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 .
This is a response to Applicant's amendment filed on May 18, 2026.
Status of Claims
No claim has been amended. No new claim has been added. Claims 1-18 are pending. Claims 1-18 are examined herein.
Response to Arguments
Applicant's Remarks/Arguments filed 05/18/2026 have been fully considered. Applicant argues that: the claim 1 and its dependent claims are not anticipated nor prima facie obvious over cited prior art(s), Lee et al. (CN 113003759A) and/or So (JPH105736A).
(a) Applicant argues that Lee only describes processing and treating fly ash wash water. See , paragraphs [0008], [0009]. Fly ash wash water is water that is contacted with fly ash and passed through a filter to remove some impurities. Fly ash wash water is not a slurry and does not include fly ash. See Remarks, page 2.
In response, the examiner respectfully disagrees.
As discussions presented in the Office action dated 02/17/2026 (see page 3), Lee discloses a method for treating fly ash sludge that includes calcium sulfate and/or calcium sulfite (page 1, Abstract). Lee discloses: A fly ash washing liquid treatment and resource utilization method is characterized by comprising the following steps: and washing the fly ash with water to obtain a washing liquid and washing slag, removing impurities and toxicity from the washing liquid, and preparing the calcium sulfate hemihydrate crystal whisker from the fly ash washing liquid after removing impurities and toxicity (page 2, claim 1).
Per MPEP, during patent examination, the pending claims must be “given their broadest reasonable interpretation consistent with the specification.” The broadest reasonable interpretation of the claims must also be consistent with the interpretation that those skilled in the art would reach (See MPEP 2111). Consequently, the claim limitation "a slurry" in claim 1 is reasonably interpreted as “a fluid, watery mixture of insoluble solids suspended in a liquid, usually water”. It is noted that the detailed chemical compostion (e.g., wt% or vol% of solid materisal in the slurry) and/or physical properteis (e.g., kinematic viscosrity, density, etc.) of the slurry is not the scopes of limitation recited in claim 1 of claimed invention. Claim 1 recites “combining water with the fly ash sludge to form a slurry” in line 3. Lee discloses “washing the fly ash with water to obtain a washing liquid and washing slag” which directs a fluid, watery mixture of fly ash suspended in water is formed, thereby Lee’s teaching does meet the recitaiton “combining water with the fly ash sludge to form a slurry”.
Applicants’ argument is not considered persuasive.
(b) Applicant argues that Lee also does not suggest treating anything to selectively capture fly ash relative to calcium sulfate/sulfite in the slurry or to selectively capture calcium sulfate/sulfite relative to the fly ash in the slurry. Lee does not suggest that calcium sulfate or calcium sulfite is present in any of the fly ash wash water, in the floes from the impurity removal step, or in the filtrate from the impurity removal step. Instead, Lee discloses that after the impurities are removed with the flocculant, a sulfate source (sodium sulfate) is added to the filtrate to react with the chloride salt and form calcium sulfate whiskers. In other words, Lee intentionally adds sodium to sulfate to the water after the flocculation step to form calcium sulfate as a product. Lee does not describe or suggest selectively separating calcium sulfate from fly ash in any way. See Remarks, page 3.
In response, the examiner respectfully disagrees.
As discussions presented in the Office action dated 02/17/2026 (see page 3), Lee discloses a method for treating fly ash sludge that includes calcium sulfate and/or calcium sulfite (page 1, Abstract). It is noted that Lee discloses sodium sulfate is added to the filtrate thereby forming calcium sulfate whiskers in the steps of treating the slurry with a flocculant (pages 3-4, Example 1).
Lee’s teachings meet the recitation “treating the slurry with a first flocculant that selectively captures fly ash in the slurry relative to the calcium sulfate and/or calcium sulfite in the slurry” recited in claim 1, lines 4-5 since the claim limitation does not explicitly recite detailed step(s), or reaction mechanism(s), or sources of chemicals while treating the slurry with flocculant.
Applicants’ argument is not considered persuasive.
It is the examiner’s position that applicants’ arguments/evidence had not been fully developed enough to overcome the rejection. In view of the foregoing, when all of the applicants’ arguments/evidence are considered, the totality of the rebuttal evidence of nonobviousness fails to outweigh the evidence of obviousness. Therefore, the previous rejections to claims 1-18 under 35 U.S.C. 103(a) are maintained.
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 of this title, 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 set forth in Graham v. John Deere Co., 383 U.S. 1, 148 USPQ 459 (1966), that are applied for establishing a background for determining obviousness under 35 U.S.C. 103(a) 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.
