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 .
Priority
Applicant’s claim to priority of US Provisional 63/408,218 filed September 20, 2022 and of US Provisional 63/339,715 filed May 9, 2022 is acknowledged.
Claim Status
This Office Action is in response to Applicant’s Claim Amendments and Remarks filed February 24, 2026.
Claims Filing Date
February 24, 2026
Amended
1, 4, 5, 6, 19
New
21-22
Cancelled
2, 3
Pending
1, 4-22
Withdrawn
5, 7-11, 17-19
Under Examination
1, 4, 6, 12-16, 20-22
The applicant argues support for the claim 1 amendments in original claims 2 and 3 and [38] and [69] of applicant’s specification (Remarks p. 8 para. 1) and support for new claims 21 and 22 in [0039] (Remarks para. spanning pp. 11-12, p. 12 para. 2).
Withdrawn Abstract Objection
The following objection is withdrawn due to abstract amendment:
The first sentence being a fragment.
Withdrawn Drawings Objection
The following drawings objection is withdrawn due to specification amendment:
Applicant’s specification at [32] mentioning reference numeral 76, the auxiliary line, however Fig. 1 nor any of the other figures including “76”.
Applicant amended the specification at [32] to recite “auxiliary line 66”, which is included at least in Fig. 1 (Remarks p. 7 para. 4).
Response to Remarks filed February 24, 2026
Bhoi
Applicant’s claim amendments, see amended claim 1 lines 3-9, filed February 24, 2026, with respect to Bhoi have been fully considered and are persuasive. The rejection of Bhoi has been withdrawn.
Amended claim 1 incorporates subject matter of previous claims 2 and 3 (Remarks p. 8 paras. 1 and 4), which were not rejected over Bhoi in the Non-Final Rejection dated October 16, 2025.
Bhoi in view of Choi
Applicant's arguments filed February 24, 2026 with respect to Bhoi in view of Choi have been fully considered but they are not persuasive.
The applicant argues in Choi particles fall through a hot zone that relies on heat to activate molecular hydrogen, whereas the hydrogen plasma of Bhoi supplies already-activated hydrogen species that more aggressively attack the oxide (Remarks p. 9 para. 3), such that the modification of Bhoi with Choi would alter the principle of operation of Bhoi because Choi has falling particles and modifying Bhoi with Choi would require significant redesign (Remarks para. spanning pp. 9-10).
In the pending rejection, a hydrogen plasma process (Bhoi Abstract, [0001], [0042], [0044]-[0058]) is modified by carrying particles to be reduced in a gas flow (Choi p. 83 left col. paras. 3-4, Fig. 4). Choi directly reduces fine iron oxide (Abstract, Experimental Materials) in a vertical split tube furnace (Fig. 4), where “The concentrate particles were injected through a tube…carried by a hydrogen flow” (p. 83 left col. para. 3). Choi also calculates the residence time of the particles in the isothermal zone based on “the linear velocity of the gas” (p. 83 left col. para. 4), supporting the particles being carried by the gas. Therefore, the particles being “carried” by a hydrogen flow reads on entraining (transporting by the flow) solid compound particles in a gas stream containing hydrogen (H2) to form a particle-entrained gas flow. This modification accurately determines the rate of individual iron oxide concentrate particles (Choi Experimental: Accurate kinetic measurements para. 1), which allows for investigation on the kinetic feasibility on the proposed technology (Choi Results and discussion: Accurate kinetics measurements para. 1). It also almost completely oxidizes the iron oxide concentrate (Choi Results and discussion: Preliminary experiments) and can also be used in a continuous process (Choi Fig. 4).
Further, as evidenced by Choi Figs. 3 and 4 and Experimental, the drop tube reactor system with flowing solid compound particles is an art recognized equivalent process to a furnace system that treats the sold compound particles on a sample tray, which is substantially similar to the process of Bhoi as seen in Fig. 1. It is prima facie obvious to substitute equivalents known for the same purpose. MPEP 2144.06(II). In light of the art recognized equivalent furnace systems, one of ordinary skill in the art would understand how to modify Bhoi based on the disclosure of Choi to entrain the particles for the cited advantages.
The applicant argues a mismatch between the reduction timescales of 35 minutes (Bhoi [0049]) and 1.0-7.0 seconds (Choi p. 83, right col.), reflecting distinct kinetic and reactor design assumptions (Remarks para. spanning pp. 9-10).
Considering the art as a whole, including the advantages and art recognized equivalency disclosed by the prior art as cited previously, one of ordinary skill would understand how the modification of Bhoi with Choi would subsequently influence the reaction kinetics, including reduction timescale.
