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 .
Election/Restrictions
Applicant’s election of species A1, Claims 5 and 12 in the reply filed on 10/22/25 is acknowledged. Because applicant did not distinctly and specifically point out the supposed errors in the restriction requirement, the election has been treated as an election without traverse (MPEP § 818.01(a)).
Claim 6 is withdrawn from further consideration pursuant to 37 CFR 1.142(b) as being drawn to a nonelected species, there being no allowable generic or linking claim. Election was made without traverse in the reply filed on 10/22/25.
Claim Objections
Claims 1-5, 7-20 are objected to because of the following informalities:
Claim 1, step (c), it is suggested to add this section after step d.
Claim 1, reactions (3) and (i), it is suggested to amend these to either (3) and (4) or (i) and (ii).
Claim 1, step d, last line “like cadmium, arsenic, and lead” are interpreted as optional features, but it is suggested to delete this part of the claim, especially since Claim 4 clarifies this feature. Alternatively, Claim 4 can be added to this section of Claim 1.
Claim 11, line 6 recites “the SA with either NA. . “. It is suggested to amend SA to sulfuric acid and NA to nitric acid.
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 1-5, 7-20 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.
Claims 2-5, 7-20 are indefinite due to their dependency on claim 1.
To Claim 1, step c, lines 2-3 “after precipitation with sulfuric acid and separation from CaSO4 as described in reaction s (iii) and (iv)” is unclear for several reasons.
First, prior to step c, there is only one step that optionally uses sulfuric acid, which is in step b. Step b states that sulfuric acid can be used, but that nitric acid or hydrochloric can be used instead. In these cases then, sulfuric acid does not have to be used and then step c would lack antecedent basis.
If there is not a prior step that uses sulfuric acid and this step in Claim 1, step C, lines 2-3 intends to introduce a sulfuric acid treatment step, then it is unclear when this step occurs because in step c, it describes regenerating HNO3 or HCl after precipitating with sulfuric acid, but that d occurs after step c. It is unclear when the second part of step c occurs in the process.
Step c recites a step (3) and a step (i), but step (3) seems to occur only if HCl is the acid used to leach in step b to react with Ca and Ca(NO3)2 of step (i) likely is formed from Ca and HNO3 if HNO3 is used. Therefore, the reactions (3) and (i) should be marked as alternatives. However, step b also suggests that sulfuric acid can be used in lieu of either of these acids. Therefore, it is possible in this claim that neither steps (3) or (i) occur and it is suggested to add a third reaction, which shows the result of Ca and H2SO4.
Claim 1, step (e) recites the limitation "the separated, washed and neutralized phosphogypsum". There is insufficient antecedent basis for this limitation in the claim. The phosphogypsum is already separated, washed and neutralized in this step and there is no method step actively performing these steps.
Claim 1, step (e), lines 1-2 “from other reactions” is unclear.
Claim 1, step (e), line 2 “with hydrocarbon fuel” does not align with the reaction described in reaction (5), which only describes CH4. It is unclear if the fuel is limited to CH4 or if other hydrocarbon fuels are useable in this reaction.
Claim 1, step (f) recites “recycling sulfuric acid” described in reaction (vi), but reaction (vi) does not describe recycling sulfuric acid. Instead, this reaction recycles SO2 and makes H2SO4. Therefore, this feature is unclear.
Claim 1, step (f) states that sulfuric acid is recycled by “integrating the phosphogypsum calcination described in (e)”, but it is unclear how the phosphogsum calcination described in step (e) is integrated into the process of step (f). It is requested that applicant specify how they are integrated, such as by connection, by heat transfer, by feeding the SO2 generated from step e to step f, etc.
Claims 2, lines 1-2, Claim 3, lines 1-2 and Claim 9, line 2, all describes that the concentration of P2O5 “in the solution” is in a range of “approximately”, but “the solution” is unclear because there is only one instance of the solution, which is in “acidic solution” in step b. It is unclear if the concentration of P2O5 in the solution is meant to refer to the concentration of step b of Claim 1.
