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 for the benefit of a prior-filed application (has PRO 62/982,811, filed on 28 February 2020; is 371 of PCT/US21/15364, filed on 28 January 2021) under 35 U.S.C. 119(e) or under 35 U.S.C. 120, 121, 365(c), or 386(c) is acknowledged.
Claim Objections
Claim 1 objected to because of the following informalities:
The phrase “substantially pure (95% or greater) mixture of (N) rare earth elements (REEs),” should be corrected to read “a substantially pure (95% or greater) mixture of (N) rare earth elements (REEs),” to correct improper grammar.
The phrase “a first and a second REEs” in step b should be corrected to read “first and second REEs” to correct improper grammar.
Claim 6 objected to because of the following informalities:
The phrase “The process of claim 5 further comprising:” should be corrected to read “The process of claim 5, further comprising:” to correct improper grammar.
Appropriate correction is required.
Claim Rejections - 35 USC § 112
The following is a quotation of 35 U.S.C. 112(b):
(b) CONCLUSION. —The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention.
Claims 1-2 are rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor (or for applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention.
Claim 1 recites the limitation “substantially pure (95% or greater).” It is unclear what purity metric is being used, including whether the percentage is weight percent, mole percent, atomic percent, or chromatographic peak area percent, and it is further unclear what the percentage is measured relative to, including whether it is relative to other rare earth elements, non-rare earth impurities, or the total collected stream. Claims 2, which depend on Claim 1, are similarly rejected by virtue of dependency.
Claim 3 recites the limitation “substantially pure (≥95%)” It is unclear what purity metric is being used, including whether the percentage is weight percent, mole percent, atomic percent, or chromatographic peak area percent, and it is further unclear what the percentage is measured relative to, including whether it is relative to other rare earth elements, non-rare earth impurities, or the total collected stream. Claims 4-7, which depend on Claim 3, are similarly rejected by virtue of dependency.
Claim 3 recites the limitation “in first column” in step (k). The antecedent basis is unclear because it is uncertain whether this “first column” refers to the first column recited in step (j) or a new first column.
Claim Rejections - 35 USC § 103
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention.
Claims 1-7 are rejected under 35 U.S.C. 103 as being unpatentable over WANG et al. (US20170166993A1, hereinafter WANG) and THEOLEYRE et al. (US20100326918A1, hereinafter THEOLEYRE).
Regarding Claims 1 and 2, WANG discloses a metal separation process using ligand-assisted chromatography (¶[0002]). A mixture of rare earth elements is dissolved in strong acid to yield rare earth ions in solution and captured in a first set of chromatography columns, the columns are washed with a salt solution to remove non-adsorbing species, and the resulting solution is co-eluted with a ligand solution and loaded onto a second set of chromatography columns, where rare earth elements are eluted separately using either a linear or stepwise change in ligand concentration or pH (¶¶[0010]–[0011]).
The ligand-assisted elution system uses titania sorbent preloaded with a ligand solution, and separation is based on differential complex stability between REEs and the ligand in solution (¶[0043]). Ligands include EDTA and DTPA (¶¶[0077]–[0078]). Pr, Nd, and Sm are separated using EDTA concentrations increasing from 0.1 M to 0.25 M to 0.4 M, with band purities reaching 95–99% (¶[0087], Table 3).
The large-scale production configuration includes a capture step prior to a separation step, as shown in FIG. 9, where a dissolved rare earth mineral solution is loaded onto a strong acid cation exchange column loaded with Na+, and protons remaining on the resin are displaced by a NaCl solution. The captured lanthanides (Ln’s) are then eluted by Na form EDTA and loaded onto an EDTA preloaded titania column, and a gradient of EDTA concentration is used to elute the adsorbed Ln’s from the titania column (¶¶[0089]–[0091]). Accordingly, FIG. 9 illustrates a multi-column operation including a cation exchange capture column and a titania separation column.
A continuous counter current chromatography process is shown for separation of 3 Ln elements (FIG. 11a) and 15 Ln elements (FIG. 11b), where eluants 1 to 15 are EDTA solutions with increasing concentrations and products 1 to 15 are different Ln elements. An entire cycle contains feeding, elution, and washing zones, where the Ln mixture is loaded in the feeding zone, different Ln’s are eluted at different EDTA concentrations in the elution zone, and the column is flushed by diluted EDTA in the washing zone, and EDTA effluents collected in waste tanks, including concentrated EDTA in the effluent, are recycled and reused, and after washing the next cycle starts with feeding (¶[0092]).
