RU2318258C2 - Radionuclide extraction by crown-ester containing extractants - Google Patents

Abstract

FIELD: extracting radionuclides from acid solutions of highly radioactive waste in radiochemical industry and recovering spent extractant.

SUBSTANCE: mixture used for the purpose has polyfluorinated alcohol-telomer, 1,1,7-trihydrodedodekafluoroheptanol-1, its chemical formula being H(CF₂CF₂)_n CH₂OH, where n - 3, and polyoxyethylene glycol esters of primary synthetic aliphatic alcohols of fraction C₁₂-C₁₄ , general formula being C_nH_{2n + 1}O(C₂H₄O)_mH, where n = 12 - 15, m = 2, used as solvent of solutions incorporating macrocyclic compounds chosen from group include crown-esters with unsubstituted aromatic fragments; crown-esters having substituted aromatic fragments incorporating alkyl and/or hydroxyl alkyl substituents of linear and/or branched composition; crown-esters having unsubstituted cyclohexane fragments; crown-esters having substituted fragments incorporating alkyl and/or hydroxyl alkyl substituents of linear and/or branched composition; crown-ester having substituted fragments -O-CHR-CH₂O-, where R is normal or branched alkyl or hydroxyl alkyl. Invention also concerns alternatives of extractants for extracting highly active wastes of radiochemical industry and methods for extracting radionuclides and for recovering spent extractants.

EFFECT: facilitated procedure.

26 cl, 21 tbl

Description

The present invention relates to the field of processing and fractionation of liquid radioactive waste from radiochemical industries, in particular to extraction technologies for the extraction, purification and concentration of radionuclides, such as strontium and cesium, from highly radioactive liquid waste from the processing of irradiated nuclear fuel.

The concept of a closed fuel cycle in nuclear energy involves the utilization of all types of radioactive waste to produce products suitable for long-term storage or disposal, for example, radionuclides in the bound state in cured materials, or suitable for further use of their radioactivity, for example, in the form of isotope products .

The bulk of the radionuclides after the regeneration of irradiated nuclear fuel is contained in high-level liquid wastes, which, along with a high content of stable macro-impurities - sodium, aluminum, iron, rare-earth and other elements, amounting to 300 g / l in total, contain small amounts of cesium radionuclides, strontium and transuranium elements.

In order to reduce the volumes of cured materials sent for burial containing radionuclides with various degrees of activity, for example, borosilicate or phosphate glasses currently used, it is necessary to increase the specific activity of radionuclides in the volume of glasses. An increase in the specific activity of solutions sent for curing for subsequent disposal is possible with a decrease in salt content in radionuclide solutions or when radionuclides sent for disposal are added to solutions of previously obtained salt-free fractions of strontium and cesium radionuclides.

Currently, the most developed areas in the technologies for fractionating liquid radioactive waste based on the extraction extraction of radionuclides, including strontium and cesium radionuclides, are two directions.

One of them is based on the use of a polyhedral carborane complex, in which chlorinated cobalt dicarbolide (CDC) is used as complexing agents for cesium extraction, and high molecular weight polyethylene glycols using fluorinated nitroaromatic diluent are used to extract strontium. However, this technology has significant drawbacks associated with the need for preliminary correction of the initial solution, high losses of extractant in the separation of raffinates and the selection of target products, and the high cost of extractant and diluent.

Another direction is related to the possibility of using macrocyclic polyesters as crown ethers of various structures, which have unique selectivity to radionuclides, including strontium-90 and cesium-137 ions, with a fairly wide range of possible crown ether diluents to create extraction mixtures.

However, the possibilities for the practical use of crown ethers are rather limited due to the low solubility of crown ethers themselves, especially those containing benzene substituents, in organic diluents and the high solubility of crown ethers themselves and their complexes with recoverable cations of radionuclides in aqueous solutions.

To increase the solubility of crown ethers in organic diluents and reduce their solubility in aqueous solutions, macrocyclic compounds from the group of crown ethers having aromatic fragments containing linear and / or branched alkyl and / or hydroxyalkyl substituents and / or cyclohexane fragments were synthesized. containing linear and / or branched alkyl and / or hydroxyalkyl substituents, and / or —O — CHR — CH ₂ O— moieties, where R is straight or branched alkyl or hydroxyalkyl.

The most common structures include: di-tert-butyl dibenzo-18-crown-6 (DTBDB18C6), di-isooctyldibenzo-18-crown-6 (DIODB18C6), dibenzo-21-crown-7 (DB21C7), bis-4.4 '(5') [1-hydroxy-2-ethylhexyl] benzo-18-crown-6 (CROWN XVII), di-tert-butyl dicyclohexano-18-crown-6 (DTBDCH18C6), di-isooctyl dicyclohexano-18-crown-6 (DIODCH18C6), dicyclohexano-18-crown-6 (DCH18C6), bis-4,4 '(5') [1-hydroxyheptyl] cyclohexo-18-crown-6 (CROWN XVI), dibenzo-18-crown-6 ( DB18C6), dibenzo-24-crown-8 (DB24C8), dibenzo-30-crown-10 (DB30C10). With the exception of DB18C6, DB21C7, DB24C8, and DB30C10, all of the crown ethers listed have higher solubility in organic, especially paraffinic, diluents and lower losses in aqueous-organic contacts, while maintaining, according to published data, high selectivity to recoverable radionuclide cations.

Thus, methods for the extraction of cesium from aqueous solutions containing other ions are known using extraction mixtures based on crown ethers bis-4,4 '(5') - (hydroxy-alkyl-benzo) -18-crown-6 in organic a diluent containing tri-n-butyl phosphate or methyl isobutyl ketone, followed by contacting the resulting organic solution with a solution of mineral acid (US, 5888398, A). Known methods for the extraction of cesium from aqueous alkaline wastes, which also contain a significant amount of other alkali metal ions, such as sodium and potassium, using extraction mixtures based on calix-arene crown ethers in a non-polar hydrocarbon solvent, for example, calix [4] arene crown ether - (bis-tert. octylbenzo-crown-6) ether in aliphatic kerosene (US, 6174503, B1).

A known method for the selective extraction of cesium-135 with an extraction mixture containing crown ether tert-butylbenzo-21-crown-7 (tBB21C7) and sodium tetraphenyl borate (FR, 2700709, A1).

Known extraction mixture for the extraction of cesium from aqueous nitric acid media containing crown ether dibenzo-21-crown-7 in a concentration of 0.1-0.2 mol / l in an organic solvent of 2,2-dihydrotrifluoroethyl pentafluoroethyl ether (SU, 1693438, A1) .

Known methods for sequential extraction extraction of cesium and strontium from acidified solutions of radioactive waste: cesium - extractant, consisting mainly of crown ethers bis-4,4 '(5') [1-hydroxy-2-ethylhexyl] benzo-18-crown-6 (hereinafter - Crown XVII) with liquid cation exchangers dinonylnaphthalene sulfonic acid (dinonylnaphtalene sulfonic acid) or didodecylnaphthalene sulfonic acid (didodecylnaphthalene sulphonic acid), and strontium with an extractant consisting mainly of crown ether bis-4,4 '(5') [1 ] cyclohexo-18-crown-6 (hereinafter Crown XVI) with the same cation exchange nicknames in a matrix solution containing tributyl phosphate and kerosene (US, 4749518, A). The disadvantage of this method of joint extraction of strontium and cesium is the reduction of the distribution coefficients of strontium and cesium in the processes of extraction of radionuclides due to the low radiation resistance of the components of the extraction mixture, as well as explosion and fire hazard.

