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 .
Response to Amendment
The amendment filed 05/11/2026 has been entered. Claim(s) 1-4, 6, 8-9, 11-15, 18-19, 22-23, 25, 27, 29, and 31-33 is/are pending in this application, of which claims 1-4, 6, 8-9, 11-15, 18-19, 22-23, 25, and 32-33 are examined herein. Claim(s) 27, 29, and 31 is/are withdrawn. Claim(s) 1-4, 6, 8-9, 11-15, 18-19, 22-23, and 25 is/are amended. Claim(s) 5, 7, 10, 16-17, 20-21, 24, 26, 28, and 30 is/are cancelled. Claim(s) 32-33 is/are new.
The rejection(s) under 35 USC 112(a) to claim(s) 25 is/are withdrawn in view of the amendments to claim(s) 25.
The rejection(s) under 35 USC 112(b) to claim(s) 1-4, 6, 8-9, 11-15, 18-19, 22-23, and 25 is/are withdrawn in view of the amendments to claim(s) 1, 2, 3, 4, 6, 8, 9, 11, 12, 15, 18, 22, 23, and 25.
Claim Objections
Applicant is advised that should claim 32 be found allowable, claim 33 will be objected to under 37 CFR 1.75 as being a substantial duplicate thereof. When two claims in an application are duplicates or else are so close in content that they both cover the same thing, despite a slight difference in wording, it is proper after allowing one claim to object to the other as being a substantial duplicate of the allowed claim. See MPEP § 608.01(m).
Claim Interpretation
Regarding the instant claims, the phrase “post-combustion” is herein interpreted as:
“PC % = 100 x (CO2+H2O)/(CO+CO2+H2+H2O),
where the symbol for each species (CO, CO2 etc) represents the molar concentration (or partial pressure) of that particular species in the gas phase.”
as defined at pg. 16 lines 28-31 of the instant specification.
Claim Rejections - 35 USC § 112
The following is a quotation of the first paragraph of 35 U.S.C. 112(a):
(a) IN GENERAL.—The specification shall contain a written description of the invention, and of the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to make and use the same, and shall set forth the best mode contemplated by the inventor or joint inventor of carrying out the invention.
The following is a quotation of the first paragraph of pre-AIA 35 U.S.C. 112:
The specification shall contain a written description of the invention, and of the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to make and use the same, and shall set forth the best mode contemplated by the inventor of carrying out his invention.
Claims 1-4, 6, 8-9, 11-15, 18-19, 22-23, 25, 27, 29 and 31 is rejected under 35 U.S.C. 112(a) or 35 U.S.C. 112 (pre-AIA ), first paragraph, as failing to comply with the written description requirement. The claim(s) contains subject matter which was not described in the specification in such a way as to reasonably convey to one skilled in the relevant art that the inventor or a joint inventor, or for applications subject to pre-AIA 35 U.S.C. 112, the inventor(s), at the time the application was filed, had possession of the claimed invention.
Claim 1 recites “a post-combustion of up to 45%”, however the instant specification only discloses a post-combustion of 35-45% at a hot end of the preheat zone (instant specification: pg. 16 lines 21-22, pg. 29 line 6), and does not disclose the broad range of “up to 45%”, and therefore does not describe the claimed invention in a manner understandable to a person of ordinary skill in the art in a way that shows that the inventor invented the claimed invention at the time of filing.
Claim 2 recites “a post-combustion of up to 45%”, however the instant specification only discloses a post-combustion of 35-45% at a hot end of the preheat zone (instant specification: pg. 16 lines 21-22, pg. 29 line 6), and does not disclose the broad range of “up to 45%”, and therefore does not describe the claimed invention in a manner understandable to a person of ordinary skill in the art in a way that shows that the inventor invented the claimed invention at the time of filing.
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.
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.
This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention.
Claims 1-4, 8-9, 11-15, 18-19, 22, 25, and 32-33 are rejected under 35 U.S.C. 103 as being unpatentable over Bleifuss et al. (US 20080302211 Al, cited in Office Action dated 10/01/2025) in view of Eisele et al. (US 20070209480 Al, cited in Office Action dated 10/01/2025) and Hwang et al. (US 20080087135 Al, cited in Office Action dated 10/01/2025).
Regarding claim 1, Bleifuss teaches a method for producing direct reduced iron (DRI) from briquettes of a composite of iron ore fragments and carbonaceous material (Title, Abstract, [0064, 0098]) in a furnace (Title, [0040]), including zones 26 (Fig. 1, [0093]). Bleifuss teaches using the carbonaceous material as a source of reductant and a heating source of the iron ore [0062]. Bleifuss teaches the zones between an inlet for briquettes of iron ore fragments and carbonaceous material and an outlet for direct reduced iron (Fig. 1, 6B, [0084, 0087]). Bleifuss teaches the zones include a preheat zone 28 that (Fig. 1, [0042, 0084]), and a reduction zone downstream from the preheat zone 30 [0042]. Bleifuss teaches a container moving apparatus 24 (i.e., a conveyor) that is movable through the zones (Fig. 1, [0042-0044]).
