System and method for recovering radium-226
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- RADTRAN LLC
- Filing Date
- 2023-05-15
- Publication Date
- 2026-05-22
Smart Images
Figure 00000000_0000_ABST
Abstract
Description
[Technical field]
[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This patent application claims priority to U.S. Provisional Patent Application No. 63 / 342,619, entitled "SYSTEMS AND METHODS FOR RECOVERING RADIUM-226," filed May 16, 2022, which is incorporated by reference in its entirety herein. [Background technology]
[0002] Radium-226 or 226 Ra is produced by radioactive decay of parent materials uranium and thorium. Radium-226 is known to be a precursor to alpha-emitting isotopes that may be useful for medical applications, see US Patent Application Publication No. 2014 / 0226774. Summary of the Invention
[0003] <Summary of disclosure> This patent application relates broadly to systems and methods for recovering radium-226 from uranium tailings and the like. [Brief description of the drawings]
[0004] [Figure 1] FIG. 1 illustrates one embodiment of a method for recovering radium-226 from a solution containing radium-226.
[0005] [Diagram 2] FIG. 2 illustrates an embodiment of the radium-226 solution of FIG.
[0006] [Diagram 3] FIG. 3 illustrates a macrocyclic polyether embodiment of the method of FIG.
[0007] [Figure 4]FIG. 4 illustrates an embodiment of the recovering step of FIG.
[0008] [Diagram 5] FIG. 5 illustrates an embodiment of a preparing step that can be used to prepare a radium-226 containing solution for recovery.
[0009] [Figure 6] FIG. 6 illustrates an embodiment for the recovery of uranium tailings effluents and radium-226. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0010] <Detailed Description> Referring to FIG. 1, in one embodiment, a method for recovering radium-226 (Ra-226) from a solution includes sorbing 100 Ra-226 from a radium-containing aqueous solution via a macrocyclic solid-phase Ra-226 selective sorbent and recovering 200 Ra-226 from the macrocyclic solid-phase Ra-226 selective sorbent. The radium-containing aqueous solution may be any suitable aqueous solution containing Ra-226. In some embodiments, the aqueous solution is obtained by mining uranium, as described in more detail below. In one embodiment, the aqueous solution is obtained from uranium ore, such as uranium tailings. In another embodiment, the aqueous solution is an ion exchange resin effluent or is obtained from an ion exchange resin effluent. The ion exchange resin is used to capture uranium from an aqueous stream containing uranium.
[0011] 1-2, in one embodiment, the radium-containing aqueous solution has a pH of 10 or less. In another embodiment, the radium-containing aqueous solution has a pH of 9 or less. In yet another embodiment, the radium-containing aqueous solution has a pH of 8 or less. In another embodiment, the radium-containing aqueous solution has a pH of 7 or less, e.g., is acidic. In yet another embodiment, the radium-containing aqueous solution has a pH of 6 or less. In another embodiment, the radium-containing aqueous solution has a pH of 5 or less. In yet another embodiment, the radium-containing aqueous solution has a pH of 4 or less. In another embodiment, the radium-containing aqueous solution has a pH of 3 or less.
[0012] In one embodiment, the radium-containing aqueous solution is an acidic solution containing Ra-226 ions. In one embodiment, the radium-containing aqueous solution is selected from the group consisting of hydrochloric acid, nitric acid, and combinations thereof, and the solution contains Ra-226 ions. In one embodiment, the radium-containing aqueous solution includes a hydrochloric acid solution containing Ra-226 ions, or is a hydrochloric acid solution containing Ra-226 ions. In another embodiment, the radium-containing aqueous solution includes a nitric acid solution containing Ra-226, or is a nitric acid solution containing Ra-226.