A known method of separation of strontium, neptunium, americium and plutonium from aqueous nitric acid solutions with an extraction mixture containing crown ether, for example, 4.4 '(5') [R, R '] dicyclohexano-18-crown-6, where R and R 'selected from the group consisting of methyl, propyl, isobutyl, t-butyl, hexyl, heptyl and n-octyl (phenyl) -N, N-diisobutylcarbamoylmethylphosphine oxide, in a solvent selected from the group consisting of tri-n-butylphosphate, normal paraffinic hydrocarbons , isoparaffin hydrocarbons (US, 5169609, A).

However, a common drawback of these methods is the reduced radiation stability of the extractants during prolonged operation of the extraction cycle.

Known methods for the extraction of radionuclides of strontium-90 and cesium-135-137 using more radiation-resistant extractants containing crown ethers with various diluents.

For example, a method is known for the extraction of metals, such as plutonium, uranium and strontium, from aqueous solutions using the cis-syn-cis isomer of crown ether of dicyclohexano-18-crown-6 (DCH18C6) in an organic solvent such as nitrobenzene or dichloroethane, or in a solid phase, such as silicon (FR, 2656149, A)

A known method of neutralizing radioactive nitric acid solutions containing strontium and sodium in a concentration of from 0.01 to 0.2 mol / l, using a mixture containing crown ether dicyclohexano-18-crown-6 (DCH18C6) and a solvent, such as chloroform CHCl ₃ , 1,1,2,2-tetrachloroethane, dichloromethane, nitrobenzene, bromobenzene, placed in a cation exchange resin (FR, 2707416, A1).

However, the use of these extraction mixtures and diluents, although it showed great radiation stability of the extractants and distribution coefficients of strontium and cesium acceptable for industrial use, nevertheless did not eliminate the significant losses of crown ethers due to their washing out during the reextraction of radionuclides with aqueous solutions.

The aim of the present invention was the development of extractants and methods for the extraction of radionuclides, including strontium and / or cesium, from high-level liquid radioactive wastes from radiochemical plants containing other macroimpurities, in particular sodium, which has a great influence on the extraction characteristics of extraction mixtures.

When creating the present invention, the task was to develop extractants containing complexing agents with a high selective ability to attach radionuclides, for example cesium and strontium cations, and reduced interaction with other ions contained in highly active waste, such as sodium, in an organic solvent with the ability to organic contacts to hold components of extractants and associates with the extracted ions of radionuclides, for example cesium and / or strontium, pre yatstvuya them leaching from the waste waters. The task was also set to develop a method for the efficient regeneration of the extractant for its subsequent return to the technological process.

The authors previously knew the use of polyfluorinated telomere alcohol 1,1,7-trihydrodeodecafluoroheptanol-1 as a component of the reaction medium in the production of fluoropolymers, and also known a method for the extraction of strontium radionuclides from nitric acid waste from an atomic energy extraction mixture containing a solution of dicyclohexyl-18-crown- 6 (DCH18C6) in an organic diluent — a mixture of 1,1,7-trihydrododecafluoroheptanol-1 and 2,4-diethylloctanol alcohol-telomere, including contacting the waste with the extraction mixture, washing the extract and r Extraction of strontium with distilled water (SU, 1706661, A1). The content of crown ether in the extractant was 0.1-0.2 mol / l in a diluent mixture with a content of 60-65% 1,1,7-trihydrodeodecafluoroheptanol-1 and 40-35% 2,4-diethyl ethanol.

The problem was solved by using a mixture containing polyfluorinated alcohol-telomer 1,1,7-trihydrodeodecafluoroheptanol-1, having the chemical formula H (CF ₂ CF ₂ ) _n CH ₂ OH, where n = 3, and polyoxyethylene glycol esters of synthetic primary higher fatty alcohols fractions C ₁₂ -C _{14 of the} general formula C _n H _{2n + 1} O (C ₂ H ₄ O) _m H, where n = 12 ÷ 14, m = 2, as a diluent for solutions containing macrocyclic compounds selected from the group including : crown ethers having unsubstituted aromatic moieties; crown ethers having substituted aromatic moieties containing linear and / or branched alkyl and / or hydroxyalkyl substituents; crown ethers having unsubstituted cyclohexane moieties; crown ethers having substituted cyclohexane moieties containing linear and / or branched alkyl and / or hydroxyalkyl substituents; crown ethers having substituted —O — CHR — CH ₂ O— moieties where R is straight or branched alkyl or hydroxyalkyl.

The problem was solved by the development of an extractant for the extraction of radionuclides from acidic aqueous solutions of high-level waste from radiochemical industries, which also contain other macroimpurities, including sodium, containing macrocyclic compounds selected from the group consisting of: crown ethers with unsubstituted aromatic fragments; crown ethers having substituted aromatic moieties containing linear and / or branched alkyl and / or hydroxyalkyl substituents; crown ethers having unsubstituted cyclohexane moieties; crown ethers having substituted cyclohexane moieties containing linear and / or branched alkyl and / or hydroxyalkyl substituents; crown ethers having substituted —O — CHR — CH ₂ O— moieties where R is straight or branched alkyl or hydroxyalkyl in an organic solvent containing a polyfluorinated telomeric alcohol 1,1,7-trihydrodeodecafluoroheptanol-1 and a mixture of synthetic polyoxyethylene glycol ethers primary higher fatty alcohols of the C ₁₂ -C ₁₄ fraction of the general formula C _n H _{2n + 1} O (C ₂ H ₄ O) _m H, where n = 12 ÷ 14, m = 2.

Moreover, according to the invention, it is desirable that the organic solvent has the following ratio of components,% by volume:

polyfluorinated alcohol-telomer 1,1,7-trihydrodeodefluoroheptanol-1 - 80-99, a mixture of polyoxyethylene glycol ethers of synthetic primary higher fatty alcohols of fraction C ₁₂ -C ₁₄ - 20-1.

In addition, the task was solved by the development of an extractant for the extraction of cesium radionuclides from acidic aqueous solutions of highly active wastes from radiochemical plants containing cesium cations, as well as other macroimpurities, including sodium containing crown ether selected from the group consisting of di-tert.butyl dibenzo -18-crown-6 (DTBDB18C6), di-isooctyl dibenzo-18-crown-6 (DIODB18C6), dibenzo-21-crown-7 (DB21C7), bis-4.4 '(5') [1-hydroxy-2 ethylhexyl] benzo-18-crown-6 (Crown XVII) in an organic solvent containing polyfluorinated 1,1,7-trigi telomere alcohol drododecafluoroheptanol-1 and a mixture of polyoxyethylene glycol ethers of synthetic primary higher fatty alcohols of the fraction C ₁₂ -C _{14 of the} general formula C _n H _{2n + 1} O (C ₂ H ₄ O) _m H, where n = 12 ÷ 14, m = 2, in the following ratio of components,% by volume:

polyfluorinated alcohol telomere 1,1,7-trihydrodeodecafluoroheptanol-1 - 80-99,

a mixture of polyoxyethylene glycol esters of synthetic primary higher fatty alcohols fraction C ₁₂ -C ₁₄ - 20 - 1.

