Separation method for separating ytterbium and lutetium by using phosphate adsorbent

Abstract

The invention relates to the technical field of rare earth element separation methods, in particular to a method for separating ytterbium and lutetium by using a phosphate adsorbent, which comprises the following steps: loading a phosphate solution on a porous solid-phase carrier by using a vacuum impregnation method, and carrying out reduced pressure evaporation and drying to obtain a phosphate solid adsorbent; filling an exchange column with the solid adsorbent to obtain the exchange column filled with the solid adsorbent; enabling a nitric acid solution containing ytterbium and lutetium to flow through an exchange column filled with a solid adsorbent to complete a column adsorption process; and performing elution, performing desorption by using a desorption solution to obtain the regenerated exchange column filled with the solid adsorbent, respectively collecting the ytterbium solution and the lutetium solution, completing the separation process, and repeating the steps. By adopting the steps, the separation of ytterbium and lutetium is directly realized from the nitric acid solution containing ytterbium Yb and lutetium Lu through column adsorption separation, leaching and desorption processes, and high-purity ytterbium and lutetium products are prepared.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of rare earth element separation methods, in particular to a separation method for separating ytterbium and lutetium using a phosphate ester adsorbent. BACKGROUND

[0002] Among the numerous radionuclides, 177 Lu has moderate half-life (6.67 days), low-energy particles (497 keV), low-energy photons (208 keV), an average energy of 134.2 keV, and a maximum penetration distance in human tissue of only 2.2 mm, and other characteristics, and is therefore very suitable for treating small-volume or diffuse tumors and single-photon emission computed tomography (SPECT) monitoring, and is one of the most clinically applicable radionuclides for diagnosis and treatment.

[0003] Producing lutetium-177 can be divided into two methods: direct production and indirect production. Among them, the most commonly used indirect preparation method is to use a high-purity Yb-176 isotope target in a reactor, and the 176Yb (n, )177Yb 177Lu reaction and - decays into Lu-177. The carrier-free lutetium-177 (NCA177Lu) produced by this method does not contain Lu-177m impurity nuclides with long half-life and natLu target nuclides, has a higher specific activity, and is also more suitable for use in clinical radiotherapy for malignant tumors. Due to the low Lu-177 production yield, the content is between 0.1%-0.0001%, and ytterbium-176 is still the main component of the target after the reaction, so an important problem faced by this method is ytterbium-lutetium separation.

[0004] Ytterbium and lutetium are two adjacent elements in the lanthanide series, and due to the lanthanide contraction principle, their atomic radii and physicochemical properties are extremely similar; and under actual working conditions, the content difference between ytterbium and lutetium is huge (10 5 : 1), and lutetium is in trace amounts, so ytterbium-lutetium separation is a challenging task. In addition, the target material used for production is usually enriched pure Yb-176 raw material, so target recovery is also important. At present, the methods used for ytterbium-lutetium separation mainly include multistage series extraction, electrochemistry, ion exchange, and chromatographic column separation. The multistage series extraction method has low extraction efficiency, difficulty in phase separation during back extraction, and difficulty in regenerating the organic phase. SUMMARY

[0005] The application aims to provide a separation method for separating ytterbium and lutetium by using a phosphate ester adsorbent, to realize the separation of ytterbium and lutetium from a nitric acid solution containing ytterbium Yb and lutetium Lu by column adsorption separation, elution and desorption, and to prepare high-purity ytterbium solution and lutetium solution.

