitric acid), the defoaming can be realized by adding a certain amount of defoaming agent (Huang’562, page 3, bottom paragraph).
Huang’562 does not explicitly disclose after neutralizing with ammonia, performing filtration to obtain a precipitation and a second solution.
With respect to the difference, Huang’948 teaches reaction of phosphorus concentration with nitric acid to reduce impurity metal and produce phosphoric acid and iron phosphate (Huang’948, Abstract). Huang’948 specifically teaches adding ammonia to the second solution to neutralize, neutralizing the ammonia until there is no new precipitate to generate end point, and then fully stirring to obtain the first mixture; the first mixture for solid-liquid separation and filtering, filtering to obtain the first solid precipitate and the third solution (Huang’948, page 2, 6th-7th paragraphs).
As Huang’948 expressly teaches, the neutralization step ensures that the impurity metal is removed as much as possible, it also ensures that the iron source is fully used, so as to ensure the quality of the iron phosphate (Huang’948, page 2, 2nd paragraph).
Huang’948 is analogous art as Huang’948 is drawn to reaction of phosphorus concentration with nitric acid to reduce impurity metal and produce phosphoric acid and iron phosphate.
In light of the motivation of conducting a neutralization step using ammonia until there is no new precipitate to generate, and using solid-liquid separation to separate solid precipitation and solution, as taught by Huang’948, it therefore would have been obvious to a person of ordinary skill in the art to conduct the neutralization step using ammonia until there is no new precipitate to generate, and using solid-liquid separation to separate solid precipitation and solution, as taught by Huang’948, in Huang’562, in order to ensure that the impurity metal is removed as much as possible, that the iron source is fully used, so as to ensure the quality of the iron phosphate, and thereby arrive at the claimed invention.
Regarding claim 2, as applied to claim 1, Huang’562 in view of Huang’948 further teaches the concentration of the nitric acid solution in the S1 is 55-65 %, and the mass ratio of the mass of the nitric acid to the phosphorus concentrate is 1.2-1.4: 1 (Huang’562, Abstract).
Regarding claim 3, as applied to claim 1, Huang’562 in view of Huang’948 further teaches defoaming, agent of polysiloxane, polyoxyethylene alcohol (i.e., polyoxyvinyl alcohol), laurylalcohol polyoxyethylene ether according to 1: 1: 1 (i.e., a mass ratio) (Huang’562, page 3, bottom paragraph).
Regarding claim 4, as applied to claim 1, Huang’562 in view of Huang’948 further teaches the concentration of the sulphuric acid in the S2 is 98 %, and the amount of the sulphuric acid is 90-98 % of the theoretical amount of calcium in the frozen mother liquid (Huang’562, Abstract).
Regarding claim 5, as applied to claim 1, Huang’562 in view of Huang’948 further teaches preferably, the pH of the filtrate after neutralization is 6-8 (Huang’562, page 3, 1st paragraph), which encompasses the range of the presently claimed.
Huang’562 in view of Huang’948 further teaches the neutralization process needs to remove all metal ions as much as possible, and the metal impurity is not generated in the reaction of the iron phosphate, so the amount of ammonia introduced in the neutralization step is excessive, so that there is no ammonium hydrogen phosphate or diammonium phosphate in the solution, the yield of the iron phosphate is high (Huang’948, page 3, 2nd paragraph).
Although there are no disclosures on the amounts of ammonia as presently claimed, it has long been an axiom of United States patent law that it is not inventive to discover the optimum or workable ranges of result-effective variables by routine experimentation. In re Peterson, 315 F.3d 1325, 1330 (Fed. Cir. 2003) ("The normal desire of scientists or artisans to improve upon what is already generally known provides the motivation to determine where in a disclosed set of percentage ranges is the optimum combination of percentages."); In re Boesch, 617 F.2d 272, 276 (CCPA 1980) ("[D]iscovery of an optimum value of a result effective variable in a known process is ordinarily within the skill of the art."); In re Aller, 220 F.2d 454, 456 (CCPA 1955) ("[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."). "Only if the 'results of optimizing a variable' are 'unexpectedly good' can a patent be obtained for the claimed critical range." In re Geisler, 116 F.3d 1465, 1470 (Fed. Cir. 1997) (quoting In re Antonie, 559 F.2d 618, 620 (CCPA 1977)).
At the time of the invention, it would have been obvious to one of ordinary skill in the art to vary the amounts of ammonia, including over the amounts presently claimed, in order to remove metal ions as much as possible, and thereby arrive at the claimed invention.
Regarding claim 6, as applied to claim 1, Huang’562 in view of Huang’948 further teaches the S1 iron source is iron powder, ferric oxide, ferrous oxide or ferric nitrate in the one kind of or several; the adding amount of the iron source is 90-95 % of the theoretical amount of the complete reaction of the iron source and the phosphoric acid in the second solution (Huang’562, Abstract; page 2, 10th-11th paragraphs).
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to KELING ZHANG whose telephone number is (571)272-8043. The examiner can normally be reached Monday - Friday: 9:00am-5:00pm EST.
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If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Ching-Yiu 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.
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/KELING ZHANG/
Primary Examiner
Art Unit 1732
Prosecution Insights