Detailed Action
This is a Non-Final Office action based on application 17/649,707 filed on February 2, 2022. The application is a 111(a) with priority to provisional application 63/154,186 filed February 16, 2021. Claims 1, 3, 5-8, 11, 15-19, 21-22, and 24-26 are pending and have been fully considered.
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 .
Continued Examination Under 37 CFR 1.114
A request for continued examination under 37 CFR 1.114, including the fee set forth in 37 CFR 1.17(e), was filed in this application after final rejection. Since this application is eligible for continued examination under 37 CFR 1.114, and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114. Applicant's submission filed on 18 June 2026 has been entered.
Status of the Rejection
The §103 rejections are withdrawn responsive to amendments
New §103 grounds are established based on references previously applied, in further view of non-patent literature by Shen et al.
Claim Rejections - 35 USC § 103
The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action.
Claims 1, 3, 6-8, 15-19, 21-22, and 24 are rejected under 35 U.S.C. 103 as being unpatentable over “Matsumiya” (Matsumiya et al, Separation and Purification Technology, 130, 91-101 (2014)), in view of “Hatchett 2013” (Hatchett et al, Electrochimica Acta, 89, 144-151 (2013)), "Shen" (Shen et al, Hydrometallurgy, 161, 152-159 (2016)), "Sutto" (US 2016/0222532 A1 to Sutto), and "Li" (US 2019/0316225 A1 to Li et al). Evidentiary support for the rejections of claims 1, 18, and 21 is provided by “Kodama” (Kodama et al, Fluid Phase Equilibria, 574, 113886 (2023)).
Regarding claim 1, Matsumiya teaches a method of extracting, separating, and/or purifying a metal (pg 91 abstract, “recycling process to recovery of rare earths (REs)”), the method comprising:
combining an aqueous acid and a particulate solid composition that comprises the metal, and mixing the aqueous acid and the particulate solid composition for at least about 1-4 hours, to form an acidic mixture (pg 92-93 §2.2, a rare earth magnet comprising neodymium was ground up into particles of about 25 µm diameter, then the particulate solid was mixed with aqueous solution of bistriflimidic acid (“HTFSA”) for 20 hours to form an acidic mixture; note per pg 92, the acronym “TFSA” refers to the bis(trifluoromethylsulfonyl)amide, and HTFSA to its conjugate acid);
filtering the acidic mixture comprising the aqueous acid to form a filtered extract (pg 93 §2.2, “After leaching, the residual wastes were separated by filtering through a 5.0 µm filter”);
combining the filtered extract with an ionic liquid to form an aqueous liquid comprising the metal, wherein water is 5 wt% to 50 wt% of the aqueous liquid comprising the metal (pg 93 §2.3, the aqueous filtered extract is combined with an ionic liquid at 1:1 by volume for liquid-liquid extraction of the metal into the ionic liquid phase; note that Matsumiya’s ionic liquid, [P2225][TFSA], is denser than water, with a density of about 1.3 g/cm3 at room temperature (evidentiary support is found in Kodama at pg 5 table 3), therefore, Matsumiya’s aqueous liquid mixture, comprising 50% of the aqueous filtrate by volume, comprises roughly 40-43% water by weight, which falls within the claimed range of 5 to 50% water by weight);
heating the aqueous liquid that is 5 wt% to 50 wt% water to at least partially remove water therefrom and to form a liquid comprising the metal, wherein the liquid comprising the metal is less than 1 wt% water (pg 93 §2.6: prior to electrodeposition, the organic phase recovered from the liquid-liquid extraction is dried under vacuum at 373 K, resulting in an ionic liquid electrolyte comprising the electrolyte and having a water content of less than 250 ppm); and
immersing an electrochemical cell comprising an anode, and a cathode comprising copper, in the liquid comprising the metal to form a layer comprising the metal on the cathode, the immersing comprising applying an electrical potential across the anode and cathode (pg 93 §2.6: into the ionic liquid electrolyte comprising the Nd metal, a three electrode cell is immersed comprising a Nd alloy anode, copper cathode, and platinum reference electrode, then a deposition potential is applied to deposit a Nd layer on the cathode; pg 99-100 §2.6 and figure 15, the electrodeposited layer comprises Nd2O3 at its surface and Nd metal in its interior).