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FIG. 9 and FIG. 11a/b from US20170166993A1
However, WANG does not explicitly disclose segregating mixed bands and routing the mixed bands between different zones and different columns as recited in steps (b) to (f).
Multi-stage separation by collecting purified cut and recycling mixed fractions, sometimes referred to as cut and recycle or recycle chromatography, is a well-known approach for increasing product purity. In this context, THEOLEYRE discloses a multi-column sequenced separation process and a device for implementing the process for separating metals from leaching effluents in hydrometallurgical processes (¶[0002]).
In on configuration, an SMB-type ion exchange chromatography facility comprises eight columns packed with ion exchange resin, and shifting steps move inlet and outlet positions across the columns. Columns 1 and 2 form a first zone, where water is introduced at the inlet of column 1 while an equal volume is withdrawn at the outlet of column 2, and the withdrawn diluted metal salt solution is returned to an upstream tank or sent to the head of another column for further processing (¶¶[0100]–[0101]).
Two displacement zones are circulated, where a first displacement zone comprises columns 2, 3, 4, and 5 and a second displacement zone comprises columns 6, 7, 8, and 1, and water is injected into columns 2 and 6 to displace fronts. Raffinate is obtained at the foot of column 5 and extract is obtained at the foot of column 1, and a water buffer is reformed between production and regeneration to avoid contamination. The displacement may be asynchronous (¶¶[0117]–[0118]).
Zone lengths may vary by changing the number of columns assigned to displacement, production, or regeneration, and one or more columns may be isolated for maintenance. Within a sequence, a chosen step may be carried out on a chosen column independently of other columns, including varying column supply fluids and reusing fluids exiting columns in subsequent columns (¶¶[0119]–[0120]).
The multi-column separation process disclosed by THEOLEYRE optimizes the quantities of regenerant, resin, and water used in separation cycles, provides better processing capacity at industrial scale, maintains high yield of metal derivatives of interest, respects environmental resources, and is economically more advantageous than prior processes (¶¶[0007]–[0008]).
In view of WANG’s ligand assisted rare earth separation achieving high purity rare earth element bands by stepwise or gradient ligand elution, a person skilled in the art would implement WANG’s cation exchange capture and ligand preloaded titania separation operations with THEOLEYRE’s multi-column sequential process to increase throughput and yield at industrial scale while reducing regenerant, resin, and water consumption.
Therefore, it would have been obvious to a person having ordinary skill in the art, prior to the effective filing date of the claimed invention, to implement a multi-column sequential separation process, as disclosed by THEOLEYRE, into the ligand assisted rare earth separation process by WANG.
Regarding Claims 3, WANG discloses a metal separation process using ligand-assisted chromatography (¶[0002]). A mixture of rare earth elements is dissolved in strong acid to yield rare earth ions in solution and captured in a first set of chromatography columns, the columns are washed with a salt solution to remove non-adsorbing species, and the resulting solution is co-eluted with a ligand solution and loaded onto a second set of chromatography columns, where rare earth elements are eluted separately using either a linear or stepwise change in ligand concentration or pH (¶¶[0010]–[0011]).
The ligand-assisted elution system uses titania sorbent preloaded with a ligand solution, and separation is based on differential complex stability between REEs and the ligand in solution (¶[0043]). Ligands include EDTA and DTPA (¶¶[0077]–[0078]). Pr, Nd, and Sm are separated using EDTA concentrations increasing from 0.1 M to 0.25 M to 0.4 M, with band purities reaching 95–99% (¶[0087], Table 3).
The large-scale production configuration includes a capture step prior to a separation step, as shown in FIG. 9, where a dissolved rare earth mineral solution is loaded onto a strong acid cation exchange column loaded with Na+, and protons remaining on the resin are displaced by a NaCl solution. The captured lanthanides (Ln’s) are then eluted by Na form EDTA and loaded onto an EDTA preloaded titania column, and a gradient of EDTA concentration is used to elute the adsorbed Ln’s from the titania column (¶¶[0089]–[0091]).