Moreover, according to the invention, it is desirable that the extractant contains crown ether dibenzo-21-crown-7 (DB21C7) in a concentration of from 0.04 mol / L to 0.095 mol / L of extractant.

The problem was also solved by the development of an extractant for the extraction of strontium radionuclides from acidic aqueous solutions of highly active wastes from radiochemical plants containing strontium cations, as well as other macroimpurities, including sodium, containing crown ether selected from the group consisting of di-tert.butyl dicyclohexano- 18-crown-6 (DTBDCH18C6), di-isooctyl dicyclohexano-18-crown-6 (DIODCH18C6), dicyclohexano-18-crown-6 (DCH18C6), bis-4,4 '(5') [1-hydroxyheptyl] cyclohexano- 18-crown-6 (Crown XVI), in an organic solvent containing polyfluoride Rowan telomeric alcohol 1,1,7-trigidrododekaftorgeptanol-1 and synthetic mixture of polyoxyethylene glycol ethers of primary higher fatty alcohols of the fraction C ₁₂ -C ₁₄ of the general formula C _n H _{2n + 1} O (C ₂ H ₄ O) _m H, where n = 12 ÷ 14, m = 2, with the following ratio of components,% by volume:

polyfluorinated alcohol telomere 1,1,7-trihydrodeodecafluoroheptanol-1 - 80-99,

a mixture of polyoxyethylene glycol esters of synthetic primary higher fatty alcohols fraction C ₁₂ -C ₁₄ - 20-1.

Moreover, according to the invention, it is advisable that the extractant contains dicyclohexano-18-crown-6 in a concentration of from 0.04 mol / l to 0, 095 mol / l of extractant.

In addition, the task was solved by developing an extractant for the joint extraction of strontium and cesium radionuclides from acidic aqueous solutions of highly radioactive waste from radiochemical industries containing strontium and cesium cations, as well as other macroimpurities, including sodium, containing a mixture of crown ethers, in which at least one crown ether is selected from the group consisting of di-tert-butyldibenzo-18-crown-6 (DTBDB18C6), di-isooctyldibenzo-18-crown-6 (DIODB18C6), dibenzo-21-crown-7 (DB21C7) , bis-4,4 '(5') [1-hydroxy-2-ethylhexyl] benzo-18-crown-6 (Crown XVII), and, at least one crown ether is selected from the group consisting of di-tert-butyl dicyclohexano-18-crown-6 (DTBDCH18C6), di-isooctyl dicyclohexano-18-crown-6 (DIODCH18C6), dicyclohexano-18-crown-6 ( DCH18C6), bis-4,4 '(5') [1-hydroxyheptyl] cyclohexano-18-crown-6 (Crown XVI), in an organic solvent containing polyfluorinated telomeric alcohol 1,1,7-trihydrodeodecafluoroheptanol-1 and a mixture polyoxyethylene glycol esters of synthetic primary higher fatty alcohols of the fraction C ₁₂ -C _{14 of the} general formula C _n H _{2n + 1} O (C ₂ H ₄ O) _m H, where n = 12 ÷ 14, m = 2, in the following ratio of components,% by volume:

polyfluorinated alcohol telomere 1,1,7-trihydrodeodecafluoroheptanol-1 - 80-99,

a mixture of polyoxyethylene glycol esters of synthetic primary higher fatty alcohols fraction C ₁₂ -C ₁₄ - 20-1.

Moreover, according to the invention, it is desirable that in the extractant, preferably, the organic solvent has the following ratio of components,% by volume:

polyfluorinated alcohol telomere 1,1,7-trihydrodeodecafluoroheptanol-1 - 87,

a mixture of polyoxyethylene glycol esters of synthetic primary higher fatty alcohols fraction C ₁₂ -C ₁₄ - 13.

Moreover, according to the invention, it is desirable that the extractant contains a mixture of crown ethers of dicyclohexyl-18-crown-6 and dibenzo-21-crown-7 at a concentration of each of the crown ethers from 0.04 mol / l to 0.095 mol / l of extractant .

The problem was also solved by creating a method for the regeneration of spent extractant containing complexes of macrocyclic compounds selected from the group including: crown ethers having unsubstituted aromatic fragments; crown ethers having substituted aromatic moieties containing linear and / or branched alkyl and / or hydroxyalkyl substituents; crown ethers having unsubstituted cyclohexane moieties; crown ethers having substituted cyclohexane moieties containing linear and / or branched alkyl and / or hydroxyalkyl substituents; crown ethers having substituted —O — CHR — CH ₂ O— moieties, where R is straight or branched alkyl or hydroxyalkyl, with recoverable cations of radionuclides in an organic solvent containing a polyfluorinated telomeric alcohol 1,1,7-trihydrodeodecafluoroheptanol-1 and polyoxyethylene glycol esters of synthetic primary higher fatty alcohols of the C ₁₂ -C ₁₄ fraction of the general formula C _n H _{2n + 1} O (C ₂ H ₄ O) _m H, where n = 12 ÷ 14, m = 2, by treating the spent extractant with an aqueous solution of potassium ethylene diamine tetra acetate at pH from 8.0 to 9.0.

Moreover, according to the invention, it is advisable to choose a concentration of potassium ethylenediaminetetraacetate in an aqueous solution in the range from 0.02 mol / L to 0.03 mol / L.

Moreover, according to the invention, it is desirable to provide a pH by adding potassium hydroxide.

The problem was also solved by the development of a method for the extraction of radionuclides from an acidic aqueous solution of highly radioactive waste from radiochemical industries containing other macronutrients, including sodium, in which an aqueous solution of the waste is treated with an extractant containing a macrocyclic compound capable of attaching radionuclide ions to form an extract, and re-extraction of radionuclides from the extract with deionized water, and the extractant contains a macrocyclic compound s selected from the group consisting of crown ethers having unsubstituted aromatic moieties; crown ethers having substituted aromatic moieties containing linear and / or branched alkyl and / or hydroxyalkyl substituents; crown ethers having unsubstituted cyclohexane moieties; crown ethers having substituted cyclohexane moieties containing linear and / or branched alkyl and / or hydroxyalkyl substituents; crown ethers having substituted —O — CHR — CH ₂ O— moieties where R is straight or branched alkyl or hydroxyalkyl in an organic solvent containing a polyfluorinated telomeric alcohol 1,1,7-trihydrodeodecafluoroheptanol-1 and a mixture of synthetic polyoxyethylene glycol ethers primary higher fatty alcohols of the C ₁₂ -C ₁₄ fraction of the general formula C _n H _{2n + 1} O (C ₂ H ₄ O) _m H, where n = 12 ÷ 14, m = 2.

Moreover, according to the invention, it is advisable that the organic solvent has the following ratio of components,% by volume:

polyfluorinated alcohol telomere 1,1,7-trihydrodeodecafluoroheptanol-1 - 80-99,

a mixture of polyoxyethylene glycol esters of synthetic primary higher fatty alcohols fraction C ₁₂ -C ₁₄ - 20-1.

