Method for separating yttrium and strontium

Abstract

A system and method for separating Y and Sr is provided. The system and method provide a combination of a solution, a container, and / or a medium that can provide a Y solution of an industrially advantageous concentration.

Description

[Technical Field]

[0001] [CROSS-REFERENCE TO RELATED APPLICATIONS] This application claims priority to U.S. Patent Application No. 16 / 780,397, entitled "Systems and Methods for Separating Yttrium and Strontium," filed February 3, 2020, which is incorporated herein by reference in its entirety. STATEMENT AS TO RIGHTS TO INVENTIONS MADE UNDER FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

[0002] This invention was made with Government support under Contract DE-AC05-76RL01830 awarded by the U.S. Department of Energy. The Government has certain rights in this invention.

[0003] The present disclosure relates to the separation of yttrium and strontium, and in certain embodiments, the present disclosure relates to the separation of yttrium and strontium isotopes and / or the preparation of enriched forms of yttrium isotopes. [Background technology]

[0004] Yttrium isotopes can typically be fission products along with strontium isotopes and can be present in the same solution as strontium isotopes. These fission products are produced by the fission of actinides. Sr cyclotron targets can produce other isotopes through (p,n) reactions. The present disclosure provides systems and methods for separating yttrium from strontium, isolating yttrium isotopes from a solution of strontium and yttrium isotopes, and / or preparing enriched forms of yttrium isotopes. Summary of the Invention

[0005] A method for separating yttrium (Y) and strontium (Sr) is provided. The method may include supplying a dilute acidic mixture containing Y and Sr to a vessel having a medium therein. The method may further include retaining at least a portion of the Y from the dilute acidic mixture in a first vessel while supplying the dilute acidic mixture, while at least eluting at least a portion of the Sr from the dilute acidic mixture to form a dilute acidic eluate.

[0006] An additional method for separating Y and Sr is provided, which can provide a vessel containing a medium and a dilute acid mixture containing Y. The method can include providing a concentrated acid mixture to the vessel, and collecting a concentrated acid eluate containing at least a portion of the Y from within the vessel while providing the concentrated acid mixture to the vessel.

[0007] An additional method for separating Y and Sr is also provided, which may include supplying a concentrated acidic mixture containing Y to a vessel having a medium therein, and retaining at least a portion of the Y from the concentrated acidic mixture within the vessel while supplying the concentrated acidic mixture to form an eluate.

[0008] Further methods are also provided, which may include a method for separating Y and Sr. The method may include providing a vessel containing a medium and a concentrated acid mixture containing Y. The method may include providing a dilute acid mixture into the vessel, and collecting a dilute acid eluate containing at least a portion of the Y from within the vessel while providing the dilute acid mixture into the vessel.

[0009] Additional methods for separating Y and Sr are also provided, which may include providing a first mixture containing Y and Sr to a first container having a first medium therein. The method may include retaining at least a portion of Y from the first mixture in the first container and providing a second mixture to the first container. The method may further include recovering a first eluate containing at least a portion of Y from the first container and providing the first eluate containing Y to a second container having a second medium therein. The method may also include retaining at least a portion of Y from the first eluate in the second container and providing a third mixture to the second container. The method may also include recovering a second eluate containing at least a portion of Y from the first container.

[0010] The method for separating Y and Sr can also include providing a first mixture of at least two components to a first container having a first medium therein, the first volume defining a first volume. The method can include retaining at least a portion of one of the two components in the first container and eluting one of the two components from the first container to a second container having a second medium therein. The second container can define a second volume, and the first volume can be greater than the second volume. The first medium can be different from the second medium. The method can include retaining at least a portion of one of the two components in the second container and eluting one of the two components from the second container. Additionally, the elution from the first container can have one component at a first concentration, and the elution from the second container can have one component at a second concentration. The second concentration can be greater than the first concentration. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a system for implementing a method according to one embodiment of the present disclosure. [Figure 2] 1 is a system for implementing a method according to one embodiment of the present disclosure. [Figure 3]1 is partition coefficient data according to an embodiment of the present disclosure. [Figure 4] 1 is a system for implementing a method according to one embodiment of the present disclosure. [Figure 5] 1 is a system for implementing a method according to one embodiment of the present disclosure. [Figure 6] 1 is a system for implementing a method according to one embodiment of the present disclosure. [Figure 7] 1 is data obtained using a system and method according to one embodiment of the present disclosure. [Figure 8] 1 is data obtained using a system and method according to one embodiment of the present disclosure. [Figure 9] 1 is data obtained using a system and method according to one embodiment of the present disclosure. [Figure 10] 1 is data obtained using a system and method according to one embodiment of the present disclosure. [Figure 11] 1 is data obtained using a system and method according to one embodiment of the present disclosure. [Figure 12] 1 is data obtained using a system and method according to one embodiment of the present disclosure. [Figure 13] 1 is data obtained using a system and method according to one embodiment of the present disclosure. [Figure 14] 1 is data obtained using a system and method according to one embodiment of the present disclosure. [Figure 15] 1 is data obtained using a system and method according to one embodiment of the present disclosure. [Figure 16] 1 is data obtained using a system and method according to one embodiment of the present disclosure. [Figure 17] 1 is data obtained using a system and method according to one embodiment of the present disclosure. [Figure 18] 1 is data obtained using a system and method according to one embodiment of the present disclosure. [Figure 19]1 is data obtained using a system and method according to one embodiment of the present disclosure. Detailed Description of the Invention

