A method for extracting Sr(II) from a solution containing Sr(II)

Abstract

The present application belongs to the technical field of extraction separation, and particularly relates to a method for extracting Sr(II) from a solution containing Sr(II). The method is to use an extraction organic phase containing a bisamide pod ether extraction agent to extract ions of II-IV in the solution containing Sr(II) into the organic phase to form a loaded organic phase, and then use a stripping aqueous phase containing a dilute acid to strip Sr(II) in the loaded organic phase into water, so as to realize the separation of Sr(II). By using the extraction method of the present application, Sr(II) can be more effectively selectively extracted and stripped from the solution containing Sr(II), so as to realize the efficient separation of Sr(II).

Description

[0001] This invention is a divisional application of the invention patent application filed on September 21, 2022, with application number 202211150126.8 and title "An extraction method for extracting Sr(II) from a solution containing Sr(II)". Technical Field

[0002] This invention belongs to the field of extraction and separation technology, and relates to a method for extracting Sr(II) from a solution containing Sr(II) based on a diamide pod ether extractant. Background Technology

[0003] As a pure β-radioactive source, Sr-90 does not produce secondary electrons. Its short-lived β-decay daughter, Y-90, can maintain radioactive equilibrium with Sr-90 for a long time. It has a high fission yield, a half-life of 28.6 years, a specific power of 0.223 W / g, and a theoretical source yield of 62%. Its thermal power decay is no more than 10%, which meets the requirements of radioactive isotope batteries. This advantage makes Sr-90 a suitable raw material for radioactive sources.

[0004] Sr-90 is a pure beta decay nuclide, generally derived from nuclear fuel reprocessing. In the civilian sector, it is mainly used for liver cancer treatment, targeted cancer therapy, rheumatoid arthritis and hemophilia treatment, scar treatment, etc. Y-90, produced from Sr-90 decay, is currently a key nuclide for the treatment of primary liver cancer. Sr-90 and Y-90 are not currently produced domestically and must be imported.

[0005] International Market Situation: According to the State Administration of Science, Technology and Industry for National Defence's "Medium- and Long-Term High-Quality Development Plan for Medical Isotopes (2021-2035)," both the United States and Canada use research reactors to produce Y-90. However, the Canadian NRU has been shut down, while the US MURR is currently in operation. The unstable international trade situation presents new challenges to the development of medical isotopes. Currently, my country's estimated demand for Sr-90 and yttrium-90 is 500 curies per year, and it is conservatively estimated to grow at a rate of 20% annually, reaching more than ten times the current demand by 2030.

[0006] Current domestic market size: According to data from Isotope & Radiation Corporation, each treatment course is expected to use 50 millicuries of Sr-90 isotope, with an import price of approximately 70,000-80,000 yuan. Based on this, it is predicted that the annual output value of the domestic medical Sr-90 market will exceed 140 million yuan per year, with an annual growth rate of 20%, and is expected to exceed 200 million yuan per year by 2025.

[0007] International market demand analysis: With the continuous progress of domestic post-processing projects, the extraction volume of Sr-90 will increase rapidly, making it possible to supply domestically produced Sr-90 to the international market. Summary of the Invention

[0008] The purpose of this invention is to provide an extraction method for extracting Sr(II) from a solution containing Sr(II), enabling more efficient separation and extraction of Sr(II) from the solution through an extraction-back-extraction process. Here, Sr(II) refers to divalent strontium, and the Sr(II) solution represents a solution containing one or more Sr isotopes.

[0009] To achieve this objective, in a basic embodiment, the present invention provides an extraction method for extracting Sr(II) from a solution containing Sr(II), comprising the following steps:

[0010] (1) The ions in the II-IV valence state of the solution containing Sr(II) are extracted into the organic phase by extraction organic phase to form a loaded organic phase. The extraction organic phase is composed of diamide ether as the extractant and phase modifier and diluent added together.

[0011] (2) Using dilute acid as a back-extraction agent, Sr(II) in the loaded organic phase is back-extracted into the aqueous phase.