Matsumiya does not teach that the anode of the electrochemical cell comprises graphite, platinum, an alloy thereof, or a combination thereof.
Hatchett 2013 teaches a method comprising:
combining an acid, an ionic liquid, and a particulate solid composition that comprises a metal, to form a liquid comprising the metal (abstract; pg 145 right column para 5, Hatchett 2013 mixes bistriflimidic acid, a quat ammonium bistriflimide ionic liquid, and solid cerium carbonate, to form a solution comprising cerium ions in ionic liquid solvent; pg 146 right column para 1); and
immersing an electrochemical cell comprising an anode and a cathode in the liquid comprising the metal (pg 146 left column para 4, the liquid is placed in a 3-electrode cell comprising anode, cathode, and counterelectrode), and applying an electrical potential across the anode and the cathode (pg 148 left column para 4 - pg 150 left column para 1), to form a layer comprising the metal on the cathode (pg 148-150, cerium metal is deposited on the working electrode by reduction at negative voltage, therefore the working electrode is the cathode),
wherein the anode comprises platinum (pg 146 left column para 4, the counter electrode is a platinum sheet) and the cathode comprises gold or carbon (pg 146 left column para 4, Hatchett 2013 tests gold, platinum, and glassy carbon as electrode materials).
It would have been obvious to a person having ordinary skill in the art at the time of the invention to use platinum as the anode material in the method of Matsumiya, because Hatchett 2013, similarly directed to recovering a lanthanide metal by electrodepositing the metal from ionic liquid solvent onto the cathode of an electrochemical cell, discloses that platinum is a suitable anode material for that reaction. The selection of a known material, which is based upon its suitability for the intended use, is within the ambit of one of ordinary skill in the art [MPEP § 2144.07].
Matsumiya does not teach the acid comprises hydrochloric acid, sulfuric acid, phosphoric acid, or a combination thereof.
Shen teaches a method of extracting, separating, and/or purifying a lanthanide metal (abstract, “the extraction of mid-heavy rare earths metals (REs) from H2SO4 media”; pg 153 left column table 1, in particular, the media includes aluminum and yttrium, as well as the lanthanide metals La, Gd, Tb, Tm, Yb, and Lu; pg 156 figure 11, all metals in the leach liquor except lanthanum and aluminum are recovered with >60% efficiency), comprising:
combining an aqueous acid with a particulate solid comprising the metal to form an acidic mixture, wherein the aqueous acid comprises sulfuric acid (pg 153 left column §2.1, “Stock solutions of REs were prepared by dissolving the oxides (99.9%) in concentrated H2SO4 solutions”)
combining the acidic mixture with an ionic liquid to extract the metal from the aqueous phase into the ionic liquid phase (pg 153 left column §2.1, “extraction experiments were performed by mixing one volume of organic phase and four volumes of aqueous phase ... The mixture was shaken ... the mixture was centrifuged”; Shen’s ionic liquid, “[A336][P507]”, as disclosed at pg 158, comprises of a quat ammonium cation and a phosphonate anion).
Shen teaches that the extraction of lanthanides from sulfuric acid into ionic liquid is effective (per pg 153 figures 1-2, log D > 0 indicating that the rare earth metals initially dissolved in the acidic mixture phrase are preferentially partitioned into the ionic liquid phase; pg 154 figure 4; pg 155 figure 7, ionic liquid extraction is about 80% efficient in extracting europium from the acidic mixture).
It would have been obvious to a person having ordinary skill in the art at the time of the invention to practice the method of modified Matsumiya using sulfuric acid as the aqueous acid for leaching metal atoms out of the particulate composition, based on Shen’s teaching that sulfuric acid is a suitable acid for use in a method of leaching lanthanide metals in acid and extracting the lanthanide metal ions from leachate into an organic ionic liquid phase. The selection of a known material, which is based upon its suitability for the intended use, is within the ambit of one of ordinary skill in the art [MPEP § 2144.07].
Matsumiya does not teach wherein the particulate solid composition, from which the rare earth metals are being extracted, comprises coal ash.