[0012] The disclosed systems and methods are described with reference to FIGS. 1-19. Referring first to FIG. 1, a system 10 is disclosed that includes at least two vessels 12 and 14 that can be fluidly connected via a conduit 16 and another conduit 18. All vessels and conduits described herein may be referred to as containers or holders, or indeed any form of device, capable of holding liquids, solid particles, and / or mixtures thereof within a confined or predetermined space. While conduits 16 and 18 are depicted as continuous here, it should be recognized throughout this specification that they may be valves operable to open or close as desired to provide or not provide fluid communication between one vessel and the other. The conduits may also be configured to supply solutions that are exchanged or supplied therethrough. Thus, by way of example, the conduits may be resistant to acids or organic acids, or may be resistant to organics, as desired. According to an exemplary implementation, a method for separating Y and Sr may include providing a dilute acidic mixture containing Y and Sr. This dilute acidic mixture of Y and Sr can be present, for example, in a container 12, and this dilute acidic mixture contains nuclides of Y (e.g., 90 Y, 89 Y, 88 Y, or 86 Y) and Sr nuclides (e.g., 90 Sr, 89 Sr, 88 Sr, or 86 This dilute acidic mixture can be sourced from Sr-containing nuclear material stocks, which can be by-products of nuclear processing. For example, 86 Y is isotopically enriched 86 It is a 14.7 hour half-life isotope produced by a (p,n) reaction on an Sr target. 86 Y / 86 For Sr, this is 86This may be the result of proton bombardment of the Sr cyclotron target.

[0013] A general recipe for preparing a solution capable of simulating Sr-containing stock material is presented in Table 1.

[0014] [Table 1]

[0015] The spike solution can also be prepared with reference to Table 2 below.

[0016] [Table 2]

[0017] According to exemplary implementations, acidic reagents can be utilized, such as, for example, solutions of dilute and concentrated acidic mixtures prepared using the reagents disclosed below.

[0018] Concentrated hydrochloric acid (HCl) can be ACS certified grade or better (Fisher Scientific, Waltham, MA). Dilutions of HCl can be prepared from deionized water (≥18 MΩ cm) using a Barnstead E-Pure water purification system (Dubuque, IA). Scintillation cocktail was UltimaGold AB (PerkinElmer, Billerica, MA).

[0019] Approximately 5 mCi in approximately 2% HNO3 90 A supply of Sr can be obtained and the solution evaporated to the nitrate salt, which can then be converted to the formate salt. 90 The Sr residue can be evaporated and converted to the chloride salt before use. An infrared lamp is used to measure the converted volume. 90 The Sr stock solution can be evaporated into a Teflon vial (7 mL round-bottom vial, Savillex, Eden Prairie, MN). As briefly described below, single element solutions containing concentrates of Ca(II), Sr(II), Ba(II), and Y(III) in 0.1 M HCl can be prepared. A Ca solution can be prepared by dissolving calcium metal chips in concentrated HCl. After evaporation of excess acid, the CaCl salt can be brought up in 0.1 M HCl. The prepared Ca(II) concentration = 99.26 mg / mL. A Sr solution can be prepared from strontium(II) carbonate salt. The salt can be saturated with concentrated HCl to destroy the carbonate and convert the salt to strontium chloride. Excess acid can be allowed to evaporate overnight. The dried salt is then added to 0.1 M HCl. The prepared Sr(II) concentration = 260.21 mg / mL. A Ba solution can be prepared from barium(II) chloride salt. The salt can be dissolved directly in 0.1M HCl. The prepared Ba(II) concentration = 8.55 mg / mL. The Y solution can be prepared from yttrium(III) chloride salt. The salt can be dissolved directly in 0.1M HCl. The prepared Y(III) concentration = 3.42 mg / mL.

