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 12/01/2025 has been entered. Claims 1-4, 6, 8-9, 11-15, 18-19, 22-23, 25, 27, 29 and 31 are pending in this application and examined herein. Claims 27, 29, and 31 are withdrawn. Claims 1-2, and 27 are amended. Claims 5, 7, 10, 16-17, 20-21, 24, 26, 28, 30, and 32 are cancelled.
Election/Restrictions
Claims 27, 29, and 31 are withdrawn from further consideration pursuant to 37 CFR 1.142(b), as being drawn to a nonelected Group II, there being no allowable generic or linking claim. Applicant timely traversed the restriction (election) requirement in the reply filed on 12/01/2025.
Applicant's election with traverse of Group I in the reply filed on 12/01/2025 is acknowledged. The traversal is on the grounds that the apparatus is specifically designed for carrying out the said process comprises special technical features which contribute over the art of record. This is not found persuasive because Bleifuss in view of Eisele and Hwang teaches all of the alleged special technical features: Bleifuss teaches producing organic volatile gases (i.e., combustible gases) in a preheater (i.e., a preheat zone) [0042, 0079], and burning off-gases (i.e., combustible gases) [0094], thus Bleifuss teaches burning combustible gases produced in the preheat zone.
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, 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. Bleifuss teaches a preheat zone and reduction zone configuration as claimed, where gas flows counter current [0079], which would enable heating in the preheat zone, where air fed burners combust combustible gases generated in the reduction zone [0079, 0094].
Thus, the disclosure of Bleifuss is held to establish a prima facie case of obviousness of a method as presently claimed.
The requirement is still deemed proper and is therefore made FINAL.
Priority
Receipt is acknowledged of certified copies of papers required by 37 CFR 1.55.
Information Disclosure Statement
The information disclosure statement(s) (IDS) submitted on 05/22/2023 and 02/20/2025 are in compliance with the provisions of 37 CFR 1.97 and is/are being considered by the examiner.
Claim Objections
Claims 14, 18, and 22 are objected to because of the following informalities:
Claim 14: “gas pressure” in lines 2-3 should read “a gas pressure”
Claim 18: “final reduction zone from the reduction zone” in lines 2-3 should read “final reduction zone flowing from the reduction zone”
Claim 22: “such feeding process” in line 3 should read “the feeding process” 1.
Appropriate correction is required.
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.
Regarding the instant claims, the phrase “relatively uniform bed of briquettes” is herein interpreted as:
“a relatively uniform layer of briquettes covering a base of the conveyor and typically having a consistent 'bed' depth, at least length ways, i.e. in the direction of briquette travel within the furnace.”
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 25 recites “discharging DRI from the discharge zone and transporting the DRI in a hot state away from the furnace at a temperature in a range of 900-11500 °C” in lines 2-3. The instant specification discloses “DRI on exiting the final reduction zone may be at a bulk temperature of at least 900°C, typically at least 1000°C, and more typically at least 900°C to up to 1150°C” (instant specification: pg. 14 lines 13-15), but does not disclose a temperature range of 900-11500 °C, 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.
Claims dependent upon claims rejected above, either directly or indirectly, are likewise rejected under this statute.
The following is a quotation of 35 U.S.C. 112(b):
(b) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention.
The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph:
The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention.
Claims 1-4, 6, 8-9, 11-15, 18-19, 22-23, 25, 27, 29 and 31 are rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor (or for applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention.
Claim 1 recites the limitation "briquettes" in lines 9, 13, 16 and 17. The limitation is indefinite as the lack of an article makes unclear whether “briquettes” in each line refer to the same briquettes as in lines 4, 9, 13, and/or 16.
Claim 2 recites the limitation "briquettes" in lines 4, 8, 9, 10, 11, 15, 18, and 20. The limitation is indefinite as the lack of an article makes unclear whether “briquettes” in each line refer to the same briquettes as in lines 2, 4, 8, 9, 10, 11, 15, and/or 18.