The 1 to 7 second disclosed reduction timescale of Choi is kinetically feasible to reduce concentrate particles within a few seconds of reaction time (Choi Results and discussion: Preliminary experiments) with a high metallization degree (Choi Introduction para. 2) to allow for direct use of large quantities of fine iron oxide concentrates (Choi Introduction para. 1). One of ordinary skill in the art would understand how to adjust the process variables of the iron ore hydrogen plasma reduction in order to achieve the 1 to 7 second residence time, such as the H2 temperature, the amount of H2, and particle size (Choi Results and discussion: Accurate kinetic measurements, Figs. 5-12).
The applicant argues falling particles in Choi, where the particles of Bhoi would be reflected by the plasma (Remarks p. 10 para. 2).
Choi directly reduces fine iron oxide (Abstract, Experimental Materials) in a vertical split tube furnace (Fig. 4), where “The concentrate particles were injected through a tube…carried by a hydrogen flow” (p. 83, left col. Para. 2). The particles being “carried” by a hydrogen flow reads on entraining (transporting by the flow) solid compound particles in a gas stream containing hydrogen (H2) to form a particle-entrained gas flow. Therefore, contrary to applicant’s argument, the particles are carried by hydrogen flow.
The applicant argues Choi separately feeds iron oxide particles and H2 reductant gas, such that the particles are falling and not entrained (Remarks para. spanning pp. 10-11, p. 11 para. 2).
In Choi Fig. 4, the iron oxide particles and H2 reductant gas combine prior to entering the reactor as evidenced by the below annotated figure. This supports Choi’s disclosure that “The concentrate particles were injected through a tube…carried by a hydrogen flow” (p. 83, left col. Para. 2).
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For the above cited reasons the rejection of Bhoi in view of Choi is maintained.
New Claim 21
Applicant's arguments filed February 24, 2026 with respect to new claim 21 have been fully considered but they are not persuasive.
The applicant argues new claim 21 recites at least a 90% reduction to elemental iron over a plasma treatment time of less than 0.5 second (applicant’s specification [0035]), whereas Bhoi teaches 35 minutes (Bhoi [0049]) and Choi teaches a residence time of 1.0 to 7.0 seconds (Choi p. 83 right col.) with one experiment attaining 90% reduction in 1.6 seconds (Choi p. 85 left col.) and concluding 90-99% reduction within 1-7 seconds at 1200-1500°C (Choi p. 88 left col.) (Remarks para. spanning pp. 11-12).
Bhoi in view of Choi discloses (reduction in excess of 99%) (Bhoi [0001], [0031], [0044]-[0055], Table 3, Figs. 2-3) with the reaction kinetics of reducing iron oxide with H2 (Experimental: Accurate kinetic measurements) influenced by the H2 temperature, the amount of H2, and particle size (Results and discussion: Accurate kinetic measurements, Figs. 5-12). Reaction kinetics are a result-effective variable (Choi Results and discussion: Accurate kinetic measurements, Figs. 5-12), and the determination of the optimum or workable ranges of said variable might be characterized as routine experimentation. MPEP 2144.05(II)(B). In support of obviousness, the process of the prior art is substantially to that claimed as evidenced by the claim 1 and 12 rejections (Bhoi Abstract, [0001], [0044]-[0058]; Choi p. 83 left col. paras. 3-4, Fig. 4).
New Claim 22
Applicant's arguments filed February 24, 2026 with respect to new claim 22 have been fully considered but they are not persuasive.
The applicant argues new claim 22 recites at least a 95% reduction to elemental iron over a plasma treatment time of less than 1.0 second, whereas Bhoi teaches a plasma treatment of 35 minutes (Choi [0049]) and Choi requires a residence time of 1-7 seconds (Cho p. 18 right col.; p. 88 left col.) (Remarks p. 12 para. 2).
Bhoi in view of Choi discloses (reduction in excess of 99%) (Bhoi [0001], [0031], [0044]-[0055], Table 3, Figs. 2-3) with a residence time of 1 to 7 seconds because it is kinetically feasible to reduce concentrate particles within a few seconds of reaction time (Choi Results and discussion: Preliminary experiments) with a high metallization degree (Choi Introduction para. 2) to allow for direct use of large quantities of fine iron oxide concentrates (Choi Introduction para. 1). Based on the combined disclosures of Bhoi in view of Choi, one of ordinary skill in the art would understand how to adjust the process variables of the iron ore hydrogen plasma reduction in order to achieve the 1 to 7 second residence time. For example, Choi discloses the reaction kinetics of reducing iron oxide with H2 (Choi Experimental: Accurate kinetic measurements) and test results, such as the influence of the H2 temperature, the amount of H2, and particle size (Choi Results and discussion: Accurate kinetic measurements, Figs. 5-12). Further, a time of 1 second is so close to a time of less than 1.0 seconds that prima facie one skilled in the art would have expected them to have the same properties. A prima facie case of obviousness exists where the claimed ranges or amounts do not overlap with the prior art but are close. MPEP 2144.05(I).