[0020] 90 Aliquots of these solutions were diluted to mimic the dissolved solids present in the Sr stock. 90 It can be added to the Sr spike solution.

[0021] According to an exemplary implementation, and referring to FIG. 1 , this dilute acidic mixture can include Y, and Sr can be provided to a vessel 14 having a first medium 20 therein. The dilute acidic mixture can have a pH less than 7, and the dilute acidic mixture can also have a pH less than 3. The dilute acidic mixture can have an acid concentration that is, for example, less than 0.1 M, but must contain sufficient acid to maintain acidity. As described herein, the dilute acidic mixture can additionally include the elements Sr, Ca, and / or Ba, and the dilute acidic mixture can include, for example, stock Sr-containing nuclear material.

[0022] Within the vessel 14 can be a first medium 20 comprising a resin. The resin can include bis(2-ethylhexyl) hydrogen phosphate (HDEHP). The first medium can also include an alkylphosphorus extractant. Alternatively, the first medium can also include Si. According to an exemplary implementation, the medium 20 can be considered the first medium.

[0023] The method for purifying Y can employ two columns or vessels in series. The first vessel 14 can have a medium 20 comprising a di-(2-ethylhexyl) phosphoric acid (HDEHP)-based extraction chromatography resin sold under the trade name Ln Resin (Eichrom Technologies, Ltd, Lisle, Illinois). The particle size distribution used was 100-150 μm, although other particle size distributions, such as 50-100 μm or 20-50 μm, are also contemplated.

[0024] The Ln resin can be packed into a column with an internal volume of approximately 0.25 cc of a 1 cc SPE tubing kit (Supelco), which can be cut to size. The column can be polypropylene with a 20 μm pore size polyethylene frit. The column can be fitted with a custom-made plastic cap (with a female Luer fitting) that can be inserted onto the top of the trimmed column.

[0025] According to an exemplary implementation, while providing a dilute acid mixture containing Y and Sr, the method may provide for retaining at least a portion of the Y from the dilute acid mixture in vessel 14, while eluting a portion of the dilute acid eluate to form a dilute acid mixture that may be provided to conduit 18. According to an exemplary implementation, the method may also include, for example, providing the dilute acid mixture from reservoir 12, and then providing the dilute acid eluate to reservoir 12, for example, via conduit 18.

[0026] According to an example implementation, the dilute acidic mixture can further include Zr, and the method can also include retaining at least a portion of the Zr from the dilute acidic mixture in vessel 14 while providing the dilute acidic mixture. The method can also include further retaining at least a portion of the Fe from the dilute acidic mixture in vessel 14. The dilute acidic mixture can include HCl, for example, an organic acid, such as formic acid, for example.

[0027] 2, system 25 is illustrated, which may include vessel 14 containing medium 20 and dilute acid mixture 22 comprising Y. According to an exemplary implementation, vessel 14 may be a vessel of system 10 after, for example, providing Y / Sr mixture 12 to vessel 14. According to an exemplary implementation, the concentrated acid mixture contained in vessel 24 may be provided to vessel 14 via conduit 26. While the concentrated acid mixture from vessel 24 is being provided to vessel 14, an acid leachate comprising at least a portion of the Y from within vessel 14 may be collected as leachate 32 in vessel 30 via conduit 28.

[0028] According to an exemplary implementation, vessel 14 can contain one or both of Zr and Fe and can retain at least a portion of or both of the Zr and Fe while providing a concentrated acid mixture from vessel 24 to vessel 14. According to an exemplary implementation, the concentrated acid mixture can include HCl, an organic acid such as formic acid, or the like. In a further embodiment, the method can provide the concentrated acid eluate 32 from within vessel 30 to another vessel containing another medium. This additional embodiment is described in more detail herein. Additionally, medium 20 remains as medium 20, for example, as described in system 10.

