DETAILED ACTION
Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Response to Amendment
The amendment filed 06/12/2026 has been entered. Claim(s) 1-14, 16, and 19-25 is/are pending in this application and examined herein. Claim(s) 1 is/are amended. Claim(s) 15, 17-18, and 26-27 is/are cancelled.
The rejection(s) under 35 USC 112(a) and (b) to claim(s) 27 is/are withdrawn in view of the cancellation of claim 27.
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and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114.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 06/12/2026 has been entered.
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.
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, 13, 16, and 19-21 are rejected under 35 U.S.C. 103 as being unpatentable over Wang et al. (CN 102534269 A, machine translation and original document supplied herein) in view of Pingitore (US 20160138133 A1, cited in Office Action dated 05/03/2024) and Zhao et al. (CN 104862502 A, provided with Office Action dated 08/27/2025).
Regarding claim 1, Wang teaches a process for extracting rare earth element (REE) from rare earth materials (i.e., REE containing ore) (Title, [0002). Wang teaches mixing REE containing ore with sulfuric acid (i.e., soaking the REE containing ore with strong acid) [0052], with a concentration of greater than 98% (i.e., greater than about 36 N) [0054]. Wang teaches mixing at a ratio of strong acid to REE containing ore of 200 g of ore to 170.81 mL of sulfuric acid by weight, a ratio of strong acid to the REE containing ore of 17.1:20 (Examples 1 and 2), which is within the claimed range. Wang teaches mixing at a temperature of room temperature [0078], which would be recognized by one of ordinary skill to be 20-25 °C (i.e., without baking the REE containing ore, wherein the REE containing ore is maintained at a temperature below 100 °C). Wang teaches leaching the REE (i.e., dissolvable REE) with an aqueous leaching solution to obtain a leachate comprising extracted REE [0053, 0079].
Wang does not teach a soak time.
Pingitore teaches methods for extraction and recovery of rare earth elements by leaching with sulfuric acid (Title, abstract); thus, Wang and Pingitore are analogous as processes for recovering rare earth elements using sulfuric acid. Pingitore teaches the ore is treated with sulfuric acid for several weeks, months, or up to several years depending on the ore [0035], which is within the “at least 2 weeks” range of the instant claim.
Because Wang is silent with respect to a soak time of the ore, in order to carry out the invention of Wang one of ordinary skill in the art would necessarily look to the art for a reference teaching a soak time suitable for use within the process of Wang, such as that of several weeks, months, or years as taught by Pingitore. As Wang and Pingitore both relate to recovery of rare earth elements from ore using sulfuric acid, one of ordinary skill would have been motivated to use the processing times of Pingitore when performing the process for extracting rare earth elements disclosed by Liu.
Wang in view of Pingitore does not teach contacting the REE containing ore with an amount of water to moisten the REE containing ore.
Zhao teaches a clean smelting process for mixed rare earth concentrate of bastnaesite and monazite (Title), where a residue (analogous to REE containing ore) is leached with sulfuric acid (analogous to soaking and leaching with an aqueous leaching solution) to recover rare earths [0017], thus Zhao and Wang are analogous to the instant application as both are directed processes for recovering rare earth elements using sulfuric acid. Zhao teaches prior to leaching with sulfuric acid, washing the REE containing ore with water (i.e., contacting the REE containing ore with an amount of water) [0016], which would moisten the REE containing ore. Zhao teaches the washing removes a large amount of phosphorous and a small amount of fluorine, which is beneficial to the leaching of rare earths during the acid leaching process [0019].
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have contacted the REE containing ore with an amount of water prior to soaking as taught by Zhao in the process of Wang as doing so would remove a large amount of any phosphorous present and a small amount of any fluorine present in the REE containing ore, improving leaching as taught by Zhao.
Regarding claims 2-3, Wang teaches wherein the strong acid comprises H2SO4 [0052].
Regarding claims 4-5, Pingitore teaches wherein the soaking step is performed for a duration of several weeks, months, or years [0035].
Pingitore teaches a soaking step is performed for a duration of several weeks, months, or years. This overlaps the claimed ranges of from about 2 weeks to about 12 weeks, and from about 4 weeks to about 8 weeks. The overlap between the ranges taught in the prior art and recited in the claims creates a prima facie case of obviousness because the prior art indicates substantial utility over the entire range disclosed therein, including that portion of the range which also falls within the claimed range. See MPEP § 2144.05(I).
Regarding claims 6-7 and 16, Wang teaches the wherein the REE containing ore is soaked with the strong acid at room temperature, which would have been recognized by one of ordinary skill to be 20 or 25° C [0078], which are within the claimed ranges.
Regarding claim 13, Wang teaches wherein the aqueous leaching solution is water [0053].
Regarding claim 19, Wang teaches mixing at a ratio of strong acid to REE containing ore of 200 g of ore to 170.81 mL of sulfuric acid, a ratio of strong acid to the REE containing ore of 8.55:10 by weight (Examples 1 and 2), which is within the claimed range.
