Method for separating boron isotope through extraction-back extraction

Abstract

The invention discloses a method for separating boron isotopes through extraction-back extraction. The method comprises the following steps: 1, carrying out esterification reaction on a boron-containing water phase and a fatty alcohol reactant to obtain a boron-containing esterification product; 2, carrying out oscillation extraction separation on the boron-containing esterification product by using an organic solvent to obtain a loaded organic phase and a raffinate water phase; 3, the loaded organic phase reacts with a stripping agent, oscillation extraction separation is conducted, and a regenerated raffinate organic phase and an extraction water phase are obtained; and 4, measuring the content of the 10B in the raffinate water phase and the extraction water phase, and determining the enrichment direction of the 10B. According to the method, the separation coefficient of the boron isotope is improved through esterification and hydrolysis, the solvent consumption is reduced by adopting a solvent recycling method, and the economical efficiency of the process is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of isotope separation, and in particular relates to a method for separating boron isotopes by extraction-re-extraction. Background Art

[0002] In nature, boron has two stable isotopes, boron-10 (10B) and boron-11 (11B). The abundances of the two are 19.3% and 80.7% respectively. Since the thermal neutron capture cross-section of 10B is times that of natural boron and 770,000 times that of 11B, 10B is widely used in the fields of nuclear industry, medicine, military equipment, electronics, etc., so it is necessary to obtain high-abundance 10B through isotope separation.

[0003] At present, there are five main methods for separating and enriching 10B isotopes: boron trifluoride chemical exchange distillation, boron trifluoride low-temperature distillation, ion exchange resin method, laser spectroscopy and electromagnetic method. Among them, chemical exchange distillation and ion exchange chromatography are the methods that have been studied more by scholars at home and abroad. However, so far, only boron trifluoride chemical exchange distillation has been truly realized in industrial production.

[0004] The boron trifluoride chemical exchange distillation method mainly uses the difference in complexing ability between boron trifluoride and the complexing agent to achieve separation. After years of technical iterations, the boron trifluoride-anisole system (α=1.02-1.04) with a higher separation coefficient is currently used. This method has high equipment investment and high energy consumption. The boron trifluoride used is highly corrosive to the equipment. Once leaked, it will cause major safety accidents and environmental damage. Researchers are committed to developing a safe and efficient method for separating boron isotopes. Extraction, as a commonly used separation method, has the advantages of easy scale-up, safe and energy-saving, simple operation, green and environmentally friendly, and a short process. The raw material boric acid has low corrosion to the equipment, is safe and easy to operate, so the extraction method is chosen to enrich 10B. On the one hand, it can achieve the safe separation of boron isotopes and reduce production costs. On the other hand, it can break the technical monopoly of boron isotopes and enhance my country's technological advantages. Summary of the invention

[0005] The significance of the present invention is to provide a method for separating boron isotopes by liquid-liquid extraction-strip extraction. The method has the advantages of being efficient, safe, simple and industrializable, and can be used to replace the current boron trifluoride chemical exchange distillation method with high equipment investment, high energy consumption and high risk factor.

[0006] The present invention is a method for separating boron isotopes by extraction-strip extraction, which comprises the following steps:

[0007] Step 1: Prepare a boron-containing aqueous phase: dissolve boric acid in deionized water, with the concentration of boric acid being 0.2-0.7 mol / L.

[0008] Step 2: Compounding of fatty alcohol reactants: Compounding dihydric fatty alcohols and monohydric fatty alcohols to obtain fatty alcohol reactants. Dihydric alcohols include, but are not limited to, 2-ethyl-1,3-hexanediol, 2,2,4-trimethyl-1,3-pentanediol, and 2,2-diethyl-1,3-propanediol. Monohydric fatty alcohols include, but are not limited to, n-octanol, isooctyl alcohol, and n-decanol. The molar ratio of dihydric fatty alcohols to monohydric fatty alcohols is 1-5:1.

[0009] Step 3: Esterification reaction: The boron-containing aqueous phase and the fatty alcohol reactant undergo an esterification reaction to obtain a boron-containing esterified product. The molar ratio of boric acid to the hydroxyl group in the fatty alcohol reactant is 1.05-1.1:1.