Sutto teaches a method of extracting, separating, and/or purifying a rare earth metal from coal ash (abstract; para [0011]), the method comprising:
contacting a coal ash comprising the rare earth metal with an aqueous acid and an ionic liquid to form a liquid comprising the metal (para [0011]-[0012]; para [0026], coal ash is contacted with a mixture of aqueous acid and ionic liquid to leach rare earth metals into the liquid phase, then the solid ash residues are filtered out);
immersing an electrochemical cell in the liquid comprising the metal, and electroplating metal out of the liquid onto the cathode (para [0023], [0026]).
Sutto teaches that it is advantageous to use such a method to remove heavy metals and rare earth metals from coal ash, because it reduces the toxicity and radioactivity of coal ash waste, and isolates the heavy metals, allowing both the depleted ash and the heavy metals to be recycled with decreased generation of toxic waste (para [0011]-[0014]).
It would have been obvious to a person having ordinary skill in the art at the time of the invention to apply the method of modified Matsumiya to a starting material comprising coal ash, based on Sutto's teaching that ionic liquid leaching and electrodeposition is effective to remove heavy metals and rare earth metals from coal ash.
Matsumiya does not teach wherein the ionic liquid comprises a (C1-C20)alkylated imidazolium cation and a tetrafluoroborate anion.
Li is directed to a method of extracting rare earth elements from particulate solids that comprise a metal (para [0004], "a method to extract rare earth elements ... from coal"), by combining the particulate with an ionic liquid to form a metal-containing liquid (para [0004], [0011]-[0015], [0020]). Li tests several different ionic liquids for the purpose of extracting rare earth elements from coal solids, and finds that 1-butyl-3-methylimidazolium tetrafluoroborate ("[Bmim][BF4]") is the most effective among them (para [0023]-[0024]).
It would have been obvious to a person having ordinary skill in the art at the time of the invention to further modify the rare earth element extraction method of Matsumiya by using [Bmim][BF4] as the ionic liquid, based on Li's teaching that [Bmim][BF4] is an effective ionic liquid for extraction of rare earth elements. The selection of a known material, which is based upon its suitability for the intended use, is within the ambit of one of ordinary skill in the art [MPEP § 2144.07].
Regarding claim 3, Matsumiya in view of Hatchett 2013, Shen, Sutto, and Li renders obvious the method of claim 1, and Matsumiya teaches the metal is neodymium (pg 92 §2.2, the solid particles from which the metal is extract are Nd rare earth magnets; pg 100 §4 “Conclusion”, the method results in deposition of metallic Nd at the cathode).
Regarding claim 6, Matsumiya in view of Hatchett 2013, Shen, Sutto, and Li renders the method of claim 1 obvious, and Matsumiya teaches the layer comprising metal comprises a combination of the metal in an elemental form and as a metal oxide (pg 100 left column para 1 and figure 15, the neodymium deposit is metallic in its interior and comprises neodymium oxide at its surface).
Regarding claim 7, Matsumiya in view of Hatchett 2013, Shen, Sutto, and Li renders the method of claim 1 obvious. Furthermore Hatchett 2013 teaches the anode comprises platinum (pg 146 left column para 4, the counter electrode is a platinum sheet).
Regarding claim 8, Matsumiya in view of Hatchett 2013, Shen, Sutto, and Li renders the method of claim 1 obvious. Matsumiya does not teach the cathode comprises gold. However, Hatchett 2013 further teaches the cathode comprises a material selected from gold, platinum, or carbon (pg 146 left column para 4, Hatchett 2013 tests gold, platinum, and glassy carbon as electrode materials), and particularly uses gold for most of the electrochemical experiments including metal electroplating (pg 148 left column para 4 - pg 150 right column para 2).
It would have been obvious to a person having ordinary skill in the art at the time of the invention to use gold as the cathode material in the method of Matsumiya, based on the teaching from Hatchett 2013 that gold is a suitable cathode material for deposition of a rare earth metal from an ionic liquid electrolyte. The selection of a known material, which is based upon its suitability for the intended use, is within the ambit of one of ordinary skill in the art [MPEP § 2144.07].