Bleifuss teaches transporting heated briquettes on the conveyor from the feeding zone 27 through preheat zone 28 and through the final reduction zone 30 [0131], with the system (including final reduction zone 30) having a controlled atmosphere to prevent oxidation [0108], and heating briquettes [0060] and reducing iron ore in briquettes and forming DRI [0075], causing gases generated in the preheat zone 28 and final reduction zone 30 to flow towards flue 40 [0079], where the gases generated [0103] include combustible gases [0094] (i.e., counter-current movement of the briquettes of iron ore fragments and carbonaceous material in a direction from the inlet to the outlet and combustible gases in an opposite direction in the furnace). Bleifuss teaches the combustible gases including combustible gases produced in the system (including final reduction zone 30) having a controlled atmosphere to prevent oxidation (i.e., under anoxic conditions) [0108] flowing to the preheat zone 28 counter-current to movement of the briquettes in the furnace [0079]. Bleifuss teaches air fed burners 38 combusting combustible gases in the preheat zone 28 [0079, 0094] and producing heat that heats the briquettes in the preheat zone 28 before the preheated briquettes move to the reduction zone 30 [0079, 0094].
Bleifuss does not teach using biomass as a source of reductant and as a heating source of the iron ore.
Eisele teaches production of iron using environmentally-benign renewable or recycled reducing agents (Title), where iron ore and a reductant of biomass material in particulate form is shaped into pellets and placed in a furnace to produce metallic iron directly from ore (Abstract), wherein the biomass comprises carbon [0009, 0042], therefore Eisele and Bleifuss are analogous to the instant application as both are directed to methods of direct reduction of pellets of iron ore and carbonaceous material to metallic iron in a furnace. Eisele teaches the invention has the advantage of allowing renewable and recyclable organics to be used as reducing agents without having to first process the organics to produce charcoal or otherwise prepare them for the smelting process, as biomass can be used in a raw form [0039], and that biomass is a surplus or waste product and thus has low costs [0039]. Eisele teaches the use of biomass material or other organic acts as a binder for the pellets holding them together until the reactions are completed, making it unnecessary to use additional binders such as bentonite clay, where the elimination of separate binders results in less contamination of the product, smaller quantities of slag and simplifies the control of slag properties [0039].
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have used biomass as the carbonaceous material used as a source of reductant and as a heating source of the iron ore as taught by Eisele (i.e., to use a composite of iron ore fragments and biomass) in the briquettes of Bleifuss as doing so would not require pretreatment of the biomass, benefit from lower costs, not require additional binders, and result in less contamination of the product, smaller quantities of slag, and simplify control of slag properties as taught by Eisele.
Bleifuss does not teach microwave energy as a heating source.
Hwang teaches a microwave heating method for iron oxide reduction (Title), where iron oxides are reduced using microwave heating in a furnace chamber that is sealed against entrance of air and produces combustible gas (Abstract), where reduction may be performed in a linear conveyor furnace [0017] thus Hwang and Bleifuss are analogous to the instant application, as both are directed to methods of reducing iron oxides in linear conveyor furnaces that maintain non-oxidizing atmospheres within. Hwang teaches supplying microwave energy into primary zone 98 A (analogous to a final reduction zone) of a furnace chamber 98 of a linear conveyor furnace 88 (Fig. 10, [0061]), where the microwaves may be supplied in addition to further heating by burners [0063]. Hwang teaches microwave heating is selective, and only heats components of the material that needs to be heated, i.e., to reduce the hematite or magnetite and does not heat nonferrous components of the feed material directly, so that the energy is much more efficiently used and the maximum temperature reached can be much lower [0006], while air injection in conventional heating results in combustion of carbon which may waste useful combustibles and adds to the carbon footprint of the process [0010].
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have used microwave energy as a heating source in the final reduction zone as taught by Hwang to the process of Bleifuss as doing so would use energy more efficiently, reduce the temperatures the furnace must be able to operate at, and reduce the carbon footprint of the process by reducing the amount of heating performed by the use of burners as taught by Hwang.
Bleifuss does not teach post-combustion percentages in the preheat zone, however, it has long been held that where 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. See MPEP 2144.05 (II) A-B. In the instant case, as Bleifuss teaches combusting combustible gases developed in the furnace, and controlling the atmosphere in the furnace to maintain a particular reducing potential (i.e., controlling the post-combustion percentage), one of ordinary skill would be motivated to combust a portion of the combustible gases sufficient to preheat the iron ore and efficiently utilize the heating value of the combustible gases.
Further, the mere recitation of a numerical parameter in an otherwise known process will not generally result in patentability of a claim directed to that process, absent evidence of criticality of the numerical parameter. In the instant case the numerical parameter (the post-combustion percentage) does not appear to be critical to the invention.
