Dissolving and leaching method of < 68 > Ge in metal gallium target

Abstract

The invention discloses a method for dissolving and leaching 68Ge in a metal gallium target, which comprises the following steps: preparing a mixed solution of sodium hydroxide and hydrogen peroxide, and in the mixed solution, the concentration of the sodium hydroxide is 0.8-0.9 M, and the mass percentage of the hydrogen peroxide is 3-4%; mixing the mixed solution with an irradiated metal gallium target, heating a mixed system to 40-50 DEG C, stirring and reacting for a set time, and separating a leaching solution from the metal gallium; and repeatedly leaching for set times. In the dissolving leachate obtained by adopting the method disclosed by the invention, 68Ge is oxygen-containing germanate, the boiling point is high, product loss caused by volatilization is avoided, and the yield of 68Ge can be effectively improved.

Description

Technical Field

[0001] The present invention belongs to 68 The technical field of Ge preparation is particularly related to a metal gallium target. 68 Dissolution leaching method of Ge. Background Art

[0002] The statements herein merely provide background information related to the present invention and do not necessarily constitute prior art.

[0003] 68 Ga is a radioactive isotope used in the diagnosis of various tumors and diseases. 68 Ga is usually obtained by elution 68 Ge / 68 Ga generator is obtained, and high quality 68 The most fundamental and key to a stable supply of Ga is to prepare high-purity 68 Ge stock solution.

[0004] existing 68 The production method of Ge stock solution is to irradiate the metal gallium target for about one month, and the total yield is 33.3-51.8GBq 68 Ge, after about two weeks of chemical treatment, is extracted from the metal gallium target 68 Ge. The extraction method is to use HCl and H 2 O 2 The metal gallium target is dissolved and leached multiple times with a solution of , which can ensure that Ge is fully dissolved into the solution. Finally, all the leaching solutions are mixed, the acidity of the leaching solution is adjusted with hydrochloric acid, and liquid-liquid solvent extraction is performed with toluene or carbon tetrachloride / hydrochloric acid to separate and purify. 68 Ge. However, the above method for extracting Ge has the following defects: on the one hand, it is difficult to control the reaction temperature during the process of dissolving and leaching the gallium target with a mixed solution of hydrochloric acid and hydrogen peroxide. In the initial stage of the reaction, the solution temperature will rise to above 80°C, which will not only lead to excessive gallium leaching, but also cause the volatilization loss of the extracted germanium tetrachloride (boiling point of about 84°C); on the other hand, the metal gallium target will produce other impurity elements such as Zn, Cu, Co, Ni, etc. through nuclear reaction. Using a mixed solution of hydrochloric acid and hydrogen peroxide to dissolve the gallium target will inevitably dissolve all the impurity elements into the dissolving solution, increasing the difficulty of the subsequent separation and purification process.

[0005] In addition, the existing 68 The Ge stock solution production technology uses a hydrochloric acid and hydrogen peroxide mixed solution to dissolve and leach the gallium target. At this time, the dissolving solution is a hydrochloric acid medium and needs to be seasoned with sodium citrate and sodium hydroxide solution. The dissolving solution is adjusted to an alkaline environment before it can be used for resin column separation and purification. Summary of the invention

[0006] In view of the shortcomings of the prior art, the present invention aims to provide a metal gallium target. 68 Dissolution leaching method of Ge.

[0007] In order to achieve the above object, the present invention is implemented through the following technical solutions:

[0008] A metal gallium target 68 The dissolution and leaching method of Ge comprises the following steps:

[0009] Prepare a mixed solution of sodium hydroxide and hydrogen peroxide, wherein the mass percentage of hydrogen peroxide in the mixed solution is 3%-4.5%;

[0010] The mixed solution is mixed with the irradiated metal gallium target, the mixed system is heated to 40-50°C, and after stirring the reaction for a set time, the leaching solution is separated from the metal gallium;

[0011] Repeat the leaching for the set number of times.