Regarding claim 2, the phrase "such as" renders the claim indefinite because it is unclear whether the limitations following the phrase are part of the claimed invention. See MPEP § 2173.05(d).
Claim 2 recites the limitation "DRI" in lines 18, 23, and 24. The limitation is indefinite as the lack of an article makes unclear whether “DRI” in each line refers to the same DRI as in lines 1, 18, and/or 23.
The term “relatively uniform” in claim 3 is a relative term which renders the claim indefinite. The specification does provide a standard for ascertaining the requisite degree of the term “relatively uniform” at pg. 11 lines 1-6 of the instant specification, however the definition discloses “understood herein to mean a relatively uniform layer of briquettes covering a base of the conveyor typically having a consistent ‘bed’ depth”, which are themselves relative terms which are not provided with a standard for what a “relatively uniform layer of briquettes covering a base of the conveyor” comprises or how “typically” a consistent bed depth must be present. Therefore, claim 3 is rendered indefinite as it is unclear how uniform the bed of briquettes on the conveyor base actually is.
Claim 4 recites the limitation "a plurality of burners" in line 2. The limitation is indefinite as it is unclear if claim 4 is further limiting the “plurality of air or oxygen-enriched air fed burners” of parent claim 2, or describe a different set of burners.
Claim 6 recites the limitation "adjusting the amount of air or oxygen-enriched air fed to each burner… to compensate for variations in combustible gases" in lines 1-3. The limitation is indefinite as it is unclear what adjustments to the amount of air or oxygen-enriched air are performed, what variations exist in the combustible gas, and how the variations and adjustments are actually related (e.g., any adjustment is made for each variation in the combustible gases; the air or oxygen-enriched air amount is adjusted to burn combustible gas in a stoichiometric ratio; or in another ratio; or the adjustments are governed by another mathematical formula).
Claim 8 recites the limitation "briquettes" in line 2. The limitation is indefinite as the lack of an article makes unclear whether the “briquettes” of claim 8 are the same as those of parent claim 2, or a different set of briquettes.
Claim 9 recites the limitation "briquettes" in line 2. The limitation is indefinite as the lack of an article makes unclear whether the “briquettes” of claim 9 are the same as those of parent claims 2 and/or 8, or a different set of briquettes.
Claim 9 recites the limitation "pre-charred biomass" in lines 3-4. The limitation is indefinite as it is unclear how a biomass may form part of the balance of the composition of the briquettes, if parent claim 9 already specifies the mass percentage of biomass in briquettes to be 20-45%, making unclear if pre-charred biomass counts as part of the percentage of biomass, of the balance, or both.
Claim 11 recites the limitation "briquettes" in line 2. The limitation is indefinite as the lack of an article makes unclear whether the “briquettes” of claim 11 are the same as those of parent claim 2, or a different set of briquettes.
Claim 12 recites the limitation "briquettes" in line 2. The limitation is indefinite as the lack of an article makes unclear whether the “briquettes” of claim 12 are the same as those of parent claim 2, or a different set of briquettes.
Claim 15 recites the limitation "briquettes" in line 3. The limitation is indefinite as the lack of an article makes unclear whether the “briquettes” of claim 15 are the same as those of parent claim 2, or a different set of briquettes.
Claim 15 recites the limitation "the reduction zone" in line 5. There is insufficient antecedent basis for this limitation in the claim, as while claim 15 discloses a “final reduction zone” there is no mention of a reduction zone generally, making unclear whether “the reduction zone” refers to the final reduction zone, or a separate reduction zone.
Claims 15 and 18 recite the limitation "“choke”" in lines 4 and lines 1 and 4 respectively. The limitation is indefinite as the use of quotation marks makes unclear whether the gas flow choke is actually a choke; or if the choke only resembles or partly performs the function of a choke, and is not actually a choke.
