Prosecution Insights
Last updated: April 19, 2026
Application No. 18/026,046

Blast furnace for ironmaking production

Final Rejection §103
Filed
Mar 13, 2023
Examiner
ABOAGYE, MICHAEL
Art Unit
1733
Tech Center
1700 — Chemical & Materials Engineering
Assignee
ArcelorMittal
OA Round
2 (Final)
75%
Grant Probability
Favorable
3-4
OA Rounds
3y 0m
To Grant
99%
With Interview

Examiner Intelligence

Grants 75% — above average
75%
Career Allow Rate
795 granted / 1054 resolved
+10.4% vs TC avg
Strong +38% interview lift
Without
With
+38.3%
Interview Lift
resolved cases with interview
Typical timeline
3y 0m
Avg Prosecution
34 currently pending
Career history
1088
Total Applications
across all art units

Statute-Specific Performance

§101
0.4%
-39.6% vs TC avg
§103
45.4%
+5.4% vs TC avg
§102
21.6%
-18.4% vs TC avg
§112
26.6%
-13.4% vs TC avg
Black line = Tech Center average estimate • Based on career data from 1054 resolved cases

Office Action

§103
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 . Status of Claims Claims 7 and 9 have been amended, claims 10-12 should designated as withdrawn, and therefore claims 7 and 9 remain under consideration in the application. Claim Objections Claims 10-12 are objected to because of the following informalities: the status identifier of these claims should be “withdrawn” as the result of the response to the restriction requirement filed on 08/21/2025. Appropriate correction is required. 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. Claims 7 and 9 are rejected under 35 U.S.C. 103 as being unpatentable over Cuscoleca et a. (US Patent No. 2,952,533). Regarding claim 7, Cuscoleca et al. teaches a blast furnace (see column 1, lines 15-25, column 4, lines 74-75 and column 5, lines 1-12) for ironmaking production, iron ore being at least partly reduced by a reducing gas injected in a stack of the blast furnace (see figure 1 shows reducing gas injector (2, 3, 4 and 5) located at planes (b, c, d, e,) above the tuyere (1) level in the area of the blast furnace, see column 5, lines 1-9 and lines 29-41 and column 5, lie 65-column 6, line 31) the blast furnace comprising: an external wall (see figure 1 shows the shell as the external wall of the bast furnace); an internal wall (i.e., the refractory lining portion of the blast furnace, see figure 1) in contact with matters charged into the blast furnace, wherein the internal wall defines a thickness (see figure 1); and an injector (i.e., nozzles (2,3,4 and 5) for injecting the reducing gas through an injection outlet in an injection area (see figure 1, column 5, lines 29-41 and column 5, lie 65-column 6, line 31); and wherein he injection outlet is aligned with the internal wall (see figure 1). Regarding the thickness of the internal wall, Cuscoleca et al. in figure 1 shows the thickness of the internal wall being substantially constant over the height above and below at least the injector (4, positioned between the planes c and d; between the planes d and e; and between the planes e and c, above and below the injector 4 on plane d) but fails to expressly teach said height as being at least 400 mm above and at least 400 mm below the injection area as claimed. Thus, Cuscoleca et al. differs from the instant claimed invention only by the magnitude or dimension of said height above and below the injection area where the thickness of the internal wall is constant. Furthermore, with reference to MPEP 2144.04. IV. A. which pertains to the obviousness of changes in size /proportion, similar to the instantly-claimed constant thickness of internal wall and that taught by Cuscoleca et al., the court held that where the only difference between the prior art and the claims was a recitation of relative dimensions of the claimed device and a device having the claimed relative dimensions would not perform differently than the prior art device, the claimed device was not patentably distinct from the prior art device. Regarding the injection speed of the reducing gas, Cuscoleca et al., does not expressly teach an injector that injects reducing gas at a speed inferior to or less than 120 m/s., however teaches a reducing gas injection speed of about 150-200 m/s. (see column 5, lines 29-40). Cuscoleca et al., also teaches that the reducing gas injection speed is dictated by the diameter of the injection nozzle (see column 6, lines 20-31), hence on the basis of this teachings of Cuscoleca et al., it would have been obvious to one of ordinary skill in the art to attain any desired reducing gas injection speed to include that being claimed by mere routine optimization by changing the diameter of the nozzle since doing so would alter the reducing gas injection speed. Also see MPEP 2144.05. II. It should further be noted that because the injector is recited as being capable of injecting the reducing gas at a speed inferior to 120 m/s.; The examiner interprets said speed of the claimed injector to be directed to the manner of operating said injection. However, it is held by the court that A claim containing a "recitation with respect to the manner in which a claimed apparatus is intended to be employed