[0012] The present invention adopts a mixed solution of sodium hydroxide and hydrogen peroxide as a leaching solution to leach the irradiated metal gallium target, recovers germanium therein, and has extremely small leaching amounts of metals such as Fe, Ni, and Co in the metal gallium target, and even less leaching amount of metal gallium, so that the impurity content in the germanium leaching solution is less, thereby effectively reducing the difficulty of separation and purification of the germanium leaching solution.

[0013] When a mixed solution of sodium hydroxide and hydrogen peroxide is used as the leaching solution, Ge is in the form of oxygen-containing germanate, which has a high boiling point and will not cause product loss due to volatilization, and the recovery rate of germanium can be effectively improved. In addition, when a mixed solution of sodium hydroxide and hydrogen peroxide is used as the leaching solution, the leaching reaction is relatively mild, and there will be no violent reaction phenomenon, which can effectively improve the safety of the production process.

[0014] In the prior art, in order to increase the reaction rate, a relatively high concentration of hydrogen peroxide solution (generally the concentration of hydrogen peroxide is higher than 10%) is generally used to dissolve germanium. However, the inventors have found in experiments that when extracting germanium from a metal gallium target, in an alkaline environment, if the concentration of hydrogen peroxide is too high, such as exceeding 4.5%, hydrogen peroxide will react with gallium to form an oxide film on the surface of gallium. The presence of the oxide film seriously hinders the leaching of germanium, thereby seriously reducing the recovery rate of germanium.

[0015] When the concentration of hydrogen peroxide in the mixed solution is too low, on the one hand, hydrogen peroxide not only reacts with germanium to form germanium oxide, but also reacts with metallic gallium to form gallium oxide. Too low a concentration of hydrogen peroxide may make it difficult to oxidize the germanium, which will eventually be leached out by the sodium hydroxide solution. On the other hand, the hydrogen peroxide solution is easy to decompose, so the decomposition loss of hydrogen peroxide needs to be considered during the reaction, so the concentration of hydrogen peroxide cannot be too low.

[0016] Since the melting point of the metal gallium target is 29.76°C, when the temperature of the mixed system is too low, the metal gallium target solidifies, affecting the leaching of germanium. Therefore, the mixed system is heated to make the metal gallium target in a molten state, which is conducive to the full leaching of germanium.

[0017] In some embodiments, in the mixed solution, the concentration of sodium hydroxide is 0.8-2M, preferably, the concentration of sodium hydroxide is 0.8-1M.

[0018] In some embodiments, the mass percentage of hydrogen peroxide in the mixed solution is 3.5%-4%.

[0019] In some embodiments, the process of leaching germanium from the mixed solution and the irradiated metal gallium target is performed in a round bottom container.

[0020] Under heating, although the metal gallium target is in a molten state, the molten metal gallium target is not miscible with the water system. In order to improve the leaching efficiency and recovery rate of germanium, the molten metal gallium target needs to be dispersed as evenly as possible in the mixed solution. However, it is found in the experiment that if a conical bottom container or a flat bottom container is used, the metal gallium target will be deposited at the conical bottom position and the bottom of the flat bottom container due to its high density. Even if it is stirred, the molten metal gallium target cannot be broken up. At this time, the droplets of the metal gallium target are large, and the leaching efficiency of germanium is very low.

[0021] When a round-bottom container is used, the metal gallium target can be better broken up, and the germanium leaching efficiency is the highest at this time.

[0022] In some embodiments, a magnet is used to stir the mixed solution.

[0023] Preferably, the rotation speed of magnetic stirring is 800-1000 rpm.

[0024] More preferably, the stirring reaction time is 30-60 min.

[0025] In some embodiments, the volume ratio of the mixed solution to the metal gallium target is 1-2:1.

[0026] In some embodiments, the leaching is repeated 2-10 times, preferably 3-6 times.

[0027] In some embodiments, the heating is water bath heating.

[0028] In some embodiments, during the process of leaching germanium from the metal gallium target using the mixed solution, the container is sealed. During the reaction, the container needs to be sealed to prevent radioactive nuclides from entering the external system along with water vapor and causing radioactive contamination.