[0013] In one method, the temperature of the radium-containing aqueous solution during the sorbing step (100) is between 1 and 75°C. In one embodiment, the temperature of the radium-containing aqueous solution during the sorbing step (100) is below 60°C. In another embodiment, the temperature of the radium-containing aqueous solution during the sorbing step (100) is below 50°C. In yet another embodiment, the temperature of the radium-containing aqueous solution during the sorbing step (100) is below 40°C. In another embodiment, the temperature of the radium-containing aqueous solution during the sorbing step (100) is below 35°C. In yet another embodiment, the temperature of the radium-containing aqueous solution during the sorbing step (100) is below 30°C. In one embodiment, the temperature of the radium-containing aqueous solution during the sorbing step (100) is at least 5°C. In another embodiment, the temperature of the radium-containing aqueous solution during the sorbing step (100) is at least 10°C. In yet another embodiment, the temperature of the radium-containing aqueous solution during the sorbing step (100) is at least 15°C. In another embodiment, the temperature of the radium-containing aqueous solution during the sorbing step (100) is at least 20° C. In one method, the sorbing step (100) is performed at about ambient temperature.
[0014] In one embodiment, the radium-containing aqueous solution does not contain sulfur, or if it does contain sulfur, the amount is trace or undetectable.
[0015] As previously discussed, the method generally involves sorbing Ra-226 from an aqueous radium-containing solution. As used herein, the term "sorbing" refers to both adsorbing and absorbing. In one embodiment, the sorbing step (100) involves adsorbing Ra-226 via a macrocyclic solid phase Ra-226-selective sorbent. In one embodiment, the sorbing step (100) involves adsorbing Ra-226 via a macrocyclic solid phase Ra-226-selective sorbent.
[0016] As noted above, the sorbing step can be accomplished, at least in part, via a macrocyclic solid phase Ra-226 selective sorbent. Referring to FIG. 3, in one embodiment, the macrocyclic solid phase Ra-226 selective sorbent is selective for the ionic diameter of radium (300). In one embodiment, the macrocyclic solid phase Ra-226 selective sorbent is or comprises a macrocyclic polyether material (310). In one embodiment, the macrocyclic polyether material is or comprises a crown ether (330). In one embodiment, the crown ether is selected from the group consisting of 18-crown-6, 21-crown-7, and combinations thereof (332, 334).
[0017] 4, as described above, the method can include recovering (200) Ra-226 from the macrocyclic solid-phase Ra-226-selective sorbent. In one embodiment, the recovering step (200) includes exposing the solid-phase Ra-226-selective sorbent to a recovery solvent. In one embodiment, the recovery solvent includes a chelating agent. In one embodiment, the recovery solvent includes EDTA (ethylenediaminetetraacetic acid [CH 2 N(CH 2 CO 2 H) 2 ] 2 In another embodiment, the recovery solvent is NTA (nitrilotriacetic acid [N(CH 2 CO 2 H) 3 )] or contains NTA. EDTA and / or NTA can chelate the Ra-226 cation and desorb the Ra-226 cation from the adsorbent. Other suitable extractants include diammonium hydrogen citrate, diethylenetriaminepentaacetic acid (DTPA), and combinations thereof, among others.
[0018] 5, in one embodiment, the method can include preparing (150) the macrocyclic material for recovery. Thereafter, the recovering step (200) can be completed. In one embodiment, the preparing step (150) includes washing (160) the macrocyclic material with a non-selective acidic solution, such as nitric acid. In one embodiment, the preparing step (150) includes neutralizing (170) the macrocyclic material with water, such as deionized water.
[0019] Referring to FIG. 6, as previously described, the radium-containing aqueous solution can be obtained from uranium ore and / or uranium precursors. In one embodiment, the uranium precursors include uranium ore and / or tailings (500). In one embodiment, the method includes converting at least a portion of the Ra-226 of the ore and / or tailings to a soluble form. In one embodiment, the converting step (not shown) includes contacting the uranium ore and / or tailings with a solution including a carbonate (e.g., sodium carbonate) to convert at least a portion of the Ra-226 to the carbonate form. In one embodiment, the method can include contacting the uranium ore and / or tailings with a solution including a carbonate (e.g., sodium carbonate) after the converting step (510), thereby producing a radium-containing effluent (520). This effluent can constitute a portion or all of the radium-containing solution of the sorbing step (100). In one embodiment, the contact solution is or includes an acid. In one embodiment, the acid is selected from the group consisting of hydrochloric acid, nitric acid, and combinations thereof. In one embodiment, the acid is or includes hydrochloric acid. In another embodiment, the acid is or includes nitric acid. In another embodiment, the uranium ore and / or tailings are processed through a uranium ion recovery system. The uranium ion recovery system includes an ion exchange resin selective for uranium, and the radium-containing solution includes an effluent of the uranium ion recovery system.