Claim 18 recites the limitation "the reduction zone" in lines 2, 3, 5, and 6. There is insufficient antecedent basis for this limitation in the claim, as while parent claim 15 discloses a “final reduction zone” there is no mention of a reduction zone generally, making unclear whether “the reduction zone” refers to the final reduction zone, or a separate reduction zone.
The term “substantial gas flow” in claim 18 is a relative term which renders the claim indefinite. The term “substantial gas flow” is not defined by the claim, the specification does not provide a standard for ascertaining the requisite degree, and one of ordinary skill in the art would not be reasonably apprised of the scope of the invention, making unclear how much gas flow must be mitigated by the choke.
Claim 18 recites the limitation "from the reduction zone side to the reduction zone side of the furnace" in lines 5-6. The limitation is indefinite as it is unclear if gas moves from the final reduction zone to the preheat zone (as disclosed in lines 2-3), if the gas moves from a side of the reduction zone to another side of the reduction zone, if the gas moves from a side of the reduction zone to the same side of the reduction zone, or a combination thereof.
Claim 22 recites the limitation "briquettes" in line 1. The limitation is indefinite as the lack of an article makes unclear whether the “briquettes” of claim 22 are the same as those of parent claim 2, or a different set of briquettes.
Claim 23 recites the limitation "briquettes" in line 4. The limitation is indefinite as the lack of an article makes unclear whether the “briquettes” of claim 23 are the same as those of parent claim 2, or a different set of briquettes.
Claim 23 recites the limitation "having residual heat as a result of passing through the furnace that contributes to heating briquettes" in lines 3-4. The limitation is indefinite as it is unclear as to whether:
Claim 23 requires that the residual heat contributes to the heating of briquettes (“having residual heat… that contributes to heating briquettes”), or
Claim 23 requires that the furnace contributes to heating briquettes (“the furnace that contributes to heating briquettes")
Claim 25 recites the limitation "DRI" in line 2. The limitation is indefinite as the lack of an article makes unclear whether “DRI” refers to the same DRI as in parent claim 2, or a different quantity or group of DRI.
Claims dependent upon claims rejected above, either directly or indirectly, are likewise rejected under this statute.
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.
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, and 25 are rejected under 35 U.S.C. 103 as being unpatentable over Bleifuss et al. (US 20080302211 A1, cited in Office Action dated 10/01/2025) in view of Eisele et al. (US 20070209480 A1, cited in Office Action dated 10/01/2025) and Hwang et al. (US 20080087135 A1, 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 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 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 briquettes in the preheat zone 28 before 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 electromagnetic 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 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 used electromagnetic 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, 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.
Bleifuss teaches feeding briquettes onto the conveyor in a charging end 20 (i.e., part of the feed zone) (Fig. 1, [0044]), transporting briquettes on the conveyor through the preheat zone 28 and heating briquettes [0131] and releasing volatiles in carbonaceous in 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 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 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 briquettes [0060] and reducing iron ore in briquettes and forming 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 briquettes on the conveyor through the furnace) [0079]. Bleifuss teaches transporting DRI on the conveyor 24 to the discharge zone 22 at the outlet and discharging 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, 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 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 briquettes onto the conveyor in a charging end 20 (i.e., part of the feed zone) (Fig. 1, [0044]), transporting briquettes on the conveyor through the preheat zone 28 and heating briquettes [0131] and releasing volatiles in carbonaceous in 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 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 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 briquettes [0060] and reducing iron ore in briquettes and forming 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 briquettes on the conveyor through the furnace) [0079]. Bleifuss teaches transporting DRI on the conveyor 24 to the discharge zone 22 at the outlet and discharging 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, 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 3, Bleifuss teaches placing briquettes 88 on containers 80 of conveyor 24 hat carries a lightweight refractory bed on which the raw material 88 is placed [0050] (Fig. 5 A), forming a relatively uniform bed of briquettes on the conveyor as best can be examined in view of the rejection of claim 3 under 35 USC 112(b).
