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 .
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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.
Claims 1-6, 8, and 10-11 are rejected under 35 U.S.C. 103 as being unpatentable over Ning (US 20210331974 A1) in view of Zuo (“Effects of CaO on Two-Step Reduction Characteristics of Copper Slag Using Biochar as Reducer: Thermodynamics and Kinetics”) and Ding (“Simultaneous Removal of NOx and SO2 from coal-fired flue gas by catalytic oxidation-removal process with H2O2”).
Regarding claim 1, Ning teaches a method for preparing a cementing material comprising an industrial slag (Abstract). Particularly, the method specifies that the comprising industrial slag is also used to perform simultaneous desulfurization and denitration of a flue gas. The method first comprises mixing the smelting industrial waste slag with a phase regulator to form a mixture [0009]. Specifically, Ning mixes an industrial slag with a phase regulator comprising CaO, Na2CO3, or B2O3 [0009, 0014]. The phase regulator has the function of converting low-activity MnS, FeS, and fayalite (2FeO·SiO2) phases into manganese oxides and iron oxides upon heat treatment, which ultimately react with SO2 and NOx- in desulfurization and denitration reactions to produce water-soluble sulfate and nitrate [0024, 0037]. Ning then performs a thermal activation treatment to the mixture to obtain an activated slag, wherein the mixture is subjected to grinding followed by roasting for 60-180 minutes at a temperature of 800-1200OC [0016]. The activated slag is then mixed with an NOx/SO2 oxidant (comprising KMnO4) and water to obtain a slurry [0011, 0017, 0043]. This slurry is subsequently introduced to a flue gas containing SO2 and NOx to perform a simultaneous denitration and desulfurization treatment [0019].
However, Ning fails to teach the inclusion of a carbon reducing agent with their industrial slag or the inclusion of hydrogen peroxide in their slurry. Additionally, Ning is silent on conducting their heat treatments in a protective atmosphere.
Zuo teaches the reduction of an iron-containing copper slag using both biochar and CaO for the purpose of recovering iron from the copper slag. Iron is present in Zuo’s slag, primarily in the form of magnetite (Fe3O4) and fayalite (2FeO·SiO2). Zuo processes their slag in the following manner (pg. 493 §2.1 “Materials” and §2.2 “Experimental Apparatus and Methods”):
Copper slag, biochar, and CaO are crushed to have a diameter smaller than 150 µm via a ball mill machine. The materials are subsequently mixed.
The mixed product is then heated/roasted in a tube furnace under a protective Ar atmosphere from 308K to 1703K (equivalently, from 30OC to 1430OC).
During the roasting process, carbon from the biochar reduces magnetite and ultimately produces zero-valent Fe, CO, and CO2 (pg. 495, Eqns. 3, 4, 6, 7). The carbon also reduces fayalite into zero-valent Fe, CO, CO2, and dissociated SiO2 (pg. 495, Eqns. 5, 8-11). The reactions are done in the solid-state via direct reduction reactions at temperatures 960-1478K (equivalently, 687-1205K) (pg. 496 § 3.2 “Effect of CaO and Reducer Addition on Copper Slag Reduction Characteristics”). These reactions are enabled by the addition of CaO in the slag-carbon mixture. To elaborate, the initial reaction temperature for the reduction of fayalite with carbon (1073K or 800OC) is higher than the reaction temperature of other present reactions. Additionally, the reduction of fayalite via CO is nonspontaneous at the temperatures corresponding to direct reductions (pg. 494-495 § 3.1 “Thermodynamic Analysis of Reduction of Copper Slag”; Figs. 8 & 9). However, Zuo finds that adding CaO to the slag-carbon mixture lowers the changes in the free energy of the fayalite-carbon/CO reactions, thereby allowing the reactions in question to occur at lower temperatures associated with direct reduction reactions (pg., 494 §3.1; Figs. 8 &9). Overall, the reduction rates of fayalite were improved upon the addition of CaO to the slag-biochar mixture (pg. 499 §4 “Conclusions”).
