Detailed Action
This is a 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, 3-8, 10-13, 15-19, 21-22, and 24 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 .
Status of the Rejection
The §103 rejections of record are maintained
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, 3-4, 6-8, 12-13, 15-16, 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” (Hatchett et al, Electrochimica Acta, 89, 144-151 (2013)). Evidentiary support for the rejections of claims 1 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 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 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 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, 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].
Regarding claim 3, modified Matsumiya 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 4, modified Matsumiya renders obvious the method of claim 1, and Matsumiya teaches the particulate solid is a recycled material comprising a critical mineral wherein the critical mineral is a rare earth element (pg 92 §2.2, the solid particles from which the metal is extract are recycled rare earth magnets comprised of an alloy comprising Nd; pg 100 §4 “Conclusion”, the method results in deposition of metallic Nd at the cathode).
Regarding claim 6, modified Matsumiya 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, modified to incorporate the anode material disclosed in Hatchett, renders the method of claim 1 obvious. Furthermore Hatchett teaches the anode comprises platinum (pg 146 left column para 4, the counter electrode is a platinum sheet).
Regarding claim 8, Matsumiya modified in view of Hatchett renders the method of claim 1 obvious. Matsumiya does not teach the cathode comprises gold. However, Hatchett further teaches the cathode comprises a material selected from gold, platinum, or carbon (pg 146 left column para 4, Hatchett 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 Hatchett 2017, based on the teaching from Hatchett 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 12, modified Matsumiya renders the method of claim 1 obvious, and Matsumiya further teaches the ionic liquid comprises an ionic liquid anion that is bis-trifluoromethanesulfonimide (pg 91 abstract, pg 93 §2.3, the ionic liquid is “triethyl-pentyl-phosphonium bis(trifluoromethyl-sulfonyl)amide ([P2225][TFSA])”).
Regarding claim 13, Matsumiya modified in view of Hatchett renders the method of claim 1 obvious. Matsumiya does not teach that the ionic liquid comprises an ionic liquid cation selected from among those listed in claim 13. However, Hatchett teaches that their ionic liquid comprises a tetra(C1–C20)alkylated ammonium (pg 144 abstract, “the ionic liquid trimethyl-n-butylammonium bis(trifluoromethanesulfonyl)imide [Me3NBu][TFSI]”).
It would have been obvious to a person having ordinary skill in the art at the time of the invention to use an ionic liquid comprising a tetra-alkylated ammonium cation in the method of Matsumiya, because Hatchett, similarly directed to recovering a lanthanide metal by electrodepositing the metal from a bistriflimide-based ionic liquid onto the cathode of an electrochemical cell, discloses that a tetraalkylated ammonium is a suitable cation for the ionic liquid to have. 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 15, modified Matsumiya renders obvious the method of claim 1 and teaches the method comprises selectively extracting, separating, and/or purifying one or more rare earth metals from the liquid comprising the metal (pg 92 left column para 3, the method involves selectively extracting rare earth metals, in particular neodymium).
Regarding claim 16, modified Matsumiya renders obvious the method of claim 1, wherein the application of electric potential is carried out for an undisclosed length of time at a temperature of 373 K (pg 93 right column para 5), which falls in the claimed range of from room temperature to 300 °C. Matsumiya does not specify that the application of electric potential is carried out for a time of between 0.1 and 24 hours, and does not specify that the amount of metal deposited onto the cathode is between 0.001 wt% and 100 wt% of the total metal originally present in the liquid comprising the metal. However, it would have been obvious to a person having ordinary skill in the art at the time of the invention to select suitable deposition conditions including deposition potential and deposition time, in order to achieve a good electrodeposition yield.
Regarding claim 19, modified Matsumiya 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, modified Matsumiya renders the method of claim 1 obvious, wherein 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, modified Matsumiya 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); and
Regarding claim 24, modified Matsumiya 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 "Sutto" (US 2016/0222532 A1 to Sutto) and "Zhang" (Zhang et al, Resources Conversion & Recycling, 166, 105282, pg 1-10 (2021)).