[0006] To achieve the above-mentioned purpose, the application provides a separation method for separating ytterbium and lutetium by using a phosphate ester adsorbent, comprising the following steps: S1, loading a phosphate ester solution on a porous solid carrier by using a vacuum impregnation method, and obtaining a phosphate ester solid adsorbent after drying by reducing pressure evaporation; S2, filling the phosphate ester solid adsorbent obtained in S1 into an exchange column to obtain a solid adsorbent-filled exchange column; S3, flowing a nitric acid solution containing ytterbium and lutetium through the solid adsorbent-filled exchange column in S2 at 15-30℃, and completing the column adsorption process when the concentration of ytterbium and lutetium in the effluent is greater than 0.1 mg / L; In S3, the pH of the nitric acid solution containing ytterbium and lutetium is 1-6.5, and the flow rate of the nitric acid solution containing ytterbium and lutetium is 0.1-0.5 mL / min; S4, eluting the solid adsorbent-filled exchange column used in S3, desorbing by using a desorption solution, obtaining a regenerated solid adsorbent-filled exchange column, and separately collecting the ytterbium solution and the lutetium solution, and completing the column separation process; In S4, the desorption solution comprises one of nitric acid, citric acid, diethylene triamine pentaacetic acid and ethylenediaminetetraacetic acid; S5, repeating steps S2-S4 to separate ytterbium and lutetium in the nitric acid solution containing ytterbium and lutetium.

[0007] Preferably, in S1, the porous solid carrier comprises one or more of silica, macroporous adsorption resin XAD.

[0008] Preferably, in S1, the loading amount of the phosphate ester on the phosphate ester solid adsorbent is 15-50%, and the average pore size of the phosphate ester solid adsorbent is 10-500 nm.

[0009] Preferably, in S1, the temperature of the vacuum impregnation is 20-50℃, the pressure is 200-500 hPa, and the time is 2-4 h.

[0010] Preferably, in S1, the phosphate ester comprises one or more of di(2-ethylhexyl) phosphate ester and 2-ethylhexyl 2-ethylhexyl phosphate ester.

[0011] Preferably, in S1, the phosphate ester solution is prepared by dissolving the phosphate ester in dichloromethane, and the concentration of the phosphate ester solution is 20-50%.

[0012] Preferably, in S1, the temperature of the reduced pressure evaporation is 30-55℃, and the time is 1.5-3h.

[0013] Preferably, in S4, the desorption temperature is 20-30℃, and the flow rate of the desorption liquid is 0.1-0.5mL / min.

[0014] Therefore, the present application adopts the above-mentioned separation method for separating ytterbium and lutetium using phosphate ester adsorbent, which has the beneficial effects of: 1. The separation method provided by the present application realizes the separation of ytterbium and lutetium from a nitric acid solution containing ytterbium Yb and lutetium Lu through column adsorption separation, elution and desorption processes, and high-purity ytterbium solution and lutetium solution are prepared, and the purity of Yb and Lu can reach 99.5%, and the recovery rate is above 96%; 2. The separation method provided by the present application almost does not use organic solvents, and the acid solution can be recycled and utilized, thereby reducing the consumption of chemical raw materials and the emission of pollutants and reducing the production cost; 3. The separation method provided by the present application is simple in process, convenient in operation, low in production cost, and suitable for the production of high-purity ytterbium and lutetium.

[0015] The technical solutions of the present application are further described in detail below with reference to the drawings and examples. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 is a separation diagram for separating ytterbium and lutetium using phosphate ester adsorbent according to the present application. DETAILED DESCRIPTION

[0017] The present application is further described below in combination with the drawings and examples. Unless otherwise defined, the technical terms or scientific terms used in the present application should be understood as the usual meanings understood by persons having ordinary skills in the art to which the present application belongs. The features mentioned in the above-mentioned features or the features mentioned in the specific examples can be combined arbitrarily, and these specific examples are only used to illustrate the present application and not to limit the scope of the present application.

[0018] The present application provides a separation method for separating ytterbium and lutetium using phosphate ester adsorbent, which comprises the following steps: S1, loading a phosphate ester solution on a porous solid carrier by using a vacuum impregnation method, and obtaining a phosphate ester solid adsorbent after reduced pressure evaporation and drying; S2, filling the phosphate ester solid adsorbent obtained in S1 into an exchange column to obtain a solid adsorbent-filled exchange column; S3, 15-30 Next, a nitric acid solution containing ytterbium and lutetium is flowed through the solid adsorbent-filled exchange column in S2, and when the concentration of ytterbium and lutetium in the effluent is greater than 0.1mg L, the column adsorption process is completed; S4, elution is performed on the solid adsorbent-filled exchange column used in S3, desorption is performed using a desorption solution, a regenerated solid adsorbent-filled exchange column is obtained, and a solution of ytterbium and a solution of lutetium are collected respectively, and the column separation process is completed; S5, repeating steps S2-S4, separating ytterbium and lutetium in the nitric acid solution containing ytterbium and lutetium.