New Grounds
In light of claim amendment and upon further consideration a new grounds of rejection over Kitamura in view of Choi is made.
Claim Rejections - 35 USC § 103
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
Claims 1, 12-16, 21, and 22 are rejected under 35 U.S.C. 103 as being unpatentable over Bhoi (US 2013/0047782) in view of Choi (Choi and Sohn. Development of green suspension ironmaking technology based on hydrogen reduction of iron oxide concentrate: rate measurements. Ironmaking and Steelmaking. 2010. Vol. 37. No. 2. 81-86.).
Regarding claim 1, Bhoi discloses a method for reducing a solid compound (iron ore) (Abstract, [0001], [0044]-[0058]), comprising:
initiating a hydrogen plasma in a reactor chamber ([0044]-[0052], [0056]-[0058]);
exposing the solid compound particles to the hydrogen plasma ([0033], Fig. 1, Samples, [0056]-[0058]);
wherein the solid compound particles are reduced by the hydrogen plasma (direct reduced iron (DRI) is produced) ([0042], [0054]-[0058]).
Bhoi is silent to entraining solid compound particles in a gas stream containing hydrogen (H2) to form a particle-entrained gas flow.
Choi discloses a method for reducing a solid compound (iron oxide) (Abstract), comprising: entraining solid compound particles in a gas stream containing hydrogen (H2) to form a particle-entrained gas flow (injected particles carried by a hydrogen flow) (p. 83 left col. para. 3, Fig. 4); injecting the particle-entrained gas flow to the reactor chamber (hydrogen reduction of fine iron oxide concentrate particles was determined by the linear velocity of the gas) (p. 83 left col. para. 4, Fig. 4).
It would have been obvious to one of ordinary skill in the art in the process of Bhoi to flow the solid compound particles through the hydrogen to accurately determine the rate of individual iron oxide concentrate particles (Choi Experimental: Accurate kinetic measurements para. 1), which allows for investigation on the kinetic feasibility on the proposed technology (Choi Results and discussion: Accurate kinetics measurements para. 1). Further, the process advantageously almost completely oxidizes the iron oxide concentrate (Choi Results and discussion: Preliminary experiments) and it can also be used in a continuous process (Choi Fig. 4). As evidenced by Choi Figs. 3 and 4 and Experimental, the drop tube reactor system with flowing solid compound particles is an art recognized equivalent process to a furnace system that treats the sold compound particles on a sample tray, which is substantially similar to the process of Bhoi as seen in Fig. 1. It is prima facie obvious to substitute equivalents known for the same purpose. MPEP 2144.06(II).
Therefore, Bhoi in view of Choi discloses a particle-entrained gas flow (Choi p. 83 left col. paras. 3-4, Fig. 4) in which the particles are exposed to a hydrogen plasma (Bhoi [0033], [0044]-[0058]). Therefore, the limitations of interacting the H2 of the particle-entrained gas flow with the initiated plasma in generating a hydrogen plasma, injecting the solid compound particles into the hydrogen plasma, and flowing the solid compound particles through the hydrogen plasma to expose the solid compound particles to the hydrogen plasma naturally flow from the disclosure of the prior art.
Regarding claim 12, Bhoi discloses the solid compound is iron ore ([0029], [0056]-[0058]).
Regarding claim 13, Bhoi discloses the solid compound particles comprise iron ore particles (iron ore lumps) with sizes of nearly 20 mm ([0056]) and pellets having 40 mm diameter and 3 mm height ([0057]-[0058]).
Bhoi is silent to iron ore particles with an average particle size in the range of 38 - 75 microns.
Choi discloses a method for reducing a solid compound (iron oxide) (Abstract) wherein solid compound particles comprise iron ore particles with an average particle size in the range of 38 - 75 microns (45-53 um) (Experimental: Materials, Fig. 2, Results and discussion: Accurate kinetics measurements para. 8, Fig. 12).
It would have been obvious to one of ordinary skill in the art in the process of Bhoi to use iron oxide (ore) particles with a size of 45-53 um because using the micron-sized particles instead of the mm sized pellets increases the reduction rate, which increases the degree of reduction while decreasing the resident time or time it takes for the reduction reaction to proceed and the temperature required for improved reduction (Choi Results and discussion: Accurate kinetics measurements para. 8, Fig. 12).
Regarding claim 14, Bhoi discloses the iron ore particles experience at least a 90% reduction to elemental iron (after process 99.05% Fe) ([0001], [0031], [0044]-[0055], Table 3, Figs. 2-3).