[0012] Furthermore, in the first embodiment of the extraction method for extracting Sr(II) from a solution containing Sr(II) as described above, step (2) further includes using an extractant identical to the components of the extracted organic phase, and by controlling the contact time between the extractant and the solution containing Sr(II), extracting other ions besides Sr(II) from the aqueous phase back into the organic phase.

[0013] Furthermore, in the second embodiment of the extraction method for extracting Sr(II) from a solution containing Sr(II) as described above, in step (1), by controlling the contact time between the extraction organic phase and the solution containing Sr(II), other ions besides Sr(II) and a small amount of Sr(II) are extracted into the organic phase; in step (2), a small amount of Sr(II) extracted into the organic phase is back-extracted into the aqueous phase using dilute acid as a back-extraction agent, and the Sr(II) back-extracted into the aqueous phase is retained in the original solution containing Sr(II).

[0014] Furthermore, the extraction method for extracting Sr(II) from a solution containing Sr(II) as described above further includes step (3), in which other ions besides Sr(II) in the loaded organic phase are back-extracted into the aqueous phase by adjusting the concentration of the back-extraction agent dilute acid.

[0015] Furthermore, in the extraction method for extracting Sr(II) from a solution containing Sr(II) as described above, in step (1), the diamide ether extractant is TODGA, Me-TODGA, DODDDGA, DMDODGA, or DMDDDGA.

[0016] Furthermore, the concentration of the diamide pod ether extractant is 0.1-1.0 mol / L.

[0017] Furthermore, in the extraction method for extracting Sr(II) from a solution containing Sr(II) as described above, in step (1), the phase modifier is TBP (tributyl phosphate) or DHOA (N,M-dihexyloctylamide).

[0018] Furthermore, the concentration of the phase modifier is 0.1-1.0 mol / L.

[0019] Furthermore, in the extraction method for extracting Sr(II) from a solution containing Sr(II) as described above, in step (1), the diluent is n-dodecane or octanol.

[0020] Furthermore, in the extraction method for extracting Sr(II) from a solution containing Sr(II) as described above, in step (2), the back-extraction agent is 0.1-1.0 mol / L HNO3.

[0021] Furthermore, in the extraction method for extracting Sr(II) from a solution containing Sr(II) as described above, in step (3), the back-extraction agent is 0.01-0.1 mol / L HNO3.

[0022] Furthermore, in the extraction method for extracting Sr(II) from a solution containing Sr(II) as described above, the extraction and back-extraction temperatures are 20-25°C.

[0023] Furthermore, in the extraction method for extracting Sr(II) from a solution containing Sr(II) as described above, the organic phase:aqueous phase (volume ratio) of the extraction process and the back-extraction process is 1:X, where X = 1-3.

[0024] Furthermore, in the extraction method for extracting Sr(II) from a solution containing Sr(II) as described above, in the first embodiment, the extraction tanks used in the extraction method include extraction tank 1A, extraction tank 1B, and extraction tank 1C.

[0025] The extraction tank 1A is an extraction section, which is used to selectively extract Sr(II) and other ions into the organic phase;

[0026] The extraction tank 1B includes a back-extraction section and a replenishment section. The back-extraction section is used to selectively back-extract Sr(II) into the aqueous phase, and the replenishment section is used to replenish other ions other than Sr(II) that have been back-extracted into the aqueous phase into the organic phase.

[0027] The extraction tank 1C is used to back-extract ions other than Sr(II) from the organic phase into the aqueous phase.

[0028] Furthermore, in the extraction method of the first embodiment described above, the extraction section of the extraction tank 1A has 1-12 stages; the replenishment extraction section of the extraction tank 1B has 1-4 stages, and the back-extraction section has 5-16 stages; the back-extraction section of the extraction tank 1C has 1-16 stages; and the residence time of the liquid in each stage of the extraction tanks 1A, 1B, and 1C is 2-5 minutes.

[0029] Furthermore, in the extraction method for extracting Sr(II) from a solution containing Sr(II) as described above, in a second embodiment, the extraction tank used in the extraction method includes extraction tank 1A and extraction tank 1B.

[0030] The extraction tank 1A includes an extraction section and a washing section. The extraction section is used to selectively extract other ions besides Sr(II) and a small amount of Sr(II) into the organic phase. The washing section is used to back-extract the small amount of Sr(II) extracted into the organic phase into the aqueous phase.

