Prosecution Insights
Last updated: April 19, 2026
Application No. 18/267,113

FLOTATION METHOD AND FLOTATION SYSTEM

Final Rejection §103
Filed
Jun 14, 2023
Examiner
PATEL, PRANAV N
Art Unit
1777
Tech Center
1700 — Chemical & Materials Engineering
Assignee
Sumitomo Metal Mining Co., Ltd.
OA Round
2 (Final)
68%
Grant Probability
Favorable
3-4
OA Rounds
3y 0m
To Grant
90%
With Interview

Examiner Intelligence

Grants 68% — above average
68%
Career Allow Rate
433 granted / 637 resolved
+3.0% vs TC avg
Strong +22% interview lift
Without
With
+22.2%
Interview Lift
resolved cases with interview
Typical timeline
3y 0m
Avg Prosecution
45 currently pending
Career history
682
Total Applications
across all art units

Statute-Specific Performance

§101
0.4%
-39.6% vs TC avg
§103
50.9%
+10.9% vs TC avg
§102
17.0%
-23.0% vs TC avg
§112
26.5%
-13.5% vs TC avg
Black line = Tech Center average estimate • Based on career data from 637 resolved cases

Office Action

§103
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 The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action. Claim(s) 1, 6-7 and 19 is/are rejected under 35 U.S.C. 103 as being unpatentable over Sherrell et al. (US 2020/0368761), in view of Kim et al. (KR 101864178B1, refer English language machine translation for claim mapping). Regarding claim 1, Sherrell teaches a flotation method of separating and recovering mineral particles through a flotation treatment, the flotation treatment including floating the mineral particles in a liquid to be treated containing the mineral particles (refer abstract, [0002], fig. 1), by using minute air bubbles having an air bubble diameter having a size range of 1 µm to 1.2 mm (refer sparger 62 introducing microbubbles, [0040] discloses microbubble size) and air bubbles having a larger diameter than the minute air bubbles in the liquid to be treated (refer agitator 70 generating bubble larger than microbubbles, [0007] disclosing larger air bubble size to be between 0.8 to 2 mm). Sherrell discloses that introducing microbubble in addition to conventional large bubbles improves removal efficiency (refer [0009]-[0011]). Selecting size of microbubbles would have been an obvious matter of choice to one of ordinary skill in the art in view of Sherrell’s disclosure of microbubble size range ( 1 µm to 1.2 mm) overlapping the claimed range of 200 µm or less. In the case where the claimed ranges "overlap or lie inside ranges disclosed by the prior art" a prima facie case of obviousness exists. In re Wertheim, 541 F.2d 257, 191 USPQ 90 (CCPA 1976); In re Woodruff, 919 F.2d 1575, 16 USPQ2d 1934 (Fed. Cir. 1990). "[A] prior art reference that discloses a range encompassing a somewhat narrower claimed range is sufficient to establish a prima facie case of obviousness." In re Peterson, 315 F.3d 1325, 1330, 65 USPQ2d 1379, 1382-83 (Fed. Cir. 2003). See also In re Harris, 409 F.3d 1339, 74 USPQ2d 1951 (Fed. Cir. 2005). "[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." In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955). Sherrell discloses that the minute air bubbles are generated by microbubble generator 60 which mixes air into recirculated slurry (refer [0147]) and larger air bubbles are generated by supplying air to stator 71 comprises a system or assembly for introducing flotation gas into the flotation cell 110 (refer [0123]). It is implied that air is supplied from outside and therefore is annex to the flotation device. Sherrel does not teach that the minute air bubble generation device and the flotation device are individually provided with flow rate valves, and the flow rate of the air bubbles generated from each of the devices is individually adjusted according to a desired flotation time, and regulating over respective flow rates of air bubbles through control using the flow rate valves by controlling the degrees of opening of the flow rate valves. Kim teaches a flotation system comprising supplying large bubbles and fine bubbles into flotation vessel (refer abstract). A blower (300) connected to air supply pipes to supply air to generate the large bubbles and minute bubbles in tank 100 (refer fig. 2, last paragraph on page 6). Kim further discloses that a flow rate measuring instrument capable of measuring the flow rate and a valve for controlling the flow rate of the air are provided in the untreated water supply pipe 113, the chemical supply pipe 115, the second air supply pipe 121 and the first discharge pipe 151, a flow meter F is provided to quantify the supply of untreated water, air, chemicals and the like, thereby controlling the phosphorus and nitrogen crystallization reaction precisely (refer last paragraph on page 8). Fig. 2 also indicates providing a valve and flowmeter on each of the air supply valves. It would have been obvious to one of ordinary skill in the art to modify the method of Sherrel such that the minute air bubble generation device and the flotation device are individually provided with flow rate valves, and the flow rate of the air bubbles generated from each of the devices is individually adjusted, and regulating over respective flow rates of air bubbles through control using the flow rate valves by controlling the degrees of opening of the flow rate valves as taught by Kim for controlling as