Claim 7 recites “the recycled HNO3”, but this lacks antecedent basis. Claim 1, step (c), line 1 describes regenerating acids and not recycled acids.
Claim 9, step (3) recites the product percent yield of anhydrous d-calcium phosphate achieves P2O5 levels above approximately 42wt%. However, the claims do not describe how P2O5 achieve P2O5.
Claim 9, step (4) recites the production percentage yield of anhydrous di-calcium phosphate achieves waste having P2O5 below approximately 20% by weight. This is unclear because there are no method steps that recite that the anhydrous di-calcium phosphate is transformed to P2O5.
Claim 16, lines 2-3 describes “a chemical product selected from the group consisting of lime and limestone”. Claim 16 depends on Claim 11. Neither Claim 11 or Claim 16 recite process steps that make lime or limestone. Therefore, this feature is unclear. Since no lime or limestone is produced in the claims, this feature will be interpreted as just adding lime and limestone.
Claim 18, lines 1-2 “on an economical basis” is unclear.
Claim 18, lines 2-3 states “compared to conventional beneficiation”. This is unclear because this process produces 80-90wt% “compared to” these conventional processes. It will be treated as either being just 80-90wt% or 80-90wt% above conventional methods, for examination purposes unless amended or persuasively clarified.
Furthermore, if this claim is meant to say that this process makes 80-90wt% more than a conventional process, this is unclear because it is unclear how much a conventional process makes.
Finally, Claim 18 and 19 are described as method steps, but they do not recite any process features.
Claim 20, lines 3-5 state that their method converts low grade “material” into high grade “materials”, which is unclear. Then this claim states that it converts these materials for production on conventional plants. It is unclear what the standard is for a conventional plant. Next, Claim 20 states that their method consumes 60-75% less sulfuric acid. This should state whether it refers to wt%, vol% or otherwise. Also, a consumption of 60-75% less sulfuric acid than in a conventional plant is unclear how much sulfuric acid is means. Finally, Claim 20 states a ”200-300% of the nominal capacity of phosphoric acid plants achieved as compared with conventional phosphates concentrate feeds”, which is unclear for several reasons. First, it is unclear what the nominal capacity is. Second, it is unclear what capacity it is referring to: energy, phosphoric acid, sulfuric, etc.
Finally, Claim 20 recites a method claim, but this claim does not describe any method steps.
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.
Claim 13 is 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 13 depends on Claim 12, which states to the P2O5 concentration is above 42wt%. However, Claim 13 describes a P2O5 concentration of below 10wt%, which is not further limiting of the features of Claim 12.
Applicant may cancel the claim(s), amend the claim(s) to place the claim(s) in proper dependent form, rewrite the claim(s) in independent form, or present a sufficient showing that the dependent claim(s) complies with the statutory requirements.
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.
Claim(s) 11, 16 is/are rejected under 35 U.S.C. 103 as being unpatentable over Takhim (EP 2186774) or alternatively Takhim and in view of IL 272456.
Takhim describes a process for the production of high purity phosphoric acid (title). As to the low-grade calcareous phosphate ore, in one example, Takhim teaches that the phosphate rock treated can have a P2O5 range of about 20-35%, in one example (para. 32). Furthermore, Takhim states, in the background of the reference, that one of the drawbacks in the prior art is that the rocks used has to be good quality and have a high P2O5 content and require fine grinding, which increases the costs (para. 3). Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention that the ore useable in the process of Takhim can have a lower P2O5 content. Furthermore, the specification of this application defines “low-grade phosphate” as being less than 20% (see PG Pub. para. 78). The range of Takhim touches the claimed range.
MPEP states that prior art which teaches a range overlapping or touching the claimed range anticipates if the prior art range discloses the claimed range with “sufficient specificity.” See 2131.03.
It has been held that a prima facie case of obviousness exists where the claimed ranges and prior art ranges do not overlap but are close enough that one skilled in the art would have expected them to have the same properties. Titanium Metals Corp. of America v. Banner, 778 F.2d 775, 227 USPQ 773 (Fed. Cir. 1985). See MPEP 2144.05.