Thus, the disclosure of Bleifuss is held to establish a prima facie case of obviousness of a method as presently claimed.
Regarding claim 2, Bleifuss teaches a method for producing direct reduced iron (DRI) from briquettes of a composite of iron ore fragments and carbonaceous material (Title, Abstract, [0064, 0098]) in a furnace (Title, [0040]), including zones 26 which are enclosed by walls 41 (i.e., a chamber) (Fig. 1, [0093]). Bleifuss teaches having the following zones between an inlet for the briquettes of iron ore fragments and carbonaceous material and an outlet for direct reduced iron (Fig. 1, 6B, [0084, 0087]): a feed zone and preheat zone 27/28 that includes the inlet (Fig. 1, [0042, 0084]), a final reduction zone 30 [0042] and a discharge zone 22 that includes the outlet [0070]. Bleifuss teaches a container moving apparatus 24 (i.e., a conveyor) that is movable through the zones (Fig. 1, [0042-0044]).
Bleifuss teaches feeding the briquettes onto the conveyor in a charging end 20 (i.e., part of the feed zone) (Fig. 1, [0044]), transporting the briquettes on the conveyor through the preheat zone 28 and heating the briquettes [0131] and releasing volatiles in carbonaceous material in the briquettes [0042]. Bleifuss teaches the atmosphere to have a reducing atmosphere [0130], and that movement of gases occurs through the preheat zone 28 [0082], thus one of ordinary skill would expect at least some reducing of iron ore in the briquettes in the preheating zone 28.
Bleifuss teaches heating including generating heat by burning combustible gases in a top space of the preheat zone 28 via a plurality of air fed burners 38 (Fig. 1, [0079, 0094]). Bleifuss teaches the presence of carbon monoxide in the furnace [0130], which is not contained in natural gas fed to the burners 38 [0094], thus the gases burned would include CO combustible gas generated within the furnace. Bleifuss teaches transporting the heated briquettes on the conveyor from the preheat zone 28 through the final reduction zone 30 [0131], with the system (including final reduction zone 30) having a controlled atmosphere to prevent oxidation (i.e., being an anoxic environment) [0108], and heating the preheated briquettes [0060] and reducing iron ore in the briquettes and forming the DRI [0075], causing gases generated in the final reduction zone 30 to flow towards flue 40 (i.e., counter-current to the direction of movement of the briquettes on the conveyor through the furnace) [0079]. Bleifuss teaches transporting the DRI on the conveyor 24 to the discharge zone 22 at the outlet and discharging the processed material (i.e., DRI) from the discharge zone 22 (Fig. 1, [0070]).
Bleifuss does not teach wherein the briquettes comprise biomass.
Eisele teaches production of iron using environmentally-benign renewable or recycled reducing agents (Title), where iron ore and a reductant of biomass material in particulate form is shaped into pellets and placed in a furnace to produce metallic iron directly from ore (Abstract), wherein the biomass comprises carbon [0009, 0042], therefore Eisele and Bleifuss are analogous to the instant application as both are directed to methods of direct reduction of pellets of iron ore and carbonaceous material to metallic iron in a furnace. Eisele teaches the invention has the advantage of allowing renewable and recyclable organics to be used as reducing agents without having to first process the organics to produce charcoal or otherwise prepare them for the smelting process, as biomass can be used in a raw form [0039], and that biomass is a surplus or waste product and thus has low costs [0039]. Eisele teaches the use of biomass material or other organic acts as a binder for the pellets holding them together until the reactions are completed, making it unnecessary to use additional binders such as bentonite clay, where the elimination of separate binders results in less contamination of the product, smaller quantities of slag and simplifies the control of slag properties [0039].
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have used biomass as the carbonaceous material as taught by Eisele (i.e., to use a composite of iron ore fragments and biomass) in the briquettes of iron ore and carbonaceous material of Bleifuss as doing so would not require pretreatment of the biomass, benefit from lower costs, not require additional binders, and result in less contamination of the product, smaller quantities of slag, and simplify control of slag properties as taught by Eisele.
Bleifuss does not teach supplying electromatic energy into the final reduction zone.
Hwang teaches a microwave heating method for iron oxide reduction (Title), where iron oxides are reduced using microwave heating in a furnace chamber that is sealed against entrance of air and produces combustible gas (Abstract), where reduction may be performed in a linear conveyor furnace [0017] thus Hwang and Bleifuss are analogous to the instant application, as both are directed to methods of reducing iron oxides in linear conveyor furnaces that maintain non-oxidizing atmospheres within. Hwang teaches supplying microwave energy into primary zone 98 A (analogous to a final reduction zone) of a furnace chamber 98 of a linear conveyor furnace 88 (Fig. 10, [0061]), where the microwaves may be supplied in addition to further heating by burners [0063]. Hwang teaches microwave heating is selective, and only heats components of the material that needs to be heated, i.e., to reduce the hematite or magnetite and does not heat nonferrous components of the feed material directly, so that the energy is much more efficiently used and the maximum temperature reached can be much lower [0006], while air injection in conventional heating results in combustion of carbo which may waste useful combustibles and adds to the carbon footprint of the process [0010].
