CS224844B1 - Separation method of uranium isotope using the controlled distribution method - Google Patents

Description

Isotope separation by controlled distribution method using mainly kinetic and equilibrium concentration effect is protected by A.A. 214 904 and CS.A.O. 214 9θ5 · It is based on isotopic separation in two-phase systems such as solid phase - liquid phase, solid phase - gas phase, or liquid phase - liquid phase under conditions where different concentrations of the separated isotopes result in different transport rates to the second phase and the isotopic exchange is retarded.

The controlled distribution method can be used to separate the isotopes of uranium in the sorbent-aqueous solution system. As sorbents, A.O. cation exchangers based on synthetic polymers, in particular styrene-vinylbenzene copolymers with sulfone groups, and generally polymeric cation exchangers with chelating groups. Isotopes were separated from aqueous solutions of uranyl salts and, due to the nature of the sorbents, were subject to separation of the cationic form of the uranium compounds.

In the cited A.O. biosorbents prepared from the mycelium of the fungus Penicilium chrysogenum were also used to separate uranium isotopes by solidification with synthetic resins by the procedures protected by A.A. Also sorbents of this type have the character of cation exchangers, resp. of the chelating cation exchanger.

Although the method of isotope separation by the controlled distribution method has wide application in biphasic systems of various types, it has undoubtedly been found and cited by A.O. it has been demonstrated that the actual result is largely dependent on the composition of the two phases. When the controlled distribution method is applied to the sorbent-aqueous solution system, the separation factor achieved is significantly dependent on the type 3 »physical 'II'

224,644 and the chemical composition of the sorbent. By varying the sorbent type and the liquid phase-dependent composition thereof, various advantages can also be expected in the technological implementation of the separation process, respectively. in economics of the enrichment process in transition to operational scale. Uranium compounds are known for their ability to easily form cationic, anionic and neutral complexes, often occurring simultaneously in solution. So far, only cationic complexes have been used for the separation of uranium isotopes by the controlled distribution method, while others have been attributed passive function in the process.

This advantage is eliminated by a method of separating uranium isotopes by a controlled distribution method using in particular a concentration isotopic phenomenon in biphasic systems, one of which is an aqueous or non-aqueous solution of uranium isotopes containing anionic uranium complexes and the other is an ion exchanger. an anion exchanger based on vinyl polymers or cellulose, i.e. a strongly basic anion exchanger based on synthetic polymers with trimethylammonium, hydroxyethyl-dimethylammonium and pyridinium active groups, or a medium-basic anion exchanger based on synthetic polymers with active amine groups, optionally anions based on spherical cellulose with active amine groups.

The process for the separation of uranium isotopes in the form of anionic complexes according to the present invention is particularly advantageous in that the anionic complexes of uranium are very easy to form and are readily available for the separation process in high concentration relative to the other complexes. For example, it is known that uranium is largely obtained from natural raw materials by leaching with sulfuric acid and is isolated by sorption on anion exchangers as an anient complex. This offers the possibility of combining the enrichment process with the recovery of uranium from natural raw materials, which is another advantage of the method of separating the isotopes of uranium according to the invention.

It has also been shown that the separation efficiency of anion exchangers in uranium enrichment is sufficiently high and in some cases higher than that of cation exchangers.

Example 1

224 844

0.5 S swollen, centrifuged, strongly basic anion exchanger based on vinyl polymers with trimethylammonium active groups, the product designation Amberlite ZRA 400 in Cl-form was contacted with stirring at 298K with 25 ml of a 0.01 M uranyl sulfate (µO) solution Sodium sulphate (Na2SO4) (pH ca. 2.5) was stirred for a further period of time, stirring was interrupted, the liquid and ion exchange phases were separated and separated. In the liquid phase, the total uranium concentration was determined (using a AZO i photometric method) and the atomic ratio of uranium (u): uranium (u) isotopes (on a MICROMASS 30B mass spectrometer). The isotopic composition of the starting solution corresponded to that of natural uranium, i.e. ^p uranium (u)! ^The value of the separation factor was calculated from the results (the separation factor is defined as the ratio of the isotopic ratio of uranium (u): uranium (u) in the ion exchange phase to the same isotopic ratio in the solution phase). The results, ie total uranium concentration and separation factors as a function of time, are summarized in the following table;