[0029] According to an exemplary embodiment, a serial column-based 90 A Y purification method is contemplated and described herein. Referring to Figure 3, the affinity for Y on Ln resin decreases approximately as a negative power function with increasing HCl concentration. At 0.1 M HCl, the partition coefficient of Y (K d ) is 10 5mL / g and by the time the HCl concentration is increased to 8M HCl, the K d is reduced by approximately six orders of magnitude. This substantial change in Y affinity between two HCl concentrations can determine what is considered a dilute or concentrated acidic mixture. According to an exemplary implementation, for the systems and methods of the present disclosure, a dilute acidic mixture is one having a K of at least 10. d whereas a concentrated acid mixture may be an acid mixture that provides, for example, a K of less than 10 d Each of these relates to Y on a HDEHP resin such as Ln resin.

[0030] Further, referring to FIG. 3, Zirconium 90 is 90 Because it is a stable decay product of Y, the old 90 Zr-90 is a contaminant of concern in Sr-containing stocks. 90 The data in Figure 3 show that Zr(IV) affinity for Ln resin is 10 over the entire range of HCl concentrations. 4 Therefore, the primary Ln resin column 90 During the Y load process 90 It is possible to remove Zr. 90 Zr is 90 Y is retained on the column during elution and can migrate to column 2 (see Table 3).

[0031] Figure 3 also shows the K of Fe(III) on a first medium such as Ln resin. d A map is also provided. During the loading step of column 1 (0.1 M HCl), Fe was approximately 10 3 mL / g K d Therefore, most, if not all, of these contaminants may have 90 Y can be retained on column 1 during the load / wash (i.e., the Y / Sr dilute acid mixture is fed to the first vessel). In addition, Fe can be dissolved in 8M HCl at approximately 1300 mL / g of K. d Therefore, Fe can have the following structure: 90Y can be retained on the column during the transfer step (see Table 3 below, according to system 25).

[0032] [Table 3]

[0033] 4, a system 35 is provided that includes a vessel 36 having a medium 38 therein in fluid communication via a conduit 44 to a vessel 40 having a mixture 42 therein, operably coupled to another conduit 46 for collecting any eluate from the vessel 36. According to an exemplary implementation, a method for separating Y and Sr is provided that can include supplying a concentrated acid mixture 42 with the acid mixture containing Y to the vessel 36 having the medium 38 therein. The concentrated acid mixture can be provided from the method and system of FIG. 2 described herein, and the vessel 36 can be aligned with the system 25, for example, to receive the acid eluate therefrom.

[0034] According to an exemplary implementation, medium 38 may include a resin, such as a diglycolimide resin, e.g., a (diglycolamide)-based extraction chromatography resin, sold under the trade name DGA-Normal Resin (Eichrom Technologies, Ltd.). The particle size distribution used may be 20-50 μm, 50-100 μm, and / or 100-150 μm. An exemplary extraction medium may include N,N,N',N'-tetra-n-octyldiglycolamide.

[0035] The concentrated acid mixture may be, for example: 90 Sr, 89 Sr, 88 Sr, or 86At least a portion of the Sr may be included as a radioactive isotope and a stable isotope of Sr, such as Sr. The method may include retaining at least a portion of the Y from the concentrated acid mixture in vessel 36 while providing the concentrated acid mixture, and forming an eluate in conduit 46 that may include at least a portion of the Sr. At least a portion of the concentrated acid mixture may include Zr, and the method may include retaining at least a portion of the Zr from the concentrated acid mixture while providing the concentrated acid mixture to vessel 36. Additionally or separately, at least a portion of the concentrated acid mixture may include Fe, and the method may include retaining at least a portion of the Fe from the concentrated acid mixture in vessel 36 while providing the concentrated acid mixture.

[0036] 5, a system 50 is provided that may include a vessel 36 having a medium 38 therein and a concentrated acid mixture 42 that includes Y. According to an exemplary implementation, a vessel 54 may contain a dilute acid mixture 56. The dilute acid mixture may be fed into the vessel 36. The method may provide for providing the dilute acid mixture 56 into the vessel 36 while collecting a dilute acid eluate in a conduit 52 that may include at least a portion of Y from within the vessel 36. The medium in the vessel 36 may be as described with reference to FIG. 4, for example.

[0037] The container 36 may be, for example: 90 Y, 89 Y, 88 Y, or 86 The vessel may contain at least a portion of Y as a radioactive isotope and a stable isotope of Y, such as Y. The vessel may also contain one or more of Zr or Fe, and the method may further include providing a dilute acid mixture 56 to the vessel 36 that elutes at least a portion of one or both of the Zr and / or Fe in the vessel 36. As described herein, the dilute acid mixture may include HCl, and the mixture may include, for example, an organic acid such as formic acid. Additionally, while providing the dilute acid mixture to the vessel 36, the method may include eluting at least a portion of the Sr in the vessel.