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have supplied microwaves to reduce iron oxide in the final reduction zone as taught by Hwang to the process of Bleifuss as doing so would use energy more efficiently, reduce the temperatures the furnace must be able to operate at, and reduce the carbon footprint of the process by reducing the amount of heating performed by the use of burners as taught by Hwang.
Bleifuss does not teach post-combustion percentages in the preheat zone, however, it has long been held that where 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. See MPEP 2144.05 (II) A-B. In the instant case, as Bleifuss teaches combusting combustible gases developed in the furnace, and controlling the atmosphere in the furnace to maintain a particular reducing potential (i.e., controlling the post-combustion percentage), one of ordinary skill would be motivated to combust a portion of the combustible gases sufficient to preheat the iron ore and efficiently utilize the heating value of the combustible gases.
Further, the mere recitation of a numerical parameter in an otherwise known process will not generally result in patentability of a claim directed to that process, absent evidence of criticality of the numerical parameter. In the instant case the numerical parameter (the post-combustion percentage) does not appear to be critical to the invention.
Thus, the disclosure of Bleifuss is held to establish a prima facie case of obviousness of a method as presently claimed.
Regarding claim 9, Eisele teaches wherein the balance of the composition of briquettes is iron ore fragments ([0024], Table 1), flux [0038], and binder materials added to the mass ([0034, 0050], Table 1). Eisele does not teach the presence of additional carbonaceous material, but as such is optional according to claim 9, Eisele teaches all of necessary features to teach claim 9 in its entirety.
Regarding claim 12, Hwang teaches wherein the final reduction zone includes microwave energy heating briquettes to 600-1200 °C [0048]. Bleifuss teaches the preheat zone to be at 538-1093 °C [0130].
Bleifuss in view of Hwang teaches a temperature change of -493 °C to 662 ° going from the preheat zone to the final reduction zone. This overlaps the claimed range of increasing the temperature by at least 250 °C in the final reduction zone. The overlap between the ranges taught in the prior art and recited in the claims creates a prima facie case of obviousness because the prior art indicates substantial utility over the entire range disclosed therein, including that portion of the range which also falls within the claimed range. See MPEP § 2144.05(I).
Regarding claim 18, Bleifuss in view of Eisele and Hwang does not teach a gas “choke”. The Examiner notes that a gas “choke” is considered in parent claim 15 as one of several options that may be used in the alternative for generating the higher pressure in the final reduction zone, and claim 15 instead is read upon by Bleifuss which teaches generating the higher pressure as a consequence of reduction of iron ore in briquettes generating gases in the zone and by supplying inert gas into the final reduction zone. As claim 18 only recites further limits of the alternative limitation, Bleifuss is considered to read upon 18 in its entirety.
Regarding claim 25, Bleifuss teaches discharging DRI from the discharge zone [0070], however Bleifuss does not teach transporting the DRI in a hot state away from the furnace at a temperature in a range of 900-1150° C.
Hwang teaches a linear conveyor furnace 88 [0061], which produces DRI [0019] which is discharged from an end of the conveyor 92 [0063]. Hwang teaches DRI may be discharged directly into an electric arc furnace for production of steel or an induction melting furnace [0053-0055].
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have directly fed DRI to an electric arc furnace for production of steel or an induction melting furnace without cooling as taught by Hwang, transporting DRI in a hot state away from the furnace for producing DRI, in the process of Bleifuss as doing so would remove the need for a cooling zone, reducing the size and cost of the furnace. Further, doing so would be recognized by one of ordinary skill to reduce the heating requirements for the DRI in the subsequent electric arc or induction melting furnace, saving energy in the following process step. As Bleifuss teaches a temperature of 2200-2700 °F (1204-1482 °C) in the melting zone 31 (Claim 40) prior to the discharging step, the DRI is transported from the DRI furnace at a temperature in the claimed range.
Regarding claims 32-33, Bleifuss in view of Eisele and Hwang as applied to claim 1 does not teach wherein the post-combustion is from 20% to 45% at a hot end of the preheat zone, however, it has long been held that where 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. See MPEP 2144.05 (II) A-B. In the instant case, as Bleifuss teaches combusting combustible gases developed in the furnace, and controlling the atmosphere in the furnace to maintain a particular reducing potential (i.e., controlling the post-combustion percentage), one of ordinary skill would be motivated to combust a portion of the combustible gases sufficient to preheat the iron ore and efficiently utilize the heating value of the combustible gases.
Further, the mere recitation of a numerical parameter in an otherwise known process will not generally result in patentability of a claim directed to that process, absent evidence of criticality of the numerical parameter. In the instant case the numerical parameter (the post-combustion percentage) does not appear to be critical to the invention, at least for the reason it is recited solely in dependent claims.