Therefore, it would have been obvious for a person having ordinary skill in the art before the effective filing date of the application to substitute the CaO in Ning’s method with the biochar in Zuo’s method because the substitution of CaO with biochar would yield the predictable result of iron being reduced from low-activity fayalite. Additionally, a person having ordinary skill in the art would be compelled to use both biochar and CaO as fayalite-reducing agents because the combination enables the advantageous result of improved reduction rates. Lastly, it would have been obvious for a person skilled in the art before the effective filing sate to roast the slag mixture in a protective Ar atmosphere (as done in Zuo) and expect a well-known and predictable result (e.g. mitigation of outside gases reacting with the slag mixture).
However, neither Ning nor Zuo teach the inclusion of hydrogen peroxide in a slurry.
Ding teaches a process wherein hydrogen peroxide (H2O2) is used to remove SO2 and NOx from a flue gas. Particularly, H2O2 is catalytically discomposed via a Fe catalyst to produce free radicals (pg. 177). These free radicals readily oxidize NOx and SO2 (see § 3.8 “reaction pathways”), leading to a sharp increase in SO2 and NOx removal efficiencies (pg. 177).
Therefore, it would have been obvious for a person having ordinary skill in the art before the effective filing date of the application to incorporate Ding’s H2O2 into the combined teachings of Ning and Zuo because the catalytic decomposition of H2O2 as taught by Ding would be enabled. That is, Ning’s taught treatment method ultimately produces an activated slag mixture wherein iron is able to catalytically decompose H2O2 introduced into the slurry, leading to reactions that ultimately oxidize SO2 and NOx in the flue gas and sharp increases in SO2 and NOx removal efficiencies.
Regarding claim 2, Zuo reports the following composition analysis of their taught Cu slag, as shown below in Table 1 (Zuo Table 1):
Table 1
Component
FeO
Fe3O4
CaO
Al2O3
MFe
SiO2
Cu
MgO
S
Zn
Others
Composition (wt %)
37.50
18.90
0.23
0.98
1.24
31.99
0.74
0.42
0.39
2.78
4.87
In total, Zuo’s copper slag comprises 56.4 wt% iron oxides, which is within the claimed iron oxide range of 35-70 wt%.
Regarding claim 3, as discussed above, Zuo uses biochar as the carbon-reducing agent, which reads on the claimed biomass.
Regarding claims 4 and 11, Ning teaches that the mass ratio of slag to phase regulator is between 10:1 and 10:3 (equivalently, 1:0.1 and 1:0.3), which reads on the claimed slag-carbon ratio of 1:0.02 to 1:0.16. In the case where the claimed ranges "overlap or lie inside ranges disclosed by the prior art" a prima facie case of obviousness exists. See MPEP 2144.05(1).
Regarding claim 5, Ning teaches that slag mixture is roasted for 60-180 minutes at a temperature of 800-1200OC [0016], which reads on the claimed reduction time of 0.5-1 h. In the case where the claimed ranges "overlap or lie inside ranges disclosed by the prior art" a prima facie case of obviousness exists. See MPEP 2144.05(1).
Regarding claim 6, Ning teaches that the activated slag is mixed with water to obtain a mass-to-volume ratio of 1g:10 mL [0051], which is outside the claimed solid-liquid ratio of the reduction product to water is of 1 g: 100 mL to 1 g: 250 mL. However, it would be obvious for a person having ordinary skill in the art to adjust the amount of water used to make the slurry to obtain a predictable and advantageous result (e.g. better mixability of the slurry, increased NOx absorption capacity, etc.) without changing the underlying chemistry (i.e. the catalytic decomposition H2O2 over dissolved Fe ions). Claimed ranges of a result effective variable, which do not overlap the prior art ranges, are unpatentable unless they produce a new and unexpected result, which is different in kind and not merely in degree from the results of the prior art. (MPEP 2144.05)
Regarding claim 8, Ning teaches that the flue gas has a NOx concentration of 200-500 ppm, which reads on the claimed NOx concentration of 250-500 ppmv (Clm. 9). In the case where the claimed ranges "overlap or lie inside ranges disclosed by the prior art" a prima facie case of obviousness exists. See MPEP 2144.05(1).