[0019] In some embodiments of the present application, in S1, the porous solid-phase carrier comprises one or more of silica, macroporous adsorption resin XAD.

[0020] In some embodiments of the present application, in S1, the loading amount of the phosphate ester on the phosphate ester solid adsorbent is 15-50%, and the average pore size of the phosphate ester solid adsorbent is 10-500 nm. The loading amount determines the adsorption capacity of the phosphate ester solid adsorbent.

[0021] In some embodiments of the present application, in S1, the temperature of vacuum impregnation is 20-50 , the pressure is 200-500 hPa, and the time is 2-4 h. Under vacuum negative pressure, the air in the pores of the porous solid-phase carrier is discharged. When the phosphate ester solution contacts the porous solid-phase carrier, the phosphate ester solution can rapidly and fully fill all the pores with the help of atmospheric pressure and capillary action, achieving uniform loading.

[0022] In some embodiments of the present application, in S1, the phosphate ester comprises one or more of di(2-ethylhexyl) phosphate ester and 2-ethylhexyl phosphate 2-ethylhexyl ester.

[0023] In some embodiments of the present application, the phosphate ester solution is prepared by dissolving the phosphate ester in dichloromethane, and the concentration of the phosphate ester solution is 20-50%.

[0024] In some embodiments of the present application, in S1, the temperature of vacuum impregnation is 20-50 , the pressure is 200-500 hPa, and the time is 2-4 h. Under vacuum negative pressure, the air in the pores of the porous solid-phase carrier is discharged. When the phosphate ester solution contacts the porous solid-phase carrier, the phosphate ester solution can rapidly and fully fill all the pores with the help of atmospheric pressure and capillary action, achieving uniform loading.

[0025] In some embodiments of the present application, in S3, the pH of the nitric acid solution containing ytterbium and lutetium is 1-6.5, and the flow rate of the nitric acid solution containing ytterbium and lutetium is 0.1-0.5 mL min. The solid-liquid ratio of the nitric acid solution containing ytterbium and lutetium to be separated and the phosphate ester solid adsorbent is 50-250, and the concentration and acidity of ytterbium and lutetium in the nitric acid solution to be separated are related.

[0026] In some embodiments of the present application, in S4, the desorption solution comprises one of 1.5-6M nitric acid, 0.5-1M citric acid, 0.001-0.1M diethylene triamine pentaacetic acid, and 0.001-0.1M ethylenediamine tetraacetic acid.

[0027] In some embodiments of the present invention, in step S4, the desorption temperature is 20-30°C. The desorption solution flow rate is 0.1-0.5 mL. min.

[0028] Example 1 like Figure 1 As shown, S1, di(2-ethylhexyl) phosphate (HDEHP) is dissolved in dichloromethane to obtain a 26% di(2-ethylhexyl) phosphate solution, 40 Under vacuum impregnation, a di(2-ethylhexyl) phosphate solution was loaded onto the micropores and surface of a porous solid support, silica (SiO2-P). The vacuum impregnation pressure was 300 hPa, and the impregnation time was 2.5 h. HDEHP was obtained after vacuum evaporation and drying. SiO2-P solid adsorbent, vacuum evaporation temperature is 35℃ The time is 1.5 hours. HDEHP The loading of phosphate esters on the SiO2-P solid adsorbent was 26.98%, and the HDEHP... The average pore size of the SiO2-P solid adsorbent is 10-200 nm.

