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 .
DETAILED ACTION
Response to Amendment
1. The amendment filed on 06/19/2026 has been made of record and entered.
Claims 1 & 12 have been amended.
Claims 2-4 have been canceled.
Claim 16 has been added.
Claims 1 & 5-16 are currently pending in this application and under consideration.
Priority
2. Receipt is acknowledged of certified copies of papers required by 37 CFR 1.55.
The foreign document SOUTH AFRICA ZA2024/08657 (filed on 11/14/2024) has been received and placed in this application.
Claim Objections
3. Claim 1 is objected to because of the following informalities:
A. In line 9, “flowrate” should change to --flow rate--.
B. In line 9, --added-- should be inserted after “water”.
Appropriate correction is required.
Claim Rejections - 35 USC § 103
4. 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) 1 & 5-16 is/are rejected under 35 U.S.C. 103 as being unpatentable over Huckabay et al. (US 4,252,776), hereinafter “Huckabay et al. ‘776”.
The claimed invention relates to a process for removal of salts from a particulate aluminum dross, which comprises the steps of:
leaching the particulate aluminum dross with a solvent to produce a brine solution and wetted dross;
separating the wetted dross from the brine solution;
removing residual brine from the wetted dross by mixing water with the wetted dross in one or more separators to produce a leaching solution;
recycling the leaching solution to serve as the solvent for leaching the particulate aluminum dross, wherein the flow rate of water (added) into the one or more separators is controlled to maintain the specific gravity of the brine solution;
hydrolyzing the wetted dross to produce gas and a hydrolyzed dross;
reacting the gas with an acid, producing a salt solution; and
removing liquid from the brine solution to produce a salt product (as recited in the instant claim 1).
Huckabay et al. '776 is in the same field of art and discloses a method for the treatment of aluminum dross comprising a mixture of water-soluble salts, aluminum oxides, and aluminum metal contaminate, which comprises:
(a) washing said oxides to remove said water-soluble salts and form an aqueous slurry of aluminum oxides containing soluble salts;
(b) heating said slurry to a temperature from 185°F to about 225°F and maintaining sufficient pressure to maintain said aqueous slurry;
(c) agitating said slurry in the presence of inert refractory particles to cause sufficient particle-to-particle attrition to remove the aluminum hydroxide protective film on the aluminum metal contaminants; and
(d) maintaining said agitation, pressure and temperature for a period of time sufficient to effect substantially complete oxidation of said aluminum metal contaminates in said slurry
with the evolution of hydrogen therefrom (col. 12, claim 1).
The waste brine solution is separated from the slurry in the washing step and is concentrated and evaporated to dryness to recover a mixture of sodium and potassium chlorides therefrom (col. 13 - col. 14, claim 11).
The gases evolved from the agitation step are collected and contacted with an aqueous spray to cool said gases and separate ammonia therefrom (col. 14, claim 14).
The aqueous spray is a spray of an aqueous solution of sulfuric acid and a dilute solution of ammonium sulfate is recovered from contacting of the collected gases with said aqueous spray (col. 14, claim 15).
Regarding claim 1, step (a) of the reference appears meeting the "leaching step" of the instant claims because the disclosed step (a) comprises washing the aluminum oxide (an aluminum dross) to remove the water-soluble salts and form an aqueous slurry of aluminum oxides (col. 12, claim 1).
Regarding the "separation step" in the instant claim 1, Huckabay et al. '776 teaches a brine solution containing salts is removed from the separator (col. 3, lines 22-27) and a waste brine solution is separated from said slurry in said washing step and is concentrated and evaporated to dryness to recover a mixture of sodium and potassium chlorides therefrom (col. 13- col. 14, claim 11).
Regarding the “removing step” in the instant claim 1, Huckabay et al. '776 teaches a plurality of separators, e.g., about four to six separators are serially interconnected to affect the washing of the salts from the oxides (col. 3, lines 19-21), which provides for a teaching of "removing residual brine from the wetted dross by mixing water with the wetted dross in one or more separators to produce a leaching solution".
Huckabay et al. ‘776 differs from the claimed method in the “recycling step”, as recited the instant claim 1. It is considered “recycling of the leaching solution to serve as the solvent for leaching the particulate aluminum dross” is obvious to a person skilled in the art for purpose of reducing the production cost and this can easily be derived from the method of Huckabay et al. ‘776, since it does not require any technical or inventive skill. Thus, it would have been prima facie obvious to a person of ordinary skill in the art (before the effective filing date of the claimed invention) to modify the method of Huckabay et al. ‘776 adding the recycling step to reuse the leaching solution as a solvent to remove more salts from the aluminum dross.