does not differentiate the claimed apparatus from a prior art apparatus" if the prior art apparatus teaches all the structural limitations of the claim. Also see MPEP 2114. II. Regarding claim 9, Cuscoleca et al., does not expressly teach that the working height H and the reducing gas injection by the injector is performed at a height w between 20% and 70% of the working height H, starting from a tuyere level; However because Cuscoleca et al., also teaches the same conventional blast furnace configured for injecting reducing gas in the stack region of the blast furnace in the same manner as the instant claimed blast furnace, it would necessarily and/or reasonably be expected that the reducing gas injection of the injector in the apparatus of Cuscoleca et al., would also be performed at a height w between 20% and 70% of the working height H, starting from a tuyere level. Furthermore, the position b, c, d, e of the injectors 2, 3, 4 and 5 along the wall of the blast furnace of Cuscoleca et al., as shown in figure 1 substantially correspond to a height w which falls between 20% and 70% of the working height H. In addition, it has been held by the Court that When the reference is a utility patent, it does not matter that the feature shown is unintended or unexplained in the specification. The drawings must be evaluated for what they reasonably disclose and suggest to one of ordinary skill in the art. Also see MPEP 2125. This figure 1 of Cuscoleca et al., reads on the claim. Response to Arguments Applicant's arguments filed on 12/23/2025 have been fully considered but they are not persuasive. Applicant argues that Cuscoleca does not disclose or render obvious "the thickness T.sub.int of the internal wall being constant over a height of at least 400 mm above and at least 400 mm below the injection area" as recited in claim 7, and that the drawings of Cuscoleca are clearly schematic, and they do not show a constant thickness over a very specific portion of the internal wall - a height of at least 400 mm above and at least 400 mm below the injection area. Cuscoleca does not depict or discuss this detail and thus as stated in MPEP 2125(II), "arguments based on measurement of the drawing features are of little value" in this regard, and that If for some reason the dimensions of the Figures of Cuscoleca are to be considered, they show that the thickness of the alleged internal walls is not constant. To the contrary, the thickness of the alleged internal walls is shown as tapered to the top above 3, and then notched and tapered between 3 and the tuyeres 1. Applicant’s characterization of figure 1 of Cuscoleca in the arguments above with respect to the rejections of claims 7 and 9 is not agreed to. In response, it should be pointed out that Applicant in the specification para [0010], [0011] and [0019], characterizes the thickness T.sub.int as substantially constant, and therefore the Examiner interprets the claimed “constant thickness” as “substantially constant thickness” in light of Applicant’s own specification; in addition the plain meaning of the word “substantially” includes: considerably, to a great extent, significantly, for the most part etc.; thereby adequately suggesting that the claimed “constant thickness” is not necessarily exactly constant. Furthermore, the specification does not appear to provide any clear numerical value(s) or range of values supporting the claimed constant thickness across the claimed interval above and below the injection area. Therefore, similar to Applicant’s characterization of the figure 1 of Cuscoleca, the Applicant’s disclosed figure 1, could also be described, absent any evidence to the contrary as being clearly schematic. On the basis of the response above, the rejection of claims 7 and 9 are maintained because Cuscoleca in figure 1 shows the thickness of the internal wall being substantially constant over the height above and below at least the injector (4, positioned between the planes c and d; between the planes d and e; and between the planes e and c, above and below the injector 4 on plane d). Conclusion The prior art made of record and not relied upon is considered pertinent to applicant's disclosure. Heinrich et al. (US-20030020212) is also cited in PTO-892, 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 MICHAEL ABOAGYE whose telephone number is (571)272-8165. The examiner can normally be reached 8:30AM-5:00PM. 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, Keith Hendricks can be reached at 571-272-1401. 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. /M.A/Examiner, Art Unit 1733 /JESSEE R ROE/Primary Examiner, Art Unit 1759
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Prosecution Timeline

Mar 13, 2023
Application Filed
Sep 20, 2025
Non-Final Rejection — §103
Dec 23, 2025
Response Filed
Mar 03, 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
75%
Grant Probability
99%
With Interview (+38.3%)
3y 0m
Median Time to Grant
Moderate
PTA Risk
Based on 1054 resolved cases by this examiner. Grant probability derived from career allow rate.

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