System and method for recovering radium-226
By using macrocyclic solid-phase selective adsorbent and chelating agent technology, the problem of efficient recovery of radium-226 from uranium tailings was solved, and efficient extraction effect under different conditions was achieved.
Patent Information
- Application Number
- CN202380040510.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2022-05-16
- Filing Date
- 2023-05-15
- Publication Date
- 2024-12-27
AI Technical Summary
The prior art is difficult to efficiently recover radium-226, and there are challenges in efficient separation and extraction of radium-226 from uranium tailings, especially in solution treatments under different pH and temperature conditions.
Adhesive radium-226 from aqueous solutions using macrocyclic solid-phase selective adsorbents and perform radium-226 through specific recovery steps and solvent extraction techniques, including the use of macrocyclic polyether substances and chelating agents such as EDTA or NTA. Selective adsorption and recovery.
It realizes efficient recovery of radium-226 under different pH values and temperature conditions, improves the extraction purity and recovery efficiency of radium-226, and is suitable for radium-226 solution produced from uranium mining.
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Figure CN119213510A_ABST
Abstract
Description
[0001] CROSS-REFERENCE TO RELATED APPLICATIONS
[0002] This patent application claims priority to U.S. Provisional Patent Application No. 63 / 342,619, filed on May 16, 2022, entitled “SYSTEMS AND METHODS FOR RECOVERING RADIUM-226,” which is incorporated herein by reference in its entirety. Background Art
[0003] Radium-226 or 226 Ra is produced from the radioactive decay of uranium and thorium precursors. Radium-226 is known to be a precursor of alpha radioisotopes, which can be used in medical applications. See U.S. Patent Application Publication No. 2014 / 0226774. Summary of the invention
[0004] Broadly speaking, this patent application relates to systems and methods for recovering radium-226, such as from uranium tailings. BRIEF DESCRIPTION OF THE DRAWINGS
[0005] Figure 1 One embodiment of a method for recovering radium-226 from a solution comprising radium-226 is shown.
[0006] Figure 2 Shows Figure 1 Embodiment of a radium-226 solution.
[0007] Figure 3 Shows Figure 1 Embodiments of the macrocyclic polyethers of the method.
[0008] Figure 4 Shows Figure 1 Implementation scheme of the recovery step.
[0009] Figure 5 An embodiment of the preparation steps that can be used to prepare a radium-226-containing solution for recovery is shown.
[0010] Figure 6 Embodiments related to the recovery of uranium tailings effluent and radium-226 are shown. DETAILED DESCRIPTION
[0011] Now refer to Figure 1In one embodiment, a method for recovering radium-226 ("Ra-226") from a solution comprises adsorbing Ra-226 from an aqueous radium-containing solution via a macrocyclic solid phase Ra-226 selective adsorbent (100), and recovering Ra-226 from the macrocyclic solid phase Ra-226 selective adsorbent (200). The aqueous radium-containing solution can be any suitable aqueous solution comprising Ra-226. In some embodiments, and as further described in detail below, the aqueous solution is derived from uranium mining. In one embodiment, the aqueous solution is derived from uranium ore, such as from uranium tailings, etc. In another embodiment, the aqueous solution is or is derived from an ion exchange resin effluent, wherein the ion exchange resin is used to capture uranium from an aqueous stream comprising uranium.
[0012] Now refer to Figure 1 to Figure 2 In one embodiment, the aqueous radium-containing solution comprises a pH of no greater than 10. In another embodiment, the aqueous radium-containing solution comprises a pH of no greater than 9. In yet another embodiment, the aqueous radium-containing solution comprises a pH of no greater than 8. In another embodiment, the aqueous radium-containing solution comprises a pH of no greater than 7, e.g., is acidic. In yet another embodiment, the aqueous radium-containing solution comprises a pH of no greater than 6. In another embodiment, the aqueous radium-containing solution comprises a pH of no greater than 5. In yet another embodiment, the aqueous radium-containing solution comprises a pH of no greater than 4. In another embodiment, the aqueous radium-containing solution comprises a pH of no greater than 3.