[0029] S2, take the HDEHPHDEHP obtained in S1 SiO2-P solid adsorbent was packed into the exchange column ( HDEHP was obtained in a column (5×50 mm, bed volume 9.81 mL). An exchange column filled with SiO2-P solid adsorbent.

[0030] S3, 25 Before adsorption separation, 20 mL of a metal ion-free nitric acid solution with pH 1 was used to react with HDEHP using a peristaltic pump. The SiO2-P solid adsorbent-packed exchange column was pre-equilibrated. 10 mL of a 1 mol / L SiO2-P solid adsorbent was added. A nitric acid solution containing ytterbium and lutetium (L) flows through an exchange column packed with solid adsorbent (S2), at a flow rate of 0.3 mL. min, when the concentrations of ytterbium and lutetium in the effluent are greater than 0.1 mg At time L, the column adsorption process is complete.

[0031] S4. Elute the exchange column packed with the solid adsorbent used in S3 with 30 mL of 0.1 M nitric acid solution (without metal ions) of the same system. Desorb the adsorbent using 250 mL of 3 M nitric acid at a desorption temperature of 25°C. The desorption fluid flow rate was 0.3 mL. min, to obtain a regenerated solid adsorbent packed exchange column, and collect the ytterbium solution and the lutetium solution separately, with a collection volume of 0.2-1 mL The column separation process is completed.

[0032] S5, repeat steps S2-S4 to separate the ytterbium and the lutetium in the nitric acid solution containing the ytterbium and the lutetium.

[0033] Example 2 S1, dissolve di(2-ethylhexyl)phosphate (HDEHP) in dichloromethane to obtain a di(2-ethylhexyl)phosphate solution with a concentration of 30%, 35 Next, use a vacuum impregnation method to load the di(2-ethylhexyl)phosphate solution on the micropore channels and surface of the porous solid carrier silica SiO2-P, with a vacuum impregnation pressure of 500 hPa and a vacuum impregnation time of 4 h. After drying by reduced pressure evaporation, obtain HDEHP SiO2-P solid adsorbent, with a reduced pressure evaporation temperature of 40 C and a time of 2.5 h. The loading amount of the phosphate on the HDEHP SiO2-P solid adsorbent is 30.11%, and the average equivalent diameter of the HDEHP SiO2-P solid adsorbent is 75 m, and the average pore size is 30-50 nm.

[0034] S2, pack the HDEHP SiO2-P solid adsorbent obtained in S1 into an exchange column (5x100 mm, with a column bed volume of 19.63 mL) to obtain a HDEHP SiO2-P solid adsorbent packed exchange column.

[0035] S3, before adsorption separation, use a peristaltic pump to pre-equilibrate the HDEHP SiO2-P solid adsorbent packed exchange column with 40 mL of a nitric acid solution with a pH of 1 and without metal ions at 30°C. Flow 30 mL of a 1 mol L nitric acid solution containing ytterbium and lutetium through the solid adsorbent packed exchange column in S2, with a flow rate of the nitric acid solution containing ytterbium and lutetium of 0.5 mL min, and complete the column adsorption process when the concentration of ytterbium and lutetium in the effluent is greater than 0.1 mg L.

[0036] S4, use 50 mL of a 0.1 M nitric acid solution without metal ions in the same system to elute the solid adsorbent packed exchange column used in S3, use 300 mL of 3 M nitric acid for desorption, with a desorption temperature of 30 ​, the flow rate of the desorption solution is 0.5 mL min, to obtain a regenerated solid adsorbent packed exchange column, and collect the ytterbium solution and the lutetium solution respectively, the collection volume is 0.2-1 mL tube, and the column separation process is completed.

[0037] S5, repeating steps S2-S4 to separate the ytterbium and the lutetium in the nitric acid solution containing the ytterbium and the lutetium.

[0038] The recovery rates in example 1 and example 2 are shown in table 1.

[0039] Table 1 Recovery rate of ytterbium and lutetium

[0040] The purity of the ytterbium and the lutetium separated in example 1 and example 2 is shown in table 2.