In one example, Takhim describes first reacting a phosphate rock with dilute HCl (para. 32). A residue with impurities is obtained and separated out (para. 32). Other compounds obtained include calcium chloride (para. 32). Although Takhim does not state that this is an impurity, since it is the same compound, it meets this feature of Claim 11.
The process then isolates precipitated 2CaHPO4 (di-calcium phosphate) (DCP, para. 33). The di-calcium phosphate is then processed with sulfuric acid to make P2O5 (para. 34) that has a high purity that is electronic-grade, food grade and pharmaceutical grade (para. 1).
Therefore, although Takhim does not state that their product is fertilizer-grade, since Takhim teaches that their di-calcium phosphate has a purity effective for electronics, food and pharmaceuticals, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention that these can effective for fertilizers or can be diluted to use in fertilizers.
Alternatively, to the rejection above, Takhim teaches that the phosphate rock treated can have a P2O5 range of about 20-35% (para. 32), but Takhim does not specifically teach that the amount of P2O5 concentration was from a low-grade calcareous phosphate ore.
As to the low P2O5 content in the phosphate rock, IL 272456 teaches describes a process for the product of a phosphate-based compound (page 1, line 6) using a phosphate rock that is reacted with sulfuric acid (page 1, lines 21-22) to create phosphoric acid (page 4, lines 12-13). The phosphate rock can include a phosphate rock with a low content of P2O5 (page 20, lines 4-5), which includes a P2O5 of less than 20% (page 20, lines 30-32).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to employ the process of Takhim with the low-phosphate ore of IL ‘456 because IL ‘456 explains that treatment of low-phosphate ore (instead of ore with a higher phosphate concentration) with sulfuric acid can still effectively produce a phosphoric acid product.
As to Claim 16, Takhim teaches that step 1 employs adding calcium carbonate to increase the pH of the solution (para. 32). Takhim also teaches that di-calcium phosphate is added by the addition of calcium carbonate (para. 33). The first acidic treatment is then neutralized with CaCO3 and impurities are removed from the product made (para. 32, see residue of impurities and liquid-solid separation).
Claim(s) 12, 13 is/are rejected under 35 U.S.C. 103 as being unpatentable over Takhim or Takhim and ‘456 as applied to claim 11 above, and further in view of IL 272456.
‘456 describes a process for the product of a phosphate-based compound (page 1, line 6) using a phosphate rock that is reacted with sulfuric acid (page 1, lines 21-22). The phosphate rock can include a phosphate rock with a low content of P2O5 (page 20, lines 4-5), which includes a P2O5 of less than 20% (page 20, lines 30-32).
The final phosphate yield after treatment can be 89% (see page 26, line 29) or 95% (page 27, line 21).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to treat low-phosphate rock using sulfuric acid to obtain a high concentration P2O5 yield of about 89% or 95%, as taught by IL ‘456 for use with the process of Takhim or Takhim and ‘456 because IL ‘456 explains that this treatment is effective in making P2O5 with these high yields.
As to Claim 13, IL ‘456 describes that the P2O5 percentage can be from 1.5 to 3% (page 13, lines 1-3) without further purifications.
Claim(s) 18 is/are rejected under 35 U.S.C. 103 as being unpatentable over IL 272456.
‘456 describes a process for the product of a phosphate-based compound (page 1, line 6) using a phosphate rock that is reacted with sulfuric acid (page 1, lines 21-22). The phosphate rock can include a phosphate rock with a low content of P2O5 (page 20, lines 4-5), which includes a P2O5 of less than 20% (page 20, lines 30-32).
The final phosphate yield after treatment can be 89% (see page 26, line 29) or 95% (page 27, line 21).
Claim(s) 19 is/are rejected under 35 U.S.C. 103 as being unpatentable over IL 272456 as applied to claim 18 above, and further in view of Yao (CN 103318863) and in view of Britton (WO 2021/072551).
IL ‘456 describes use of a low-phosphate ore, but it does not teach that the product used was rejected due to the low P2O5 content or high impurities content selected from the list in Claim 19.