[0031] The extraction tank 1B is used to back-extract ions other than Sr(II) from the organic phase into the aqueous phase.

[0032] Furthermore, in the extraction method of the second embodiment described above, the extraction section of the extraction tank 1A has 1-6 stages, and the washing section has 7-16 stages; the back-extraction section of the extraction tank 1B has 1-16 stages; and the residence time of the liquid in each stage of the extraction tank 1A and the extraction tank 1B is 2-5 minutes.

[0033] The beneficial effects of this invention are as follows:

[0034] (1) Diamide pod ether extractants contain only four elements: C, H, O, and N, and can be completely incinerated;

[0035] (2) Using only dilute acid as the back-extraction agent, Sr(II) is directly back-extracted from the supported organic phase, resulting in good separation effect;

[0036] (3) No aqueous complexing agent was introduced into the extraction system. Separation of ions with different valence states was achieved only by adjusting the concentrations of the extraction and back-extraction agents.

[0037] (4) After separation using this method, the yield of Sr is not less than 99.9%. Attached Figure Description

[0038] Figure 1 This is a flowchart of an extraction method for extracting Sr(II) from a solution containing Sr(II) in the first embodiment of the present invention.

[0039] Figure 2 This is a flowchart of an extraction method for extracting Sr(II) from a solution containing Sr(II) according to a second embodiment of the present invention. Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0041] This invention provides an extraction method for extracting Sr(II) from a solution containing Sr(II) based on a diamide pod-ether extractant. The extraction method is as follows:

[0042] The diamide pod ether extractant can be TODGA, Me-TODGA, DODDDGA, DMDODGA or DMDDDGA (the structural formulas are as follows).

[0043]

[0044] (1) Using bis(2-2)-amide ether as the extractant at a concentration of 0.1-1.0 mol / L, TBP (tributyl phosphate) or DHOA (N,M-dihexyloctylamide) as the phase modifier at a concentration of 0.1-1.0 mol / L, and n-dodecane or octanol as the diluent, the extractant organic phase is formed together. The extractant organic phase extracts ions in the II-IV valence states from the Sr(II) solution into the organic phase, forming a supported organic phase.

[0045] (2) HNO3 is used as the back-extraction agent at a concentration of 0.1-1.0 mol / L, which is the aqueous phase for back-extraction. The aqueous phase for back-extraction extracts Sr(II) from the above-mentioned loaded organic phase into the aqueous phase.

[0046] (3) HNO3 is used as the back-extraction agent at a concentration of 0.01-0.1 mol / L, which is the aqueous phase for back-extraction. The aqueous phase for back-extraction extracts other ions from the loaded organic phase, except for Sr(II), into the aqueous phase.

[0047] In the above method, the temperature of the extraction and back-extraction processes is 20-25℃, and the volume ratio of the organic phase to the aqueous phase (organic phase: aqueous phase) in the extraction and back-extraction processes is 1:X, where X = 1-3.

[0048] The extraction and separation method provided by this invention has two implementation methods. The first method is to separate and extract Sr(II) from the original solution through "extraction-back-extraction". The second method is based on the fact that other ions besides Sr(II) will enter the organic phase before Sr(II). By controlling the contact time between the extraction organic phase and the solution containing Sr(II), other ions besides Sr(II) in the original solution are separated and extracted through "extraction-back-extraction", while Sr(II) is retained in the original solution. The two methods are described below through examples.

[0049] Example 1

[0050] Extraction process as follows Figure 1 As shown:

[0051] (1) Extraction tank 1A is used to selectively extract Sr(II) and small amounts of An(III) (actinide ions) and Ln(III) (lanthanide ions) into the organic phase, with a total of 12 stages. The flow rate of the original solution 1AF is set to 0.8-1.20 mL / min; 1AX is an extractant system containing diamide ether and TBP or DHOA, n-dodecane or octanol, with a composition of 0.1-1.0 mol / L diamide ether + 0.1-1.0 mol / L TBP or DHOA, and its flow rate is set to 0.8-1.20 mL / min. The residence time of the feed solution in each stage of tank 1A is 2-5 min.