Regarding claim 15, Bhoi discloses a treatment time of 35 min ([0049]).
Bhoi is silent to the iron ore particles are treated by the plasma for a treatment time of not greater than 10 seconds.
Choi discloses a method for reducing a solid compound (iron oxide) (Abstract) wherein iron ore particles are treated by the plasma for a treatment time of not greater than 10 seconds (1 to 7 seconds) (Experimental: Accurate kinetic measurements, Results and discussion: Accurate kinetic measurements paras. , Figs. 8, 9, 12).
It would have been obvious to one of ordinary skill in the art in the process of Bhoi to have a residence time of not greater than 10 seconds (1 to 7 seconds) because it is kinetically feasible to reduce concentrate particles within a few seconds of reaction time (Choi Results and discussion: Preliminary experiments) with a high metallization degree (Choi Introduction para. 2) to allow for direct use of large quantities of fine iron oxide concentrates (Choi Introduction para. 1). Based on the combined disclosures of Bhoi in view of Choi, one of ordinary skill in the art would understand how to adjust the process variables of the iron ore hydrogen plasma reduction in order to achieve the 1 to 7 second residence time. For example, Choi discloses the reaction kinetics of reducing iron oxide with H2 (Choi Experimental: Accurate kinetic measurements) and test results, such as the influence of the H2 temperature, the amount of H2, and particle size (Choi Results and discussion: Accurate kinetic measurements, Figs. 5-12).
Regarding claim 16, Bhoi disclose the iron ore particles experience at least a 95% reduction over a plasma treatment (after process 99.05% Fe) ([0001], [0031], [0044]-[0055], Table 3, Figs. 2-3).
Bhoi is silent to a plasma treatment time of not greater than 9 seconds.
Choi discloses a method for reducing a solid compound (iron oxide) (Abstract) wherein iron ore particles experience at least a 95% reduction over a plasma treatment time of not greater than 9 seconds (1 to 7 seconds) (Experimental: Accurate kinetic measurements, Results and discussion: Accurate kinetic measurements, Figs. 8, 9, 10, 12).
It would have been obvious to one of ordinary skill in the art in the process of Bhoi to have a residence time of not greater than 9 seconds (1 to 7 seconds) because it is kinetically feasible to reduce concentrate particles within a few seconds of reaction time (Choi Results and discussion: Preliminary experiments) with a high metallization degree (Choi Introduction para. 2) to allow for direct use of large quantities of fine iron oxide concentrates (Choi Introduction para. 1). Based on the combined disclosures of Bhoi in view of Choi, one of ordinary skill in the art would understand how to adjust the process variables of the iron ore hydrogen plasma reduction in order to achieve the 1 to 7 second residence time. For example, Choi discloses the reaction kinetics of reducing iron oxide with H2 (Choi Experimental: Accurate kinetic measurements) and test results, such as the influence of the H2 temperature, the amount of H2, and particle size (Choi Results and discussion: Accurate kinetic measurements, Figs. 5-12).
Regarding claim 21, Bhoi discloses the iron ore particles experience at least a 90% reduction to elemental iron (reduction in excess of 99%) (Bhoi [0001], [0031], [0044]-[0055], Table 3, Figs. 2-3).
Bhoi is silent to a plasma treatment time of less than 0.5 second.
Choi discloses a method for reducing a solid compound (iron oxide) (Abstract) wherein iron ore particles are treated by the plasma (Experimental: Accurate kinetic measurements, Results and discussion: Accurate kinetic measurements paras. , Figs. 8, 9, 12), where the reaction kinetics of reducing iron oxide with H2 (Experimental: Accurate kinetic measurements) and test results, are influenced of the H2 temperature, the amount of H2, and particle size (Results and discussion: Accurate kinetic measurements, Figs. 5-12).
It would have been obvious to one of ordinary skill in the art in the process of Bhoi to have a plasma treatment time of less than 0.5 second because the process of the prior art is substantially to that claimed as evidenced by the claim 1 and 12 rejections (Bhoi Abstract, [0001], [0044]-[0058]; Choi p. 83 left col. paras. 3-4, Fig. 4). Further, reaction kinetics are a result-effective variable (Choi Results and discussion: Accurate kinetic measurements, Figs. 5-12), such that the determination of the optimum or workable ranges of said variable might be characterized as routine experimentation. MPEP 2144.05(II)(B).
Regarding claim 22, Bhoi discloses the iron ore particles experience at least a 95% reduction (reduction in excess of 99%) (Bhoi [0001], [0031], [0044]-[0055], Table 3, Figs. 2-3).