Regarding claim 10, Ning grinds their slag-carbon mixture to a particle size of 200-300 meshes before grinding ([0016], Clm. 5). This reads on the claimed limitation of the carbon reducing agent being able to pass through a 200-mesh screen. In the case where the claimed ranges "overlap or lie inside ranges disclosed by the prior art" a prima facie case of obviousness exists. See MPEP 2144.05(1).
Claims 7 and 9 are rejected under 35 U.S.C. 103 as being unpatentable over Ning (US 20210331974 A1), Zuo (“Effects of CaO on Two-Step Reduction Characteristics of Copper Slag Using Biochar as Reducer: Thermodynamics and Kinetics”), and Ding (“Simultaneous Removal of NOx and SO2 from coal-fired flue gas by catalytic oxidation-removal process with H2O2”) as applied to claim 1 above, and further in view of Sun (“The removal of NO from flue gas by NaOH-catalyzed H2O2 system: Mechanism exploration and primary experiment”).
When examining claims 7 and 9, it is noted that the applicant uses NaOH to modulate the pH of the slurry during denitration, as per the specification.
Regarding claim 7, Ning, Zuo, and Ding are silent on the amount of H2O-2 used with the slurry.
Sun teaches that a mixture of NaOH and H2O2 can be used to denitrate NOx from flue gas (Abstract). Sun found that, when compared to denitration systems utilizing only H2O2, the NaOH/H2O2 mixture exhibits high NO removal efficiencies (pg. 3 §3.1 “Comparison of different systems”; Fig, 2). This is attributed to the reaction between NaOH and H2O2 (Eqns. 4 & 5), which produces more free radicals in the form of *OH and *O2- when compared to NaOH and H2O2 separately (Fig. 3).
Additionally, Sun found that the NO removal efficiency maximizes when H2O2 concentration is set between 1.00 and 1.50 mol/L (Fig. 9). Further increases in the H2O2 concentration decreases NO removal efficiencies as it promotes the conversion of *O2- radicals into O2, effectively removing the quantity of free radicals available to react with NO gas (pg. 6 § 3.3.2 “Effect of H2O2 concentration on the removal of NO”). The taught H2O2 concentrations read on the claimed hydrogen peroxide concentration of 1.5-5 mol/L. In the case where the claimed ranges "overlap or lie inside ranges disclosed by the prior art" a prima facie case of obviousness exists. See MPEP 2144.05(1).
Sun also uses a 30% H2O2 solution when conducting their experimental method. This concentration is sufficiently close to the claimed solution concentration of 35% that a person having ordinary skill in the art would expect similar results when utilizing either value. Claims that differ from the prior art only by slightly different (non-overlapping) ranges are prima facie obvious without a showing that the claimed range achieves unexpected results relative to the prior art (MPEP 2144.05).
Therefore, it would have been obvious for a person having ordinary skill in the art before the effective filing date of the application to incorporate both NaOH and H2O2 into the slurry as taught in the combined teachings of Ning, Zuo, and Ding because utilizing NaOH in tandem with H2O-2 as taught by Sun creates more free radicals when compared to H2O-2 alone. The increase quantity of free radicals will ultimately react with NO in flue gas and increase NOx removal efficiencies. Additionally, it would have been obvious for a person having ordinary skill in the art before the effective filing date of the application to utilize Sun’s H2O2 concentrations because it ultimately enables optimal NO removal efficiencies.
Regarding claim 9, Sun conducted their experiments at a pH between 10.1-11.93. Particularly, Sun found that the NO removal efficiency maximizes and stabilizes at pH values greater than 10.78 (pg. 6 §3.3.1 “Effect of initial pH on the removal of NO”; Fig. 8). Sun’s optimal ranges read on the claimed pH range of 9-11. In the case where the claimed ranges "overlap or lie inside ranges disclosed by the prior art" a prima facie case of obviousness exists. See MPEP 2144.05(1).
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Any inquiry concerning this communication or earlier communications from the examiner should be directed to JAVIER FLORES whose telephone number is 571-272-9130. The examiner can normally be reached Mon-Fri 7:30AM-5:00PM.
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/J.F./Examiner, Art Unit 1735
/KEITH WALKER/Supervisory Patent Examiner, Art Unit 1735
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