CN106621811A

CN106621811A - Method for carrying out centrifugal separation on boron isotope

Info

Publication number: CN106621811A
Application number: CN201611170055.2A
Authority: CN
Inventors: 周明胜; 裴根; 潘建雄
Original assignee: Tsinghua University
Current assignee: Tsinghua University
Priority date: 2016-12-16
Filing date: 2016-12-16
Publication date: 2017-05-10
Also published as: CN107684829A

Abstract

The invention belongs to the technical field of separation production of an isotope, and particularly relates to a method for carrying out centrifugal separation on a boron isotope. The method comprises the following steps of: (1) using boron trichloride as a separation medium, and purifying the boron trichloride by fractionation; (2) carrying out isotope separation by using a gas centrifugation method; (3) carrying out abundance analysis on components with different molecular weights in a centrifugal separation product by using a gas mass spectrometer. According to the method disclosed by the invention, boron trichloride is used as the separation medium, and thus, the raw material is easy to obtain, and production cost is low; the gas centrifugation method is used, and thus, the method has the characteristics of low energy consumption, good economy, flexible production scale and the like; the gas mass spectrometer is used for carrying out abundance analysis, and thus, high abundance analysis measurement accuracy an be provided.

Description

A kind of method of centrifugation boron istope

Technical field

The invention belongs to isotopic separation production technical field, more particularly to a kind of method of centrifugation boron istope.

Background technology

Stable isotope has been widely used for the sides such as health care, Agro-ecology, bio-pharmaceuticals, basic physicses research Face, correspondingly, to the preparation method of stable isotope product requirements at the higher level is it is also proposed.Boron element in nature has¹⁰B and¹¹Two kinds of stable isotopes of B.Due to¹⁰B is easy to produce (n, α) reaction with thermal neutron, and the absorption cross-section of thermal neutron is up to 3837barn, is good neutron-absorbing material, thus has important application in nuclear industry, such as high boron steel and boron carbide can be used for The control rod manufacture of reactor, gaseous boron trifluoride, the boron oxide of solid-state or boron carbide can be used to manufacture neutron detector etc.. In addition,¹⁰B can be used for boron neutron capture therapy (Boron Neutron Capture Therapy, BNCT) technology so as to treat Cancer.¹¹B is minimum due to neutron absorption cross-section, and only 5 × 10^-3Barn, thus the dopant of semiconductor devices is can serve as, have Effect lifts the radioresistance antijamming capability of electronic equipment under specific environment.

At present the industrialized preparing process of boron istope only has boron trifluoride chemical exchange distillation, and additive method is such as low The warm way of distillation, low temperature exchange process, ion-exchange etc. are all not implemented industrial production.But boron trifluoride chemical exchange distillation is present The shortcomings of equipment investment is big, energy ezpenditure is high, requirement of shelter is tight, economy has much room for improvement.

The content of the invention

High energy consumption, the problem of high cost in order to overcome current boron istope industrial production, the present invention propose it is a kind of from The method of heart Separation of boron isotopes, concrete technical scheme is as follows.

A kind of method of centrifugation boron istope, it is characterised in that the method comprising the steps of：

(1) selection and purification of separating medium：

Using boron chloride (molecular formula BCl₃) as separating medium, it is purified by fractionating process, to improve it Chemical purity, meets the needs of isotopic separation；

The concrete mode of purification is：With liquid nitrogen and " liquid nitrogen-absolute ethyl alcohol " mixture as cooling agent, using light impurity and three The difference of boron chloride saturated vapour pressure is purified.

(2) isotopic separation is carried out using gas centrifugation, sets up centrifugation cascade unit：

At normal temperatures, the boron chloride after purification is passed through in the form of a vapor cascade unit, carries out isotopic separation, Light component stream end takes high abundance¹⁰B isotope products, restructuring part-streams end takes high abundance¹¹B isotope products, or carry out thing Material is recycled.If separating medium uses isotopically pure³⁵Boron chloride made by Cl, can greatly promote boron istope Separative efficiency.

(3) enrichment analysis are carried out using mass spectrometer：

Light, the sampling of restructuring part-streams end to boron chloride, using the ion source device of mass spectrometer sample is destroyed BCl₃In an electronics, make (BCl₃)⁺Ion, carries out the enrichment analysis of boron chloride different molecular weight component.

Beneficial effects of the present invention are：

1. using boron chloride as separating medium：Boron chloride as P-type dopant and plasma etching gas, extensively General to be applied to semicon industry, raw material is easily obtained, and production cost is relatively low；Boron chloride has heat endurance, disclosure satisfy that gas Requirement of the centrifugal process to separating medium；In the component of boron chloride different molecular weight, the minimum component of molecular weight¹⁰B³⁵Cl³⁵Cl³⁵Cl is comprised only¹⁰B, is easy to be concentrated at light component stream end, the maximum component of molecular weight¹¹B³⁷Cl³⁷Cl³⁷Cl containing only Have¹¹B, is easy in the concentration of restructuring part-streams end.

2. separated using industrializing very ripe gas centrifugation, gas centrifugation have low energy consumption, good economy performance, The features such as production scale is flexible, can meet the diversified demand to isotope product.

If 3. separating medium uses isotopically pure³⁵Boron chloride made by Cl, can greatly promote boron istope Separative efficiency, so as to reduce cascade scale, further reduces production cost.