Thus, the disclosure of Bleifuss is held to establish a prima facie case of obviousness of a method as presently claimed.
Claim(s) 3-4, 8, 11, 13-15, 19, and 22 remain(s) rejected as set forth in the Office Action dated 01/09/2026. The amendments to claim(s) 2-4, 8, 11, 13-15, 19, and 22 are of an editorial nature and do not materially affect any statements made in the rejection in the prior Office Action. Therefore, the previously presented grounds of rejection set forth how the prior art teaches or suggests all of the limitations of the claim(s).
Claim 23 is rejected under 35 U.S.C. 103 as being unpatentable over Bleifuss in view of Eisele and Hwang as applied to claim 2 above, and further in view of Kiesel et al. (US 20120198966 A1, cited in Office Action dated 01/09/2026).
Claim(s) 23 remain(s) rejected as set forth in the Office Action dated 01/09/2026. The amendments to claim(s) 23 are of an editorial nature and do not materially affect any statements made in the rejection in the prior Office Action. Therefore, the previously presented grounds of rejection set forth how the prior art teaches or suggests all of the limitations of the claim(s).
Double Patenting
The nonstatutory double patenting rejection is based on a judicially created doctrine grounded in public policy (a policy reflected in the statute) so as to prevent the unjustified or improper timewise extension of the “right to exclude” granted by a patent and to prevent possible harassment by multiple assignees. A nonstatutory double patenting rejection is appropriate where the conflicting claims are not identical, but at least one examined application claim is not patentably distinct from the reference claim(s) because the examined application claim is either anticipated by, or would have been obvious over, the reference claim(s). See, e.g., In re Berg, 140 F.3d 1428, 46 USPQ2d 1226 (Fed. Cir. 1998); In re Goodman, 11 F.3d 1046, 29 USPQ2d 2010 (Fed. Cir. 1993); In re Longi, 759 F.2d 887, 225 USPQ 645 (Fed. Cir. 1985); In re Van Ornum, 686 F.2d 937, 214 USPQ 761 (CCPA 1982); In re Vogel, 422 F.2d 438, 164 USPQ 619 (CCPA 1970); In re Thorington, 418 F.2d 528, 163 USPQ 644 (CCPA 1969).
A timely filed terminal disclaimer in compliance with 37 CFR 1.321(c) or 1.321(d) may be used to overcome an actual or provisional rejection based on nonstatutory double patenting provided the reference application or patent either is shown to be commonly owned with the examined application, or claims an invention made as a result of activities undertaken within the scope of a joint research agreement. See MPEP § 717.02 for applications subject to examination under the first inventor to file provisions of the AIA as explained in MPEP § 2159. See MPEP § 2146 et seq. for applications not subject to examination under the first inventor to file provisions of the AIA . A terminal disclaimer must be signed in compliance with 37 CFR 1.321(b).
The filing of a terminal disclaimer by itself is not a complete reply to a nonstatutory double patenting (NSDP) rejection. A complete reply requires that the terminal disclaimer be accompanied by a reply requesting reconsideration of the prior Office action. Even where the NSDP rejection is provisional the reply must be complete. See MPEP § 804, subsection I.B.1. For a reply to a non-final Office action, see 37 CFR 1.111(a). For a reply to final Office action, see 37 CFR 1.113(c). A request for reconsideration while not provided for in 37 CFR 1.113(c) may be filed after final for consideration. See MPEP §§ 706.07(e) and 714.13.
The USPTO Internet website contains terminal disclaimer forms which may be used. Please visit www.uspto.gov/patent/patents-forms. The actual filing date of the application in which the form is filed determines what form (e.g., PTO/SB/25, PTO/SB/26, PTO/AIA /25, or PTO/AIA /26) should be used. A web-based eTerminal Disclaimer may be filled out completely online using web-screens. An eTerminal Disclaimer that meets all requirements is auto-processed and approved immediately upon submission. For more information about eTerminal Disclaimers, refer to www.uspto.gov/patents/apply/applying-online/eterminal-disclaimer.
Claim 1 is provisionally rejected on the ground of nonstatutory double patenting as being unpatentable over claims 1-20 of copending Application No. 19/142,316 (reference application).
Although the claims at issue are not identical, they are not patentably distinct from each other because using biomass as a reductant in a hearth furnace would intrinsically result in the biomass developing heat (i.e., using biomass as a heating source of the iron ore), and supplying microwave energy to facilitate reduction of iron (i.e., electromagnetic energy) would intrinsically act as a heating source. While the ‘316 application does not teach post-combustion percentages in the preheat zone, it has long been held that where 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. See MPEP 2144.05 (II) A-B. In the instant case, one of ordinary skill would be motivated to combust a portion of the combustible gases sufficient to preheat the iron ore and efficiently utilize the heating value of the combustible gases. Thus, the disclosure of the ‘316 application is held to establish a prima facie case of obviousness of a method as presently claimed.
This is a provisional nonstatutory double patenting rejection.