[0010] Step 4: Extraction: Use an organic solvent to shake and extract the boron-containing esterification product to obtain a loaded organic phase and a residual water phase. The organic solvent is a product that is immiscible with water, including but not limited to toluene, xylene, Exxsol D80, n-heptane, etc.

[0011] Step 5, stripping process: the loaded organic phase reacts with the stripping agent, and is extracted and separated by shaking to obtain a regenerated raffinate organic phase and a stripping aqueous phase.

[0012] Step 6, determine the enrichment direction of 10B: perform a 10B abundance test on the raffinate water phase obtained in step 4 and the stripping water phase obtained in step 5 to determine the enrichment direction of 10B.

[0013] Compared with the prior art, the present invention has the advantages of

[0014] 1) The present invention separates boron isotopes by using an extraction-strip extraction method, and there is no highly toxic or highly corrosive raw material in the reaction process, thereby avoiding the problems of high equipment investment and high risk factor.

[0015] 2) The efficient separation of boron isotopes was achieved by combining esterification, hydrolysis with extraction and back-extraction.

[0016] 3) The present invention uses fatty alcohol reactants as media, and the boron isotope separation factor is higher than 1.02, which is higher than the industrial requirements.

[0017] 4) The extracted organic phase can be regenerated and recycled, saving the amount of organic solvent used and reducing operating costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 The present invention is a process flow chart of an extraction-strip extraction method for separating boron isotopes. DETAILED DESCRIPTION

[0019] Example 1

[0020] Step 1: Prepare the boron-containing aqueous phase: prepare 300 mL of 0.2 mol / L boric acid solution.

[0021] Step 2: Compounding of fatty alcohol reactants: Compounding of 2-ethyl-1,3-hexanediol and n-octanol in a molar ratio of 3:1, with a compounding amount of 4.7 g.

[0022] Step 3: Esterification reaction: The boron-containing aqueous phase is subjected to an esterification reaction with a fatty alcohol reactant, the reaction time is 4 hours, and the reaction temperature is 35°C.

[0023] Step 4, extraction: the organic phase is extracted with xylene, and the mixed solution of xylene and the boron-containing esterification product is in a mass ratio of 1:1, and the oscillation extraction time is 24 hours. After the extraction is completed, centrifuge and separate the phases. The obtained xylene extract is used for standby use and the raffinate water.

[0024] Step 5, stripping process: Sodium hydroxide with a concentration of 0.1 mol / L is used as the stripping solution, and the stripping solution and the xylene extract are in a mass ratio of 2:1. The oscillation extraction time is 24 hours. After the extraction is completed, centrifuge and separate the phases. The xylene is recovered for recycling, and the stripping solution is used for the next step.

[0025] Step 6, determine the enrichment direction of 10B: the raffinate water phase obtained in step 4 and the stripping water phase obtained in step 5 were tested for 10B abundance, and it was found that 10B was enriched in the stripping solution, and the monopolar separation factor was 1.028.

[0026] Example 2

[0027] Step 1: Prepare the boron-containing aqueous phase: prepare 300 mL of 0.4 mol / L boric acid solution.

[0028] Step 2: Compounding of fatty alcohol reactants: Compounding 2,2,4-trimethyl-1,3-pentanediol and isooctyl alcohol in a molar ratio of 1:1, with a compounding amount of 10 g.

[0029] Step 3: Esterification reaction: The boron-containing aqueous phase is subjected to an esterification reaction with a fatty alcohol reactant, the reaction time is 4 hours, and the reaction temperature is 35°C.

[0030] Step 4, extraction: toluene is used to extract the organic phase, and the mixed solution of toluene and the boron-containing esterification product is in a mass ratio of 1:1. The oscillation extraction time is 24 hours. After the extraction is completed, centrifuge and separate the phases. The obtained xylene extract is used for standby use and the raffinate water.

[0031] Step 5, stripping process: potassium hydroxide with a concentration of 0.1 mol / L is used as the stripping solution, the stripping solution and the xylene extract are in a mass ratio of 2:1, the oscillation extraction time is 24 hours, and after the extraction is completed, the phases are separated by centrifugation, the xylene is recovered for recycling, and the stripping solution is used for the next step.

[0032] Step 6, determine the enrichment direction of 10B: the raffinate water phase obtained in step 4 and the stripping water phase obtained in step 5 were tested for 10B abundance, and it was found that 10B was enriched in the stripping solution, and the monopolar separation factor was 1.021.