Bhoi is silent to a treatment time of less than 1.0 seconds.
Choi discloses a method for reducing a solid compound (iron oxide) (Abstract) wherein iron ore particles are treated by the plasma for a treatment time of less than 1.0 seconds (1 to 7 seconds) (Experimental: Accurate kinetic measurements, Results and discussion: Accurate kinetic measurements paras. , Figs. 8, 9, 12).
It would have been obvious to one of ordinary skill in the art in the process of Bhoi to have a residence time of 1 to 7 seconds because it is kinetically feasible to reduce concentrate particles within a few seconds of reaction time (Choi Results and discussion: Preliminary experiments) with a high metallization degree (Choi Introduction para. 2) to allow for direct use of large quantities of fine iron oxide concentrates (Choi Introduction para. 1). Based on the combined disclosures of Bhoi in view of Choi, one of ordinary skill in the art would understand how to adjust the process variables of the iron ore hydrogen plasma reduction in order to achieve the 1 to 7 second residence time. For example, Choi discloses the reaction kinetics of reducing iron oxide with H2 (Choi Experimental: Accurate kinetic measurements) and test results, such as the influence of the H2 temperature, the amount of H2, and particle size (Choi Results and discussion: Accurate kinetic measurements, Figs. 5-12). A time of 1 second is so close to a time of less than 1.0 seconds that prima facie one skilled in the art would have expected them to have the same properties. A prima facie case of obviousness exists where the claimed ranges or amounts do not overlap with the prior art but are close. MPEP 2144.05(I).
Claim 4 is rejected under 35 U.S.C. 103 as being unpatentable over Bhoi (US 2013/0047782) in view of Choi (Choi and Sohn. Development of green suspension ironmaking technology based on hydrogen reduction of iron oxide concentrate: rate measurements. Ironmaking and Steelmaking. 2010. Vol. 37. No. 2. 81-86.) as applied to claim 1 above and further in view of Saitou (JP S53-102818 machine translation).
Regarding claim 4, Bhoi in view of Choi discloses a gas of the (carrier) gas stream is H2 (Choi Experimental: Accurate kinetic measurements para. 5).
Bhoi in view of Choi is silent to a mixture of H2 and argon.
Saitou discloses a method for reducing a solid compound (reducing powdered iron ore using plasma jets) ([0001]) wherein a gas of the gas stream (carrier) is a mixture of H2 and argon (where the larger the hydrogen content the better the reduction rate) ([0002]).
It would have been obvious to one of ordinary skill in the art in the process of Bhoi in view of Choi for the carrier gas to be a mixture of hydrogen and argon to allow for adjustment of the hydrogen gas concentration, which influences the reduction rate of the iron oxide (Saitou [0002]).
Claim 6 is rejected under 35 U.S.C. 103 as being unpatentable over Bhoi (US 2013/0047782) in view of Choi (Choi and Sohn. Development of green suspension ironmaking technology based on hydrogen reduction of iron oxide concentrate: rate measurements. Ironmaking and Steelmaking. 2010. Vol. 37. No. 2. 81-86.) as applied to claim 1 above and further in view of Sabat (Sabat and Murphy. Hydrogen Plasma Processing of Iron Ore. Metallurgical and Materials Transactions B. Volume 48B, June 2017, 1561-1594.).
Regarding claim 6, Bhoi in view of Choi is silent to the charge of the solid compound particles.
Sabat discloses a method for reducing a solid compound (Abstract) including a step of flowing solid compound particles through the plasma (in-flight reduction of iron ore particles) (Abstract) includes at least some of the solid compound particles being negatively charged (III.1.C. Role of the Polarity of the Charge/Melt).
It would have been obvious to one of ordinary skill in the art in the process of Bhoi in view of Choi for at least some of the solid compound particles to be negative charged because a negatively charged surface will repel electrons and attract positive molecular and atomic irons and the positively charged ions have high reducing ability, where a negative polarity (charge) indicates that the likelihood of the reduction reaction proceeding is extremely high (Sabat III.1.C. Role of the Polarity of the Charge/Melt).
Claim 20 is rejected under 35 U.S.C. 103 as being unpatentable over Bhoi (US 2013/0047782) in view of Choi (Choi and Sohn. Development of green suspension ironmaking technology based on hydrogen reduction of iron oxide concentrate: rate measurements. Ironmaking and Steelmaking. 2010. Vol. 37. No. 2. 81-86.) as applied to claim 1 above, and further in view of Mishra (Mishra, Sabat, and Paramguru. Production of Nano Size Iron Cobalt Alloy Powder by Solid State Reduction of Oxides with Cold Hydrogen Plasma. IN 201631027536. Date 10th August, 2016. Published 16.02.2018.).