In addition, the problem was solved by the creation of a method for the extraction of cesium radionuclides from acidic aqueous solutions of highly active wastes from radiochemical plants containing cesium cations, as well as other macroimpurities, including sodium, in which an aqueous solution of wastes is treated with an extractant containing at least one a macrocyclic compound capable of attaching cesium radionuclide ions to form an extract, and re-extraction of cesium radionuclides from the deionized extract while the extractant contains crown ether selected from the group consisting of di-tert.butyl dibenzo-18-crown-6 (DTBDB18C6), di-isooctyl dibenzo-18-crown-6 (DIODB18C6), dibenzo-21-crown -7 (DB21C7), bis-4,4 '(5') [1-hydroxy-2-ethylhexyl] benzo-18-crown-6 (Crown XVII), in an organic solvent containing polyfluorinated telomeric alcohol 1,1, 7-trihydrodeodecafluoroheptanol-1 and a mixture of polyoxyethylene glycol ethers of synthetic primary higher fatty alcohols of the C ₁₂ -C ₁₄ fraction of the general formula C _n H _{2n + 1} O (C ₂ H ₄ O) _m H, where n = 12 ÷ 14, m = 2, in the following ratio of components,% by volume:

polyfluorinated alcohol telomere 1,1,7-trihydrodeodecafluoroheptanol-1 - 80-99,

mixture of synthetic primary higher fatty alcohols, polyoxyethylene glycol ethers of fraction C ₁₂ -C ₁₄ - 20-1.

Moreover, according to the invention, it is advisable that the extractant contains crown ether dibenzo-21-crown-7 (DB21C7) in a concentration of from 0.04 mol / l to 0.095 mol / l of extractant.

The problem was also solved by the development of a method for the extraction of strontium radionuclides from acidic aqueous solutions of highly radioactive wastes of radiochemical plants containing strontium cations, as well as other macroimpurities, including sodium, in which an aqueous solution of waste is treated with an extractant containing at least one macrocyclic compound capable of attaching strontium radionuclide ions to form an extract, and reextracting strontium radionuclides from deionisir extract bath water, and the extractant contains crown ether selected from the group consisting of di-tert-butyl dicyclohexano-18-crown-6 (DTBDCH18C6), di-isooctyl dicyclohexano-18-crown-6 (DIODCH18C6), dicyclohexano-18- crown-6 (DCH18C6), bis-4,4 '(5') [1-hydroxyheptyl] cyclohexano-18-crown-6 (Crown XVI), in an organic solvent containing polyfluorinated telomeric alcohol 1,1,7-trihydrodeodefluoroheptanol -1 and a mixture of polyoxyethylene glycol ethers of synthetic primary higher fatty alcohols of the C ₁₂ -C ₁₄ fraction of the general formula C _n H _{2n + 1} O (C ₂ H ₄ O) _m H, where n = 12 ÷ 14, m = 2, in the following ratio to mponentov% by volume:

polyfluorinated alcohol telomere 1,1,7-trihydrodeodecafluoroheptanol-1 - 80-99,

a mixture of polyoxyethylene glycol esters of synthetic primary higher fatty alcohols fraction C ₁₂ -C ₁₄ - 20-1.

Moreover, according to the invention, it is desirable that the extractant contains dicyclohexano-18-crown-6 in a concentration of from 0.04 mol / L to 0, 095 mol / L of extractant.

The problem was also solved by the creation of a method for the joint extraction of radionuclides of cesium and strontium from acidic aqueous solutions of high-level waste from radiochemical plants containing cesium and strontium cations, as well as other macroimpurities, including sodium, in which an aqueous solution of waste is treated with an extractant containing macrocyclic compounds, capable of attaching cesium and strontium radionuclide ions to form an extract, and re-extraction of cesium and strontium radionuclides the extract with deionized water, and the extractant contains a mixture of crown ethers in which at least one crown ether is selected from the group consisting of di-tert.butyl dibenzo-18-crown-6 (DTBDB18C6), di-isooctyl dibenzo- 18-crown-6 (DIODB18C6), dibenzo-21-crown-7 (DB21C7), bis-4.4 '(5') [1-hydroxy-2-ethylhexyl] benzo-18-crown-6 (Crown XVII) and at least one crown ether is selected from the group consisting of di-tert.butyl dicyclohexano-18-crown-6 (DTBDCH18C6), di-isooctyl dicyclohexano-18-crown-6 (DIODCH18C6), dicyclohexano-18-crown- 6 (DCH18C6), bis-4,4 '(5') [1-hydroxyheptyl] cyclohexo-18-crown-6 (Crown XVI), op a solvent containing polyfluorinated telomere alcohol 1,1,7-trihydrodeodecafluoroheptanol-1 and a mixture of polyoxyethylene glycol esters of synthetic primary higher fatty alcohols of fraction C ₁₂ -C _{14 of the} general formula C _n H _{2n + 1} O (C ₂ H ₄ O) _m H , where n = 12 ÷ 14, m = 2, with the following ratio of components,% by volume:

polyfluorinated alcohol telomere 1,1,7-trihydrodeodecafluoroheptanol-1 - 80-99,

a mixture of polyoxyethylene glycol esters of synthetic primary higher fatty alcohols fraction C ₁₂ -C ₁₄ - 20-1.

Moreover, according to the invention, it is preferable that the organic solvent has the following ratio of components,% by volume:

polyfluorinated alcohol telomere 1,1,7-trihydrodeodecafluoroheptanol-1 - 87,

a mixture of polyoxyethylene glycol esters of synthetic primary higher fatty alcohols fraction C ₁₂ -C ₁₄ - 13.

Moreover, according to the invention, it is desirable that the extractant contains a mixture of dicyclohexano-18-crown-6 and dibenzo-21-crown-7 at a concentration of each of the crown ethers in the mixture from 0.04 mol / l to 0.095 mol / l of extractant.

In addition, according to the invention, it is desirable in the methods of extraction extraction of strontium or cesium or strontium and cesium to additionally separate the recycle extractant containing complexes of macrocyclic compounds with cations of radionuclides and regenerate it for reuse by treating the recycle extractant with an aqueous solution of potassium ethylene diamine tetraacetate at pH 8 , 0 to 9.0.

Moreover, according to the invention, it is desirable to choose a concentration of potassium ethylenediaminetetraacetate in an aqueous solution in the range from 0.02 mol / L to 0.03 mol / L.

Moreover, according to the invention, it is desirable to ensure the pH of the aqueous solution by adding potassium hydroxide.

Moreover, according to the invention, it is advisable to carry out all operations of the methods in a dynamic countercurrent mode.

The invention is further explained in the description of specific examples of its implementation. When describing specific options, specific narrow terminology is used for clarity, however, the invention is not limited to accepted terms and it should be borne in mind that each such term covers all equivalent terms used to solve the same problems.