[0029] The beneficial effects achieved by one or more embodiments of the present invention are as follows:

[0030] The present invention adopts a mixed solution of sodium hydroxide and hydrogen peroxide, and the leaching amount of metals such as Fe, Ni, and Co is extremely small, unlike the hydrochloric acid solution which almost completely dissolves the impurity metals; at the same time, the leaching amount of gallium is even smaller, which can effectively reduce the difficulty of the subsequent solution separation and purification process.

[0031] In the dissolving leaching solution obtained by the method of the present invention, 68 Ge is an oxygen-containing germanate with a high boiling point. It will not cause product loss due to volatilization and can effectively improve 68 In addition, the reaction of the present invention is relatively mild and will not cause violent reactions, thus ensuring 68 The security of the Ge generation process.

[0032] The dissolving liquid medium obtained by the method of the present invention is an alkaline solution, and the dissolving liquid seasoning process can be completed by simply adding a sodium citrate solution, which is beneficial to simplifying the separation and purification operations. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0034] Figure 1 is a diagram showing the dispersion state of metal gallium when a round bottom container is used in an embodiment of the present invention;

[0035] Figure 2 is a diagram showing the dispersion state of metal gallium when a pointed bottom container is used in an embodiment of the present invention;

[0036] Figure 3 is a diagram showing the dispersion state of metal gallium when a flat-bottom container is used in an embodiment of the present invention;

[0037] Figure 4 1 is a comparison diagram of the solution states after hydrogen peroxide directly reacts with germanium powder in an embodiment of the present invention; wherein ① is a diagram of the solution state after a mixed solution of hydrochloric acid and hydrogen peroxide reacts with germanium powder; ② is a diagram of the solution state after a 5% concentration of hydrogen peroxide reacts with germanium powder; ③ is a diagram of the solution state after a 10% concentration of hydrogen peroxide reacts with germanium powder; ④ is a diagram of the solution state after a 30% concentration of hydrogen peroxide reacts with germanium powder;

[0038] Figure 5 This is the reaction result when the hydrogen peroxide concentration is too high in the embodiment of the present invention. DETAILED DESCRIPTION

[0039] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0040] The present invention will be further described below in conjunction with the embodiments.

[0041] Example

[0042] Experimental purpose: Literature and verified processes show that hydrochloric acid / hydrogen peroxide mixed solution can achieve the extraction and recovery of germanium from gallium targets. In the early experimental process, it was found that the reaction rate of hydrochloric acid / hydrogen peroxide mixed solution with gallium target was fast and difficult to control, which could easily cause the temperature of the solution system to rise to above 80°C, which may cause the loss of Ge-68 product. This section optimizes the type of metal gallium target solvent by exploring the dissolution of germanium powder and germanium-gallium mixture by different types of solvents.

[0043] (1) Experimental study on dissolving germanium powder in hydrogen peroxide solutions of different concentrations

[0044] Purpose of the experiment: Through literature research, it was found that hydrogen peroxide solution can dissolve metallic germanium powder. This experiment attempts to use hydrogen peroxide solutions of different concentrations to dissolve metallic germanium powder.

[0045] Material to be dissolved: black germanium powder; solvent: 5%-30% hydrogen peroxide solution; dissolving conditions: stirring in a 40-50°C water bath.

[0046] Experimental phenomenon: 5%, 10%, and 30% hydrogen peroxide were used to react with 0.1g germanium powder, respectively, at a reaction temperature of 45°C and a solvent volume of 10mL. The higher the hydrogen peroxide concentration, the faster the reaction. After the reaction, the solution was white and turbid, and sediment was observed at the bottom of the centrifuge tube. Figure 4 As shown, No. 2-4 is the state of the solution after the reaction of hydrogen peroxide solution with different concentrations and germanium powder. It can be clearly found that sediment appears at the bottom of the centrifuge tube. Subsequently, 4M hydrochloric acid is added to the No. 2-4 solution after the reaction, and the sediment does not dissolve. The sediment is germanium dioxide generated by the reaction of germanium powder and hydrogen peroxide.