[0052] (2) Extraction tank 1B consists of a back-extraction section and a replenishment section, totaling 16 stages. The back-extraction section (stages 5-16) is used to selectively back-extract Sr(II) into the aqueous phase. 1BS is 0.1-1.0 mol / L HNO3, with a flow rate set at 0.8-1.20 mL / min. The replenishment section (stages 1-4) is used to replenish small amounts of An(III) and Ln(III) from the back-extracted aqueous phase into the organic phase. The replenishment agent 1BX has the same composition as 1AX, with a flow rate set at 0.4-0.60 mL / min. The residence time of the feed solution in each stage of tank 1B is 2-5 min.

[0053] (3) Extraction tank 1C is used for back-extraction of An(III) and Ln(III), with 16 back-extraction stages. Tank 1CX is an aqueous system for back-extracting An(III) and Ln(III), composed of 0.01-0.1 mol / L HNO3, with a flow rate set at 0.8-1.20 mL / min. The residence time of the feed liquid in each stage of tank 1C is 2-5 min.

[0054] 1AF is the feed liquid, and the concentration of metal ions in it is shown in Table 1.

[0055] Table 1 Composition of Feed Liquid 1AF

[0056]

[0057]

[0058] Using a mixing and clarification tank as the extraction equipment, employing Figure 1The process shown separates and extracts Sr(II) from the feed solution 1AF. Extraction tank 1A has 1-12 extraction stages, extraction tank 1B has 1-4 supplementary extraction stages, and extraction tank 1C has 5-16 back-extraction stages. The retention time for each stream in each stage of tanks 1A, 1B, and 1C is set to 2 minutes. The composition and flow rate of each stream are shown in Table 2.

[0059] Table 2 Composition and Flow Ratio of Each Logistics Stream

[0060]

[0061] After equilibrium was reached, the activities of Am and Cm in each stream were determined using alpha energy dispersive spectroscopy, the concentration of Ln(III) in each stream was determined using ICP-MS, and the activity of Sr in each stream was determined using a low-background liquid scintillation counter. The Sr(II) content in each stream was then calculated, as shown in Table 3. It can be seen that the yields of Sr(II), An(III), and Ln(III) are all between 97% and 100%, indicating good material balance. Furthermore, through this process, over 99.97% of Sr(II) enters the Sr(II) stream.

[0062] Table 3. Content of each element in the product and extraction residue.

[0063]

[0064]

[0065] Example 2

[0066] Extraction process as follows Figure 2 As shown:

[0067] (1) Extraction tank 1A consists of an extraction section and a washing section, totaling 16 stages. The extraction section consists of stages 1-6, used to selectively extract ions other than Sr(II) and a small amount of Sr(II) into the organic phase. The flow rate of the original solution 1AF is set to 0.8-1.20 mL / min. 1AX is an extractant system containing diamide ether and TBP or DHOA, n-dodecane or octanol, with a composition of 0.1-1.0 mol / L diamide ether + 0.1-1.0 mol / L TBP or DHOA, and its flow rate is set to 0.8-1.20 mL / min. The washing section consists of stages 7-16. 1AS is an aqueous phase system for back-extracting a small amount of Sr(II), with a composition of 0.1-1.0 mol / L HNO3, and a flow rate set to 0.4-0.6 mL / min. The residence time of the feed solution in each stage of extraction tank 1A is 2-5 min.

[0068] (2) Extraction tank 1B is used for back-extraction of ions other than Sr(II), with 16 back-extraction stages. 1BX is an aqueous system for back-extracting ions other than Sr(II) (An(III) + Ln(III)), composed of 0.01-0.1 mol / L HNO3, with a flow rate set at 0.8-1.20 mL / min. The residence time of the feed solution in each stage of extraction tank 1B is 2-5 min.

[0069] 1AF is the feed liquid, and the concentration of metal ions in it is shown in Table 1.

[0070] Using a mixing and clarification tank as the extraction equipment, employing Figure 2 The process shown separates and extracts Sr(II) from the 1AF feed solution. Extraction tank 1A has extraction stages 1-6 and washing stages 7-16. Extraction tank 1B has back-extraction stages 1-16. The retention time for each stream in each stage of tanks 1A and 1B is set to 2 minutes. The composition and flow rate of each stream are shown in Table 4.