1. The selective ability of the extractants according to the invention for the extraction of radionuclides.

1.1. Selective ability of crown ether extractants in various solvents.

Studies have been carried out to determine the distribution coefficients of radionuclides, for example strontium or cesium, using extractants according to the invention containing various crown ethers as a complexing agent: di-tert-butyl dibenzo-18-crown-6 (hereinafter DTBDB18C6), di- isooctyl dibenzo-18-crown-6 (hereinafter DIODB18C6), di-tert-butyl dicyclohexano-18-crown-6 (hereinafter DTBDCH18C6), di-isooctyl dicyclohexano-18-crown-6 (hereinafter DIODCH18C6), dicyclohexano-6-18-crown hereinafter DCH18C6) or dibenzo-21-crown-7 (hereinafter DB21C7), in an organic diluent according to clearly invention polyfluorinated telomeric alcohol 1,1,7-trigidrododekaftorgeptanol-1 (1,1,7-trihydrododecafluoroheptanol-1) (hereinafter - ftorgeptanol n _3).

For comparison, the distribution coefficients of strontium and cesium were determined using extractants containing similar crown ethers in another organic diluent - decane.

For testing, experimental aqueous nitric acid solutions containing strontium and cesium at a concentration of 1 g / l with a nitric acid content of about 3.0 mol / l were taken. The obtained distribution coefficients of strontium and cesium for various extraction systems No. 1-12 are presented in table 1.

Table 1 The distribution coefficients of strontium and cesium during extraction with organic solutions of crown ethers Crown ether, 0.095 mol / l System number Diluent Distribution coefficient Notes Strontium Cesium DTBDB18C6 one dean Gel in the organic phase 2 fluoroheptanol n ₃ 0.11 15.45 DIODB18C6 3 dean 0.05 0.004 four fluoroheptanol n ₃ 0.06 4.23 DTBDCH18C6 5 dean <0.001 - 6 fluoroheptanol n ₃ 1.91 - DIODCH18C6 7 dean <0.001 0.004 8 fluoroheptanol n ₃ 0.106 - Dch18c6 9 dean - - Third phase 10 fluoroheptanol n ₃ 1,6 - DB21C7 eleven dean - - Not soluble 12 fluoroheptanol n ₃ - 10.7

From the data of Table 1 it follows that due to the low distribution coefficients of strontium and cesium, the use of extraction systems with crown ethers in paraffin hydrocarbons such as decane is practically impossible.

The size of the alkyl chain has a significant effect on the extraction characteristics of crown ethers, probably creating steric hindrances when placing the cation in the cavity of the macrocycle. The strontium distribution coefficients for organic solutions DCH18C6 (system No. 10) and DTBDCH18C6 (system No. 6) in fluoroheptanol n ₃ have approximately the same values (1.91 and 1.6), but with an increase in the number of carbon atoms of the attached radical, for example, to isooctyl (system No. 8), reduces them by more than an order of magnitude.

Cesium extraction using extractants containing dibenzo-crown ether derivatives is effective only in fluoroheptanol n ₃ . It should also be noted that with an increase in the number of carbon atoms in the alkyl chain of a substituent, the cesium distribution coefficients determined under the same experimental conditions (systems No. 2 and No. 4) significantly decrease.

1.2. Solubility of crown ether extractants in acidic and aqueous-organic contacts.

Studies were conducted on the solubility of the extractants according to the invention and extractants containing similar crown ethers in other solvents, in aqueous and nitric acid solutions. For tests, extractants containing crown ethers DCH18C6 or DB21C7 at a concentration of 0.095 mol / L in various organic diluents were taken. The extractants were mixed with aqueous or nitric acid solutions with a nitric acid content of 3 mol / L in a closed thermostatic container for 3 hours. Then the obtained aqueous-organic systems were separated. The water part after sedimentation and filtration was analyzed for the content of crown ethers by photometric methods. The test results are presented in table.2.

table 2 Solubility of crown ethers in water and in nitric acid when used in extractants with various organic diluents No. Diluent The concentration of crown ether in the aqueous phase, mol / l × 10 ^-3 Notes Dch18c6 DB21C7 HNO ₃ H ₂ O HNO ₃ H ₂ O one carbon tetrachloride 0.139 0.258 0.159 0.173 2 trichlorethylene 0.94 0.65 0.218 0.188 3 tetrachloropropane 1.72 0.968 Not soluble four trichlorobenzene 2,016 1,142 0.173 0.168 5 2,2-dihydrotrifluoroethyl-pentafluoroethyl ether 0.344 0,301 0,112 0,071 6 fluoroheptanol n ₃ 0,086 <0.027 0,068 <0.025

The research results shown in Table 2 show that the minimum solubility of crown ethers in aqueous and nitric acid solutions is observed for crown ether extractants in fluoroheptanol n ₃ according to the invention.

1.3. The selective ability of the extractants according to the invention depending on the composition of the waste processed.

The differences in the compositions of high-level waste solutions were investigated, affecting the selective ability of the extractants according to the invention.

1.3.1. Determination of the components of solutions affecting the extraction of radionuclides.

The composition of the real initial solutions of 1 and 2 radiochemical plants was determined, subjected to extraction processing for the extraction of radionuclides. At the same time, for research, solution 1 was a simulator of an evaporated raffinate of fuel cell processing, most often used in Russia, and solution 2 was a simulator of highly active liquid waste, most often used in the USA (INEEL). The average composition is presented in table.3.

From table 3 it is seen that the main difference in the compositions of solutions No. 1 and No. 2, which may affect the processes of extraction of radionuclides, is a high concentration of macronutrients, such as sodium and potassium, against the background of low concentrations of recoverable elements.

1.3.2. Determination of the concentration of nitric acid in the initial solution, affecting the extraction of sodium with extractants according to the invention.

For studies, extractants containing crown ethers were chosen: DB18C6, DTBDB18C6, DCH18C6 or DB21C7 at a concentration of 0.095 mol / L in fluoroheptanol n ₃ . As experimental solutions, aqueous solutions of sodium nitrate were used, the concentration of which was determined by radiometric methods according to a previously introduced aliquot of the sodium isotope-22. The test results are presented in table.4.

Table 4

The effect of the concentration of nitric acid on the extraction of sodium with extractants according to the invention

The concentration of nitric acid, mol / l Sodium Distribution Coefficients DB18C6 + fluoroheptanol n ₃ DTBDB18C6 + fluoroheptanol n ₃ DCH18C6 + fluoroheptanol n ₃ DB21C7 + fluoroheptanol n ₃ 0 0,025 0,03 0.1 0 0.1 0.04 0.04 0.12 0 0.5 0.15 0.17 0.12 0.005 1,0 0.21 0.27 0.05 0.01 3.0 0.49 0.55 0.02 0.1 5,0 0.67 0.64 0.01 0.12

From table 4 it is seen that extractants containing crown ethers DB18C6 and DTBDB18C6 have minimal distribution coefficients of sodium in solutions with nitric acid concentrations from 0 to 0.1 mol / L, after which the sodium extraction increases. The extractant containing DB21C7, in the range of concentrations of nitric acid from 0 to 0.1 mol / l, sodium practically does not extract and at higher concentrations of nitric acid it extracts sodium slightly. The extractant containing DCH18C6, in the region of low concentrations of nitric acid from 0 to 0.5 mol / L, has low distribution coefficients of sodium, and with an increase in the concentration of nitric acid in the initial solution above 0.5 mol / L, the extraction of sodium decreases almost to zero.

1.3.3. Determination of sodium concentrations affecting the extraction of radionuclides with extractants according to the invention.