[0047] The above results show that hydrogen peroxide solution reacts with germanium powder to generate insoluble germanium dioxide, which is as difficult to dissolve in hydrochloric acid as commercially available germanium dioxide. However, when hydrochloric acid and hydrogen peroxide are mixed and added to germanium powder for reaction, the in-situ generated germanium oxide immediately reacts with hydrochloric acid, and finally the black germanium powder is completely dissolved, and the solution is clear. Hydrogen peroxide solution alone cannot achieve the extraction and recovery of germanium from the metal gallium target.

[0048] (2) Sodium hydroxide + hydrogen peroxide mixed solution exploration experiment

[0049] Experimental purpose: To explore the dissolution of germanium powder by hydrogen peroxide solutions of different concentrations. The experimental results show that it is difficult to dissolve the metal germanium powder by hydrogen peroxide solution alone, and the mixed solution of hydrochloric acid + hydrogen peroxide dissolves the germanium powder very quickly. However, the hydrochloric acid + hydrogen peroxide solution is also more conducive to the dissolution of impurity elements such as Zn and Co produced by the irradiation of the metal gallium target, which increases the difficulty of subsequent separation and purification. This experiment attempts to use a mixed solution of sodium hydroxide + hydrogen peroxide to dissolve the metal germanium powder.

[0050] Material to be dissolved: black germanium powder; solvent: 4M sodium hydroxide solution + 30% hydrogen hydroxide (volume ratio 8:1), 16 mL; water bath temperature: 45°C; magnetic stirring.

[0051] Experimental phenomenon: After adding the solvent, as the reaction proceeds, the germanium powder reacts completely with the solvent, and the final solution is clear and transparent, with all the black germanium powder dissolved. Compared with the hydrochloric acid + hydrogen peroxide mixed solution system, the sodium hydroxide + hydrogen peroxide system reacts slower.

[0052] Experimental conclusion: The above experimental phenomena show that the mixed solution of sodium hydroxide + hydrogen peroxide can also achieve complete dissolution of germanium. Subsequently, the mixed solution of sodium hydroxide + hydrogen peroxide was used as a solvent to simulate the dissolution and leaching experiment of gallium target.

[0053] (3) Influence of leaching times

[0054] Solvent: 1M sodium hydroxide + 30% hydrogen peroxide solution (volume ratio 8:1), 50 mL.

[0055] Heating method: water bath heating, water bath temperature 40-50℃.

[0056] Stirring method: magnetic stirring, rotation speed 800-1000rpm, stirring with round bottom centrifuge tube.

[0057] Simulated gallium target: 30g simulated gallium target. The preparation method of the simulated gallium target is as follows: 50ml of 4M hydrochloric acid solution, 40g of metal gallium and 1g of germanium powder are mixed, and then magnetically stirred at a speed of 900rpm. After stirring for 1h, the residual liquid is sucked away, and then after the metal gallium solidifies, the surface germanium powder is washed with deionized water to obtain the target. During the experiment, the required mass of simulated gallium target can be weighed.

[0058] Experimental steps:

[0059] 1. Add about 30 g of simulated gallium target to a 50 mL centrifuge tube and place the round-bottom centrifuge tube in a water bath at 45 °C.

[0060] 2. Add 10 mL of a mixed solution of sodium hydroxide and hydrogen peroxide to the centrifuge tube, start stirring and adjust the speed to allow the simulated gallium target to mix with the solvent, and stop stirring after 30 minutes.

[0061] 3. Separate the dissolution leaching solution from the simulated gallium target and analyze the Ga and Ge contents in the single dissolution leaching solution.

[0062] 4. Repeat the above operation for five times of dissolution and leaching. Until Ge is almost undetectable in the dissolution and leaching solution, indicating that Ge has been almost completely extracted and recovered. The leaching results of each time are shown in Table 1.

[0063] Table 1

[0064]

[0065] The total gallium leaching amount in 5 dissolution experiments was about 3g, and Ge was almost completely extracted and recovered. At the same time, the pH of the solution after the reaction with 1M sodium hydroxide solvent was between 12-13, which was beneficial to the seasoning process.