[0020] In one embodiment, the method includes recovering Ra-226 from the uranium ore and / or tailings by contacting the uranium ore and / or tailings with sulfuric acid. After the contacting step, at least a portion of the Ra-226 ions are contained in the sulfuric acid. The method includes converting at least a portion of the Ra-226 in the sulfuric acid into a carbonate form (e.g., RaCO) by, for example, adding sodium carbonate to the solution. 3 The precipitated radium carbonate can be recovered, such as by filtration. The radium carbonate can be converted to an ionic form, for example, by dissolving it in nitric acid. Nitric acid can be used as the radium-containing aqueous solution described with respect to step 100 of FIG. 1.
[0021] Although various embodiments of the present disclosure have been described in detail, it is apparent that those skilled in the art may make modifications and adaptations to these embodiments, but such modifications and adaptations should be expressly understood to be within the spirit and scope of the present disclosure.
Claims
1. (a) Sorbating Ra-226 from a radium-containing aqueous solution via a macrocyclic solid phase Ra-226 selective sorbent, and (b) A method comprising recovering Ra-226 from the macrocyclic solid phase Ra-226 selective sorbent.
2. The method according to claim 1, wherein the solid phase Ra-226 selective sorbent is selective for ions having an ionic diameter consistent with radium.
3. The method according to claim 2, wherein the macrocyclic solid phase Ra-226 selective sorbent comprises a macrocyclic polyether material.
4. The method according to claim 3, wherein the macrocyclic polyether material is a crown ether.
5. The method according to claim 4, wherein the crown ether is selected from the group consisting of 18-crown-6, 21-crown-7, and combinations thereof.
6. The method according to claim 1, wherein the radium-containing aqueous solution has a pH of 10 or less.
7. The method according to claim 6, wherein the radium-containing aqueous solution does not contain sulfur.
8. The method according to claim 7, wherein the radium-containing aqueous solution is acidic.
9. The method according to claim 8, wherein the radium-containing aqueous solution is selected from the group consisting of hydrochloric acid, nitric acid, and combinations thereof.
10. The method according to claim 1, wherein the recovery step (b) comprises exposing the solid phase Ra-226 selective sorbent to a recovery solvent.
11. The method according to claim 10, wherein the recovery solvent includes a chelating agent.
12. The method according to claim 10, wherein the recovery solvent comprises at least one of EDTA and NTA.
13. The method according to claim 10, comprising washing the macrocyclic solid phase Ra-226 selective soapbent with a non-selective acidic solution prior to the exposure step.
14. The method according to claim 13, wherein the non-selective acidic solution contains nitric acid.
15. The method according to claim 13, comprising neutralizing the macrocyclic solid phase Ra-226 selective sorbent with water after the washing step and before the exposure step.
16. The method according to claim 1, wherein the radium-containing aqueous solution is obtained from a uranium precursor.
17. The uranium precursor includes uranium tailings. The method according to claim 16, wherein the method is to produce at least a portion of a radium-containing solution by contacting the uranium tailings with an acid.
18. The method according to claim 17, wherein the acid is selected from the group consisting of nitric acid, hydrochloric acid, sulfuric acid, and combinations thereof.
19. The method according to claim 16, comprising converting at least a portion of the Ra-226 of the uranium tailings into a carbonate form before the contact step.
20. The method according to claim 16, wherein the uranium precursor comprises uranium tailings, the uranium tailings are processed through a uranium ion recovery system, and the radium-containing solution comprises the wastewater from the uranium ion recovery system.