[0038] Referring now to FIG. 6, a system 60 is provided in which a vessel 14 and a vessel 36 are arranged in series, and an eluate 52 containing Y is prepared using the embodiments of the systems 10, 25, 35, and 50 described herein together. According to an exemplary implementation, referring to FIG. 6, a first mixture 12a containing Y and Sr can be provided to a first vessel 14 having a first medium 20 therein. The first mixture can be a dilute acidic solution, and the first medium can be an alkylphosphorus extractant resin, such as HDEHP resin. At least a portion of the Y from the first mixture 12a can be retained in the vessel 14, for example, using the medium 20.

[0039] According to an exemplary implementation, the second mixture 24a can be provided to the first vessel 14, and the method can further include collecting the first eluate 28 and providing the first eluate 28 containing Y to a second vessel 36 having a second medium 38 therein. The second mixture can be a strong acid or concentrated acid solution, such as HCl, and the second medium can be a diglycolamide resin, such as N,N,N',N'-tetra-n-octyldiglycolamide. The method can further include, for example, retaining at least a portion of Y from the first eluate 28 in the second vessel 36 using the medium 38, providing a third mixture 42 to the second vessel 36, and collecting a second eluate 52 containing at least a portion of Y from the first vessel 14 when providing the third mixture 42. The third mixture can be a weak acid, such as HCl, or a dilute acid mixture.

[0040] 6, a first mixture 12a containing Y and Sr can be supplied to a first vessel 14 having a first medium 20 therein. At least a portion of the Y from the first mixture 12a can be retained within the vessel 14, for example, using the medium 20. According to this embodiment, the first mixture can be a strong acid or concentrated acid solution such as HCl, and the first medium can be a diglycolamide resin such as N,N,N',N'-tetra-n-octyldiglycolamide.

[0041] Continuing with this embodiment, the second mixture 24a can be provided to the first vessel 14, and the method can further include collecting the first eluate 28 and providing the first eluate 28 containing Y to a second vessel 36 having a second medium 38 therein. This second mixture can be a dilute or weakly acidic solution that can include HCl, and the first medium can be an alkylphosphorus extractant resin, such as HDEHP resin.

[0042] The method may further include, for example, retaining at least a portion of Y from the first eluate 28 in a second vessel 36 using a medium 38, providing a third mixture 42 to the second vessel 36, and recovering a second eluate 52 containing at least a portion of Y from the first vessel when providing the third mixture 42. This third mixture may be a strong acid or concentrated acid mixture, such as HCl.

[0043] Additionally, the present method may provide that vessel 14 and vessel 36 are of substantially different sizes, with vessel 14 being at least as large, but possibly larger, than vessel 36. In such a configuration, Y recovered from the process system and method may be in a concentrated form and suitable for industrial use. Thus, the volume of vessel 14 may be greater than the volume of vessel 36.

[0044] Table 3 above also shows 90 Y transfer, secondary cleaning, and 90The behavior of four selected ions on the second medium (DGA resin) during the Y elution step is shown.

[0045] An exemplary system schematic 60 is shown in Figure 6, with the numbers defined below in Table 4. System 60 includes three pumps (PP, SP1, and SP2), which are provided as one or more of many potential fluid delivery systems, which may also include gravity.

[0046] [Table 4]

[0047] The system 60 can be programmed to perform the sequence of steps outlined below in Table 5. The volume and flow rate of the delivery reagent through the column may be set as described below.

[0048] The reagent volume programmed to be delivered to the system 60 can be a function of the fluid delivery system sump volume, for example, one (or two) syringe volumes delivered for a particular step. The delivered volume can be intentionally programmed to be in excess (i.e., a large total volume of reagent delivered through the column).

[0049] [Table 5]

[0050] The flow rate may ultimately be limited by several factors, which may include: backpressure produced by the fluid path (primarily the column); the amount of backpressure the column or fittings or pump can handle before leaking; the amount of backpressure the extraction chromatography resin can handle before excess extractant leaches; and the adsorption / desorption rate of the analyte on the column resin. The flow rate ranges shown in Table 5 represent two exemplary flow rate values ​​that were evaluated. Lower flow rates may be performed for Runs 1 through 4, and higher flow rates may be performed for Run 5.

[0051] The elapsed time required to carry out the protocol described in Table 5 is shown in Table 6.