4. mass spectrometer enrichment analysis, using the teaching of the invention it is possible to provide very high abundance measurement precision.

Above-mentioned several features so that the method for centrifugation boron istope proposed by the present invention have obvious economy and Technical feasibility.

Description of the drawings

Fig. 1 is the separation principle schematic diagram of the present invention.

Fig. 2 is the mass spectrometry results that unit separates boron chloride in specific embodiment.

Specific embodiment

(1) boron chloride is selected as separating medium, and it is purified

The molecular formula of boron chloride is BCl₃, molecular weight is 117.17g/mol, be at normal temperatures and pressures with hay taste and The colourless toxic gas of strong odor.Meet water energy direct hydrolysis and generate boric acid and hydrochloric acid, so moist gas attack is very strong.Gas Volume density is 5.326g/L, and fluid density is 1.35g/cm³(11 DEG C), boiling point is 12.5 DEG C (1atm), and fusing point is -107.3 DEG C (1atm).Its saturated vapour pressure such as table 1, the saturated vapour pressure under room temperature is about 1.3 atmospheric pressure, disclosure satisfy that gas centrifugation Needs.

Boron chloride (the BCl of table 1₃) saturated vapour pressure

Natural boron element contains¹⁰B and¹¹Two kinds of stable isotopes of B, its natural abundance is respectively 19.9%, 80.1%.My god So chlorine element contains³⁵Cl and³⁷Two kinds of stable isotopes of Cl, its natural abundance is respectively 75.76%, 24.24%.Boron chloride The isotopics of molecule and its natural abundance are shown in Table 2.Due to the presence of chlorine isotope so that separating medium BCl₃Isotope Component has 8 kinds, belongs to the polynary separation in isotopic separation.While boron istope is concentrated,³⁵Cl and³⁷Cl also exists respectively Gently, restructuring part-streams end is enriched with, therefore the chlorine isotope for having important application in Agro-ecology can be obtained as byproduct Take.

The isotopics of the boron chloride molecule of table 2 and its natural abundance

Molecular composition	Molecular weight	In natural B Cl₃Middle abundance/%
			¹⁰B³⁵Cl³⁵Cl³⁵Cl	115	8.52
¹¹B³⁵Cl³⁵Cl³⁵Cl	116	34.57
			¹⁰B³⁵Cl³⁵Cl³⁷Cl	117	8.28
¹¹B³⁵Cl³⁵Cl³⁷Cl	118	33.60
			¹⁰B³⁵Cl³⁷Cl³⁷Cl	119	2.68
¹¹B³⁵Cl³⁷Cl³⁷Cl	120	10.88
			¹⁰B³⁷Cl³⁷Cl³⁷Cl	121	0.29
¹¹B³⁷Cl³⁷Cl³⁷Cl	122	1.18

(2) isotopic separation is carried out using gas centrifugation

Centrifugation cascade unit is set up, at normal temperatures, the boron chloride after purification cascade is passed through in the form of a vapor Device, carries out isotopic separation, and at light component stream end high abundance is taken¹⁰B isotope products, restructuring part-streams end takes high abundance¹¹B isotope products, or boron chloride material recycle is carried out, its application in semicon industry is not still affected, on the contrary Because the effect of centrifugation so as to which chemical purity increases.Separation principle schematic diagram is shown in Fig. 1.

(3) enrichment analysis are carried out using mass spectrometer

To light, restructuring part-streams end sampling, using the ion source device of mass spectrometer sample BCl is destroyed₃In molecule One electronics, makes (BCl₃)⁺Ion, measures the mole percent situation of change of boron chloride different molecular weight component.Gas The mass spectrometry results of body centrifugal process unit separating experiment are as shown in Figure 2.Polynary separation in for isotopic separation, generally makes Separating effect is weighed with overall separation factor, by data in Fig. 2, according to the polynary separation theorem of centrifugation, list can be calculated Level overall separation factor is 1.08.By be 115 by molecular weight, 117,119, the mole percent of 121 4 kind of component be added, It is obtained in isotope product¹⁰The abundance of B.Centrifugation cascade unit is built, the industrialized production of boron istope is capable of achieving, Fully demonstrate the feasibility of the method for the invention.

Claims

1. a kind of method of centrifugation boron istope, it is characterised in that the method comprising the steps of：

(1) selection and purification of separating medium：Using boron chloride as separating medium, it is purified by fractionating process；

(2) isotopic separation is carried out using gas centrifugation：Centrifugation cascade unit is set up, at normal temperatures, after purification Boron chloride is passed through in a gaseous form cascade unit, carries out isotopic separation, and at light component stream end high abundance is taken¹⁰B isotopes Product, restructuring part-streams end takes high abundance¹¹B isotope products；

(3) enrichment analysis are carried out using mass spectrometer：Centrifugation product is destroyed using the ion source device of mass spectrometer BCl₃In an electronics, make (BCl₃)⁺Ion, carries out the enrichment analysis of boron chloride different molecular weight component.

2. method according to claim 1, it is characterised in that the purification described in step (1) be with liquid nitrogen and " liquid nitrogen- Absolute ethyl alcohol " mixture is cooling agent, is purified with the difference of boron chloride saturated vapour pressure using light impurity.

3. method according to claim 1, it is characterised in that in step (2), be also performed to material recycle.