The claim feature on “wherein the flow rate of water added into the one or more separators is controlled to maintain the specific gravity of the brine solution” in the instant claim 1 appears met by the reference (see col. 6, line 56- col. 7, line 14). The water added is controlled by a controller to dilute the product sufficiently to avoid solidification.
Regarding the "hydrolyzing step" of the instant claims 1 & 7, the claims are met by the agitating step (c) of the reference (col. 12, claim 1). The gases, which includes ammonia, evolved from the agitation step are collected (col. 14, claim 14).
Regarding the claimed process step on "reacting the gas with an acid, producing a salt solution" in claims 1, 8, & 9, it is met by the reference teaching of aqueous spray is a spray of an aqueous solution of sulfuric acid and a dilute solution of ammonium sulfate is recovered from contacting the collected gases with said aqueous spray (col. 14, claim 15).
Regarding the claimed process step on "removing liquid from the brine solution to produce a salt product" in claim 1, the reference teaches the filtrate is separated in the filter containing sodium and potassium chlorides in water, is passed to multiple evaporators where it is concentrated to obtain a concentrate solution and the salts in the stream are recovered as dried product (col. 11, lines 26-42), thus the instant claimed limitation is met.
Regarding claim 5, the teaching of passing the fines concentrate from the vessel to a filter to separate as a filter cake and remove to obtain a pure product (col. 5, lines 15-29) provides for a teaching of "removing fine dross particles from the brine solution before removing the liquid".
Regarding claim 6, the claim further defines "the wetted dross is separated from the brine solution using one or more spiral washers". Fig. 3 of the reference, element 145 and element 147 showing the elements are spiral, which appear to be the same as element 312 and element 146 in Fig. 4 of the instant application.
Regarding claim 10, Huckabay et al. '776 teaches to pass the fines concentrate from vessel to a suitable filter, such as a felt filter or a rotary filter, to separate as a filter cake and remove to obtain a pure product (col. 5, lines 15-29), meeting the claim limitation on "separating fine dross particles from the brine solution in one or more filtration assemblies".
Regarding claim 11, Huckabay et al. '776 disclosed "vessel 119 where the alum is discharged as a spray by pressure reduction valve. Alternatively, a droplet forming nozzle and a spinner ...could be mounted in vessel 119. The droplets of alum fall countercurrent to a dry air stream supplied by a blower 97 and solidified in vessel 119 from which they can be removed as
alum prills by line 99" (col. 7, lines 55-61). This teaching appears meeting the claim limitation on "removing liquid from the brine solution by spray drying" (col. 7, lines 55-61).
Regarding claim 12, Huckabay et al. '776 teaches the salt unit comprises a plurality of treatment stages to concentrate the brine removed from the solid liquid separators to crystallize the salts (col. 5, lines 9-14), provides for a teaching of "removing the liquid from the brine solution by crystallization".
Regarding claims 13 & 14, Huckabay et al. '776 is silent with respect to the claimed feature on "maintaining the specific gravity of the brine solution at between 1.15 and 1.20" and "at 1.18", respectively. It is expected that the brine solution disclosed would have the same specific gravity values in view of the same process disclosed and claimed.
Regarding claim 15, the salt product obtained by the disclosed process is a mixture of sodium chloride and potassium chloride (col. 11, lines 26-42).
Regarding claim 16, Huckabay et al. '776 teaches a plurality of separators, e.g., about four to six separators are serially interconnected to affect the washing of the salts from the oxides (col. 3, lines 19-21), which provides for a teaching of "removing residual brine from the wetted dross in one or more separators which are in a counter-current flow arrangement". Fig. 3 of the reference, element 145 and element 147 showing the elements are spiral, which appear to be the same as element 312 and element 146 in Fig. 4 of the instant application.
Claims 1 & 5-16 are unpatentable as being obvious over Huckabay et al. ‘776.
Response to Applicant’s Arguments
5. Applicant’s remarks submitted with the amendment on 06/19/2026 have been fully reviewed, however the arguments are not deemed persuasive in view of the new ground of rejection(s) and/or objection(s) above.
6. 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.
Conclusion
7. Claims 1 & 5-16 are pending. Claims 1 & 5-16 are rejected. No claims are allowed.
Contacts
8. Any inquiry concerning this communication or earlier communications from the examiner should be directed to Primary Examiner CAM N. NGUYEN whose telephone number is (571)272-1357. The examiner can normally be reached on M-F (8:30 am - 5:00 pm) at alternative worksite or at cam.nguyen@uspto.gov.
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If attempts to reach the examiner by telephone are unsuccessful, the examiner's supervisor, Anthony Zimmer, can be reached at 571-270-3591. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
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/Cam N. Nguyen/
Primary Patent Examiner, AU-1736
/CNN/
July 10, 2026
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