[0066] (4) Effect of sodium hydroxide concentration

[0067] Solvent: 4M sodium hydroxide + 30% hydrogen peroxide solution (volume ratio 8:1), 50 mL.

[0068] Heating method: water bath heating, water bath temperature 45℃.

[0069] Stirring method: magnetic stirring, rotation speed 800-1000rpm, stirring with round bottom centrifuge tube.

[0070] Simulated gallium target: 25 g simulated gallium target. The preparation method of the simulated gallium target is the same as above.

[0071] Experimental steps:

[0072] 1. Add about 25 g of simulated gallium target to a 50 mL centrifuge tube and place the centrifuge tube in a water bath at 45 °C.

[0073] 2. Add 10 mL of a mixed solution of sodium hydroxide and hydrogen peroxide to the centrifuge tube, start stirring and adjust the speed to allow the simulated gallium target to mix with the solvent, and stop stirring after 30 minutes.

[0074] 3. The dissolution leaching solution was separated from the simulated gallium target, and the Ga and Ge contents in the single dissolution leaching solution were analyzed. The results are shown in Table 2.

[0075] Table 2

[0076]

[0077] The cumulative gallium leaching amount after 5 dissolution experiments was about 7.2g, and Ge could be almost completely extracted and recovered. However, the sodium hydroxide concentration in the leachate after the reaction of 4M sodium hydroxide solvent was too high, and it was necessary to dilute or add hydrochloric acid to adjust the pH of the solution, but dilution resulted in too large a solution volume. In addition, the cumulative gallium leaching amount was also greater than the cumulative leaching amount under the conditions of 1M sodium hydroxide solution.

[0078] (5) Effect of single leaching time

[0079] Solvent: 1M sodium hydroxide + 30% hydrogen peroxide solution (volume ratio 8:1), 50 mL.

[0080] Heating method: water bath heating, water bath temperature 45℃.

[0081] Stirring method: magnetic stirring, rotation speed 900rpm, stirring in a round-bottom centrifuge tube.

[0082] Simulated gallium target: 30 g simulated gallium target, prepared as above.

[0083] Experimental steps:

[0084] 1. Add about 30 g of simulated gallium target to a 50 mL centrifuge tube and place the centrifuge tube in a water bath at 45 °C.

[0085] 2. Add 10 mL of a mixed solution of sodium hydroxide and hydrogen peroxide to the centrifuge tube, start stirring and adjust the speed to allow the simulated gallium target to mix with the solvent as much as possible. After stirring for 30 minutes, take the supernatant for analysis.

[0086] 3. Continue stirring and take samples every 30 minutes for a total of 150 minutes. Analyze the metal content of the supernatant respectively. The results are shown in Table 3.

[0087] Table 3

[0088] Reaction time / min Ga content in the dissolution leaching solution / g Ge content in the dissolution leaching solution / μg 30 0.64 835 60 0.80 842 90 1.12 845 120 1.20 850 150 1.45 848

[0089] A single dissolution and leaching reaction of 30 minutes can reach the reaction dissolution equilibrium, so the optimized single dissolution and leaching time is between 30-60 minutes.

[0090] (6) Container selection

[0091] Solvent: 1M sodium hydroxide + 30% hydrogen peroxide solution (volume ratio 8:1), 50 mL.

[0092] Heating method: water bath heating, water bath temperature 45℃.

[0093] Stirring method: magnetic stirring, speed 900rpm, using round-bottom centrifuge tubes, conical centrifuge tubes and flat-bottom tubes for stirring.

[0094] Simulated gallium target: 30 g simulated gallium target, prepared as above.

[0095] Experimental steps:

[0096] About 30 g of metal gallium target was added to a round-bottom centrifuge tube, a conical centrifuge tube and a flat-bottom tube respectively, and each tube was placed in a water bath at a temperature of 45°C.

[0097] Add 10 mL of a mixed solution of sodium hydroxide and hydrogen peroxide to each tube, turn on stirring and adjust the speed to 900 rpm.