Extractions to extract cesium were subjected to initial solutions containing 1.0 g / l of cesium in nitric acid with a concentration of 3.0 mol / l at various concentrations of sodium. The solutions were treated with extractants according to the invention containing crown ether DTBDB18C6 at a concentration of 0.095 mol / L in fluoroheptanol n ₃ . The research results are given in table.5.

Table 5 The effect of sodium concentration on cesium extraction with the extractant according to the invention Experience number The concentration of sodium nitrate in the initial solution, mol / l Cesium distribution coefficient one 0 16,0 2 0.02 9.0 3 0,03 9.1 four 0.04 9.3 5 0.20 3.0

From table 5 it is seen that even small concentrations of sodium nitrate in the initial solution reduce the distribution coefficients of cesium, occupying the capacity of the extractant.

We studied the characteristics of the extractants according to the invention for the extraction of sodium from acidic aqueous solutions of high-level waste, for which we analyzed the concentration of sodium in the organic and aqueous phases containing extractants based on DTBDB18C6 or DCH18C6 or DB21C7 at a concentration of 0.05 mol / L in fluoroheptanol n ₃ . The results are shown in table.6.

Table 6 The interaction of the extractants according to the invention with sodium No. of experience Extractant The concentration of sodium, mol / l in the organic phase in the water phase one DTBDB18C6 + 0 0.01 2 fluoroheptanol n ₃ 0,035 0.1 3 0,07 0.2 four 0.14 0.4 5 DCH18C6 + 0 0.01 6 fluoroheptanol n ₃ 0.003 0.1 7 0.005 0.2 8 0.009 0.4 9 DB21C7 + 0 0.01 10 fluoroheptanol n ₃ 0.01 0.1 eleven 0.018 0.2 12 0,035 0.4

From table 6 it can be concluded that the extractants according to the invention based on non-alkylated crown ethers DCH18C6 and DB21C7 have lower sodium distribution coefficients compared to the extractant containing non-alkylated crown ether DTBDB18C6. This property is important when choosing extractants for the extraction of radionuclides from highly active wastes containing significant amounts of sodium, for example, from highly concentrated solutions with a sodium concentration of 0.4 mol / L, which corresponds to a sodium concentration of about 10 g / L, and higher, leaving at this free complexing agent capacity sufficient for extraction and radionuclides.

1.3.4. Determination of nitric acid concentrations affecting the extraction of radionuclides from waste solutions.

Studies were conducted on the dependence of cesium extraction with organic solutions of DTBDB18C6 in fluoroheptanol n ₃ and DB21C7 in fluoroheptanol n ₃ on the concentration of nitric acid in the initial solution. As the source used solution No. 1, the composition of which is described in table.2. The research results are given in table.7.

Table 7 The effect of the concentration of nitric acid on the selective ability of the extractants according to the invention Experience number The concentration of nitric acid, mol / l Cesium distribution coefficients DTBDB18C6 + fluoroheptanol n ₃ DB21C7 + fluoroheptanol n ₃ one 0 2,5 0.25 2 OD 7.1 1,0 3 0.5 12.8 3.2 four 1,0 12.3 7.8 5 2.0 10.3 10,2 6 3.0 8.2 12,2 7 4.0 6.0 11,4 8 5,0 4.0 10.0 9 6.0 2.7 8.0 10 7.0 1,1 6.2 eleven 8.0 0 5,0

From the results shown in Table 7, it can be seen that the extractant according to the invention, containing DTBDB18C6 in fluoroheptanol n ₃ , has, starting from pH regions, cesium distribution coefficients in the neutral, low- and medium-acid region sufficient for a dynamic countercurrent extraction process cesium, and the maximum extraction characteristics - with a concentration of nitric acid in the range from 0.3 to 1.5 mol / l, and therefore can extract cesium from neutral media, which include numerous contour, sump, sewage and legged other waters.

The extractant according to the invention containing DB21C7 in fluoroheptanol n ₃ , in solutions with a concentration of nitric acid from 0 to 0.7 mol / L, has low extraction characteristics, and exhibits the best selective ability to extract cesium at nitric acid concentrations in the range from 2.0 to 5 , 0 mol / L with a maximum at 3.0 mol / L.

2. Selective ability of the extractants according to the invention in comparison with the known extractants based on Crown XVI and Crown XVII.

Studies were carried out on the extraction of cations of various metals from aqueous nitric acid solutions containing them by treatment with extractants containing, according to the invention, DCH18C6 or DB21C7 in an organic solvent containing: fluoroheptanol n ₃ - 80% by volume and syntanol - 20% by volume, at a concentration of crown esters of 0.05 mol / L and a nitric acid content of 190 g / L. For comparison, we used the data given in the description of the patent (US, 4749518, A) for similar tests of extractants containing Crown XVI or Crown XVII with a cation exchanger - dinonylnaphthalene sulfonic acid in a matrix solution containing tributyl phosphate and kerosene.

The solutions were contacted with the extractants according to the invention in thermostatic separating funnels at 25 ± 3 ° C for 5 minutes, with a ratio of organic and aqueous phases of 1: 1. After settling for 60 minutes, the phases were separated and the aqueous phase was analyzed to determine the concentrations of the elements. The distribution coefficients of the corresponding elements calculated from the results of the analyzes are given in Table 8.

Table 8 Extraction and cations of various metals Structure Source
concentration, g / l Distribution ratios DCH18C6 based extractant * Extractant based on Crown XVI DB21C7 based extractant * Extractant based on Crown XVII Al 6.0 0,03 - 0.02 - Ba 1,0 2.03 4.2 1,02 0,03 Fe 10.0 0.017 - 0.014 - Y 1,0 - 0.02 - 0.02 Ca 2.0 0.12 - 0.02 - Mn 0.4 0.06 - 0.04 - Ni 4.0 0,023 - 0,03 - Pd 0.3 - 0.05 0,03 0.22 Ru 0.75 0.16 0.26 0.004 0.31 2 REE 25.0 0.04 0.06 0.04 0.17 Rb 0.12 - 0.11 0.02 0.29 Pb 0.05 4.2 0.02 - Sr 1,0 3.6 3.84 0.02 0.06 Cr 1,0 0.02 0.02 - Cs 1,0 0.02 0,03 1.8 1,59 Zr 1,0 0.018 1.41 0,038 2.09 Na 10.0 0.01 - 0,047 - * according to patent (US, 4749518, A)

From the data given in table 8, we can conclude that the extraction characteristics of the extraction of strontium and cesium by the proposed and known methods differ slightly.

3. The choice of the range of concentrations of crown ether in the extractants according to the invention.

The selective ability of the extractants according to the invention was investigated, containing a mixture of crown ethers DCH18C6 and DB21C7, each in different concentrations, in an organic solvent containing,% by volume:

fluoroheptanol n ₃ - 87%, syntanol - 13%, depending on the concentration of crown ether, during the extraction of radionuclides of strontium and cesium. Aqueous solutions of strontium and cesium with a concentration of 1 g / l in each and a concentration of nitric acid of 3.0 mol / l with aliquots of strontium-85 and cesium-134 introduced beforehand were contacted with the indicated extractants in the separation funnels thermostated at 25 ± 3 ° С in for 5 minutes, with a ratio of organic and aqueous phases of 1: 1. After settling for 60 minutes, the phases were separated and the aqueous phase was analyzed. The concentrations of strontium and cesium in aqueous solutions were determined by the radiometric method. The results obtained are presented in table.9.