Claims 1, 4-11 and 14-18 are rejected under 35 U.S.C. 103 as being unpatentable over Lee et al. (CN 113003759A, please refer to the English translation document, hereinafter “Lee”), in view of So (JPH105736A, please refer to the English translation document, hereinafter “So”).
In regard to claim 1, Lee discloses a method for treating fly ash sludge that includes calcium sulfate and/or calcium sulfite (page 1, Abstract), the method comprising (page 1, claims 1-3):
(i) combining water with the fly ash sludge to form a slurry (obtaining a washing liquid by mixing fly ash and water, page 1, claim 1);
(ii) treating the slurry (washing liquid) with a coagulant and a flocculant (i.e., a first flocculant) that produce flocculants and filtering the flocculants (i.e., a second sludge); and
(iii) clarifying the treated slurry to provide an overflow stream (a washing liquid) that includes relatively higher amounts of the calcium sulfate and/or calcium sulfite as compared to the slurry.
Since most of the calcium sulfate and calcium sulfite is contained in the overflow stream, it is reasonably expected that the filtered flocculants (second sludge) contain relatively higher amounts of the fly ash as compared to the slurry.
Since the coagulant and flocculant taught by Lee acts as an agent for separating the overflow liquid from the filtered flocculants, one skilled in the art would have reasonably expected that the coagulant and flocculant taught by Lee selectively captures fly ash in the slurry relative to the calcium sulfate and/or calcium sulfite in the slurry as recited in claimed invention.
The teachings of Lee render the recitation of claim 1 prima facie obvious.
In regard to claims 4 and 5, Lee discloses the step of treating the overflow stream with a second flocculant (sodium sulfate) that selectively captures calcium sulfate and/or calcium sulfite thereby obtain a slurry (a third sludge). Thereafter clarifying the slurry (a third sludge) to obtain calcium sulfate hemihydrate whiskers (page 2, claim 6-steps (1)-(4)).
In regard to claim 6, since Lee discloses the same process of treating fly ash sludge as that recited in claim 1, it is asserted, absent evidence to the contrary, that one would reasonably expect that the process as taught by Lee to function the same as the process recited in claim 1. Specifically, it is asserted that one would reasonably expect the process of Lee would results in the third sludge includes more than 80 wt.% of calcium sulfate and calcium sulfite on a dry basis. See MPEP 2112.01 and 2112.02.
In regard to claims 7 and 8, Lee discloses the flocculant comprises a polyacrylamide (page 1, claims 3-4).
In regard to claims 9, 10 and 11, Lee discloses the flocculant comprises a polyacrylamide (page 1, claims 3-4). Since the function of the flocculant is to change ionic charge of the target material (fly ash), the recitations of claims 9 and 11 are considered as a natural consequence of adding flocculant to the fly ash.
In regard to claims 14, 15 and 16, since Lee discloses the same process of treating fly ash sludge as that recited in claim 1, it is asserted, absent evidence to the contrary, that one would reasonably expect that the process as taught by Lee to function the same as the process recited in claim 1. Specifically, it is asserted that one would reasonably expect the process of Lee would results in the fly ash sludge has a solids content that is in a range of from 20 wt.% to 80 wt.%, or the slurry has a solids content that is in a range of from 5 wt.% to 30 wt.%, or the treated slurry is a floc mixture having floc with a specific density that is in a range of from 1.1 to 2.5 as recited in claims 14-16. See MPEP 2112.01 and 2112.02.
In regard to claims 17, Lee discloses the source of fly ash as waste incineration plant (page 2, Background) which renders the recitation of “fly ash sludge from a coal combustion residuals pond” prima facie obvious.
In regard to claim 18, Lee discloses a method for treating fly ash sludge that includes calcium sulfate and/or calcium sulfite (page 1, Abstract), the method comprising (page 1, claims 1-3):
(i) combining water with the fly ash sludge to form a slurry (obtaining a washing liquid by mixing fly ash and water, page 1, claim 1);
(ii) treating the slurry (washing liquid) with a coagulant and a flocculant (i.e., a first flocculant) that produce flocculants and filtering the flocculants (i.e., a second sludge); and
(iii) clarifying the treated slurry to provide an overflow stream (a washing liquid) that includes relatively higher amounts of the calcium sulfate and/or calcium sulfite as compared to the slurry.
In the next stage of the process, Lee discloses the steps of adding sodium sulfate powder (another flocculant) to precipitate a sludge containing calcium sulfate and/or calcium sulfite. Thereafter, a calcium sulfate hemihydrate crystal whisker is obtained/separated from the liquid.