Claims 2 and 13-14 are provisionally rejected on the ground of nonstatutory double patenting as being unpatentable over claims 1-20 of copending Application No. 19/142,316 (reference application) in view of Bleifuss et al. (US 20080302211 A1, cited in Office Action dated 10/01/2025).
Although the claims at issue are not identical, they are not patentably distinct from each other because claims 1 and 7-8 of the reference application contain every element of claim 2, except for wherein the furnace includes a discharge zone that includes the outlet, wherein the iron ore and biomass are in the form of briquettes, feeding in a feeding zone, burning combustible gases in a top space of the preheat zone, and post combustion of up to 45% at a hot end of the preheat zone and of at least 7% at a cold end of the preheat zone.
Bleifuss teaches using briquettes of a composite of iron ore fragments and biomass (Title, Abstract, [0064, 0098]) in a furnace (Title, [0040]), where the briquettes would be recognized by one of ordinary skill to improve handling and reduce generation of fines. Bleifuss teaches a discharge zone 22 that includes the outlet [0070], feeding into a feed zone 27 (Fig. 1, [0044-0046]), and burning combustible gases in a top space of the preheat zone (Fig. 1, [0079, 0094]). As the ‘316 reference is silent to how the raw materials are added to the furnace and finished product is removed from the furnace, thus one of ordinary skill would necessarily look to the art for suitable means of adding and removing material from the furnace and a suitable location for burning the combustible gases.
While the ‘316 application does not teach post-combustion percentages in the preheat zone, it has long been held that where 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. See MPEP 2144.05 (II) A-B. In the instant case, one of ordinary skill would be motivated to combust a portion of the combustible gases sufficient to preheat the iron ore and efficiently utilize the heating value of the combustible gases. Thus, the disclosure of the ‘316 application is held to establish a prima facie case of obviousness of a method as presently claimed.
Further reference claims 7 and 8 contain every element of instant claims 13 and 14 respectively.
This is a provisional nonstatutory double patenting rejection.
Claims 1 is provisionally rejected on the ground of nonstatutory double patenting as being unpatentable over claims 1-3, 5-7, 10-19, 21-22, 25, and 27 of copending Application No. 18/038,139 (the reference application).
Although the claims at issue are not identical, they are not patentably distinct from each other because using biomass as a reductant in a hearth furnace would intrinsically result in the biomass developing heat (i.e., using biomass as a heating source of the iron ore), and supplying microwave energy to facilitate reduction of iron (i.e., electromagnetic energy) would intrinsically act as a heating source. While the ‘139 application does not teach post-combustion percentages in the preheat zone, it has long been held that where 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 the instant case, one of ordinary skill would be motivated to combust a portion of the combustible gases sufficient to preheat the iron ore and efficiently utilize the heating value of the combustible gases. Thus, the disclosure of the ‘316 application is held to establish a prima facie case of obviousness of a method as presently claimed.
Claims 2-3, 8, 11, 12, 13, and 14 are provisionally rejected on the ground of nonstatutory double patenting as being unpatentable over claims 1-3, 5-7, 10-19, 21-22, 25, and 27 of copending Application No. 18/038,139 in view of Bleifuss.
Although the claims at issue are not identical, they are not patentably distinct from each other because claim 1 of the reference application contains every element of instant claim 2, except for wherein gases generated in the final reduction zone flow counter-current to a direction of movement of briquettes on the conveyor through the furnace and wherein the furnace is operated such that there is post-combustion of up to 45% at a hot end of the preheat zone and of at least 75% at a cold end of the preheat zone. Bleifuss teaches a DRI reduction furnace where gases generated in the final reduction zone 30 flow towards flue 40 (i.e., counter-current to the direction of movement of briquettes on the conveyor through the furnace) [0079], which performs drying in the preheat zone by using gases from the final reduction zone [0103], where it would have been obvious to use a counter-current flow of gases as it dries material in the preheat zone.
While the ‘139 application does not teach post-combustion percentages in the preheat zone, it has long been held that where 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 the instant case, one of ordinary skill would be motivated to combust a portion of the combustible gases sufficient to preheat the iron ore and efficiently utilize the heating value of the combustible gases. Thus, the disclosure of the ‘316 application is held to establish a prima facie case of obviousness of a method as presently claimed.
Further reference claims 2, 10, 13, 14, 15, 16 contain every element of instant claims 3, 8, 11, 12, 13, and 14 respectively, and as such anticipate claims 3, 8, and 11-14 of the instant application.
This is a provisional nonstatutory double patenting rejection.
Claims 2 and 8-9 are provisionally rejected on the ground of nonstatutory double patenting as being unpatentable over claims 1-3, 5-7, 10-19, 21-22, 25, and 27 of copending Application No. 18/038,139 in view of Bleifuss and Eisele et al. (US 20070209480 A1, cited in Office Action dated 10/01/2025).
Claim 2 is provisionally rejected over the ‘139 application in view of Bleifuss as noted above.