[0013] In one embodiment, the aqueous radium-containing solution is an acidic solution including Ra-226 ions. In one embodiment, the aqueous radium-containing solution is selected from the group consisting of hydrochloric acid, nitric acid, and combinations thereof, the solution including Ra-226 ions. In one embodiment, the aqueous radium-containing solution includes or is a hydrochloric acid solution including Ra-226 ions. In another embodiment, the aqueous radium-containing solution includes or is a nitric acid solution including Ra-226 ions.
[0014] In one approach, during the adsorption step (100), the temperature of the aqueous radium-containing solution is between 1 and 75°C. In one embodiment, during the adsorption step (100), the temperature of the aqueous radium-containing solution is no greater than 60°C. In another embodiment, during the adsorption step (100), the temperature of the aqueous radium-containing solution is no greater than 50°C. In yet another embodiment, during the adsorption step (100), the temperature of the aqueous radium-containing solution is no greater than 40°C. In another embodiment, during the adsorption step (100), the temperature of the aqueous radium-containing solution is no greater than 35°C. In yet another embodiment, during the adsorption step (100), the temperature of the aqueous radium-containing solution is no greater than 30°C. In one embodiment, during the adsorption step (100), the temperature of the aqueous radium-containing solution is at least 5°C. In another embodiment, during the adsorption step (100), the temperature of the aqueous radium-containing solution is at least 10°C. In yet another embodiment, during the adsorption step (100), the temperature of the aqueous radium-containing solution is at least 15°C. In another embodiment, during the adsorption step (100), the temperature of the aqueous radium-containing solution is at least 20° C. In one approach, the adsorption step (100) is performed at near ambient temperature.
[0015] In one embodiment, the aqueous radium-containing solution is free of sulfur, including trace levels of sulfur or undetectable levels of sulfur.
[0016] As described above, the method generally comprises adsorbing Ra-226 from an aqueous radium-containing solution. As used herein, "sorbing" includes both adsorption and absorption. In one embodiment, the adsorption step (100) comprises adsorbing Ra-226 via a macrocyclic solid phase Ra-226 selective adsorbent. In one embodiment, the adsorption step (100) comprises absorbing Ra-226 via a macrocyclic solid phase Ra-226 selective adsorbent.
[0017] As described above, adsorption can be accomplished at least in part via a macrocyclic solid phase Ra-226 selective adsorbent. Figure 3 In one embodiment, the macrocyclic solid phase Ra-226 selective adsorbent is selective for the ion diameter of radium (300). In one embodiment, the macrocyclic solid phase Ra-226 selective adsorbent is or includes a macrocyclic polyether substance (310). In one embodiment, the macrocyclic polyether substance is or includes a crown ether (330). In one embodiment, the crown ether is selected from the group consisting of 18-crown-6 (332), 21-crown-7 (334), and combinations thereof.
[0018] Now refer to Figure 4As described above, the method may include recovering Ra-226 from a macrocyclic solid phase Ra-226 selective adsorbent (200). In one embodiment, the recovery step (200) includes exposing the solid phase Ra-226 selective adsorbent to a recovery solvent. In one embodiment, the recovery solvent includes a chelating agent. In one embodiment, the recovery solvent is or includes EDTA (ethylenediaminetetraacetic acid [CH2N(CH2CO2H)2]2). In another embodiment, the recovery solvent is or includes NTA (nitrilotriacetic acid [N(CH2CO2H)3]). EDTA and / or NTA can chelate Ra-226 cations, thereby desorbing them from the adsorbent. Other suitable extractants include diammonium hydrogen citrate, diethylenetriaminepentaacetic acid (DTPA), combinations thereof, and the like.
[0019] Now refer to Figure 5 In one embodiment, the method may include preparing the macrocyclic material for recovery (150). Subsequently, the recovery step (200) may be completed. In one embodiment, the step of preparing (150) includes washing the macrocyclic material with a non-selective acidic solution, such as nitric acid (160). In one embodiment, the step of preparing (150) includes neutralizing the macrocyclic material with water, such as deionized water (170).