flow rate. Selecting controlling air flow for how long and how much would have been an obvious matter of choice to one of ordinary skill in the art because Kim discloses that the growth rate of the crystal can be adjusted by the air supply amount of the micro-bubble diffuser (refer beginning of page 11). Regarding claim 6, modified Sherrel teaches limitations of claim 1 as set forth above. Kim teaches that the minute air bubble generation device and the flotation device are individually connected to pressurized gas supply device (300). Regarding claim 7, Sherrell teaches limitations of claim 1 as set forth above. Sherrell teaches that minerals have particle size D80 of less than 200 µm (refer [0078]). Selecting size of particles would have been an obvious matter of choice to one of ordinary skill in the art in view of Sherrell’s disclosure of mineral particles size being less than 200 µm overlapping the claimed range. In the case where the claimed ranges "overlap or lie inside ranges disclosed by the prior art" a prima facie case of obviousness exists. In re Wertheim, 541 F.2d 257, 191 USPQ 90 (CCPA 1976); In re Woodruff, 919 F.2d 1575, 16 USPQ2d 1934 (Fed. Cir. 1990). "[A] prior art reference that discloses a range encompassing a somewhat narrower claimed range is sufficient to establish a prima facie case of obviousness." In re Peterson, 315 F.3d 1325, 1330, 65 USPQ2d 1379, 1382-83 (Fed. Cir. 2003). See also In re Harris, 409 F.3d 1339, 74 USPQ2d 1951 (Fed. Cir. 2005). "[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." In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955). Regarding claim 19, Sherrell teaches limitations of claim 6 as set forth above. Sherrell teaches that minerals have particle size D80 of less than 200 µm (refer [0078]). Selecting size of particles would have been an obvious matter of choice to one of ordinary skill in the art in view of Sherrell’s disclosure of mineral particles size being less than 200 µm overlapping the claimed range. In the case where the claimed ranges "overlap or lie inside ranges disclosed by the prior art" a prima facie case of obviousness exists. In re Wertheim, 541 F.2d 257, 191 USPQ 90 (CCPA 1976); In re Woodruff, 919 F.2d 1575, 16 USPQ2d 1934 (Fed. Cir. 1990). "[A] prior art reference that discloses a range encompassing a somewhat narrower claimed range is sufficient to establish a prima facie case of obviousness." In re Peterson, 315 F.3d 1325, 1330, 65 USPQ2d 1379, 1382-83 (Fed. Cir. 2003). See also In re Harris, 409 F.3d 1339, 74 USPQ2d 1951 (Fed. Cir. 2005). "[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." In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955). Response to Arguments Applicant’s arguments with respect to claim(s) 1 have been considered but are moot because the new ground of rejection does not rely on any reference applied in the prior rejection of record for any teaching or matter specifically challenged in the argument. Conclusion The prior art made of record and not relied upon is considered pertinent to applicant's disclosure. Szatkowski et al. (US 4737272) teaches a froth flotation method and apparatus comprising two air supply lines provided with valves to regulate air flow. Negeri (US 5746910) teaches a flotation apparatus (refer fig. 3) comprising two air supply lines, each provided with flow controllers. 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. Any inquiry concerning this communication or earlier communications from the examiner should be directed to PRANAV PATEL whose telephone number is (571)272-5142. The examiner can normally be reached M-F 6AM-4PM. Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice. If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Bobby Ramdhanie can be reached at (571) 270-3240. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300. Information regarding the status of published or unpublished applications may be obtained from Patent Center. Unpublished application information in Patent Center is available to registered users. To file and manage patent submissions in Patent Center, visit: https://patentcenter.uspto.gov. Visit https://www.uspto.gov/patents/apply/patent-center for more information about Patent Center and https://www.uspto.gov/patents/docx for information about filing in DOCX format. For additional questions, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000. /PRANAV N PATEL/Primary Examiner, Art Unit 1777
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Prosecution Timeline

Jun 14, 2023
Application Filed
Aug 05, 2025
Examiner Interview (Telephonic)
Aug 13, 2025
Non-Final Rejection — §103
Sep 04, 2025
Interview Requested
Sep 10, 2025
Applicant Interview (Telephonic)
Sep 10, 2025
Examiner Interview Summary
Nov 07, 2025
Response Filed
Feb 21, 2026
Final Rejection — §103 (current)

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Study what changed to get past this examiner. Based on 5 most recent grants.

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Prosecution Projections

3-4
Expected OA Rounds
68%
Grant Probability
90%
With Interview (+22.2%)
3y 0m
Median Time to Grant
Moderate
PTA Risk
Based on 637 resolved cases by this examiner. Grant probability derived from career allow rate.

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