Regarding claim 11, Matsumiya in view of Hatchett 2013, Shen, Sutto, and Li renders the method of claim 1 obvious, and Li further teaches that the ionic liquid comprises 1-butyl-3-methylimidazolium tetrafluoroborate (para [0023]-[0024]).
Regarding claim 17, Matsumiya in view of Hatchett 2013, Shen, Sutto, and Li renders the method of claim 1 obvious, but does not teach removing the layer comprising the metal from the cathode.
Sutto teaches a method of extracting, separating, and/or purifying a rare earth metal from coal ash (abstract; para [0011]), the method comprising:
contacting a coal ash comprising the rare earth metal with an aqueous acid and an ionic liquid to form a liquid comprising the metal (para [0011]-[0012]; para [0026], coal ash is contacted with a mixture of aqueous acid and ionic liquid to leach rare earth metals into the liquid phase, then the solid ash residues are filtered out);
immersing an electrochemical cell in the liquid comprising the metal, and electroplating metal out of the liquid onto the cathode (para [0023], [0026]); and
removing the layer comprising the metal from the cathode (para [0024]).
Sutto teaches that an advantage of their process is that it regenerates the ionic liquid and the electrodes for further separation of further metal from further source material, rather than discarding them after a single cycle (para [0013]).
It would have been obvious to a person having ordinary skill in the art at the time of the invention to modify the method of Matsumiya by removing the metal from the cathode as taught in Sutto, so that the cathode can be re-used for further deposition of further metal, as taught in Sutto (para [0013], [0024]).
Regarding claim 18, Matsumiya teaches a method of extracting, separating, and/or purifying a metal (pg 91 abstract, “recycling process to recovery of rare earths (REs)”), the method comprising:
combining an aqueous acid and a particulate solid composition that comprises the metal, and mixing the aqueous acid and the particulate solid composition for at least about 1-4 hours, to form an acidic mixture (pg 92-93 §2.2, a rare earth magnet comprising neodymium was ground up into particles of about 25 µm diameter, then the particulate solid was mixed with aqueous solution of bistriflimidic acid (“HTFSA”) for 20 hours to form an acidic mixture; note per pg 92, the acronym “TFSA” refers to the bis(trifluoromethylsulfonyl)amide, and HTFSA to its conjugate acid);
filtering the acidic mixture comprising the aqueous acid to form a filtered extract (pg 93 §2.2, “After leaching, the residual wastes were separated by filtering through a 5.0 µm filter”);
combining the filtered extract with an ionic liquid to form an aqueous liquid comprising the metal, wherein water is 5 wt% to 50 wt% of the aqueous liquid comprising the metal (pg 93 §2.3, the aqueous filtered extract is combined with an ionic liquid at 1:1 by volume for liquid-liquid extraction of the metal into the ionic liquid phase; note that Matsumiya’s ionic liquid, [P2225][TFSA], is denser than water, with a density of about 1.3 g/cm3 at room temperature (evidentiary support is found in Kodama at pg 5 table 3), therefore, Matsumiya’s aqueous liquid mixture, comprising 50% of the aqueous filtrate by volume, comprises between 5 and 50% water by weight);
heating the aqueous liquid that is 5 wt% to 50 wt% water to at least partially remove water therefrom and to form a liquid comprising the metal, wherein the liquid comprising the metal is less than 1 wt% water (pg 93 §2.6: prior to electrodeposition, the organic phase recovered from the liquid-liquid extraction is dried under vacuum at 373 K, resulting in an ionic liquid electrolyte comprising the electrolyte and having a water content of less than 250 ppm); and
immersing an electrochemical cell comprising an anode comprising graphite, platinum, an alloy thereof, or a combination thereof, and a cathode comprising gold, carbon paper, glassy carbon, indium tin oxide (IT), fluoride-doped tin oxide (FTO), copper, an alloy thereof, or a combination thereof, in the liquid comprising the metal to form a layer comprising the metal on the cathode, the immersing comprising applying an electrical potential across the anode and cathode (pg 93 §2.6: into the ionic liquid electrolyte comprising the Nd metal, a three electrode cell is immersed comprising a Nd alloy anode, copper cathode, and platinum reference electrode, then a deposition potential is applied to deposit a Nd layer on the cathode; pg 99-100 §2.6 and figure 15, the electrodeposited layer comprises Nd2O3 at its surface and Nd metal in its interior).
wherein the metal is a rare earth metal (pg 91 abstract, the metal is a rare earth metal and in particular embodiment is neodymium).