Table 9

The effect of the concentration of crown ethers on the extraction characteristics of the extractants according to the invention

The concentration of each of the crown ethers: DCH18C6 and DB21C7 in the extractant, mol / l Distribution ratios Strontium Cesium 0.04 1.65 1.16 0.05 2,32 2,32 0.06 2.99 3.47 0,07 3.66 4.64 0.08 4.33 5.79 0.09 5,0 6.95 0.1 5.67 8.11

From the results presented in Table 9, it can be concluded that in the entire range of crown ether concentrations, the extractants according to the invention quite efficiently extract strontium and cesium, and individual crown ether concentrations can be selected in relation to the composition of the processed aqueous solution.

4. Determination of the optimal concentration of syntanol in the extractant according to the invention.

The selectivity of the extractants according to the invention, containing a mixture of crown ethers DCH18C6 and DB21C7, each at a concentration of 0.05 mol / L, in an organic solvent containing fluoroheptanol n ₃ and syntanol, depending on the quantitative ratio in the solvent, was investigated. An aqueous nitric acid solution of a composition similar to that described above, with aliquots of strontium-85 and cesium-134 introduced beforehand, was contacted with the indicated extractant in dividing funnels thermostated at 25 ± 3 ° С for 5 minutes, with a 1: 1 ratio of organic and aqueous phases. After settling for 60 minutes, the phases were separated and the aqueous phase was analyzed. The concentrations of strontium and cesium in aqueous solutions were determined by the radiometric method. The results are presented in table 10.

Table 10 Extraction of radionuclides depending on the concentration of syntanol in the extractant according to the invention The concentration of syntanol in the solvent,% by volume Distribution ratios Strontium Cesium 5 1.26 2.80 10 1.80 2,56 fifteen 2.69 2.16 twenty 3.10 1.79

From table 10 it is seen that increasing the concentration of syntanol in the organic solvent of the extractant according to the invention affects the extraction of strontium positively, and the extraction of cesium - negatively. From a graphical comparison of the extraction results, we can conclude that for the extractants according to the invention for the joint extraction of strontium and cesium, the optimal concentration of syntanol in a solvent containing fluoroheptanol n ₃ is 13% by volume.

5. The radiation resistance of the extractants according to the invention.

Studies have been conducted of the radiation resistance of the extractants according to the invention, used to extract radionuclides of strontium or cesium. For this, reaction mixtures, which are two-phase aqueous-organic systems, containing extractants based on crown ethers DCH18C6 or DB21C7 in fluoroheptanol n ₃ and aqueous nitric acid solutions of waste, and, for comparison, reaction mixtures containing extractants based on crown ethers Crown XVI or Crown XVII with a cation exchanger of dinonylnaphthalene sulfonic acid in a matrix solution containing tributyl phosphate and kerosene, was irradiated with Co ⁶⁰ gamma rays in a thermostatic stainless steel cell with continuous stirring and bubbling oxygen. The maximum integral radiation dose was 80 W · h / l (285.3 kGy). Extractant samples were tested to determine the extraction characteristics before and after irradiation to determine the decrease in the distribution coefficient D _Me due to radiolytic degradation of the extractant components. The results obtained are presented in table.11.

Table 11 The radiation resistance of the extractants according to the invention No. Crown ether extractant Recoverable radionuclide Distribution coefficient before exposure after dose exposure 100.0 kGy (10 ⁷ rad) 285.3 kGy D _me % of ref. D _me % of ref. one Dch18c6 Sr 3.6 3.4 94.4 3.0 83.3 2 Crown xvi Sr 1.98 1,56 78.78 - 3 DB21C7 Cs 2.83 2.83 100.0 2.65 93.8 four Crown xvii Cs 1,59 1,04 65.41 -

From the results presented in Table 11, it can be seen that after irradiation with a dose of 100.0 kGy, the Crown XVI-based extractant loses about 21% of the strontium distribution coefficient, and the Crown XVII-based extractant reduces the cesium distribution coefficient by 35%. After irradiation with a dose of 285.3 kGy, the extractants based on Crown XVI and Crown XVII practically do not work. Losses of the distribution coefficients of strontium and cesium extractants according to the invention after irradiation with a dose of 100.0 kGy are negligible, and extractants remain operational even after irradiation with a dose significantly exceeding 100.0 kGy.

6. Regeneration of extractants according to the invention.

Due to the fact that crown ethers are expensive products, studies have been conducted on the possibility of regeneration of extractants containing crown ethers for their reuse. To obtain the extractant according to the invention, 23.64 g of DB21C7 crown ether (0.06 mol / L) and 29.8 g of DCH18C6 (0.08 mol / L) were sequentially dissolved in 1 liter of the organic solvent of the invention containing syntanol - 13% by volume and fluoroheptanol n ₃ - 87% by volume, the obtained organic phase of the extractant was kept for an hour and cooled. Then sequentially:

- the organic phase was contacted with the initial aqueous solution, the composition of which is indicated for solution No. 1 in table 3, after settling the phases were separated,

- the aqueous phase (raffinate) was analyzed, and the organic phase was subsequently contacted with deionized water (two contacts) with the release of aqueous strips to analyze the contained extractable elements and the organic phase, the reverse extractant;

the circulating extractant was contacted with an aqueous solution of potassium ethylene diamine tetraacetate (hereinafter EDATA (K)) at a concentration of 0.025 mol / L (one contact) at a pH of from about 8.0 to about 9.0, achieved by introducing potassium hydroxide into the solution.

The conditions of contacting, separation, and phase analysis are similar to those described in clause 4. The distribution coefficients of metal cations calculated from the phase analysis are shown in Table 12.

Table 12 The regeneration of the extractant according to the invention in the implementation of the method of extraction of radionuclides according to the invention Contact number The composition of the aqueous phase Element Distribution Coefficients Cesium Strontium Barium Lead one Stock solution 2.6 2,8 2.2 4.15 2 Water 0.8 0.7 0.6 4.22 3 Water 0.24 0.13 0.11 4.21 four EDATA (K) 0.05 0.01 0.01 0.11 + potassium hydroxide to a solution pH of from about 8.0 to about 9.0

From table 12 it is seen that the extraction, washing with water and re-extraction of cesium, strontium and barium with water occurs with satisfactory distribution coefficients. Contacting the circulating extractant with EDATA (K) makes it possible to completely restore the complexing agent of the extractant according to the invention for subsequent use, which is an important property for organizing the dynamic mode of the radionuclide extraction process cyclically in the organic phase by the method according to the invention. Since lead is not re-extracted with water, a regeneration cascade is required to remove it from the circulating extractant, in which the potassium salt of ethylenediaminetetraacetic acid can be used as the aqueous phase.