Regarding claim 20, Bhoi discloses iron ore lumps with sizes of nearly 20 mm ([0056]) and pellets having 40 mm diameter and 3 mm height ([0057]-[0058]).
Bhoi is silent to micron-sized solid compound particles.
Choi discloses a method for reducing a solid compound (iron oxide) (Abstract) wherein solid compound particles are micron-sized (Experimental: Materials, Fig. 2, Results and discussion: Accurate kinetics measurements para. 8, Fig. 12).
It would have been obvious to one of ordinary skill in the art in the process of Bhoi to use iron oxide (ore) particles that are micron-sized because using the micron-sized particles instead of the mm sized pellets increases the reduction rate, which increases the degree of reduction while decreasing the resident time or time it takes for the reduction reaction to proceed and the temperature required for improved reduction (Choi Results and discussion: Accurate kinetics measurements para. 8, Fig. 12).
Bhoi in view of Choi is silent to following the step of exposing, the solid compound particles are reduced to nanometer-sized metal particles.
Mishra discloses a method for reducing a solid compound ([0001]), wherein following the step of exposing, the solid compound particles are reduced to nanometer-sized metal particles ([0020], [0032], [0063]).
It would have been obvious to one of ordinary skill in the art in the process of Bhoi in view of Choi to reduce the solid compound particles to nanometer-sized metal particles because this is the particle that results from solid state reduction of iron oxide with hydrogen plasma (Mishra [0020], [0023], [0027], [0031]-[0032], [0063]), which is a simple, environmentally friendly process (Mishra [0014]) that is not energy intensive and does not require external heating and heat transfer (Mishra [0018]).
Claims 1, 12-16, 21, and 22 are rejected under 35 U.S.C. 103 as being unpatentable over Kitamura (Kitamura et al. In-flight reduction of Fe2O3, Cr2O3, TiO2 and Al2O3 by Ar-2 plasma. Thermal Plasma Applications in Materials and Metallurgical Processing. Edited by N. El-Kaddah. The Minerals, Metals & Materials Society, 1992.) in view of Choi (Choi and Sohn. Development of green suspension ironmaking technology based on hydrogen reduction of iron oxide concentrate: rate measurements. Ironmaking and Steelmaking. 2010. Vol. 37. No. 2. 81-86.).
Regarding claim 1, Kitamura discloses a method for reducing a solid compound (Abstract, In-Flight Reduction of Oxides), comprising:
initiating a hydrogen plasma in a reactor chamber (In-Flight Reduction of Oxides: Experimental Procedure, Fig. 6);
entraining solid compound particles in a gas stream to form a particle-entrained gas flow (In-Flight Reduction of Oxides: Experimental Procedure, Fig. 6, Table 2);
injecting the particle-entrained gas flow to the reactor chamber(In-Flight Reduction of Oxides: Experimental Procedure, Fig. 6, Table 2), including;
interacting the particle-entrained gas flow with the initiated plasma in generating a hydrogen plasma (In-Flight Reduction of Oxides: Experimental Procedure, Fig. 6, Table 2),
injecting the solid compound particles into the hydrogen plasma (In-Flight Reduction of Oxides: Experimental Procedure, Fig. 6, Table 2),
flowing the solid compound particles through the hydrogen plasma to expose the solid compound particles to the hydrogen plasma (In-Flight Reduction of Oxides: Experimental Procedure, Fig. 6, Table 2);
wherein the solid compound particles are reduced by the hydrogen plasma (In-Flight Reduction of Oxides: Experimental Procedure, Fig. 6, Table 2).
Kitamura is silent to a gas stream containing hydrogen (H2).
Choi discloses a method for reducing a solid compound (Abstract), comprising: a gas stream containing hydrogen (H2) (p. 83 left col. paras. 3-4, Fig. 4).
It would have been obvious to one of ordinary skill in the art in the process of Kitamura to entrain the solid compound particles in a gas stream containing hydrogen (H2) because it participates in the reaction (reduction) of the particles (Choi p. 83 left col. paras. 3-4). Further, in a plasma H atoms have a much higher temperature than Ar due to energy relation process, such that including H2 in the plasma decreases relaxation time from the collisional frequency (Kitamura Temperature Measurements of Plasma: Discussion).
Regarding claim 12, Kitamura in view of Choi discloses the solid compound is iron ore (Fe2O3) (Kitamura In-Flight Reduction of Oxides: Experimental Procedure; Choi Abstract).
Regarding claim 13, Kitamura discloses particles with a radius of 100 um (Table 4).
Kitamura is silent to the iron ore particles with an average particle size in the range of 38 - 75 microns.