Matsumiya does not teach the anode comprises platinum or the cathode comprises gold.
Hatchett 2013 teaches a method comprising:
combining an acid, an ionic liquid, and a particulate solid composition that comprises a metal, to form a liquid comprising the metal (abstract; pg 145 right column para 5, Hatchett 2013 mixes bistriflimidic acid, a quat ammonium bistriflimide ionic liquid, and solid cerium carbonate, to form a solution comprising cerium ions in ionic liquid solvent; pg 146 right column para 1); and
immersing an electrochemical cell comprising an anode and a cathode in the liquid comprising the metal (pg 146 left column para 4, the liquid is placed in a 3-electrode cell comprising anode, cathode, and counterelectrode), and applying an electrical potential across the anode and the cathode (pg 148 left column para 4 - pg 150 left column para 1), to form a layer comprising the metal on the cathode (pg 148-150, cerium metal is deposited on the working electrode by reduction at negative voltage, therefore the working electrode is the cathode),
wherein the anode comprises platinum (pg 146 left column para 4, the counter electrode is a platinum sheet) and the cathode comprises gold or carbon (pg 146 left column para 4, Hatchett 2013 tests gold, platinum, and glassy carbon as electrode materials; pg 148 left column para 4 - pg 150 right column para 2, Hatchett 2013 uses gold as the cathode material for most of the subsequent electrochemical experiments including the metal electroplating).
It would have been obvious to a person having ordinary skill in the art at the time of the invention to use platinum as the anode material and gold as the cathode material in the method of Matsumiya, because Hatchett 2013, similarly directed to recovering a lanthanide metal by electrodepositing the metal from ionic liquid solvent onto the cathode of an electrochemical cell, discloses that platinum is a suitable anode material and gold a suitable cathode material for that reaction. The selection of a known material, which is based upon its suitability for the intended use, is within the ambit of one of ordinary skill in the art [MPEP § 2144.07].
Matsumiya does not teach the acid comprises hydrochloric acid, sulfuric acid, phosphoric acid, or a combination thereof.
Matsumiya does not teach the acid comprises hydrochloric acid, sulfuric acid, phosphoric acid, or a combination thereof.
Shen teaches a method of extracting, separating, and/or purifying a lanthanide metal (abstract, “the extraction of mid-heavy rare earths metals (REs) from H2SO4 media”; pg 153 left column table 1, in particular, the media includes aluminum and yttrium, as well as the lanthanide metals La, Gd, Tb, Tm, Yb, and Lu; pg 156 figure 11, all metals in the leach liquor except lanthanum and aluminum are recovered with >60% efficiency), comprising:
combining an aqueous acid with a particulate solid comprising the metal to form an acidic mixture, wherein the aqueous acid comprises sulfuric acid (pg 153 left column §2.1, “Stock solutions of REs were prepared by dissolving the oxides (99.9%) in concentrated H2SO4 solutions”)
combining the acidic mixture with an ionic liquid to extract the metal from the aqueous phase into the ionic liquid phase (pg 153 left column §2.1, “extraction experiments were performed by mixing one volume of organic phase and four volumes of aqueous phase ... The mixture was shaken ... the mixture was centrifuged”; Shen’s ionic liquid, “[A336][P507]”, as disclosed at pg 158, comprises of a quat ammonium cation and a phosphonate anion).
Shen teaches that the extraction of lanthanides from sulfuric acid into ionic liquid is effective (per pg 153 figures 1-2, log D > 0 indicating that the rare earth metals initially dissolved in the acidic mixture phrase are preferentially partitioned into the ionic liquid phase; pg 154 figure 4; pg 155 figure 7, ionic liquid extraction is about 80% efficient in extracting europium from the acidic mixture).