[0020] Now refer to Figure 6 As described above, the aqueous radium-containing solution may be derived from uranium mining and / or uranium precursors. In one embodiment, the uranium precursor comprises uranium ore and / or tailings (500). In one embodiment, the method comprises converting at least some Ra-226 of the ore and / or tailings into a soluble form. In one embodiment, the step of conversion (not shown) comprises contacting the uranium ore and / or tailings with a solution comprising a carbonate (e.g., sodium carbonate) to convert at least some radium-226 into a carbonate form. In one embodiment, after the step of conversion, the method may comprise contacting the uranium ore and / or tailings with a contact solution (510), thereby producing a radium-containing effluent (520), which may constitute part or all of the radium-containing solution in the adsorption step (100). In one embodiment, the contact solution is or comprises 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 comprises hydrochloric acid. In another embodiment, the acid is or comprises nitric acid. In another embodiment, the uranium ore and / or tailings are processed via a uranium ion recovery system, wherein the uranium ion recovery system comprises an ion exchange resin selective for uranium, and wherein the radium-containing solution comprises an effluent from the uranium ion recovery system.
[0021] In one embodiment, the method includes recovering Ra-226 from uranium ore and / or tailings by contacting the uranium ore and / or tailings with sulfuric acid. After the contacting step, the sulfuric acid contains at least some Ra-226 ions. The method may further include converting at least some of the Ra-226 in the sulfuric acid into a carbonate form (e.g., RaCO3), such as by adding sodium carbonate to the solution. The precipitated radium carbonate may then be recovered, such as by filtering. The radium carbonate may then be converted into an ionic form, such as by dissolving the radium carbonate with nitric acid. The nitric acid may then be used as described above with respect to Figure 1 The aqueous radium-containing solution described in step 100.
[0022] Although various embodiments of the disclosure have been described in detail, it is obvious that those skilled in the art will think of modifications and adaptations to these embodiments. However, it should be clearly understood that such modifications and adaptations are within the spirit and scope of the disclosure.
Claims
1. A method comprising: (a) adsorption of radium-226 from an aqueous radium-containing solution via a macrocyclic solid phase radium-226 selective adsorbent; as well as (b) recovering radium-226 from the macrocyclic solid phase radium-226 selective adsorbent.
2. The method of claim 1, wherein the solid phase radium-226 selective adsorbent is selective for ions having an ion diameter consistent with radium.
3. A method according to any one of the preceding claims, wherein the macrocyclic solid phase radium-226 selective adsorbent comprises a macrocyclic polyether substance.
4. The method of claim 3, wherein the macrocyclic polyether substance is a crown ether.
5. The method of 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 of any one of the preceding claims, wherein the aqueous radium-containing solution comprises a pH of no greater than 10.
7. A method according to any one of the preceding claims, wherein the aqueous radium-containing solution is free of sulfur.
8. A method according to any one of the preceding claims, wherein the aqueous radium-containing solution is acidic.
9. The method of claim 8, wherein the aqueous radium-containing solution is selected from the group consisting of hydrochloric acid, nitric acid, and combinations thereof.
10. The method of any one of the preceding claims, wherein the recovery step (b) comprises exposing the solid phase radium-226 selective adsorbent to a recovery solvent.
11. The method of claim 10, wherein the recovery solvent comprises a chelating agent.
12. The method of claim 10, wherein the recovery solvent comprises at least one of EDTA and NTA.
13. A method according to any one of the preceding claims, comprising: Prior to the exposing step, the macrocyclic solid phase radium-226 selective adsorbent is washed with a non-selective acidic solution.
14. The method of claim 13, wherein the non-selective acidic solution comprises nitric acid.
15. The method according to claim 13, comprising: After the washing step and before the exposing step, the macrocyclic solid phase radium-226 selective adsorbent is neutralized with water.
16. The method of claim 15, wherein the water comprises deionized water.
17. A method according to any one of the preceding claims, wherein the aqueous radium-containing solution is derived from a uranium precursor.
18. The method of claim 17, wherein the uranium precursor comprises uranium tailings, and wherein the method comprises: The uranium tailings are contacted with an acid, thereby producing at least a portion of the radium-containing solution.
19. The method of claim 18, wherein the acid is selected from the group consisting of nitric acid, hydrochloric acid, sulfuric acid, and combinations thereof.
20. The method of claim 17, comprising: Prior to the contacting step, at least some of the radium-226 in the uranium tailings is converted to a carbonate form.
21. The method of claim 17, wherein the uranium precursor comprises uranium tailings, wherein the uranium tailings are processed via a uranium ion recovery system, and wherein the radium-containing solution comprises effluent from the uranium ion recovery system.