[0033] Example 3

[0034] Step 1: Prepare the boron-containing aqueous phase: prepare 300 mL of 0.3 mol / L boric acid solution.

[0035] Step 2: Compounding of fatty alcohol reactants: Compounding of 2-ethyl-1,3-hexanediol and n-octanol in a molar ratio of 5:1, with a compounding amount of 6.6 g.

[0036] Step 3: Esterification reaction: The boron-containing aqueous phase and the fatty alcohol reactant are subjected to esterification reaction, the reaction time is 4 hours, and the reaction temperature is 35°C.

[0037] Step 4, extraction: the organic phase is extracted with Exxsol D80, and the mixed solution of Exxsol D80 and the boron-containing esterification product is in a mass ratio of 1:1. The extraction time is shaken for 24 hours. After the extraction is completed, the phases are separated by centrifugation. The obtained xylene extract is used for standby use and the raffinate water is extracted.

[0038] Step 5, stripping process: Sodium hydroxide with a concentration of 0.1 mol / L is used as the stripping solution, and the stripping solution and the xylene extract are in a mass ratio of 2:1. The oscillation extraction time is 24 hours. After the extraction is completed, centrifuge and separate the phases. The xylene is recovered for recycling, and the stripping solution is used for the next step.

[0039] Step 6, determine the enrichment direction of 10B: the raffinate water phase obtained in step 4 and the stripping water phase obtained in step 5 were tested for 10B abundance, and it was found that 10B was enriched in the stripping solution, and the monopolar separation factor was 1.031.

[0040] Example 4

[0041] Step 1: Prepare the boron-containing aqueous phase: prepare 300 mL of 0.3 mol / L boric acid solution.

[0042] Step 2: Compounding of fatty alcohol reactants: Compounding 2,2,4-trimethyl-1,3-pentanediol and n-decanol in a molar ratio of 2:1, with a compounding amount of 7.1 g.

[0043] Step 3: Esterification reaction: The boron-containing aqueous phase is subjected to an esterification reaction with a fatty alcohol reactant, the reaction time is 4 hours, and the reaction temperature is 35°C.

[0044] Step 4, extraction: the organic phase is extracted with xylene, and the mixed solution of xylene and the boron-containing esterification product is in a mass ratio of 1:1, and the oscillation extraction time is 24 hours. After the extraction is completed, centrifuge and separate the phases. The obtained xylene extract is used for standby use and the raffinate water.

[0045] Step 5, stripping process: Sodium hydroxide with a concentration of 0.1 mol / L is used as the stripping solution, and the stripping solution and the xylene extract are in a mass ratio of 2:1. The oscillation extraction time is 24 hours. After the extraction is completed, centrifuge and separate the phases. The xylene is recovered for recycling, and the stripping solution is used for the next step.

[0046] Step 6, determine the enrichment direction of 10B: the raffinate water phase obtained in step 4 and the stripping water phase obtained in step 5 were tested for 10B abundance, and it was found that 10B was enriched in the stripping solution, and the monopolar separation factor was 1.023.

[0047] Example 5

[0048] Step 1: Prepare the boron-containing aqueous phase: prepare 300 mL of 0.4 mol / L boric acid solution.

[0049] Step 2: Compounding of fatty alcohol reactants: Compounding 2,2,4-trimethyl-1,3-pentanediol and n-octanol in a molar ratio of 2:1, with a compounding amount of 9.6 g.

[0050] Step 3: Esterification reaction: The boron-containing aqueous phase is subjected to an esterification reaction with a fatty alcohol reactant, the reaction time is 4 hours, and the reaction temperature is 35°C.

[0051] Step 4, extraction: the organic phase is extracted with xylene, and the mixed solution of xylene and the boron-containing esterification product is in a mass ratio of 1:1, and the oscillation extraction time is 24 hours. After the extraction is completed, centrifuge and separate the phases. The obtained xylene extract is used for standby use and the raffinate water.

[0052] Step 5, stripping process: Sodium hydroxide with a concentration of 0.1 mol / L is used as the stripping solution, and the stripping solution and the xylene extract are in a mass ratio of 2:1. The oscillation extraction time is 24 hours. After the extraction is completed, centrifuge and separate the phases. The xylene is recovered for recycling, and the stripping solution is used for the next step.

