DETAILED ACTION
Claim(s) 1-6 were rejected in Office Action mailed on 04/16/2026.
Applicant filed a response, amended claim(s) 1-2 and 4-5, on 07/16/2026.
Claim(s) 1-6 are pending.
Claim(s) 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 .
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).
Response to Arguments
Applicant primarily argues:
“However, Huang'562 deliberately retains the strong acid effect of the solution that reacts with the iron source, and accordingly deliberately omits a denitrification step. Specifically, paragraph [0017] of Huang'562 explicitly states: "The claimed invention omits the step of removing nitric acid (denitrification), thereby saving energy. In the presence of nitric acid, phosphoric acid can react directly with an iron source to produce iron phosphate, fully utilizing the strong acid effect of nitric acid to promote the reaction of phosphoric acid and iron source to generate iron phosphate, thereby improving the efficiency of iron phosphate production." In contrast, Huang'948 involves neutralization with ammonia after a denitrification step. This step would significantly neutralize the nitric acid in the solution, shifting the solution from strongly acidic to neutral or weakly alkaline.
Therefore, if one were to combine the teachings of Huang'562 and Huang'948 as proposed by the Office, the addition of ammonia to the phosphoric acid solution, whether or not a denitrification step is included, would invariably weaken the acidity of the solution, rendering it impossible to fully utilize the strong acid effect of nitric acid to promote the reaction as taught by Huang'562. Such a combination would directly contradict the purpose and underlying principle of Huang'562's invention. A person of ordinary skill in the art, having read both Huang'562 and Huang'948, would have no motivation to combine them to arrive at the claimed invention.”
Remarks, p. 6-7
The Examiner respectfully traverses as follows:
Firstly, Huang’562 teaches, preferably, the second solution is neutralized by ammonia before adding iron source (Huang’562, 4th paragraph from bottom).
Secondly, Huang’948 is only used to teach after neutralizing with ammonia, performing filtration to obtain a precipitation and a second solution (emphasis added).
Applicant further argues:
“Even if a person of ordinary skill were to attempt to introduce the teachings of Huang'948 into Huang'562, there is no reasonable expectation of success in arriving at the claimed invention.
Huang'948 is directed to a method for reducing the content of impurity metals in an ammonium phosphate raw material used for iron phosphate production. To this end, Huang'948 teaches neutralization with ammonia after a denitrification step, followed by solid-liquid separation and filtration to remove the first solid precipitate (which contains impurity metals), thereby obtaining a purified solution for subsequent production of high-quality iron phosphate. The core technical concept of Huang'948 is therefore purification, and the separated solid is a process waste to be discarded.
The clear teaching that a person of ordinary skill would derive from Huang'948 is that, to obtain higher-quality iron phosphate, one needs to introduce a denitrification step, and after neutralization with ammonia, remove the solid precipitate generated by the neutralization reaction through filtration.
In contrast, the present application does not involve a denitrification step. Instead, the nitrate ions remaining after the reaction are retained in the third solution in the form of ammonium nitrate, which can be mixed with the phosphate salts of impurity metals to prepare a nitro-phosphorus fertilizer, thereby achieving full utilization of the by-products from iron phosphate production. Moreover, the precipitate A separated in step (S13) of the present application is not an impurity to be discarded, but rather a raw material for the subsequent preparation of a fertilizer by-product. Thus, the teaching of neutralization with ammonia after denitrification, followed by solid-liquid separation and filtration to remove a first solid precipitate as provided by Huang'948 is not equivalent to step (S13) of the present application. The two differ significantly in technical purpose, process conditions, and the fate of the resulting products. The result of introducing Huang'948 into Huang'562 would at best be a process that improves the purity of iron phosphate by denitrification, neutralization with ammonia, and removal of the solid precipitate generated by the neutralization, but would not be the claimed process of the present application.”
Remarks, p. 7-8
The Examiner respectfully traverses as follows:
Firstly, Huang’562 teaches, preferably, the second solution is neutralized by ammonia before adding iron source (Huang’562, 4th paragraph from bottom).
Huang’948 is only used to teach after neutralizing with ammonia, performing filtration to obtain a precipitation and a second solution (emphasis added), as set forth above.
Secondly, Huang’562 and Huang’948 are both drawn to a method for preparation of iron phosphate, and Huang’948 provides proper motivation to combine, namely 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. See page 5 set forth above. Therefore, it is the Examiner’s position that there would be a reasonable expectation of success by combining Huang’562 and Huang’948.
Further, it is noted that it is well settled that obviousness does not require absolute predictability of success; all that is required is a reasonable expectation of success. In re Kubin, 561 F.3d 1351, 1360 (Fed. Cir. 2009); In re O’Farrell, 853 F.2d 894, 903-04 (Fed. Cir. 1988). See MPEP 2143E.
Applicant further argues:
“The claimed invention achieves unexpected technical effects by overcoming the above technical obstacles.
The method of the claimed invention is not a simple iron phosphate preparation process. By retaining the nitrate ions without denitrification and performing neutralization with ammonia under specific conditions to generate and retain precipitate A, the claimed invention achieves, in a single continuous process, the simultaneous production of two high-value products including iron phosphate and a by-product nitrogen-phosphorus fertilizer through the value-added utilization of the intermediate product. This technical effect of achieving both iron phosphate production and full utilization of by-products through the deliberate retention of an intermediate product is neither taught nor suggested by the prior art, including Huang'562 and Huang'948.”
Remarks, p. 8
The Examiner respectfully traverses as follows:
The data to show advantageous effects by the method for preparing iron phosphate in the present invention is not persuasive for the following reasons.
Firstly, the data is not commensurate in scope with the scope of the claims. The specification only provides data for a method for preparing iron phosphate using ammonium phosphate, comprising the steps of: at specific temperature, decomposing a specific phosphorus concentrate with specific concentrations and mass ratios of nitric acid; using a specific type and amount of defoamer; adding specific concentration and amount of sulfuric acid; adding specific concentration and amount of ammonia, adding specific type and amount of iron sources to obtain iron phosphate.
However, the claims broadly recite a method for preparing iron phosphate using ammonium phosphate, comprising the steps of: at any temperature, decomposing any phosphorus concentrate with any concentrations and mass ratios of nitric acid; using any type and amount of defoamer; adding any concentration and amount of sulfuric acid; adding any concentration and amount of ammonia, adding any type and amount of iron sources to obtain iron phosphate.
Therefore, the Examiner has fully considered Applicant’s arguments, but they are found unpersuasive.
Conclusion
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 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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/KELING ZHANG/
Primary Examiner
Art Unit 1732
Prosecution Insights