[0052] [Table 6]

[0053] 1.25 Ci / mL 90 An exemplary product solution with Sr activity concentration contained the stable Group 2 element concentrations listed in column 2 of Table 7 for Ca, Sr, and Ba. The Y concentration is a function of this activity concentration. 90 Sr present in solution 90 The elements and activity concentrations in Table 7 were based on the approximate mass concentration of Y. 90 This is only one example of the Sr product composition and may differ from other 90 May not represent Sr batch.

[0054] [Table 7]

[0055] An exemplary value of 1.25 Ci / mL 90 Considering the Sr radioactivity concentration, it is 8 Ci of synthetic 90 It was estimated that 6.4 mL of this solution was required to obtain the Sr solution. A 6.0 mL sample injection loop could be installed in the system 60 ("SL", FIG. 6), which would provide a solution with a salt content of approximately 7.5 Ci. 90 The simulated strontium was equivalent to 90 This allows for routine injection of Sr solutions. Based on this 6.0 mL injection, the total μg (and μmol) of Group 2 elements are listed in Table 7.

[0056] closely mimicking the elemental composition of the stock Sr-containing solution 90 Sr / 90 A Y-containing solution was prepared. The stable element composition of the solution is listed in Tables 1 and 7. 90 Sr radioactivity values ​​are listed in Table 2.

[0057] Isolates produced by this (or any) purification method for medical purposes 90 Y is often ≥ 1 × 10 6 :1 90 Y: 90 Therefore, the Sr activity ratio of 1 Ci in the isotopic product is 90 For each Y, up to 1 x 10 -6 Ci (1μCi) 90 Sr is acceptable. Based on the molar specific activity in Table 8, 1 μCi 90 Sr is a Group 2 element (e.g., a simulated element listed in Table 7). 90 4.7 x 10 Sr stock solution (see -4 Equivalent to μmole (0.47 nmole).

[0058] [Table 8]

[0059] The present disclosure 90 Using the Y isolation and purification process, 90 for Sr 90 At least 10 of Y 6 A radioactivity concentration of 100 times higher can be achieved. 90 Based on Sr radioactivity levels, 90 Maximum in Y product fraction 90 Sr activity levels are shown in Table 9.

[0060] [Table 9]

[0061] 90 The Y isolation and purification method (Table 5) can be carried out using the system 60 shown in Figure 6. This process contains high Ca, Sr, Ba, and Y levels to mimic the approximately 7.5 Ci level of the exemplary 90Sr product solution. 90 Five injections of Sr solution can be performed. 90Sr radioactivity levels are shown in Table 9. These radioactivities can be dissolved in 6 mL of solution and injected into the fluidics system using a sample injection loop (SL, Figure 6).

[0062] The series column process can include an Ln resin and a DGA resin column, respectively. 90 Sr / 90 Once the Y solution is loaded into the sample injection loop in a semi-automated manner, for example by a peristaltic pump, 90 The Y isolation and purification process can be fully automated.

[0063] The smallest of the five runs 90 Sr / 90 For Run 1, which contained Y radioactivity, a fraction collector can be employed to collect fractions of approximately 2 mL volume throughout the process ( 90 (Except for the Y elution step, during which fractions of less than 1 mL were collected). 90 The Y radioactivity chromatogram is shown immediately after the end of the run, once the sample had reached permanent equilibrium (Figure 7). The first three chromatograms, representing 0.85 mL, 90 The Y elution fraction is the amount of the eluate in the injected sample. 90 It may contain 83% of Y.

[0064] In the fraction 90 Sr 90 When equilibrium with Y is reached, the unretained 90 The Sr profile can be determined. The exemplary fractions shown can be 2 mL each in volume. 90 The Sr is in the first 6 mL volume. The next 2 mL fraction contains the remaining 90 This approximately 30 μCi of Sr may contain most of the 90 Sr can be carried from the sample injection loop, for example, as a segment of wash fluid trapped between two air segments. 90Sr radioactivity may be present at baseline in the remainder of the column wash. Overall, 90 It can account for 97% of Sr.

[0065] Runs 2 to 5 are the same as Run 1. 90 Sr / 90 Some fractions ( 90 Sr-loaded effluent and initial 90 Y elution) can be divided into two parts. 90 For Sr loading, first and second 10 mL fractions can be collected (except for run 2, where first 18.2 mL and second 2.35 mL were collected). 90 For the Y elution, the initial 0.72–0.84 mL was collected in one fraction, followed by a 2.5 mL fraction. 90 The remainder of the Y elution volume can be collected in a second fraction.