Choi discloses a method for reducing a solid compound (iron oxide) (Abstract) wherein solid compound particles comprise iron ore particles with an average particle size in the range of 38 - 75 microns (45-53 um) (Experimental: Materials, Fig. 2, Results and discussion: Accurate kinetics measurements para. 8, Fig. 12).
It would have been obvious to one of ordinary skill in the art in the process of Kitamura to use iron oxide (ore) particles with a size of 45-53 um to increase the reduction rate, which increases the degree of reduction while decreasing the resident time or time it takes for the reduction reaction to proceed and the temperature required for improved reduction (Choi Results and discussion: Accurate kinetics measurements para. 8, Fig. 12).
Regarding claim 14, Kitamura discloses the iron ore particles experience at least a 90% reduction to elemental iron (Fe2O3 reduced to metal by Fe2O3 evaporated completely (100%) as metal atoms in the plasma) (Abstract, In-Flight Reduction of Oxides: Experimental Results; Discussion: Thermodynamics; Heat Transfer; Mechanism of Reaction in Plasma, Table 3, Figs. 7, 12, 16).
Regarding claim 15, Kitamura discloses the iron ore particles are treated by the plasma for a treatment time of not greater than 10 seconds (on order of ms) (In-Flight Reduction of Oxides: Discussion: Heat Transfer, Mechanism of Reaction in Plasma, Table 4, Figs. 12, 16).
Regarding claim 16, Kitamura discloses the iron ore particles experience at least a 95% reduction (Fe2O3 reduced to metal by Fe2O3 evaporated completely (100%) as metal atoms in the plasma) over a plasma treatment time of not greater than 9 seconds (on order of ms) (Abstract, In-Flight Reduction of Oxides: Experimental Results; Discussion: Thermodynamics; Heat Transfer; Mechanism of Reaction in Plasma, Table 3, Figs. 7, 12, 16).
Regarding claim 21, Kitamura discloses the iron ore particles experience at least a 90% reduction to elemental iron (Fe2O3 reduced to metal by Fe2O3 evaporated completely (100%) as metal atoms in the plasma) over a plasma treatment time of less than 0.5 second (on order of ms) (Abstract, In-Flight Reduction of Oxides: Experimental Results; Discussion: Thermodynamics; Heat Transfer; Mechanism of Reaction in Plasma, Table 3, Figs. 7, 12, 16).
Regarding claim 22, Kitamura discloses the iron ore particles experience at least a 95% reduction to elemental iron (Fe2O3 reduced to metal by Fe2O3 evaporated completely (100%) as metal atoms in the plasma) over a plasma treatment time of less than 1.0 second (on order of ms) (Abstract, In-Flight Reduction of Oxides: Experimental Results; Discussion: Thermodynamics; Heat Transfer; Mechanism of Reaction in Plasma, Table 3, Figs. 7, 12, 16).
Claim 4 is rejected under 35 U.S.C. 103 as being unpatentable over Kitamura (Kitamura et al. In-flight reduction of Fe2O3, Cr2O3, TiO2 and Al2O3 by Ar-2 plasma. Thermal Plasma Applications in Materials and Metallurgical Processing. Edited by N. El-Kaddah. The Minerals, Metals & Materials Society, 1992.) in view of Choi (Choi and Sohn. Development of green suspension ironmaking technology based on hydrogen reduction of iron oxide concentrate: rate measurements. Ironmaking and Steelmaking. 2010. Vol. 37. No. 2. 81-86.) as applied to claim 1 above and further in view of Saitou (JP S53-102818 machine translation).
Regarding claim 4, Kitamura discloses the gas stream is argon (In-Flight Reduction of Oxides: Experimental Procedure, Fig. 6).
Choi discloses the gas stream is H2 (p. 83 left col. paras. 3-4).
Saitou discloses a method for reducing a solid compound (reducing powdered iron ore using plasma jets) ([0001]) wherein a gas of the gas stream (carrier) is a mixture of H2 and argon (where the larger the hydrogen content the better the reduction rate) ([0002]).
It would have been obvious to one of ordinary skill in the art in the process of Kitamura in view of Choi for the carrier gas to be a mixture of hydrogen and argon to allow for adjustment of the hydrogen gas concentration, which influences the reduction rate of the iron oxide (Saitou [0002]). Furthermore, Kitamura discloses the plasma kinetics for an Ar-H2 plasma (Kitamura Temperature Measurements of Plasma: Apparatus and Experimental Procedure, Experimental Results, Discussion, Figs. 1-5, Table 1; In-Flight Reduction of Oxides: Experimental Procedure, Fig. 6), such that it is within the scope of Kitamura for the plasma to include for Ar and H2.