Regarding claim 5, modified Matsumiya renders the method of claim 4 obvious but Matsumiya does not teach the composition comprises lignite 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.
Sutto does not specify that the coal ash is 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 and contains heavy metals.
Claim 10 is rejected under 35 U.S.C. 103 as being unpatentable over modified Matsumiya as applied to claim 1 above, in further view of "Turgis" (US 2018/0230572 A1 to Turgis et al).
Regarding claim 10, modified Hatchett 2017 renders the method of claim 1 obvious, but does not teach the aqueous acid comprises hydrochloric acid, sulfuric acid, phosphoric acid, or a combination thereof.
Turgis teaches a method of extracting, separating, and/or purifying a metal (para [0001], "extraction of tantalum"), the method comprising:
combining an aqueous acid and a particulate solid composition that comprises the metal, to form an acidic mixture (para [0074], ore is leached with acid to form an acidic mixture with dissolved tantalum values);
combining the acidic mixture with an ionic liquid to form an aqueous liquid comprising the metal (para [0015]-[0016], the acidic mixture is mixed with an ionic liquid), wherein water is 5 wt% to 50 wt% of the aqueous liquid comprising the metal (per para [0258], [0263], [0294], the aqueous acid mixture and the ionic liquid are mixed at a ratio of 1:1 by volume; in the example of para [0294]-[0310] and Table 5, the ionic liquids are either an dialkyl-piperidinium bistriflimide or a butylmethylimidazolium bistriflimide; per Yadav pg 69 table 2, butylmethylimidazolium bistriflimide ("[bmim][(CF3SO2)2N]") has a density of 1.44 at room temperature, and a dialkyl piperidinium bistriflimide ("[pmpip][(CF2SO2)2N]") has a density of 1.40 at room temperature; therefore, in Turgis's mixture of the aqueous acid and the ionic liquid at a volume ratio of 1:1, water comprises roughly 40% of the mixture by weight, which falls within the claimed range of 5 wt% to 50 wt%) ;
immersing an electrochemical cell comprising an anode and a cathode into the liquid containing the metal, and applying an electrical potential across the cathode, to form a layer comprising the metal on the cathode (para [0336]-[0343]).
Turgis further teaches the aqueous acid comprises one or more of hydrofluoric acid, sulfuric acid, nitric acid, phosphoric acid and hydrochloric acid (para [0075]), with sulfuric acid being particularly preferred (para [0076], [0110]-[0123]).
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 Turgis's teaching that sulfuric acid is a suitable acid for a similar role in a similar method of leaching and electroplating a heavy metal. 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].
Claim 11 is rejected under 35 U.S.C. 103 as being unpatentable over modified Matsumiya as applied to claim 1 above, in further view of "Li" (US 2019/0316225 A1 to Li et al).
Regarding claim 11, modified Matsumiya renders the method of claim 1 obvious, but does not teach the ionic liquid comprises 1-butyl-3-methylimidazolium tetrafluoroborate.
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 teaches that 1-butyl-3-methylimidazolium tetrafluoroborate ("[Bmim][BF4]") is a suitable choice of ionic liquid for the purpose of extracting rare earth elements (para [0023]).
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].
Claim 17 is rejected under 35 U.S.C. 103 as being unpatentable over modified Matsumiya as applied to claim 1 above, in further view of Sutto.
Regarding claim 17, modified Matsumiya 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]).
Claim 18 is rejected under 35 U.S.C. 103 as being unpatentable over Matsumiya, in view of Hatchett, Turgis, and Sutto. Evidentiary support is provided by Kodama.
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 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 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 tests gold, platinum, and glassy carbon as electrode materials; pg 148 left column para 4 - pg 150 right column para 2, Hatchett 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, 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 and Hatchett do not teach the acid comprises hydrochloric acid, sulfuric acid, phosphoric acid, or a combination thereof.