[0066] In Figure 8, and with reference to Tables 11 and 14, for Run 2, the values ​​can be determined in the first elution fraction. 90 The yield can be 95%. 90 Sr recovery can be as high as 98%. In Figure 9, for Run 3, the Sr recovery in the first elution fraction was 90 The yield of Y can be 86%. 90 Sr recovery can be as high as 97%. In Figure 10, for Run 4, the Sr recovery in the first elution fraction was 90 The yield of Y can be 86%. 90 Sr recovery can be 100%. In Figure 11, for Run 5, 90 The yield of Y can be 89%. 90 The Sr recovery rate can be 104%.

[0067] Additionally, a 2 μL aliquot of the Run 5 primary column load / wash fraction effluent can be sampled immediately upon collection. The aliquot can be added to a scintillation cocktail and the resulting sample can be counted by a liquid scintillation analyzer (LSA). This sample can be counted by adding a 2 μL aliquot of the Run 5 primary column load / wash fraction effluent immediately upon collection. 90 Sr / 90 The LSA pulse height spectrum after the "near zero" point is shown in Figure 12. 90 Y β - The emission region is composed of over 1000 channels of low energy 90 Sr β - It is clearly above the emission region. The spectrum at time "0" is 90 This indicates that Y is virtually absent from the sample (it is adsorbed onto the primary Ln resin column). 90 From Sr's parents 90 Y ingrowth is observed.

[0068] An exemplary performance of the serial purification process is shown below: 90 Y is shown in Table 10. The table shows the total amount of 90 Sr / 90 Y and the determined over all collected fractions 90 Table 11 provides the Y radioactivity across all fractions using the data in Table 10. 90 Y Total recovery rate (radioactivity balance %) and column 2 elution 90 Calculate the Y recovery rate.

[0069] [Table 10]

[0070] Across all five runs, we were able to account for 97.2 ± 5.0% of the radioactivity injected into the system. This ± 5.0% was assessed as the uncertainty in the measurement approach. Consequently, this same relative uncertainty was used to estimate the individual90 Uncertainty can be assigned to the Y elution yield. Averaged over all five runs 90 The Y elution fraction is the total injected 90 It can be determined that the elution rate was 87.8 ± 4.3% of Y. Run 5 was performed at a higher flow rate (e.g., twice as high) than Runs 1 to 4. 90 Y yield is statistically indistinguishable from other orchids 90 Y product yield.

[0071] [Table 11]

[0072] Each primary in five runs 90 The decay of the Y elution fraction can be monitored periodically radiometrically. 90 The radioactivity of the Y sample can be normalized to "1" at approximately zero time point, and then the radioactivity fraction over the next approximately 60 days can be calculated. 90 Decays superimposed on Y decay rate 90 Y elution fractions are shown. In all cases, 90 The Y elution fractions can remain above the theoretical curve. 90 Any Y product fraction 90 When Sr was present, the data began to rise above the theoretical curve.

[0073] When the number of days counted approaches approximately 60 days, 90 Y product fraction 90 The radioactivity may become too low to be accurately measured by a radioactivity detector. 90A portion of the volume of the Y elution fraction may be sacrificed and injected into scintillation cocktail. Samples can then be counted by LSA for several more days. Due to the low radioactivity levels, samples may be counted over extended periods (2 hours each) to obtain count rates, which may then be converted to net count rates and finally to decay units (Bq).

[0074] The decay rates from the LSA samples above can be converted to decay rates on each analysis day. 90 The results for Y product fraction radioactivity (Bq) are shown in FIG. 90 The time elapsed between the Y purification run and the LSA analysis is shown in Table 12. As shown in Figure 18, the decay rate of the sample continues to decrease over time. This indicates that the primary source of radioactivity in the sample 90 Therefore, these decay rates are consistent with the trace levels of methylcellulose present in the sample. 90 Permanent equilibrium with Sr 90 It should continue to decrease until Y is achieved.

[0075] [Table 12]

[0076] Using the LSA data in Figure 18, 90 in the Y product fraction 90 The Sr decontamination factor can be calculated as shown in Figure 19. As the radioactivity levels continue to decrease in the LSA samples, 90 The Sr decontamination factor continues to increase over time.