Since (1) sodium sulfate powder (another flocculant) selectively captures calcium sulfate and/or calcium sulfite in the slurry in the slurry relative to fly ash in the slurry, and (2) the liquid (an overflow stream which is expected to containing relatively higher amounts of the fly ash as compared to the slurry) is separated from calcium sulfate hemihydrate crystal whisker (a second sludge), the teachings of Lee render the recitations of claim 18 “treating the slurry with a flocculant that selectively captures calcium sulfate and/or calcium sulfite in the slurry in the slurry relative to fly ash in the slurry;” and “clarifying the treated slurry to provide (i) an overflow stream that includes relatively higher amounts of the fly ash as compared to the slurry, and (ii) a second sludge that includes relatively higher amounts of the calcium sulfate and/or calcium sulfate as compared to the slurry” prima facie obvious.
Claim 2 and 3 are rejected under 35 U.S.C. 103 as being unpatentable over Lee, as applied to claim 1 above, and further in view of So (JPH105736A, please refer to the English translation document, hereinafter “So”).
In regard to claim 2, Lee discloses the step of producing flocculants and filtering the flocculants (i.e., a second sludge) (page 2, claim 2).
But Lee does not explicitly disclose the step of dewatering the second sludge to produce a recovered fly ash product.
However, So discloses a method of reducing volume of and detoxicating alkaline fly ash (page 1, Abstract). So discloses that: in a treatment method for reducing and detoxifying alkaline fly ash, water is added to the fly ash to prepare a water slurry, and the prepared water slurry is subjected to wet specific gravity ore separation to obtain a particle size. A method for treating alkaline fly ash, wherein the finely divided slaked lime having a low specific gravity is used to separate the upper slurry from fly ash. The solid content obtained by separating and separating the upper layer slurry from the fly ash or the solid content obtained by separating the alkaline leachate is washed and dried to be used as a construction material (paragraphs [0011]-[0013]).
It is noted that both the Lee and So references direct a method for treating fly ash sludge.
Therefore, before the effective filing date of the claimed invention, it would have been prima facie obvious to one of ordinary skill in the art to modify the method of Lee to provide the step of dewatering the second sludge to produce a recovered fly ash product, as taught by So, because the recited feature of dewatering the second sludge to produce a recovered fly ash product is a known, effective method for producing useful resources from fly ash as taught by So (page 1, Abstract; paragraphs [0011]-[0013]), and (2) this involves application of a known technique to improve a known method for treating fly ash sludge to yield predictable results.
In regard to claim 3, since Lee, in view of So, discloses the same process of treating fly ash sludge as that recited in claim 2, it is asserted, absent evidence to the contrary, that one would reasonably expect that the process as taught by Lee, in view of So, to function the same as the process recited in claim 2. Specifically, it is asserted that one would reasonably expect the process of Lee, in view of So, would results in the recovered fly ash product has a fly ash content that is in a range of from 80 wt.% to 99.9 wt.%. See MPEP 2112.01 and 2112.02.
Claims 12 and 13 are rejected under 35 U.S.C. 103 as being unpatentable over Lee, as applied to claim 4 above, and further in view of Lioliou et al. (Calcium sulfate precipitation in the presence of water-soluble polymers, Journal of Colloid and Interface Science 303 (2006) 164–170, hereinafter “Lioliou”).
In regard to claims 12 and 13, Lee discloses the flocculant (a first flocculant) comprises a polyacrylamide (page 1, claims 3-4).
But Lee does not explicitly disclose the second flocculant is a polymeric flocculant.
However, Lioliou discloses a method for precipitation of calcium sulfate using different polymers (Abstract). Lioliou discloses the polymer comprises poly(acrylic acid) having a molecular weight of from 2000 to about 20,000 (page 166, Table 1).
It is noted that both the Lee and Lioliou references direct a precipitation of calcium sulfate in aqueous solution using polymer flocculant.
Therefore, before the effective filing date of the claimed invention, it would have been prima facie obvious to one of ordinary skill in the art to modify the method of Zhang, to provide the features of the second flocculant is a polymeric flocculant as taught by Lioliou, because polymer flocculant such as poly(acrylic acid) having a molecular weight of from 2000 to about 20,000 is a known, effective flocculant for precipitation of calcium sulfate in aqueous solution as taught by Lioliou (Abstract; page 166, Table 1).
Since the polymer flocculant such as poly(acrylic acid) having a molecular weight of from 2000 to about 20,000 is a known, effective flocculant, the recitation of “the second flocculant has a molecular weight that is smaller than the first flocculant” (claim 13) is considered prima facie obvious by controlling the molecular weight of the second flocculant material relative to the molecular weight of the first flocculant.
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 YOUNGSUL JEONG whose telephone number is (571)270-1494. The examiner can normally be reached on Monday-Friday 9AM-5PM.
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/YOUNGSUL JEONG/Primary Examiner, Art Unit 1772
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