[0053] Step 6, determine the enrichment direction of 10B: the raffinate water phase obtained in step 4 and the stripping water phase obtained in step 5 were tested for 10B abundance, and it was found that 10B was enriched in the stripping solution, and the monopolar separation factor was 1.028.

[0054] Example 6

[0055] Step 1: Prepare the boron-containing aqueous phase: prepare 300 mL of 0.5 mol / L boric acid solution.

[0056] Step 2: Compounding of fatty alcohol reactants: Compounding 2,2-diethyl-1,3-propanediol and n-decanol in a molar ratio of 1:1, with a compounding amount of 14 g.

[0057] Step 3: Esterification reaction: The boron-containing aqueous phase is subjected to an esterification reaction with a fatty alcohol reactant, the reaction time is 4 hours, and the reaction temperature is 35°C.

[0058] Step 4, extraction: the organic phase is extracted with xylene, and the mixed solution of xylene and the boron-containing esterification product is in a mass ratio of 1:1, and the oscillation extraction time is 24 hours. After the extraction is completed, centrifuge and separate the phases. The obtained xylene extract is used for standby use and the raffinate water.

[0059] Step 5, stripping process: Sodium hydroxide with a concentration of 0.1 mol / L is used as the stripping solution, and the stripping solution and the xylene extract are in a mass ratio of 2:1. The oscillation extraction time is 24 hours. After the extraction is completed, centrifuge and separate the phases. The xylene is recovered for recycling, and the stripping solution is used for the next step.

[0060] Step 6, determine the enrichment direction of 10B: the raffinate water phase obtained in step 4 and the stripping water phase obtained in step 5 were tested for 10B abundance, and it was found that 10B was enriched in the stripping solution, and the monopolar separation factor was 1.022.

[0061] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A method for separating boron isotopes by extraction-strip extraction, characterized by the following steps: Step 1: Prepare the boron-containing aqueous phase Step 2: Prepare fatty alcohol reactant Step 3, the boron-containing aqueous phase and the fatty alcohol reactant are subjected to an esterification reaction to obtain a boron-containing esterification product; Step 4: Extraction process: using an organic solvent to shake and extract the boron-containing esterification product to obtain a loaded organic phase and a raffinate aqueous phase; Step 5, stripping process: the loaded organic phase reacts with the stripping agent, and is subjected to oscillation extraction and separation to obtain a regenerated raffinate organic phase and a stripping aqueous phase; Step 6, determine the enrichment direction of 10B: perform a 10B abundance test on the raffinate water phase obtained in step 2 and the stripping water phase obtained in step 3 to determine the enrichment direction of 10B.

2. According to the method for separating boron isotopes by extraction-strip extraction as described in claim 1, the content of boric acid in the boron-containing aqueous phase is 0.2-0.7 mol / L.

3. According to the method for separating boron isotopes by extraction-strip extraction as described in claim 1, the fatty alcohol reactant is a mixture of dihydric fatty alcohol and monohydric fatty alcohol. The dihydric fatty alcohol includes but is not limited to 2-ethyl-1,3-hexanediol, 2,2,4-trimethyl-1,3-pentanediol, 2,2-diethyl-1,3-propylene glycol. The monohydric fatty alcohol includes but is not limited to n-octanol, isooctyl alcohol, and n-decanol.

4. According to claim 3, the molar ratio of dihydric fatty alcohol to monohydric fatty alcohol is 1-5:

1.

5. According to the method for separating boron isotopes by extraction-strip extraction as described in claim 1, the molar ratio of boric acid to hydroxyl groups in the fatty alcohol reactant is 1.05-1.1:

1.

6. According to the method for separating boron isotopes by extraction-strip extraction as described in claim 1, the organic solvent is a solvent that is immiscible with water, including but not limited to toluene, xylene, Exxsol D80, n-heptane, etc.

7. According to the method for separating boron isotopes by extraction-strip extraction as described in claim 1, the stripping aqueous phase is an alkaline aqueous solution, including but not limited to potassium hydroxide aqueous solution, sodium hydroxide aqueous solution, ammonia water, etc.

8. According to the method for separating boron isotopes by extraction-strip extraction according to claim 7, the stripping aqueous phase is an alkaline aqueous solution with a concentration of 0.1-0.5 mol / L.

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