Reference claim 12 contains every element of instant claims 8-9, except for wherein the mass percentage of biomass in briquettes is 20-45% by weight on a wet (as-charged) basis. Eisele teaches using biomass in briquettes of iron ore and biomass used to produce DRI (Title, abstract), where the briquettes comprise moisture (i.e., the material is “wet”) [0034-0035, 0050], and wherein the mass percentage of biomass in briquettes is 20-30% by weight on an as-charged basis (Table 1), which is within the claimed range, where it would have been obvious to one of ordinary to skill to use a percentage of biomass in the briquettes known to be effective to reduce iron ore to DRI, as the ‘139 application and Bleifuss are silent to a suitable percentage of biomass.
This is a provisional nonstatutory double patenting rejection.
Response to Arguments
Applicant's arguments filed 05/11/2026 have been fully considered but they are not persuasive.
Regarding Applicant’s argument that the rejections of claims 1 and 2 and their dependents under 35 USC 112(a) should be withdrawn, as the instant application discloses a typical post-combustion profile may be of 35-45% (see pg. 8-9 of remarks), the Examiner respectfully disagrees.
While as Applicant notes, a positive disclosure in the instant specification that the post-combustion profile may be one range would not preclude the post-combustion profile from being another range, and the instant application discloses that “The combustion profile may be any suitable profile.” at pg. 16 lines 25-26 of the instant specification; the 35-45% postcombustion disclosed at pg. 16, 24, and 29, of the instant specification is the only disclosure of a “suitable profile” for the hot end of the preheat zone in the specification. The instant application for example, does not disclose whether 0%, 10%, or 34% post-combustion would comprise “suitable profiles” of the combustion profile at the hot end, and thus cannot be asserted by Applicant to have been possessed by the inventor at the time the application was filed, as the application does not disclose or reasonably suggest that any value of “up to 45%” may be used at the hot end of the preheat zone. While as Applicant notes, the instant application discloses “the combustible gases being combusted in the preheat zone by air or oxygen-enriched air fed burners and producing heat that heats briquettes in the preheat zone before the preheated briquettes move to the reduction zone” at paragraph 26 of the instant specification, the cited portion of the specification does not disclose anything regarding what post-combustion profile is achieved or which profiles would comprise “suitable profiles”, let alone within the claimed range of “up to 45%” at the hot end, and instead only discloses generally that some amount of combustion of combustible gases may occur in the preheat zone. Therefore, the rejections of claims 1 and 2 and their dependents as failing to comply with the written description requirement are maintained.
Regarding Applicant’s argument that Bleifuss does not teach a combustion gradient defined by specific post combustion % at opposite ends of the zone, (see pg. 11-13 of remarks), the Examiner respectfully disagrees.
While as Applicant notes, Bleifuss is based on distributed combustion along the furnace, and Bleifuss removes gases from the preheating zone using a flue and exhaust system, Bleifuss does not completely ignore post-combustion of gases as alleged by Applicant. Instead, while Bleifuss only notes that all gases, combustion products, water vapor, volatiles, and reaction products may be removed using the flue (Bleifuss: [0079]) in a single embodiment, and more generally Bleifuss teaches that the combustion gases, water vapor, organic volatiles, flux calcinations products, and chemical reaction products only eventually are removed via the discharge flue (Bleifuss: [0079]).
Bleifuss further discloses that the flue 40 is located in the preheat zone 28 (with a counter flow of gas compared to the movement of the solids in the furnace) (e.g., Fig. 1, 6A-6B, [0079]), while (as Applicant notes) the burners are placed along the length of the furnace, therefore Bleifuss teaches that combustion occurs throughout the furnace. As the post-combustion products only are removed by the flue in the preheat zone, such an arrangement intrinsically results in a gradient across the furnace, with a greater amount of post-combustion products at the flue in the preheat zone 28 than e.g., within the preheat zone 28 but further along the furnace (i.e., the post-combustion % would be intrinsically greater near the flue than further from the flue and the front of the preheat zone, as a greater amount of post-combustion products [H2O and CO2] would be present nearer to the flue).
Bleifuss further discloses controlling for example the temperature in response to sensors in the furnace [0045], and that the burners (the use of which would introduce new CO, H2, H2O, and CO2, or at least H2O and CO2) specifically can be controlled by use of carbon dioxide, carbon monoxide, and oxygen sensors to control the reducing potential throughout the furnace [0130]. As Bleifuss also teaches the presence of volatiles (which comprises carbon monoxide) (e.g., [0079, 0130]), and as hydrogen and carbon monoxide are reducing gases, controlling the reducing potential (i.e., the relative proportion of gases including carbon monoxide) throughout the furnace also controls the post-combustion %, as the post combustion % as defined by Applicant is based in part on the concentration of carbon monoxide.