Claim 6 is rejected under 35 U.S.C. 103 as being unpatentable over Kitamura (Kitamura et al. In-flight reduction of Fe2O3, Cr2O3, TiO2 and Al2O3 by Ar-2 plasma. Thermal Plasma Applications in Materials and Metallurgical Processing. Edited by N. El-Kaddah. The Minerals, Metals & Materials Society, 1992.) in view of Choi (Choi and Sohn. Development of green suspension ironmaking technology based on hydrogen reduction of iron oxide concentrate: rate measurements. Ironmaking and Steelmaking. 2010. Vol. 37. No. 2. 81-86.) as applied to claim 1 above and further in view of Sabat (Sabat and Murphy. Hydrogen Plasma Processing of Iron Ore. Metallurgical and Materials Transactions B. Volume 48B, June 2017, 1561-1594.).
Regarding claim 6, Kitamura in view of Choi is silent to the charge of the solid compound particles.
Sabat discloses a method for reducing a solid compound (Abstract) including a step of flowing solid compound particles through the plasma (in-flight reduction of iron ore particles) (Abstract) includes at least some of the solid compound particles being negatively charged (III.1.C. Role of the Polarity of the Charge/Melt).
It would have been obvious to one of ordinary skill in the art in the process of Kitamura in view of Choi for at least some of the solid compound particles to be negative charged because a negatively charged surface will repel electrons and attract positive molecular and atomic irons and the positively charged ions have high reducing ability, where a negative polarity (charge) indicates that the likelihood of the reduction reaction proceeding is extremely high (Sabat III.1.C. Role of the Polarity of the Charge/Melt).
Claim 20 is rejected under 35 U.S.C. 103 as being unpatentable over Kitamura (Kitamura et al. In-flight reduction of Fe2O3, Cr2O3, TiO2 and Al2O3 by Ar-2 plasma. Thermal Plasma Applications in Materials and Metallurgical Processing. Edited by N. El-Kaddah. The Minerals, Metals & Materials Society, 1992.) in view of Choi (Choi and Sohn. Development of green suspension ironmaking technology based on hydrogen reduction of iron oxide concentrate: rate measurements. Ironmaking and Steelmaking. 2010. Vol. 37. No. 2. 81-86.) as applied to claim 1 above and further in view of Mishra (Mishra, Sabat, and Paramguru. Production of Nano Size Iron Cobalt Alloy Powder by Solid State Reduction of Oxides with Cold Hydrogen Plasma. IN 201631027536. Date 10th August, 2016. Published 16.02.2018.).
Regarding claim 20, Kitamura discloses the solid compound particles are micron-sized (Table 4, In-Flight Reduction of Oxide Particles: Discussion: Mechanism of Reaction in Plasma, Fig. 16), and further wherein following the step of exposing, the solid compound particles are reduced in size (In-Flight Reduction of Oxide Particles: Experimental Results, Table 3, Photo. 1(a))
Kitamura is silent to the solid compound particles being reduced to nanometer-sized metal particles.
Mishra discloses a method for reducing a solid compound ([0001]), wherein following the step of exposing, the solid compound particles are reduced to nanometer-sized metal particles ([0020], [0032], [0063]).
It would have been obvious to one of ordinary skill in the art in the process of Kitamura in view of Bhoi to reduce the solid compound particles to nanometer-sized metal particles because this is the particle that results from solid state reduction of iron oxide with hydrogen plasma (Mishra [0020], [0023], [0027], [0031]-[0032], [0063]), which is a simple, environmentally friendly process (Mishra [0014]) that is not energy intensive and does not require external heating and heat transfer (Mishra [0018]).
Related Art
Kropf (EP 1275739 machine translation)
Kropf discloses a method for reducing a solid compound ([0001], [0011]) of fine-grained feed material of metal oxide particles fed into a transport reduction reactor ([0008]-[0010], [0013]-[0021], [0036], [0055]) through hydrogen ([0010]-[0011], [0019], [0038]-[0039]) in a continuous process (Kropf [0047], [0052]-[0053]) to form a fine distribution of the metal oxide in the carrier gas stream for a more uniform distribution of feedstock in the reducing gas, such that an energetically and/or kinetically more favorable reduction process can be achieved (Kropf [0007], [0015]) with a significantly faster and more complete reduction of the fine metal oxides (Kropf [0016]).
Tanner-Jones (US 2004/0060387)
Tanner-Jones chemical processing of materials in a plasma ([0001]) including reducing haematite (Fe2O3) by in-flight entrainment in a cyclone reactor ([0187]-[0198], Figs, 9(a)-9(c)), where the in-flight process is an alternative to a reaction chamber process ([0077], Fig. 2).
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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/STEPHANI HILL/Examiner, Art Unit 1735
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