Turgis teaches a method of extracting, separating, and/or purifying a metal (para [0001], "extraction of tantalum"), the method comprising:
combining an aqueous acid and a particulate solid composition that comprises the metal, to form an acidic mixture (para [0074], ore is leached with acid to form an acidic mixture with dissolved tantalum values);
combining the acidic mixture with an ionic liquid to form an aqueous liquid comprising the metal (para [0015]-[0016], the acidic mixture is mixed with an ionic liquid), wherein water is 5 wt% to 50 wt% of the aqueous liquid comprising the metal (per para [0258], [0263], [0294], the aqueous acid mixture and the ionic liquid are mixed at a ratio of 1:1 by volume; in the example of para [0294]-[0310] and Table 5, the ionic liquids are either an dialkyl-piperidinium bistriflimide or a butylmethylimidazolium bistriflimide; per Yadav pg 69 table 2, butylmethylimidazolium bistriflimide ("[bmim][(CF3SO2)2N]") has a density of 1.44 at room temperature, and a dialkyl piperidinium bistriflimide ("[pmpip][(CF2SO2)2N]") has a density of 1.40 at room temperature; therefore, in Turgis's mixture of the aqueous acid and the ionic liquid at a volume ratio of 1:1, water comprises roughly 40% of the mixture by weight, which falls within the claimed range of 5 wt% to 50 wt%) ;
immersing an electrochemical cell comprising an anode and a cathode into the liquid containing the metal, and applying an electrical potential across the cathode, to form a layer comprising the metal on the cathode (para [0336]-[0343]).
Turgis further teaches the aqueous acid comprises one or more of hydrofluoric acid, sulfuric acid, nitric acid, phosphoric acid and hydrochloric acid (para [0075]), with sulfuric acid being particularly preferred (para [0076], [0110]-[0123]).
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 Turgis's teaching that sulfuric acid is a suitable acid for a similar role in a similar method of leaching and electroplating a heavy metal. 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, Hatchett, and Turgis do 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.
Response to Arguments
Applicant's arguments filed January 6, 2026 have been fully considered but they are not persuasive.
Argument I(A). Applicant argues that Hatchett cannot be relied upon to suggest altering Matsumiya’s neodymium alloy anode to a platinum anode. Particularly, Applicant argues that by Matsumiya’s teaching of an Nd alloy anode must be understood as a teaching away from anode materials that are not Nd alloy. Applicant argues, since Matsumiya had platinum available to them and chose not to use it as their anode, the reference is implicitly teaching that platinum is an unsuitable anode material.
This argument is unpersuasive because disclosed examples and preferred embodiments do not constitute a teaching away from a broader disclosure or nonpreferred embodiments (In re Susi, 440 F.2d 442, 169 USPQ 423 (CCPA 1971)). The Matsumiya article does not make any statement expressing a reason for choosing one anode material over the other. Matsumiya’s disclosure of a Nd alloy anode therefore does not constitute a teaching away from a platinum anode, because “such disclosure does not criticize, discredit, or otherwise discourage the solution claimed” (In re Fulton, 391 F.3d 1195, 1201, 73 USPQ2d 1141, 1146 (Fed. Cir. 2004)).
Applicant’s argument, that Matsumiya must have believed platinum to be an unsuitable anode material if they had it at their disposal and chose not to use it, is also unpersuasive because Matsumiya did in fact use platinum as their anode in some experiments. Per pg 93-94 §2.6, pg 99-100 §3.4, and pg 99 fig 14, Matsumiya carried out cyclic voltammetry experiments in a three electrode cell in which all three electrodes were platinum, to identify which of their ionic liquids was suitable for Nd deposition; then, after Matsumiya found that [P2225][TFSA] was a suitable candidate for Nd deposition, they carried out potentiostatic deposition in a different cell having Nd alloy anode and Cu cathode.