Therefore, post-combustion, even if not recognized using the same terminology or quantified using the same calculations as Applicant, is a phenomenon both recognized and controlled within the process of Bleifuss, and therefore it would have been a matter of routine optimization to adjust the post-combustion % to desired or optimal values at cold and hot ends of the preheat zone of Bleifuss.
Regarding Applicant’s argument that there is not an articulated reasoning with some rational underpinning to support the conclusion of obviousness given the alleged complexities of the methods described in the instant claims (see pg. 11-12 and 13-14 of remarks) and that there is no reasonable expectation of success in achieving the claimed coordinated behavior (see pg. 16 of remarks), the Examiner respectfully disagrees.
As noted at b. above, the complexity of the effect of post combustion % is understood and addressed by Bleifuss.
Regarding using electromagnetic energy, Bleifuss teaches that other types of temperature modification apparatus besides gas burners may be used, for example electric heating apparatus (which would include microwave heating) (Bleifuss: [0094]), thus Bleifuss already envisages that other forms of heating may be used, which would affect the generation of gas in the furnace, and therefore the control of gases and any considerations of energy balance within Bleifuss in turn would already be designed to account for such.
Regarding using biomass as a source of reductant, Eisele discloses using biomass material as the reductant and subjecting it to heating in any convenient manner, such as electric heating (where microwave heating is a type thereof) (e.g., Eisele: [0025]), thus Eisele does not appear to suggest that using biomass as the reductant is limited to e.g., only certain types of heating, and instead whatever variables need to be accounted for based on the choice of heating, if any, would be well within the ability of one of ordinary skill to recognize and address. While Applicant notes the effect of biomass tars, nothing in the instant claims or specification discloses the presence of such tars, let alone that such must be carefully or at all accounted for in designing the methods of the instant application.
Therefore, the prior art and combination thereof address Applicant’s noted complexities to the extent they are supported in the instant claims and specification, and would have a reasonable expectation of success.
Further, in response to applicant's argument that the references fail to show certain features of the invention, it is noted that the features upon which applicant relies (i.e., coordinated control of pressure and combustion staging) are not recited in the rejected claim(s). Although the claims are interpreted in light of the specification, limitations from the specification are not read into the claims. See In re Van Geuns, 988 F.2d 1181, 26 USPQ2d 1057 (Fed. Cir. 1993).
Regarding Applicant’s argument that the defined post-combustion gradient is particularly significant (see pg. 15 of remarks), the Examiner respectfully disagrees.
Nothing in the instant spec discusses any particular criticality or significance of the percentage of post-combustion at the hot and cold ends of the preheat zone, and as noted at item b. above, Bleifuss teaches the post-combustion % to be a result-effective variable that may be controlled to affect the reducing potential in the furnace, therefore, Bleifuss renders obvious the claimed ranges.
Regarding Applicant’s argument that the proposed modifications would alter the principle of operation of Bleifuss (see pg. 15-16 of remarks), the Examiner respectfully disagrees.
It has long been held that a person of ordinary skill is ‘not an automaton’ limited to physically combining references. See University of Maryland v. Presens, No. 16-2745 (Fed. Cir. 2017). As noted at item b. above, thus while using microwave heating and using biomass as a reductant may take some degree of reconstruction and redesign, as Bleifuss already teaches using heating sources besides burners such as electrical heating as noted above, such reconstruction and redesign is already contemplated by Bleifuss. Further, there is clear motivation within the art to make such modifications, as Hwang teaches the use of microwaves as a heating source is more energy efficient, reduces the temperatures the furnace must be able to operate at, and reduces the carbon footprint of the process, while Eisele teaches the use of biomass as a reductant to benefit from lower costs, not require additional binders, and result in less contamination of the product, smaller quantities of slag, and simplify control of slag properties.
Regarding Applicant’s argument that the instant claims do not merely add microwave heating and biomass fuel to a known furnace, and require a reconfiguration in which the final reduction zone is anoxic and electromagnetic-energy heated, where gases are intentionally routed upstream to a burner-controlled preheat zone with post-combustion levels that vary longitudinally (see pg. 16 of remarks),the Examiner respectfully disagrees.
Bleifuss teaches a configuration where the final reduction zone is under reducing conditions and controlled to prevent oxidation (i.e., predominantly anoxic), and is taken in view of Hwang to teach electromagnetic energy heating. Gases are intentionally routed upstream to the preheat zone as the flue 40 of Bleifuss is located in the preheat zone (and in turn all gases in generated in the furnace move towards the preheat zone and flue), and Bleifuss teaches control over the burners and post-combustion levels as noted at b. above
In response to applicant's argument that the references fail to show certain features of the invention, it is noted that the features upon which applicant relies (i.e., “staged thermodynamic energy recycling”) are not recited in the rejected claim(s). Although the claims are interpreted in light of the specification, limitations from the specification are not read into the claims.
Conclusion
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.
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/Keith D. Hendricks/Supervisory Patent Examiner, Art Unit 1733
/NIKOLAS TAKUYA PULLEN/Examiner, Art Unit 1733
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