The method of chromatographic separation and rare earth elements transplutonium

 

The invention relates to the field of chromatographic separation transplutonium elements and rare earth elements. The method of chromatographic separation of rare earth and transplutonium elements includes a strong acid sorption on sulfacetamide in the hydrogen form. This was followed by elution with a solution of diethylenetriaminepentaacetate ammonium through a layer of strongly acidic sulfacetamide in the form of a transition metal ion. The elution is conducted with a solution of diethylenetriaminepentaacetate, optionally containing nitrilotriacetic alkali metal or ammonium. Used sulfatation may be in the form of ions of bivalent transition metals from the group Ni, Co, Cu, Zn, Cd, Pb, Fe. The use of the invention will increase the degree of purification of promethium and samarium from yttrium, while maintaining the purity of curium and americium from europium, as well as to speed up the process. 2 C.p. f-crystals, 2 ill., table 1.

The invention relates to the field of chromatographic separation transplutonium (TPE) and rare earth elements (REE), in particular to methods for selection of curium, americium, promethium samarium and from solutions obtained after reprocessing of irradiated nuclear fuel (SNF) is orodno form and subsequent elution through a cation exchanger in copper form using a 2%-aqueous solution of ammonium ethylenediaminetetraacetate (EDTA) at pH 8.5. The disadvantages of this method are: - the low solubility of most ethylendiaminetetraacetic acid and complexes of EDTA with REE, resulting in the column can fall precipitation and decreases the permeability of the column; small concentrations of REE in eluent, which requires a lot of time for carrying out the separation process.

The closest in technical essence and the achieved effect to the claimed method is a method /2/ cation-exchange allocation curium, americium, samarium and promethium. Way /2/ includes sorption on the strongly acidic sulfonic cation exchanger Dowex-50W in the hydrogen form, subsequent washing with distilled water and elution through a cation exchanger in zinc form at a temperature of 70oWith a solution of diethylenetriaminepentaacetate ammonia (DTPA) concentration 20 g/l at the output of the chromatographic column discharge elements are arranged in stripes in the following order: Zn-(Cm+Am)-Eu-Sm-Y-Pm-Nd.

Adjacent strip elements are mixing zone. The size of the mixing zone does not depend on the number of items. Therefore, when small quantities, such as promethium, it all gets into the zone of mixing with yttrium, which is undesirable. In Fig.1 presents the results and americium use nitrilotriacetate ammonium (NTA) concentration of 20 g/L.

The disadvantages of this method are: - the low clearance of promethium from yttrium, which requires additional operations of refining PM; - insufficient treatment of Samaria from yttrium; - significant during the process because of the low speed streaks sorbed elements through the column.

An object of the invention is to increase the degree of purification of promethium and samarium from yttrium, while maintaining the purity of curium and americium from europium, and accelerate.

This object is achieved in that the sorption of the partial elements of the initial solution is performed on the strongly acidic sulfonic cation exchanger KU-2 in the hydrogen form, and the elution is conducted with a solution containing 10-20 g/l NTA and 5-30 g/l DTPA ammonium or alkali metal through a cation exchanger in the form of ions of bivalent transition metals (Ni, Co, cu, Zn, Cd, Pb, Fe) at a temperature of 70oC. under these conditions the output of the chromatographic column zones identified elements are clearly in the following order: Ni (Zn, Co,... )-(Cm+Am)-Eu-Y-Sm-Pm-Nd.

If the PM does not have a mixing zone with yttrium and is provided with sufficient clearance of curium and americium from europium and samarium and promethium - from yttrium (Fig.2).

When elution with elution using NTA: Y-(Am+Eu)-Sm-Pm-Nd Obtained using the mixture of eluents, DTPA+NTA the order of the zones identified elements a priori not obvious and cannot be calculated from the values of the constants of complexation of REE and TPE used in the process of chelating agents, because one of the chelating agents, namely NTA forms with elements of two types of complexes MeR and MeR2, the ratio of which can be varied and depends on many factors, which cannot be taken into account in the calculation.

When using an eluent containing NTA <10 g/l or DTPA>30 g/l, increased penetration of yttrium in the area of Samaria, and then PM and decreases the degree of purification from last yttrium.

With the increasing content of NTA in the eluting solution is more than 20 g/l and the content DPA<5 g/l of reduced clearance of curium and americium from europium.

The main feature of this method is the use of a solvent consisting of a mixture of chelating agents, DTPA and NTA.

The claimed technical solution meets the criterion of "significant differences" because of its distinctive feature - elution with a mixture of chelating agents, DTPA+NTA - not known in the scientific literature. In addition, the claimed technical solution leads to new technical property of an object, namely, to change the order of leaching of elements, which in turn leads to a positive effect: to increase the degree of purification of promethium and samarium from yttrium, while maintaining the degree of purification of americium and curium from europium and obespechivali, promethium.