However, WANG does not explicitly disclose the multi-zone, multi-column segregating and routing sequence of steps (h) to (m), including segregating mixed bands and sending the mixed bands to different zones in different columns for further separation.
Multi-stage separation by collecting purified cut and recycling mixed fractions is a well-known approach for increasing product purity. In this context, THEOLEYRE discloses a multi-column sequenced separation process and a device for implementing the process for separating metals from leaching effluents in hydrometallurgical processes (¶[0002]).
In one configuration, an SMB-type ion exchange chromatography facility comprises eight columns packed with ion exchange resin, where shifting steps move inlet and outlet positions across the columns and a withdrawn diluted metal salt solution is returned to an upstream tank or sent to the head of another column for further processing (¶¶[0100]–[0101]).
Advantageously, the multi-column separation process disclosed by THEOLEYRE optimizes the quantities of regenerant, resin, and water used in separation cycles, provides better processing capacity at industrial scale, maintains high yield of metal derivatives of interest, respects environmental resources, and is economically more advantageous than prior processes (¶¶[0007]–[0008]).
In view of WANG’s ligand assisted rare earth separation by stepwise or gradient ligand elution, a person skilled in the art would implement WANG’s cation exchange capture and ligand preloaded titania separation operations in THEOLEYRE’s multi-column sequential process to increase throughput and yield at industrial scale while reducing regenerant, resin, and water consumption.
Therefore, it would have been obvious to a person having ordinary skill in the art, prior to the effective filing date of the claimed invention, to implement a multi-column sequential separation process, as disclosed by THEOLEYRE, into the ligand assisted rare earth separation process by WANG.
Regarding Claims 4 and 5, modified WANG makes obvious a method for separating rare earth elements using ligand-assisted chromatography of Claim 3. WANG discloses that the sorbent is presaturated with a ligand prior to introduction of REEs, where Table 1 illustrates “Presaturant and Eluant Concentration” in an isocratic elution setup, and ligand selectivity controls elution order based on REE ligand complex stability, and further discloses loading a dissolved rare earth mineral solution onto a strong acid cation exchange column loaded with Na+ (¶[0046], ¶[0089], Table 1). THEOLEYRE discloses a multi-zone multi-column chromatography facility comprising eight columns, where shifting steps form zones across the columns (¶¶[0100]–[0101]). Applying the presaturation conditions to each zone is a routine implementation choice in a multi-zone chromatography process.
Regarding Claim 6, modified WANG makes obvious a method for separating rare earth elements using ligand-assisted chromatography of Claim 5. WANG discloses that after a mixture of Pr, Nd, and Sm is loaded onto the column, a 0.05 M HNO₃ solution is introduced as a displacer to displace the adsorbed rare earth ions from the stationary phase (¶[0066]). The resulting elution behavior shows that Pr, Nd, and Sm are released by the advancing acid front (¶[0075]).
Regarding Claim 7, modified WANG makes obvious a method for separating rare earth elements using ligand-assisted chromatography of Claim 6. WANG discloses ethylene-diamine-tetra-acetic acid (EDTA) and di-ethylene-tri-amine-penta-acetic acid (DTPA) as ligands (¶¶[0077]–[0078]), and sodium as a presaturant during rare earth element capture on a strong acid cation exchange column (¶[0089]). A displacement test is conducted using 0.05 M nitric acid (HNO₃), which provides hydrogen ions (H⁺) as a displacer for eluting adsorbed rare earth ions from the stationary phase (¶[0066], ¶[0075]).
Response to Arguments
Applicant’s arguments, see REMARKS, filed October 27, 2025, with respect to the rejection(s) of claim(s) 1–7 under 35 U.S.C. 103 have been fully considered and are persuasive. Therefore, the rejection has been withdrawn. However, upon further consideration, a new ground(s) of rejection under 35 U.S.C. 103 is made in view of WANG and THEOLEYRE.
Additionally, a new ground(s) of 35 U.S.C. 112(b) rejection is made.
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.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to TAK L. CHIU whose telephone number is (703)756-1059. The examiner can normally be reached M-F: 9:00am - 6:00pm (CST).
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/TAK L. CHIU/ Examiner, Art Unit 1777
/KRISHNAN S MENON/ Primary Examiner, Art Unit 1777
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