Regarding claim 4, Bleifuss teaches generating heat in the preheat zone (i.e., during step (b)) by burning combustible gases in a plurality of burners 38 that are spaced apart along the length of the top space of the preheat zone 28 of the furnace (e.g., Fig. 1 and 3) and spaced across the width of the preheat zone 28 of the furnace (e.g., Fig. 2-3).
Regarding claim 8, Eisele teaches the biomass comprises 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.
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).
Regarding claim 11, Bleifuss teaches preheating the briquettes to 1000-2000 °F (538 – 1093 °C) [0130] (i.e., controlling the method so that the bulk temperature of briquettes is at least 500°C when briquettes leave the preheat zone and pass to the final reduction zone).
Regarding claim 12, Hwang teaches wherein the final reduction zone includes electromagnetic 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 13, Bleifuss teaches releasing volatiles in the briquettes in the preheat zone [0042, 0130], wherein the briquettes comprise carbonaceous material (analogous to biomass) [0062]. As Bleifuss does not disclose the further presence of volatiles in the briquettes or releasing of volatiles in subsequent zones, it would be recognized by one of ordinary skill that Bleifuss in view of Eisele results in the release of essentially all of the volatiles in the biomass, teaching releasing at least 90% of volatiles in biomass in the briquettes as a gas in the preheat zone.
Regarding claim 14, Bleifuss teaches the furnace to operate as a counter-current furnace [0079], where an exhaust fan 53 vents gases from the furnace through exit flue 40 ([0079-0080], Fig. 1), where as gas flows from the reducing zone 30 to the preheat zone 28 prior to being withdrawn from the exit flue 40 [0079], Bleifuss intrinsically includes generating a higher pressure of gases in the final reduction zone compared to gas pressure in the preheat zone, thereby causing gases generated in the final reduction zone to flow counter-current to the direction of movement of briquettes on the conveyor through the furnace.
Regarding claim 15, Bleifuss teaches generating off-gases from the direct reduction process in the furnace zone 25, which comprises final reduction zone 30 (i.e., generating the higher pressure in the final reduction zone as a consequence of reduction of iron ore in briquettes in the final reduction zone generating gases in the zone) ([0042, 0103], Fig. 1). Bleifuss teaches the use of burners 38 in the final reduction zone 30 which produces combustion gases [0079] and are fed with natural gas [0094], where the combustion gases of natural gas (i.e., CH4) would comprise CO2 (an inert gas) (i.e., supplying inert gas into the final reduction zone).
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 19, Bleifuss teaches discharging gas produced in the furnace 10 by heating and/or combustion within the furnace as a flue gas through a flue gas outlet 40 in the feed zone 27/28 ([0079], Fig. 1).
Regarding claim 22, Bleifuss teaches feeding briquettes 88 onto the conveyor 24 in the feed zone 27 ([0084-0085, 0101], Fig. 1). Bleifuss teaches conveyor 24 is shown generally in FIG. 2 as being sealed using a structural enclosure 91 to represent that the container moving apparatus 24 is a substantially mechanically sealed apparatus such that gases in the zones 26 are retained therein [0083], thus Bleifuss teaches restricting outflow of furnace gases through such feeding process.
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 900-11500° 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.
Claim 6 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 Heitmann (US 3663201 A).
Bleifuss teaches both the inlet and outlet of the furnace are fitted with sealed doors that are only opened as required to allow the insertion or ejection of containers from the furnace thereby minimizing infiltration of ambient air therein [0084] and that container moving apparatus 24 is shown generally in FIG. 2 as being sealed using a structural enclosure 91 to represent that the container moving apparatus 24 is a substantially mechanically sealed apparatus such that gases in the zones are retained therein [0083], however Bleifuss does not teach adjusting the amount of air or oxygen-enriched air fed to each burner in step (b) to compensate for variations in combustible gases in the top space of the preheat zone.