Yao describes a method for processing a low-grade phosphate ore with sulfuric acid to make P2O5 (abstract).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to use a low-grade phosphate ore to make P2O5, as taught by Yao for use with IL 272456 because Yao explains that it is an effective means for producing P2O5.
As to the yield, Britton describes a method for phosphate processing to produce phosphoric acid (abstract). In the background, Britton explains that phosphate rocks are typically processed in a benefication process, but the presence of dolomite, which is a Mg source is highly undesirable (para. 5). There is typically a desire to avoid low-grade phosphate rocks (para. 6), but there is a desire to economically make use of these low-grade phosphate rocks (para. 6).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention that this method would be effective to make P2O5 in an amount of 80-90wt% greater to a conventional beneficiation because Britton explains that it is typical to avoid low-grade phosphate rocks for processing phosphate.
Claim(s) 20 is/are rejected under 35 U.S.C. 103 as being unpatentable over IL ‘456 as applied to claim 18 above, and further in view of Yao (CN 103318863).
As to the 200-300% nominal capacity of the phosphoric acid plant, the specification of this application states that use of the traditional approach based on calcination of low-grade calcareous phosphate ore reduces the phosphate acid plants capacity by more than 50% (see Published specification, para. 4).
As to this feature, IL 272456 teaches that their process treats a phosphate source with sulfuric acid as an initial treatment step (page 6, lines 16-18). The reference does not perform a calcination process prior. Therefore, since the process steps are the same as claimed, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention that the same steps used with the same compositions would have the same capacity levels.
As to the sulfuric acid consumed, Yao teaches a method for processing phosphate ore with sulfuric acid (abstract). Yao explains that after reacting the ore with excess sulfuric acid to produce P2O5 (abstract). The process removes sulfuric acid and recycles the acid (abstract).
Therefore, since Yao describes adding excess sulfuric acid and then recycling the unreacted portion, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention that both the addition of excess sulfuric acid and the recycling of that sulfuric acid, as taught by Yao would reduce the amount of sulfuric acid needed in the reaction of IL ‘456.
As to the amount of sulfuric acid reduced by 60-70%, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention that increasing the amount of sulfuric acid excess added and the amount of sulfuric acid recycled, as taught by Yao is adjustable and will effect the amount of sulfuric acid needed in the phosphoric acid production process.
Allowable Subject Matter
Claims 1-10, 14, 15, 17 would be allowable if rewritten or amended to overcome the rejection(s) under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), 2nd paragraph, set forth in this Office action.
As allowable subject matter has been indicated, applicant's reply must either comply with all formal requirements or specifically traverse each requirement not complied with. See 37 CFR 1.111(b) and MPEP § 707.07(a).
The following is a statement of reasons for the indication of allowable subject matter: Takhim (EP 2186774). Takhim describes a process for the production of high purity phosphoric acid (title). As to the low-grade calcareous phosphate ore, in one example, Takhim teaches that the phosphate rock treated can have a P2O5 range of about 20-35%, in one example (para. 32). Furthermore, Takhim states, in the background of the reference, that one of the drawbacks in the prior art is that the rocks used has to be good quality and have a high P2O5 content and require fine grinding, which increases the costs (para. 3).
In one example, Takhim describes first reacting a phosphate rock with dilute HCl (para. 32). A residue with impurities is obtained and separated out (para. 32). Other compounds obtained include calcium chloride (para. 32). The process then isolates precipitated 2CaHPO4 (di-calcium phosphate) (DCP, para. 33). The di-calcium phosphate is then processed with sulfuric acid to make P2O5 (para. 34) that has a high purity that is electronic-grade, food grade and pharmaceutical grade (para. 1).
This reference does not teach the features of (e), (f) and (g), which include (e): calcining CaSO4 in the presence of methane and heat, (f): recycling sulfuric acid and (g): reacting CO2 with CaO to produce CaCO3.
Conclusion
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/SHENG H DAVIS/Primary Examiner, Art Unit 1732 November 21, 2025