Regarding claim 20, Wang teaches mixing at a ratio of strong acid to REE containing ore of 200 g of ore to 170.81 mL of sulfuric acid, a ratio of strong acid to the REE containing ore of 1.71:2 by weight (Examples 1 and 2), which is within the claimed range.
Regarding claim 21, Zhao teaches wherein the solid liquid ratio during washing is 10:1-5:1 [0028], which corresponds to 100-200 mL of water per kg of REE containing ore, which is within the claimed range.
Claims 9-12 are rejected under 35 U.S.C. 103 as being unpatentable over Wang in view of Pingitore and Zhao as applied to claim 1 above, and further in view of Cui et al. (CN 106319247 A, machine translation supplied with Office Action dated 05/03/2024).
Regarding claim 9, Wang teaches recovery of rare earths from fluorine-containing rare earth materials (Title) comprising slag [0002], but does not teach wherein the acid soaking step is performed with an additive.
Cui teaches a method for recovering rare earth from rare earth-containing phosphate ore (Title) where rare earth mixed slag is treated with concentrated sulfuric acid followed by water leaching [0018]; therefore, Wang and Cui are analogous as both relate to recovery of rare earth elements from ores by treatment with sulfuric acid followed by water leaching. Cui teaches adding calcium and/or magnesium-containing substance with the sulfuric acid [0049] causes any fluorine in the ore to be fixed and loss of rare earth to precipitation as rare earth phosphates or fluorides eliminated, and the escape of fluorine element as polluting hydrogen fluoride is avoided [0050]. Cui teaches the calcium and magnesium are added in the form of dolomite and magnesite [0051], where calcium and magnesium are in an ionic form (“an additive comprising metal ions” as claimed).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have added magnesium and/or calcium-containing substance as taught by Cui during the strong acid soaking of Liu, as doing so would prevent loss of rare earths and prevent escape of fluorine as polluting hydrogen fluoride.
Regarding claims 10 and 12, Cui teaches magnesium ions in accord with the instant claims
[0049].
Regarding claim 11, Cui teaches wherein the additive comprises a single type of metal ions or a
combination of two types of metal ions [0049], which recites “magnesium and/or calcium-containing
substance”, considered equivalent to “a single” type or a “combination of two” types of ions as recited
in the instant claim.
Claims 14 and 22-23 are rejected under 35 U.S.C. 103 as being unpatentable over Wang in view of Pingitore and Zhao as applied to claim 1 above, and further in view of Dreisinger et al. (US 20170204499 A1, cited in Office Action dated 08/27/2025).
Regarding claim 14, Wang does not teach wherein the leaching step comprises heap leaching or tank or vat leaching.
Dreisinger teaches acid leaching of rare earth minerals (Title), where ore is contacted with acid to render rare earth elements extractable in a subsequent water leach [0007], therefore Dreisinger and Wang are analogous to the instant application as both are directed to recovery of rare earth elements from ores by treatment with sulfuric acid followed by water leaching. Dreisinger teaches wherein the leaching step occurs in a small reactor (i.e., a tank or vat) [0015].
Because Wang is silent with respect to where the leaching tanks place, in order to carry out the invention of Wang one of ordinary skill in the art would necessarily look to the art for a reference teaching a location or unit operation suitable for use within the process of Wang, such as that of a tank or vat as taught by Dreisinger. As Wang and Dreisinger both relate to recovery of rare earth elements from ores by treatment with sulfuric acid followed by water leaching, one of ordinary skill would be motivated to use the tank or vat of Dreisinger.
Regarding claim 22, Wang does not teach wherein before the soaking, the process further comprises grinding and/or milling the REE containing ore.
Dreisinger teaches wherein before the soaking, the process further comprises crushing (analogous to grinding and/or milling) to a size greater than 10 mesh (greater than 2 mm) (claim 1), such as ¼” (6.35 mm) (Fig. 2 Test: WLAB2), which is within the claimed range. Dreisinger teaches that crushing to ¼” improves extraction of REE (Fig. 2 Test: WLAB2) compared to extraction from larger particles (Fig. 2 Test: WLAB1).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have ground/milled the ore of Wang to obtain a 6.35 mm ore as taught by Dreisinger as doing so would improve extraction of REE as taught by Dreisinger.
Regarding claim 23, Wang does not teach wherein before the soaking, the process further comprises crushing the REE containing ore.
Dreisinger teaches wherein before the soaking, the process further comprises crushing the REE containing ore [0007, 0015] to approximately 6 mesh particle size [0015], where achieving a 6 mesh particle size material would be recognized by one of ordinary skill to be performed by separating the crushed REE containing ore by passing through a size 6 mesh. Dreisinger teaches that crushing to 6 mesh improves extraction of REE (Fig. 2 Test: WLAB3) compared to extraction from larger particles (Fig. 2 Test: WLAB1, WLAB2).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have crushed and separated the ore of Wang to obtain a particle size 6 mesh ore as taught by Dreisinger as doing so would improve extraction of REE as taught by Dreisinger.