Heitmann teaches a process for production of sponge iron (Title), where iron ore admixed with carbonaceous reducing agent is passed through a rotary kiln (i.e., a furnace) countercurrent to a reducing gas stream to direct reduce iron ore (Abstract, claim 1), thus Heitmann and Bleifuss are analogous to the instant application as both are directed to processes for direct reducing iron from iron ore in a furnace using a countercurrent gas stream. Heitmann teaches the total rate of air or other oxygen-containing gas fed to the furnace is selected in dependence on the amount of volatile constituents (i.e., combustible gases) in the coal (analogous to biomass) to maintain at least neutral or preferably reducing conditions (Col. 2 lines 18-22) (i.e., adjusting the amount of air or oxygen-enriched air fed to compensate for variations in combustible gases), which prevent reoxidation of the iron (Col. 2 lines 23-29).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have adjusted the amount of combustion air introduced at the burners of Bleifuss to compensate for variations in combustible gases (which would include combustible gases at the top space of the preheat zone) as taught by Heitmann, as doing so would prevent reoxidation of the reduced iron in the furnace as taught by Heitmann. Doing so would have been further obvious as it would limit the presence of oxygen and maintain a reducing atmosphere in the furnace, which is a goal of Bleifuss.
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).
Bleifuss teaches moving empty containers 15 of container moving apparatus 24 (analogous to a part of a conveyor) in an endless path, returning the conveyor 24 to the feed zone 27 of the furnace from the discharge zone 34 of the furnace via return apparatus 14 (analogous to a part of a conveyor conveyor) (Fig. 1, [0044-0046]).
Bleifuss does not teach the conveyor having residual heat as a result of passing through the furnace that contributes to heating briquettes loaded onto the conveyor.
Kiesel teaches a system and method for making metallic iron with reduced CO2 emissions (Title), where metallic iron nodules (i.e., reduced iron) are produced in a linear hearth furnace (Abstract) with a preheat zone 12 ([0023, 0036], Fig. 1-2), and a conversion zone 13 and a fusion zone 14 where iron is reduced and fused (i.e., a final reduction zone) (Fig. 1-2, [0036]), where the metallic iron is produced from compacts such as briquettes comprising reducible material such as iron ore and reducing carbonaceous material [0068], where the briquettes are conveyed on hearth cars 21 (Fig. 1-2, [0037]), thus Kiesel and Bleifuss are analogous to the instant application as both are directed to methods for producing reduced iron from briquettes of iron ore and carbonaceous material in a furnace with a preheat zone and final reduction zone where the briquettes are transported on a conveyor. Kiesel teaches after passing through the furnace, the conveyor 21 is returned to the transfer table 91 for returning the conveyor to the furnace [0038], where the conveyor is heated or at least the rate of cooling is reduced in shrouded return 30 by flue gas from the final reduction zone 13/14 (Fig. 1-2, [0039]), where as the conveyor is heated or cooling of the conveyor is slowed, the conveyor would retain at least some residual heat from passing through the furnace, which would intrinsically contribute to heating the briquettes when fed onto the conveyor. Kiesel teaches the conveyor is maintained at a temperature of 425-650 °C by the heating in the return 30, which improves the energy efficiency of the system [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 maintained a temperature of 425-650 °C on the conveyor as taught by Kiesel in the process of Bleifuss, as doing so would improve energy efficiency in the system as taught by Kiesel. Doing so would have a reasonable expectation of success, as Bleifuss teaches its conveyor should be cooled to the degree that it may accept agglomerate (Bleifuss: [0060]), and Kiesel teaches the briquettes (i.e., agglomerates) are loaded onto the conveyor maintained at 425-650 °C (Fig. 1-2, [0053, 0077].
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.
Conclusion
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/Keith D. Hendricks/Supervisory Patent Examiner, Art Unit 1733
/NIKOLAS TAKUYA PULLEN/Examiner, Art Unit 1733