[0071] Table 4 Composition and Flow Ratio of Each Logistics Stream

[0072]

[0073]

[0074] After equilibrium was reached, the activities of Am and Cm in each stream were determined using alpha energy dispersive spectroscopy, the concentration of Ln(III) in each stream was determined using ICP-MS, and the activity of Sr in each stream was determined using a low-background liquid scintillation counter. The Sr(II) content in each stream was then calculated, as shown in Table 5. It can be seen that the yields of Sr(II), An(III), and Ln(III) are all between 97% and 100%, indicating good material balance. Furthermore, through this process, over 99.97% of Sr(II) enters the Sr(II) stream.

[0075] Table 5. Content of each element in the product and extraction residue.

[0076]

[0077] Other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein. Thus, the invention also intends to include such variations and adaptations if they fall within the scope of the claims and their equivalents.

[0078] The above embodiments are merely illustrative examples of the present invention. The present invention may also be implemented in other specific ways or forms without departing from its spirit or essential characteristics. Therefore, the described embodiments should be considered illustrative rather than limiting in any respect. The scope of the present invention should be defined by the appended claims, and any variations equivalent to the intent and scope of the claims should also be included within the scope of the present invention.

Claims

1. A method for extracting Sr(II) from a solution containing Sr(II) and also containing La, Eu, Na, Zr, Ba ions, characterized in that, Includes the following steps: ​ (1) By extracting Sr(II) ions in the II-IV valence states from the solution into the organic phase, a loaded organic phase is formed. The organic phase is composed of 0.1-1.0 mol / L bisamide ether as the extractant, and a phase modifier and a diluent are added. (2) Using 0.1-1.0 mol / L HNO3 as the back-extraction agent, Sr(II) in the loaded organic phase is back-extracted into the aqueous phase; using a supplementary extractant with the same composition as the extracted organic phase, the other ions besides Sr(II) in the aqueous phase are supplemented into the organic phase by controlling the contact time between the supplementary extractant and the solution containing Sr(II); (3) By adjusting the concentration of the back-extraction agent dilute acid to 0.01-0.1 mol / L, other ions in the supported organic phase except Sr(II) are back-extracted into the aqueous phase; The extraction methods in steps (1)-(3) utilize extraction tanks 1A, 1B, and 1C. The extraction tank 1A is an extraction section, which has 1-12 stages. The extraction section is used to selectively extract Sr(II) and other ions into the organic phase. The extraction tank 1B includes a back-extraction section and a replenishment section. The replenishment section has 1-4 stages, and the back-extraction section has 5-16 stages. The back-extraction section is used to selectively back-extract Sr(II) into the aqueous phase, and the replenishment section is used to replenish other ions other than Sr(II) that have been back-extracted into the aqueous phase into the organic phase. The back-extraction section of the extraction tank 1C is 1-16 stages. The extraction tank 1C is used to back-extract ions other than Sr(II) from the organic phase into the aqueous phase. The residence time of the liquid in extraction tanks 1A, 1B and 1C is 2-5 minutes in each stage.

2. The process for the extraction of Sr(II) from a solution containing Sr(II) according to claim 1, characterized in that, In step (1), the diamide pod ether extractant is TODGA, Me-TODGA, DODDDGA, DMDODGA or DMDDDGA.

3. The method for extracting Sr(II) from a solution containing Sr(II) according to claim 1, characterized in that, In step (1), the phase modifier is TBP or DHOA.

4. The method for extracting Sr(II) from a solution containing Sr(II) according to claim 3, characterized in that, The concentration of the phase modifier is 0.1-1.0 mol / L.

5. The method for extracting Sr(II) from a solution containing Sr(II) according to claim 1, characterized in that, In step (1), the diluent is n-dodecane or octanol.

6. The method for extracting Sr(II) from a solution containing Sr(II) according to claim 1, characterized in that, The extraction and back-extraction temperatures are 20-25℃.

7. The method for extracting Sr(II) from a solution containing Sr(II) according to claim 1, characterized in that, The organic phase and aqueous phase ratio in the extraction and back-extraction processes is 1:X, where X = 1-3.

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