Argument I(B). Applicant argues that Hatchett cannot be relied upon to suggest altering Matsumiya’s neodymium alloy anode to a platinum anode, because Hatchett omits the steps, disclosed in Matsumiya, of leaching the rare earth metal in aqueous acid, filtering the acidic leachate to form a filtered extract, mixing the filtered extract with an ionic liquid for liquid-liquid extraction, drying the ionic liquid, and electrodepositing the metal from the dried ionic liquid. Applicant argues that one skilled in the art, starting from Matsumiya’s disclosure, would not have considered Hatchett’s teachings to be reasonably pertinent.
Applicant’s argument, that one skilled in the art would not have considered the references to be sufficiently analogous to one another, is unpersuasive because works of art are considered analogous if they are in the same field of endeavor (In re Oetiker, 977 F.2d 1443, 24 USPQ2d 1443 (Fed. Cir. 1992)). The Matsumiya reference, the Hatchett reference, and the instant invention are analogous to one another because all three are directed to electroplating of rare earth metals from ionic liquid electrolyte, placing them well within in the same field of endeavor. Moreover note that the analogous art requirement only requires prior art works to be analogous to the claimed invention, it does not require them to be analogous to one another (See Sanofi-Aventis Deutschland GMbH v. Mylan Pharms. Inc., 66 F.4th 1373, 1380, 2023 USPQ2d 552 (Fed. Cir. 2023) and Corephotonics, Ltd. v. Apple Inc., 84 F.4th 990, 1007, 2023 USPQ2d 1202 (Fed. Cir. 2023); see MPEP 2141.01(a)(I)). Matsumiya and Hatchett are reasonably pertinent to one another, but even if they were not, they could still be relied upon in a §103 rejection so long as they were both reasonably pertinent to the claimed invention.
Argument I(C). Applicant argues that there is no apparent motivation to substitute Matsumiya’s anode with Hatchett’s anode, because Matsumiya’s method does not need improvement.
In response to Applicant’s argument that there is no articulated motivation to substitute Matsumiya’s anode material with Hatchett’s, note that the simple substitution of one component for an equivalent component is considered obvious even without a finding of motivation to combine. Such a modification is obvious so long as the substituent and its function are known in the art and could be implemented into the base invention in predictable fashion (MPEP 2143(B)). “Express suggestion to substitute one equivalent for another need not be present to render such substitution obvious” (In re Fout, 675 F.2d 301, 213 USPQ 536 (CCPA 1982)).
Argument I(D). Applicant argues that a platinum anode could not be implemented predictably in Matsumiya’s method. Applicant argues that, since Hatchett’s experiments are carried out on a “clean” electrolyte prepared by dissolution of an already-pure salt, rather than on a leachate of waste material as disclosed in Matsumiya, Hatchett’s demonstration of a platinum counterelectrode does not suggest that a platinum counterelectrode would behave predictably in Matsumiya’s electrolyte.
This argument is unpersuasive because obviousness does not require conclusive proof of efficacy, it merely requires a reasonable expectation of success (MPEP 2143.02). While Examiner acknowledges that Hatchett’s solvent and metal species are not identical, Examiner maintains that Hatchett’s reaction (electroplating a lanthanide ion from an ionic liquid) is sufficiently similar to Matsumiya’s reaction (electroplating a different lanthanide from a different ionic liquid) that one would reasonably expect Hatchett’s anode (i.e. the counterelectrode in a cathodic deposition) would be able to perform a similar role in Matsumiya’s method. Matsumiya’s demonstration of cyclic voltammetry analysis on their electrolyte using a platinum counterelectrode (pg 93-94 §2.6, pg 99-100 §3.4, and pg 99 fig 14) is further evidence that platinum can be reasonably expected to behave predictably as the anode in cathodic deposition of the same.
Applicants arguments II through VI each argue that none of the various other cited references can remedy the alleged nonobviousness of combining Matsumiya with Hatchett. These arguments are unpersuasive because, as established above, the combination of Matsumiya with Hatchett is obvious on its own.
The rejections of record are therefore maintained.
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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/ANDREW KOLTONOW/Examiner, Art Unit 1795
/ALEXANDER W KEELING/Primary Examiner, Art Unit 1795
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