Method of extraction-type separation of americian and curium

FIELD: radiochemistry; analytical chemistry.

SUBSTANCE: proposed method consists in treatment of solution containing elements to be separated, diethylene triamine, pentaacetic acid, carbamide or formic acid, extracting agent in form of solution of chlorinated cobalt dicarbollide and polyethylene glycol in organic solvent or solution of cobalt dicarbollide, zirconium slat of dibutyl phosphoric acid and polyethylene glycol in organic solvent. Americian passes into organic solution at higher degree as compared with curium. Proposed method takes into account factor of separation of americian and curium and facilitates the process due to avoidance of salting-out agent.

EFFECT: enhanced efficiency.

4 cl, 2 tbl, 2 ex

 

The invention relates to the field of radiochemistry and, in particular, to the field of extraction of the allocation of long-lived radionuclides from spent nuclear fuel and irradiated targets and can be used in analytical chemistry for separation and concentration of elements

Known methods of separating americium and curium, including precipitation, sorption and extraction processes [1 Penniman, Tkined. Radiochemistry of americium and curium. M: Foreign literature; 1961; M.Kamoshida, T.Fukusava in Global-99; radiochemistry t, No. 2, s, 1979].

The disadvantages of these methods is either the complexity of the process or lack of radiation and chemical resistance of the used extractants or sorbents or low degree of separation of these elements during one stage of extraction, which requires the implementation process on a large number of stages of extraction with careful control of the flow ratio of organic and aqueous phase.

The closest technical solution to the claimed invention is a method of extraction separation of americium and curium extractant based on amines or their salts in non-polar solvents using complexing agents diethylenetriaminepentaacetic acid - DTPA [Vmichael, Eaasily, Ragusano. Technology transplutonium elements. SSC RF RIAR, 2000 THE, s.].

How is that an aqueous solution containing americium and curium visivel-nitrate lithium, sodium or aluminum, complexing agents-diethylenetriaminepentaacetic acid-DTPA, in contact with the extractant is an organic solution of amine or its salt with nitric acid. While americium passes into the organic solution to a greater extent than curium. The ratio of the distribution coefficients of americium and curium - separation factor judge about the efficiency of the separation process elements. The higher the value of the separation factor, the higher the efficiency of the process of extraction separation of americium and curium and the smaller is the number of stages of extraction required to achieve the necessary figures for cleaning one element from another.

The disadvantage of this method is that the separation of americium and curium necessary additive of vicariates - lithium nitrate or aluminum, which complicates subsequent treatment with an aqueous solution of the highlighted item. In addition, the achieved degree of separation of americium and curium(βAm/Cm) is relatively low and in most cases (βAm/Cm≤4), therefore, for an effective separation requires a sufficiently large number of stages of extraction.

The objective of the invention is to increase the efficiency of the process extracti the frame separation of americium and curium by increasing the values of their separation factor and simplify the process by eliminating from it vicariates.

The problem is solved by contact of an aqueous solution containing americium and curium, diethylenetriaminepentaacetic acid and urea or formic acid in an amount of 20-100 g/l with a solution of chlorinated cobalt dicarbollide - HDC and polyethylene glycol - PEG in an organic solvent containing components of 0.05-0.3 mol/l and 0.001 to 0.15 mol/l, respectively. While americium passes into the organic solution to a much greater extent than curium, resulting in efficient separation of these elements. As the organic solution can also be used a solution of chlorinated cobalt dicarbollide, zirconium salt dibutylamino acid - CA DBFC and polyethylene glycol in an organic solvent with the concentration of components of 0.05-0.3 mol/l, 0.1-0.5 mol/l, 0.001 to 0.15 mol/l, respectively. As the organic solvent can be used in a polar organic solvent or mixture of polar and nonpolar solvents.

Example 1.

The influence of the composition of the aqueous solution on the distribution of americium III and curium III extractant based HTC and PEG are shown in table 1. Organic phase: 0.3 mol/l HDC, 6% PEG in a mixture of polar and nonpolar solvents orthonitrophenol-Hexachlorobutadiene-(1:1)

The table is a 1
Urea, g/lDTPA, g/lThe distribution coefficientsThe separation factor
Am IIICm IIIAm/Cm)
5020.410.02218.6
7020.240.0337.3
10020.250.0337.6
300.55.420.4811.3
1000.51.340.245.6

Example 2.

The influence of the composition of the aqueous solution on the distribution of americium III and curium III extractant composition: 0.05 mol/l HDC, 0.5% PEG, 0.07 mol/l CA DBFC in polar solvent mechanicalinternational shown in table 2.

Table 2
DTPA, g/lUrea, g/lFormic acid, g/lThe distribution coefficientsThe separation factor
Am IIICm IIIAm/Cm)
4500,35being 0.036the 9.7
4700,330,0506,6
41000,360,0546,7
2301,210,1012,1
2500,790,155,3
21500,40,0557,3
4501,70,117
6501,820,36,1
101501,630,116,3

CA DBFC - zirconium salt dibutylamino acid is added to the extractant to increase the degree of extraction of rare earth and transplutonium elements.

Compared with the prototype allows to simplify the process of extraction separation of americium and curium due to a significant increase in their separation factor and not using vicariates.

. Method of extraction separation of americium and curium by extraction of americium from aqueous solution containing diethylenetriaminepentaacetic acid, characterized in that the extractant use a solution of chlorinated cobalt dicarbollide and polyethylene glycol in an organic solvent or a solution of chlorinated cobalt dicarbollide, zirconium salt dibutylamino acid and polyethylene glycol in an organic solvent, and the initial aqueous solution contains urea or formic acid.

2. The method according to claim 1, characterized in that the organic solvent used polar organic solvent or mixture of polar and non-polar solvent.

3. The method according to claim 1, characterized in that the concentration of chlorinated cobalt dicarbollide, zirconium salt dibutylamino acid and glycol in the extractant 0.05-0.3 mol/l, ≤0.5 mol/l and 0.001 to 0.15 mol/l, respectively.

4. The method according to claim 1, characterized in that the concentration of urea or formic acid in aqueous solution is from 20 to 100 g/l



 

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1 cl, 1tbl

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2 cl, 1 dwg, 2 tbl, 4 ex

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8 cl, 1 dwg, 1 ex

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10 cl, 1 ex

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4 cl, 6 ex, 3 dwg

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1 ex

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