[0098] The dispersion states of the metal gallium target in the solvent are Figure 1 , Figure 2 and Figure 3 , it can be seen that when the container is a round-bottom container, the metal gallium target can be evenly dispersed in the solvent without large droplets visible to the naked eye, such as Figure 1 As shown; when the container has a conical bottom and a flat bottom, the metal gallium target cannot be evenly dispersed in the solvent, such as Figure 2 and Figure 3 shown.

[0099] (7) Selection of hydrogen peroxide concentration

[0100] Solvent: 1 M sodium hydroxide + 30% hydrogen peroxide solution (volume ratios are 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, 11:1, respectively), 50 mL.

[0101] Heating method: water bath heating, water bath temperature 45℃.

[0102] Stirring method: magnetic stirring, rotation speed 900rpm, stirring in a round-bottom centrifuge tube.

[0103] Simulated gallium target: 30 g simulated gallium target, prepared as above.

[0104] Experimental steps:

[0105] 1. Add about 30 g of simulated gallium target to a 50 mL centrifuge tube and place the centrifuge tube in a water bath at 45 °C.

[0106] 2. Add 10 mL of a mixed solution of sodium hydroxide and hydrogen peroxide to the centrifuge tube, start stirring and adjust the speed to allow the simulated gallium target to mix with the solvent. After stirring for 40 minutes, take the supernatant and analyze it. The results are shown in Table 4.

[0107] Table 4

[0108]

[0109] When the volume ratio of 1M sodium hydroxide to 30% hydrogen peroxide solution is between 3:1-5:1, the simulated gallium target turns black, as shown in FIG. Figure 5 As shown, after analysis, it is known that black gallium oxide is generated on the surface of the simulated gallium target. When the volume ratio of 1M sodium hydroxide to 30% hydrogen peroxide solution is 6:1, 7:1, 8:1, 9:1, 10:1 and 11:1, no black substance is produced. However, when the volume ratio is 10:1 and 11:1, the amount of germanium leaching is small due to the low concentration of hydrogen peroxide.

[0110] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A metal gallium target 68 The dissolution leaching method of Ge is characterized by: The steps include: Prepare a mixed solution of sodium hydroxide and hydrogen peroxide, wherein the mass percentage of hydrogen peroxide in the mixed solution is 3%-4.5%; The mixed solution is mixed with the irradiated metal gallium target, the mixed system is heated to 40-50°C, and after stirring the reaction for a set time, the leaching solution is separated from the metal gallium; Repeat the leaching for the set number of times.

2. The metal gallium target according to claim 1 68 The dissolution leaching method of Ge is characterized by: The process of leaching germanium from the mixed solution and the irradiated metal gallium target is carried out in a round bottom container.

3. The metal gallium target according to claim 1 68 The dissolution leaching method of Ge is characterized by: The mixed solution was stirred by a magnetic stirrer.

4. The metal gallium target according to claim 3 68 The dissolution leaching method of Ge is characterized by: The rotation speed of magnetic stirring is 800-1000 rpm, and the stirring reaction time is 30-60 min.

5. The metal gallium target according to claim 4 68 The dissolution leaching method of Ge is characterized by: In the mixed solution, the concentration of sodium hydroxide is 0.8-2M, preferably, the concentration of sodium hydroxide is 0.8-1M.

6. The metal gallium target according to claim 1 68 The dissolution leaching method of Ge is characterized by: The volume ratio of the mixed solution to the metal gallium target is 1-2:

1.

7. The metal gallium target according to claim 1 68 The dissolution leaching method of Ge is characterized by: The leaching is repeated 2-10 times, preferably 3-6 times.

8. The metal gallium target according to claim 1 68 The dissolution leaching method of Ge is characterized by: In the mixed solution, the mass percentage of hydrogen peroxide is 3.5%-4%.

9. The metal gallium target according to claim 1 68 The dissolution leaching method of Ge is characterized by: The heating is water bath heating.

10. The metal gallium target according to claim 1 68 The dissolution leaching method of Ge is characterized by: In the process of leaching germanium from the metal gallium target using the mixed solution, the container is set in a sealed manner.

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