It would have been obvious to a person having ordinary skill in the art at the time of the invention to practice the method of modified Matsumiya using sulfuric acid as the aqueous acid for leaching metal atoms out of the particulate composition, based on Shen’s teaching that sulfuric acid is a suitable acid for use in a method of leaching lanthanide metals in acid and extracting the lanthanide metal ions from leachate into an organic ionic liquid phase. The selection of a known material, which is based upon its suitability for the intended use, is within the ambit of one of ordinary skill in the art [MPEP § 2144.07].
Matsumiya does not teach the particulate solid composition comprises coal ash.
Sutto teaches a method of extracting, separating, and/or purifying a rare earth metal from coal ash (abstract; para [0011]), the method comprising:
contacting a coal ash comprising the rare earth metal with an aqueous acid and an ionic liquid to form a liquid comprising the metal (para [0011]-[0012]; para [0026], coal ash is contacted with a mixture of aqueous acid and ionic liquid to leach rare earth metals into the liquid phase, then the solid ash residues are filtered out);
immersing an electrochemical cell in the liquid comprising the metal, and electroplating metal out of the liquid onto the cathode (para [0023], [0026]).
Sutto teaches that it is advantageous to use such a method to remove heavy metals and rare earth metals from coal ash, because it reduces the toxicity and radioactivity of coal ash waste, and isolates the heavy metals, allowing both the depleted ash and the heavy metals to be recycled with decreased generation of toxic waste (para [0011]-[0014]).
It would have been obvious to a person having ordinary skill in the art at the time of the invention to apply the method of modified Matsumiya to a starting material comprising coal ash, based on Sutto's teaching that ionic liquid leaching and electrodeposition is effective to remove heavy metals and rare earth metals from coal ash.
Matsumiya does not teach wherein the ionic liquid comprises a (C1-C20)alkylated imidazolium cation and a tetrafluorobotrate anion.
Li is directed to a method of extracting rare earth elements from particulate solids that comprise a metal (para [0004], "a method to extract rare earth elements ... from coal"), by combining the particulate with an ionic liquid to form a metal-containing liquid (para [0004], [0011]-[0015], [0020]). Li tests several different ionic liquids for the purpose of extracting rare earth elements from coal solids, and finds that 1-butyl-3-methylimidazolium tetrafluoroborate ("[Bmim][BF4]") is the most effective among them (para [0023]-[0024]).
It would have been obvious to a person having ordinary skill in the art at the time of the invention to further modify the rare earth element extraction method of Matsumiya by using [Bmim][BF4] as the ionic liquid, based on Li's teaching that [Bmim][BF4] is an effective ionic liquid for extraction of rare earth elements. The selection of a known material, which is based upon its suitability for the intended use, is within the ambit of one of ordinary skill in the art [MPEP § 2144.07].
Regarding claim 19, Matsumiya in view of Hatchett 2013, Shen, Sutto, and Li renders the method of claim 1 obvious. Additionally, Matsumiya teaches a method of determining whether the liquid comprising the metal is suitable for use in the method of claim 1, the method comprising collecting a cyclic voltammogram of the liquid comprising the metal (pg 99, left column para 1 – right column para 2 and figure 14), and selecting the liquid comprising the metal if the cyclic voltammogram shows that the liquid comprising the metal has at least one reduction peak (pg 99 right column para 1 – 3, “cathodic peak related with [Nd(TBP)3]3+ was appeared approximately at −2.4 V ... Based on the above fundamental electrochemical analysis, the electrodepostion of Nd metal was conducted against the extracted sample”).
Regarding claim 21, Matsumiya in view of Hatchett 2013, Shen, Sutto, and Li renders the method of claim 1 obvious, and Matsumiya teaches water is 10 wt% to 50 wt% of the aqueous liquid comprising the metal (pg 93 §2.3, the aqueous filtered extract is combined with an ionic liquid at 1:1 by volume for liquid-liquid extraction of the metal into the ionic liquid phase; note that Matsumiya’s ionic liquid, [P2225][TFSA], is denser than water, with a density of about 1.3 g/cm3 at room temperature (evidentiary support is found in Kodama at pg 5 table 3), therefore, Matsumiya’s aqueous liquid mixture, comprising 50% of the aqueous filtrate by volume, comprises about 40 - 43% water by weight, which falls within the claimed range of 10 to 50% by weight).