Examples of implementation method:
Example 1 (Fig.2): 200 ml of the initial solution composition: nitrate salts europium - 2; yttrium - 1,5; samarium - 4,5; PM - 0,025; curium and americium -0,25; neodymium - 2 mg/ml (for metal); nitric acid 1 mol/l is passed through the sorption column (height H=20 cm, cross-section S=1,2 sq. cm) containing a strongly acidic, sulfonation KU-2 in the hydrogen form. After operation of the sorption column to connect three consecutive separation column containing a cation exchange resin KU-2 in the Nickel form (N1=N2=N3=80 cm; S1=0,6; 82= 0,3; S3=0.2 sq. cm). Elution is carried out at a temperature of 70+-2oUsing the eluent containing 10 g/l DTPA and 15 g/l NTA. The results of the separation are shown in Fig.2 and table. When this fraction of promethium does not contain yttrium, 1 g of samarium contains 0.05 g of yttrium, purification of americium and curium from europium not degraded in comparison with the method of the prototype. The speed of the strip sorbed elements along a column of 30 cm/h

Other examples on the declared value of the concentrations of DTPA and NTA and salt forms of the cation are the same as example 1. The results are shown in the table.

As follows from the examples of execution of the method, the advantages of the claimed technical rise from yttrium, while maintaining the degree of purification of americium and curium from europium (yttrium content in Samaria less than 0.05 g per 1 g of samarium, yttrium in the fraction of PM is not found; while in the experiment carried out on the prototype method, the content of yttrium in Prometei 1.5 g of yttrium on 1 g of promethium, and in Samaria - 0.3 g of yttrium on 1 g of samarium), which provides simultaneous selection of three target products: Kyrie + americium, samarium and promethium (without additional refining operations);
- reduces the time of the experiment at least three times (2-3 times due to the lack of operations of refining and washing and approximately 1.5 times due to the faster movement of the strip of sorbed elements along a column).

Sources of information
1. Spedding Powell Wilrich. The use of copper as a restraint ion during desorption of rare earth elements solutions ethylenediaminetriacetate ammonium. - Sat. Rare earth metals. Edited by L. N. The Komissarova and C. E. ivy. Ed. IL, M, 1957, S. 216.

2. Wheelwright, E. G., F. P. Roberts, The use of alternating DTPA and HTA cation exchange flowsheets for the simultaneous recovery and purification of Pm, Am, Cm - Report BNWL - 1072, Battele Northwest Laboratory Richlang, July, 1969.


Claims

1. The method of chromatographic separation of rare earth and transplutonium elements, including strong acid sorption on sulfacetamide in vakalatnama of sulfacetamide in the form of a transition metal ion, characterized in that the elution of rare earth and transplutonium elements hold the solution diethylenetriaminepentaacetate, optionally containing nitrilotriacetic alkali metal or ammonium.

2. The method according to p. 1, characterized in that the elution of ions of rare earth and transplutonium elements hold the solution composition diethylenetriaminepentaacetate alkali metal or ammonium concentration of 5-30 g/l + nitrilotriacetate alkali metal or ammonium concentration of 10-20 g/l at pH 6-8.

3. The method according to p. 1, characterized in that sulfatation is used in the form of ions of bivalent transition metals from the group Ni, Co, cu, Zn, Cd, Pb, Fe.

 

Same patents:
The invention relates to a method for decontamination of radioactive liquids accumulated in reservoirs-pits, and having the possibility of contamination of surrounding areas as a result of tornadoes, heavy winds, and similar phenomena, with the help of mineral substances
The invention relates to the purification of natural water from radioactive isotopes of strontium 90, 89 and cesium 137 and can be used for decontamination of water water systems (rivers, ponds, lakes, reservoirs)

The invention relates to the purification technology of radionuclides from radioactive waste
The invention relates to the field of processing of intermediate level liquid waste from nuclear power plants, nuclear power plants, reprocessing plants, nuclear research centers

The invention relates to the chemical treatment technology solutions from radioactive elements

The invention relates to the treatment of aqueous media from radioactive contaminants by sorption and can be used in the process of operation of energy transport facilities

The invention relates to the purification of the environment, namely to extract radioactive isotopes from contaminated soil

The invention relates to radiochemistry, namely, the purification of liquid radioactive waste

The invention relates to the field of separation of racemates of optically active compounds by chromatography

The invention relates to the field of radiochemistry and can be used in analytical chemistry and in chemical engineering

The invention relates to the field of analytical chemistry and chemical technology and can be used for separation, testing, and determination of ions of Co, Cu and Zn

The invention relates to a preparative chromatographic systems

FIELD: organic chemistry, chemical technology.

SUBSTANCE: invention relates to a method for separation of high-molecular lactone-containing compound. Invention describes a method for separation of lactone-containing compounds wherein mixture of lactone-containing compound showing the main chemical structure as 1,14-dihydroxy-12-[2-(4-hydroxycyclohexyl)-1-methylvinyl]-23,25-dimethoxy-13,19,21,27-tetramethyl-11,28-dioxa-4-azatricyclo[22.3.1.04,9]octacoz-18-ene-2,3,10,16-tetraone and at least one among (C2-C6)-alkenyl group and (C1-C6)-alkoxy-group as a side chain and similar compounds is subjected for one or both the following stages in any order: stage (A) of the mixture adsorption on non-ionic adsorbing resin and elution with an aqueous solvent containing silver ions; and stage (B) of the mixture absorption on basic aluminum oxide and elution with organic solvent for separation of each compound. Invention provides the development of effective method for separation of high-molecular compounds being without their chemical structure.

EFFECT: improved method for separation.

14 cl, 2 dwg, 2 tbl, 3 ex

Up!