[0077] 90 Stocks of Sr-containing materials can be considered consumables in the described process. 90 By Y milking cycle 90 Some loss of Sr is expected. However, 90 At the end of the Y separation process, 90 It is desirable to retain Sr. High 90Sr recovery can be beneficial for at least two reasons: (1) it is not recovered; 90 Sr requires additional purchases to replace stock losses, and (2) in process effluents and peripheral components. 90 Sr activity levels increase waste disposal costs.

[0078] Therefore, high yield and high purity 90 In addition to obtaining the Y product, at the end of each purification cycle 90 A method that results in high recovery of Sr would be beneficial. Ideally, 90 Virtually all of the Sr is 90 It may be recovered in the effluent of the Y extraction column.

[0079] Radioactivity results for fractions collected during the tandem column purification process (Figures 7-11). 90 The radioactivity of the fractions around time "0" (left) and around 50-60 days after the Y purification process (right) is shown. 90 The fraction of Y radioactivity is presented, but the figure on the right 90 The fraction of Sr radioactivity was presented.

[0080] recovered from all dual column effluents and peripheral components involved in the series column purification process 90 The distribution of Sr is listed in Table 13. The top shaded row indicates the amount of Sr injected into each of the five runs. 90 The determined spike radioactivities of Sr are presented. These range from approximately 400 to approximately 770 μCi. Bold lines indicate the activity of the spikes in column 1. 90 Recovered in the load / wash effluent of Y 90 The shaded cells at the bottom represent all the Sr activity that was occupied during the in-line column purification process. 90 Present the sum of Sr.

[0081] [Table 13]

[0082] The data in Table 13 are 90 This indicates that virtually all of the Sr radioactivity was present in the load / wash fraction of column 1. 90 Fractions with Sr activity were ≤1.8 × 10 for the load / wash fractions. -3 (See "System Rinse" in Run 5).

[0083] The data in Table 14 spans each of the five runs. 90 The Sr yield is summarized below. 90 The Sr fraction accounted for the "Total Fraction" vs. "Injected Radioactivity Standard" values ​​in Table 13. Overall, 90 Y. Regarding the reference aliquot that may be sampled before starting the purification process: 90 It may be possible to account for 99.4±3.2% of the Sr. A relative uncertainty of ±3.2% is employed to account for the "Column 1 Load / Wash" fraction. 90 An uncertainty can be assigned to the Sr activity based on an average of 99.3 ± 3.1% in the column 1 load / wash effluent across all five runs. 90 The Sr recovery rate can be obtained. 90 Virtually all of the material injected into the Y refining process 90 Sr may be recoverable in the fluid exiting the primary Ln resin column.

[0084] [Table 14]

Claims

1. A method for separating Y and Sr, comprising the steps of: Supplying a dilute acidic mixture having an acid concentration of 0.1 M or less and containing Y and Sr to a first vessel having a first medium therein; retaining at least a portion of the Y from the dilute acidic mixture in the first vessel while supplying the dilute acidic mixture, while eluting at least a portion of the Sr from the dilute acidic mixture to form a dilute acidic eluate having an acid concentration of 0.1 M or less.

2. the dilute acidic mixture ９０ Y and ９０ The method of claim 1 , comprising Sr.

3. The method of claim 1 , wherein the dilute acidic mixture additionally comprises stable Sr, Ca, and / or Ba.

4. The method of claim 1 , wherein the dilute acidic mixture comprises Sr-containing nuclear material that is a by-product of nuclear processing.

5. The method of claim 1 , wherein the first medium comprises a resin.

6. The method of claim 1 , wherein the first medium comprises HDEHP resin.

7. 10. The method of claim 1, wherein the first medium comprises an alkylphosphorus extractant.

8. 10. The method of claim 1, wherein the dilute acidic eluate comprises at least a portion of the Sr from the dilute acidic mixture.

9. providing the dilute acid mixture from a reservoir; and providing the dilute acidic eluate to the reservoir.

10. The method of claim 1 , wherein the dilute acidic mixture further comprises Zr.

11. 11. The method of claim 10, further comprising retaining at least a portion of the Zr from the dilute acidic mixture in the first vessel while providing the dilute acidic mixture.

12. The method of claim 1 , wherein the dilute acidic mixture further comprises Fe.

13. 13. The method of claim 12, further comprising retaining at least a portion of the Fe from the dilute acid mixture in the first vessel while providing the dilute acid mixture.

14. The method of claim 1 , wherein the dilute acidic mixture comprises HCl.

15. The method for separating Y and Sr according to claim 1, wherein the dilute acidic mixture has a K d of at least 10 mL / g.

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