Regarding claim 22, Matsumiya in view of Hatchett 2013, Shen, Sutto, and Li renders the method of claim 1 obvious, and Matsumiya further teaches wherein, when the aqueous liquid is heated to at least partially remove water therefrom and form a liquid comprising the metal, the liquid comprising the metal is less than 0.5 wt% water (pg 93 §2.6: prior to electrodeposition, the organic phase recovered from the liquid-liquid extraction is dried under vacuum at 373 K, resulting in an ionic liquid electrolyte comprising the electrolyte and having a water content of less than 250 ppm water, which falls within the claimed range of 0.5 wt% water or less).
Regarding claim 24, Matsumiya in view of Hatchett 2013, Shen, Sutto, and Li renders the method of claim 1 obvious, and Matsumiya further teaches wherein the heating of the aqueous liquid to at least partially remove water therefrom comprises heating the aqueous liquid to a temperature in the claimed range of from 100 °C to 110 °C (pg 93 §2.6, “dried under vacuum at 373 K”).
Claim 5 is rejected under 35 U.S.C. 103 as being unpatentable over modified Matsumiya as applied to claim 1 above, in further view of "Zhang" (Zhang et al, Resources Conversion & Recycling, 166, 105282, pg 1-10 (2021)).
Regarding claim 5, Matsumiya in view of Hatchett 2013, Shen, Sutto, and Li renders the method of claim 1 obvious, with Sutto teaching wherein the particulate solid composition comprises coal ash. Matsumiya, Hatchett 2013, Shen, Sutto, and Li do not teach the composition comprises lignite coal ash.
Zhang teaches that lignite coal is widely used to power coal plants (pg 1 left column), lignite coal generates considerable amounts of ash which are of significant environmental concern (pg 1 left column - pg 2 left column para 2), and that lignite coal ash contains heavy metals (pg 3 section 2.2; pg 5-8 sections 3.3 - 3.4; pg 6).
It would have been obvious to a person having ordinary skill in the art at the time of the invention to apply the method of modified Matsumiya and Sutto, which is useful for remediating heavy metals from coal ash, to lignite coal ash in particular, because Zhang teaches that lignite coal ash is a contaminant of significant concern (pg 1 left column - pg 2 left column para 2) and contains heavy metals (pg 3 section 2.2; pg 5-8 sections 3.3 - 3.4; pg 6).
Claims 25-26 are rejected under 35 U.S.C. 103 as being unpatentable over modified Matsumiya as applied to claim 1 above, in further view of "Hatchett 2017" (US 2017/0306514 A1 to Hatchett et al)
Regarding claim 25, Matsumiya in view of Hatchett 2013, Shen, Sutto, and Li renders the method of claim 1 obvious. However, Matsumiya does not teach the method comprises selectively forming the layer comprising the metal on the cathode, the selectively forming comprising applying one or more electrical potentials across the anode and cathode that favor formation of the layer comprising the metal on the cathode comprising one or more metals in preference to one or more other metals.
Hatchett 2017 is similarly directed to a method of extracting, separating, and/or purifying a metal (para [0004], "processes for recovering rare earth elements, such as lanthanides"), the method comprising:
combining water, an aqueous acid, a particulate solid composition that comprises the metal, and an ionic liquid, to form an aqueous liquid comprising the metal (para [0004], "adding water and a nonaqueous acid to an ionic liquid, and dissolving an oxide of a first rare earth element directly into the ionic liquid to form an ionic solution"; note per para [0027], a portion of the "nonaqueous" acid dissolves into the water and becomes aqueous acid),
treating the aqueous liquid to at least partially remove water therefrom and to form a liquid comprising the metal (para [0028], "Water ... may be removed from the ionic solution prior to electrochemical deposition of the rare earth metal ... For example, ... using degassing (e.g., using a nitrogen purge) and/or molecular sieves"), and
immersing an electrochemical cell in the liquid comprising the metal to form a layer comprising the metal on the cathode (para [0034]-[0039], the liquid comprising the metal is reduced in an electrochemical cell to deposit a metal coating on the negative electrode), the immersing comprising applying an electrical potential across the anode and cathode (para [0036]), wherein the cell comprises a cathode comprising carbon paper (para [0036], "reduction ... onto grafoil working electrodes").