Claims 24-25 are rejected under 35 U.S.C. 103 as being unpatentable over Wang in view of Pingitore and Zhao as applied to claim 1 above, and further in view of Vaisanen et al. (US 20150211094 A1, cited in Office Action dated 08/27/2025).
Regarding claim 24, Wang does not teach wherein the process further comprises contacting the extracted rare earth element with oxalate and a reducing agent.
Vaisanen teaches a method for processing fly ash (title), where rare earth elements are extracted by using a sulfuric acid comprising extraction solution ([0021], Fig. 1), thus Vaisanen and Wang are analogous to the instant application as both are directed to recovering rare earth elements by contacting with sulfuric acid. Vaisanen teaches contacting the extracted rare earth element 15 with oxalic acid to form a mixture comprising an REE oxalate precipitate and a solution ([0021], Fig. 2 b). As oxalic acid (H2C2O4) comprises oxalate (C2O42-), and positively charged hydrogen (i.e., a reducing agent), Vaisanen teaches contacting with oxalate and a reducing agent. Vaisanen teaches about 80% of the rare earth elements are precipitated [0035], which would indicate at least some REEs remain in solution, thus the solution comprises a REE oxalate as best can be examined in view of the rejection of claim 24 above
Vaisanen teaches separating the REE oxalate from the REE oxalate precipitate [0038], and that the precipitate can be heated, for example at a temperature of 800 degrees, when oxides of the rare earth elements will be formed, where the exploitable product will then be a mineral concentrate containing oxides of rare earth elements (i.e., processing the separated REE oxalate to obtained a purified REE) [0026].
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have contacted the extracted rare earth elements with oxalate and reducing agent to form an oxalate precipitate and further process the oxalate to obtain a purified REE as taught by Vaisanen as doing so would produce an exploitable product, which would be recognized by one of ordinary skill to have commercial value and industrial applicability.
Regarding claim 25, Vaisanen teaches wherein the pH of the mixture is adjusted to pH 1.5±0.3 using NH3 [0026], which is within the claimed range.
Response to Arguments
Applicant's arguments filed 06/12/2026 have been fully considered but they are not persuasive.
Regarding Applicant’s argument that A person of skill in the art would have no motivation to combine Zhao with the teachings of Wang and Pingitore because the person of skill in the art would not consider Zhao in the first place, as Zhao requires smelting (see pg. 6-7 of remarks), the Examiner respectfully disagrees.
It has long been held that to rely on a reference under 35. USC 103, wherein: (1) the reference is from the same field of endeavor as the claimed invention (even if it addresses a different problem); or (2) the reference is reasonably pertinent to the problem faced by the inventor (even if it is not in the same field of endeavor as the claimed invention). See MPEP 2141.01(a). In the instant case the reference is from the same field of endeavor as the claimed invention, as Zhao is directed to a process for recovering rare earth elements from ore using sulfuric acid treatment, the same underlying mechanism of recovering rare earths as in the instant application.
Even if the later processing steps in Zhao including smelting were to differentiate Zhao to the degree that it would belong to a “different field of endeavor”, Zhao is pertinent to the problem faced by the inventor (“a need to optimize the initial extraction of REEs” as discussed at [0008] of the instant specification), as Zhao teaches the washing step removes a large amount of phosphorous and a small amount of fluorine, which is beneficial to the leaching of rare earths during the acid leaching process (i.e., optimizing leaching of rare earths).
Regarding Applicant’s argument that Zhao expressly requires baking, a sub-process that the instant claims have been specifically recited to avoid and exclude, and thus one of ordinary skill cannot consider Zhao in any capacity (see pg. 7 of remarks), the Examiner respectfully disagrees.
While as Applicant notes, Zhao discloses smelting, Zhao is not relied upon to e.g., add a smelting operation to the process of Wang in view of Pingitore. Instead, Zhao is relied upon only to suggest contacting the REE containing ore of Wang with an amount of water prior to soaking in strong acid as taught by Zhao, as Zhao teaches such a step to remove phosphorous and fluorine impurities present in the ore, and would therefore remove any phosphorous or fluorine in the ore of Wang. Such an advantage is not contingent on, or inseparable from, performing a subsequent smelting operation, nor would one of ordinary skill expect such a relationship. Instead, removing impurities from REE containing ore would be recognized to be applicable to a wide variety of processes of recovering REE from ores, such as e.g., soaking REE containing ore with strong acid to recover REEs, as the presence of impurities is undesirable in recovered REEs, regardless of the method used for recovery.
As the process of Wang already teaches a process that does not comprise baking the REE containing ore, and the modifications suggested by Pingitore (using a soak time in accord with the method as claimed) and Zhao (a washing step that would comprise contacting the REE containing ore with an amount of water to moisten the REE containing ore) also do not suggest steps that would require or incorporate baking, Wang in view of Pingitore and Zhou teaches wherein the REE containing ore is without baking the REE containing ore as claimed.
Conclusion
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/Keith D. Hendricks/Supervisory Patent Examiner, Art Unit 1733
/NIKOLAS TAKUYA PULLEN/Examiner, Art Unit 1733
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