Time (min) 0 5 10 20 May 40 80 Total concentration 0.01 0.0074 0,0065 0.0055 0.0045 0,0033 uranium (m) Separation factor 1,000 0,989 0.991 0.996 0.999 0.999

Example 2

Using the same procedure as in Example 1, the time change of the total uranium concentration and the uranium sorption separation factor to the strongly basic anion exchanger based on vinyl polymers with active hydroxyethyl-dimethyl-ammonium groups, product designation Amberlite IRA-410 was determined:

time (min)

20 40

Total uranium concentration (m)

Separation factor

0.01

1,000

0.0087

1,003

0,0084

0,986

0.0076

0.991

0,0065

0.997

0.0053

0.999

Example 3

The same procedure as in Example 1 was used _to determine the total uranium concentration and the uranium sorption factor for the sorption of uranium to a medium basic anion exchanger based on vinyl polymers with active amine groups, the product designation Amberlite KA-93 in Cl 'form:

Time (min) 0 5 10 20 May 4o 80 Total concentration 0.01 0.0079 0.0072 0.0066 0.0055 0.0048 uranium (m) Separation factor 1,000 1,006 1,020 1,013 1,007 0.998

Example 4

Using the same procedure as in Example 1, the time change of the total uranium concentration and sorp or uranium separation factor to a medium basic anion exchanger based on vinyl polymers with active amine groups, manufacturing designation Amberlite IRA-93 in OH-form was determined:

Time (min) 0 5 10 20 May 4o 80 Total uranium concentration (m) 0.01 0.0074 0,0065 0.0060 0.0055 0.0047 Separation factor 1,000 1,014 1,037 1,007 1,002 1,001

Example 5

Using the same procedure as in Example 1, but with a solution of 0.01 M uranyl sulphate (uOgSO4) (natural uranium), the time change of the total uranium concentration and the uranium sorption factor to the strongly basic anion exchanger based on vinyl polymers with active pyridinium groups, manufacturing name Varion AP in SO * form:

224 844

Time (min) 0 2 5 20 May 4o 160 Total uranium concentration (m) 0.01 0.0094 0,0091 .0,0078 0,0062 0.0046 Separation factor 1,000 0.860 0,941 0,982 0,987 0.994

Example 6

1.0 g of a swollen, centrifuged, weakly basic anionic resin with an aminoethyl functional group, based on pearl cellulose, in OH form, was contacted with stirring, at 293K, with 20 ml of a 0.01 M UO 2 SO 4 solution (pH ca. 3) ). The next procedure was the same as in Example 1. The results, ie the values of total uranium concentration and separation factors as a function of time, are summarized in the following table:

Time (min) 0 2 5 10 30 60 Total concentration θ Uranium (m) * 0.0095 0.0094 0.0082 0.0071 0,0061 Separation factor 1,000 0,977 0.994 0.996 0.999 1,000

Claims (4)

A method for the separation of uranium isotopes by a controlled distribution method using in particular a concentration isotopic phenomenon in two-phase systems, wherein one of the phases is an aqueous or non-aqueous uranium isotope solution containing anionic uranium complexes and the other phase is an ion exchanger. anion exchanger based on vinyl polymers or cellulose. 2. Process according to claim 1, characterized in that a strongly basic anion exchanger based on synthetic polymers with active groups trimethylammonium, hydroxyethyl dimethyl ammonium and pyridinium is used as the ion exchanger. 3. The process according to claim 1, wherein the ion exchanger is a medium basic anion exchanger based on synthetic polymers with active amine groups. 4. A method for bonding a bodto characterized by an anion exchanger based on a spherical amine. The method according to claim 1, characterized in that cellulose with active groups is used as the ion exchanger