Hatchett 2017 further teaches selectively forming the layer comprising the metal on the cathode, the selectively forming comprising applying one or more electrical potentials across the anode and cathode that favor formation of the layer comprising the metal on the cathode comprising one or more metals in preference to one or more other metals (para [0006], [0032], [0039]). Hatchett 2017 teaches that, by choosing a deposition potential that favors formation of one metal over the other, they can achieve selective recovery of a target metal from a solution comprising multiple metals, and/or deposition of mixed metal films with desired concentrations or concentration gradients.
It would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention, when performing the leaching and electrodeposition method of Matsumiya, to apply across the anode and cathode an electrical potential that is chosen to favor the deposition of one metal over another, as taught by Hatchett 2017, in order to selectively recover a desired metal from an extractant solution that may comprise multiple dissolved metal species, as taught in Hatchett 2017 (para [0032]).
Regarding claim 26, Matsumiya in view of Hatchett 2013, Shen, Sutto, and Li and Hatchett 2017 renders obvious the method of claim 25. Hatchett 2017 further teaches wherein the applying of the one or more electrical potentials comprises applying a plurality of different electrical potentials across the anode and cathode, each of the plurality of different electrical potentials favoring formation of the layer comprising the metal on the cathode comprising a different one or more metals in preference to one or more other metals (para [0032], [0039]).
Response to Arguments
Applicant’s arguments, see Remarks field 18 June 2026, have been fully considered but are not persuasive. The rejections of record are withdrawn responsive to applicant’s amendments, and new grounds of rejection are introduced. The claims remain rejected on §103 grounds based on Matsumiya as modified by other references.
Applicant argues (Remarks pg 10 and 14) that the modification of Matsumiya, by substituting Matsumiya’s aqueous acid (triflimidic acid) with one of the recited acids (hydrochloric, phosphoric, or sulfuric acid), would be nonobvious because it would render the method ineffective for its intended purpose. Applicant points out that Matsumiya (at pg 95 right column) directly compared extraction of aqueous Nd(TFSA)3 against extraction of aqueous Nd(NO3)3 and showed that the latter was much less efficient.
Examiner respectfully disagrees. Matsumiya’s disclosure that extraction efficiency from a nitrate acid mixture was poor does not constitute a teaching away from any acid other than nitric acid, and Matsumiya is silent with respect to the efficacy of hydrochloric, phosphoric, and sulfuric acid. Meanwhile, “Turgis” (US 2018/0230572 A1) as discussed at pg 12-13 of the previous Office Action at pg 12-13 discloses that leaching in sulfuric acid and extracting therefrom into ionic liquid is an effective method to recover tantalum. The present action cites instead to Shen (see pg 6-7) who discloses that lanthanide metals too (as Matsumiya is using) can likewise be leached in sulfuric acid and then extracted from sulfuric acid into ionic liquid. As Matsumiya is silent with respect to the matter in question (the use of hydrochloric, phosphoric, or sulfuric acid as the aqueous acid), and other works in the art indicate that the use of these acids could be practiced with reasonable expectation of success, Applicant’s argument is therefore found unpersuasive.
Applicant argues (Remarks pg 11-12) that the method of Li differs from that of Matsumiya, in that Matsumiya dissolves rare earth metals in aqueous acid and then extracts the metals from acid into ionic liquid, whereas Li instead leaches a particulate solid with ionic liquid directly. Applicant argues that Li fails to teach the use of an ionic liquid for liquid-liquid extraction.
This argument is unpersuasive because the rejection does not rely on Li to teach liquid-liquid extraction from an aqueous acid into an ionic liquid; this feature is already present in the base disclosure of Matsumiya. Li is relied upon only for the suggestion that the particular ionic liquid claimed (alkyl-imidazolium tetrafluoroborate) is an effective extractant for rare earth metals, and therefore would be an obvious ionic liquid composition to consider using in combination with the method steps of Matsumiya.
Conclusion
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/ANDREW KOLTONOW/Examiner, Art Unit 1795
/LUAN V VAN/Supervisory Patent Examiner, Art Unit 1795
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