[0041] Table 2 Recovery purity of ytterbium and lutetium

[0042] As can be seen from table 1 and table 2, using the separation method provided by the present application, the separation of ytterbium and lutetium from the nitric acid solution containing ytterbium and lutetium can be effectively realized, and high-purity ytterbium solution and lutetium solution can be obtained.

[0043] Therefore, by using the above-mentioned separation method for separating ytterbium and lutetium using phosphate ester adsorbent, the separation of ytterbium and lutetium from the nitric acid solution containing ytterbium Yb and lutetium Lu is realized through column adsorption separation, elution and desorption process, and high-purity ytterbium solution and lutetium solution are prepared, the purity of Yb and Lu can reach 99.5%, and the recovery rate is above 96%.

[0044] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application but not to limit it, although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can still be modified or replaced by equivalents, and these modifications or equivalent replacements cannot make the modified technical solutions deviate from the spirit and scope of the technical solutions of the present application.

Claims

1. A separation process for separating ytterbium and lutetium using a phosphate ester adsorbent, characterised in that: The method comprises the following steps: S1, loading a phosphate ester solution on a porous solid carrier by a vacuum impregnation method, and obtaining a phosphate ester solid adsorbent after drying by evaporation under reduced pressure; S2, filling the phosphate ester solid adsorbent obtained in S1 into an exchange column to obtain a solid adsorbent-filled exchange column; S3, flowing a solution containing ytterbium and lutetium nitrate through the solid adsorbent-filled exchange column in S2 at 15-30℃, and completing the column adsorption process when the concentration of ytterbium and lutetium in the effluent is greater than 0.1 mg / L; In S3, the pH of the solution containing ytterbium and lutetium nitrate is 1-6.5, and the flow rate of the solution containing ytterbium and lutetium nitrate is 0.1-0.5 mL / min; S4, eluting the solid adsorbent-filled exchange column used in S3, desorbing using a desorption solution, obtaining a regenerated solid adsorbent-filled exchange column, and separately collecting ytterbium and lutetium solutions to complete the column separation process; In S4, the desorption solution comprises one of nitric acid, citric acid, diethylene triamine pentaacetic acid and ethylenediamine tetraacetic acid; S5, repeating steps S2-S4 to separate ytterbium and lutetium in the solution containing ytterbium and lutetium nitrate.

2. The separation method of separating ytterbium and lutetium using a phosphate ester adsorbent according to claim 1, characterized by: In S1, the porous solid carrier comprises one or more of silica, macroporous adsorption resin XAD.

3. The separation method for ytterbium and lutetium using a phosphate ester adsorbent according to claim 1, characterized in that: In S1, the loading amount of phosphate ester on the phosphate ester solid adsorbent is 15-50%, and the average pore size of the phosphate ester solid adsorbent is 10-500 nm.

4. The separation method for ytterbium and lutetium using a phosphate ester adsorbent according to claim 1, characterized in that: In S1, the temperature of vacuum impregnation is 20-50℃, the pressure is 200-500 hPa, and the time is 2-4 h.

5. The separation method for ytterbium and lutetium using a phosphate ester adsorbent according to claim 1, characterized in that: In S1, the phosphate ester comprises one or more of di(2-ethylhexyl) phosphate ester and 2-ethylhexyl phosphate 2-ethylhexyl ester.

6. The separation method for ytterbium and lutetium using a phosphate ester adsorbent according to claim 1, characterized in that: In S1, the phosphate ester solution is prepared by dissolving phosphate ester in dichloromethane, and the concentration of the phosphate ester solution is 20-50%.

7. The separation method for ytterbium and lutetium using a phosphate ester adsorbent according to claim 1, characterized in that: In S1, the temperature of evaporation under reduced pressure is 30-55℃, and the time is 1.5-3 h.

8. The separation method for separating ytterbium and lutetium using a phosphate ester adsorbent according to claim 1, characterized in that: In S4, the desorption temperature is 20-30℃, and the flow rate of the desorption solution is 0.1-0.5 mL / min.

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