It follows from the foregoing that the extractants according to the invention containing crown ethers capable of extracting radionuclides and selected from the group consisting of: crown ethers having unsubstituted aromatic fragments; crown ethers having substituted aromatic moieties containing linear and / or branched alkyl and / or hydroxyalkyl substituents; crown ethers having unsubstituted cyclohexane moieties; crown ethers having substituted cyclohexane moieties containing linear and / or branched alkyl and / or hydroxyalkyl substituents; crown ethers having substituted —O — CHR — CH ₂ O— moieties, where R is straight or branched alkyl or hydroxyalkyl in an organic solvent containing a polyfluorinated telomeric alcohol 1,1,7-trihydrodeodecafluoroheptanol-1 and a mixture of synthetic polyoxyethylene glycol ethers primary higher fatty alcohols of the fraction C ₁₂ - C _{14 of the} general formula C _n H _{2n + 1} O (C ₂ H ₄ O) _m H, where n = 12 ÷ 14, m = 2, have the following properties:

- high extraction characteristics in relation to radionuclides, for example strontium or cesium, weakly dependent on the acidity and elemental composition of the macroimpurities of the initial solution;

- resistance to radiation exposure;

- the diluent used in extractants makes it possible to obtain the concentration of crown ethers necessary for the effective extraction of strontium and cesium, while retaining both the crown ethers themselves and their associates with recoverable cations in contact with aqueous solutions and nitric acid solutions, which can be used for re-extraction of radionuclides;

- the possibility of regeneration of the spent extractant according to the invention for subsequent reuse, which allows the use of extractants according to the invention in industrial conditions in a dynamic mode repeatedly.

It also follows from the foregoing that, as illustrated by the above examples of methods for the extraction of strontium and / or cesium radionuclides from aqueous acidic solutions of highly active waste using extractants according to the invention, it is possible to make an optimal choice of the quantitative and qualitative composition of complexing agents and solvent of the extractant according to the invention for solving specific the tasks of extracting radionuclides from media having different contents of macroimpurities, including tria, different acidity and different composition of radioactive elements.

7. Extraction of radionuclides from acidic aqueous solutions of radiochemical plants according to the invention using extractants according to the invention under industrial conditions.

Specialists working in the field of processing high-level waste from radiochemical industries know that in the developed technologies for their fractionation by treatment with extractants containing chlorinated cobalt dicarbolide (CDC), extraction extraction of cesium from solutions containing large concentrations of elements of I-III groups is limited. Due to the low selectivity of CDK, the initial solutions are diluted almost twice, thus increasing the volume of secondary radioactive waste. CDK-based extractants show maximum distribution coefficients at nitric acid concentrations from 2.0 to 4.0 mol / L. A solution of cesium re-extraction for the extractant with CDK is a solution of hydrazine in nitric acid with a concentration of from 3.0 to 8.0 mol / L. According to the fire and explosion safety of the evaporation and vitrification processes, the hydrazine content in the processed solutions should not exceed 1.0 g / l, which also necessitates dilution of the obtained reextracts before vitrification.

With the use of CDK, several variants of technological schemes have been proposed: the combined release of strontium and cesium, followed by their separate reextraction with a solution of hydrazine in nitric acid or a complex scheme for the isolation of all radionuclides in one extraction cycle. At the same time, there is one complexing agent in the extractant - CDK, which extracts cesium with rather high distribution coefficients, but does not have high selectivity, since it also extracts other elements. The individual release of strontium using CDK is impossible.

The possibility of using industrial technologies for the extraction of radionuclides, including strontium and cesium, using extractants containing crown ethers, was constrained by the high solubility of the crown ethers themselves and their complexes with recoverable cations in aqueous solutions. Many studies using chlorinated hydrocarbons, tributyl phosphate in paraffins, and others as diluents for crown ethers, have not allowed the creation of an industrial technology for the extraction of radionuclides using crown ethers.

Moreover, any of the schemes for the methods of extraction of extraction of radionuclides includes the steps of contacting the extractant with the solutions to be treated, extracting an extract containing an organic phase saturated with extractable cations, and an aqueous phase, washing the organic phase from impurities and subsequent re-extraction, joint or separate, of radionuclides with water or solutions of various complexones.

In accordance with the invention, an exhaustive extractant regeneration operation may additionally be carried out.

The authors have developed methods for the extraction of radionuclides using extractants according to the invention, allowing them to be carried out under industrial conditions in a dynamic mode.

7.1. The method of extracting strontium according to the invention in a dynamic mode.

The initial aqueous solution, the composition and concentrations of the components of which are given in Table 3 for solution No. 1, was contacted with an extractant according to the invention containing 0.05 mol / L DCH18C6 in a solvent containing 20% by volume of syntanol and 80% by volume of fluoroheptanol n ₃ in a continuous, countercurrent mode at the installation of extractors of the mixer-settler type with pulsating mixing and phase transport. The extraction scheme included eight stages of extraction, two stages of washing, eight stages of stripping and two stages of regeneration of the circulating extractant. The compositions and consumption of the components of the extraction scheme are given in table.13.

Table 13 Composition and consumption of components Extraction Scheme Component Flow rate, ml / hour Structure Stock solution 57.3 See table 3, solution No. 1, Extractant 59.0 0.05 mol / L DCH18C6 + solvent: syntanol - 20% by volume and fluoroheptanol n ₃ - 80% by volume Wash solution 5.66 Deionized water Reextracting Solution 33.3 Deionized water Regenerating solution 5.66 0.025 mol / L aqueous solution
potassium ethylenediaminetetraacetate + potassium hydroxide to a pH of from about 8.0 to about 9.0

During the operation of the installation, the strontium concentrations in the raffinates, reextracts, and regenerates, as well as the concentration of crown ethers in the products of the extraction scheme were monitored radiometrically. Technological parameters of the process and solubility of crown ether (averaged indicators of a number of experiments) are given in table.14.

Table 14 Extraction of strontium by the method according to the invention Extraction Scheme Product Strontium content in the products of the extraction scheme,% of the initial * The concentration of crown ether in the products of the extraction scheme, mg / l Raffinate 0.35 80 Reextract 99.55 172 Regenerate <0.1 thirty * taking into account the costs of products

From table 14 it is seen that the extraction of strontium is over 99%. Received an average concentration of about 1.7 times. The residual content of the elements is completely extracted by the regenerating solution, which allows returning the circulating extractant to the cycle and making the process continuous. The insignificance of the loss of the organic phase with the aqueous products of the technological scheme allows for continuous continuous processes without adjusting the composition of the organic phase of the extractant according to the invention.

7.2. The method of extraction of cesium according to the invention in a dynamic mode.

The process scheme and conditions for the extraction of cesium by the method according to the invention are similar to those described in 7.1 above, but the extractants according to the invention containing DB21C7 solutions at a concentration of 0.05 mol / L in an organic solvent containing syntanol - 5% by volume were used as the organic phase for the extraction of cesium and fluoroheptanol n ₃ - 95% by volume. The compositions and costs of the components of the extraction scheme are given in table.15.

Table 15 Composition and cost of components Extraction Scheme Component Flow rate, ml / hour Structure Stock solution 57.3 See example 7.1. Extractant 59.0 0.05 mol / L DB21C7 + solvent: syntanol - 5% by volume and fluoroheptanol n ₃ - 95% by volume Wash solution 5.66 Deionized water Reextracting Solution 33.3 Deionized water Regenerating solution 11.32 0.025 mol / L aqueous solution potassium ethylenediaminetetraacetate + potassium hydroxide to a pH of from about 8.0 to about 9.0

During the operation of the installation, the cesium concentrations in raffinates, strips, and regenerates, as well as the concentration of crown ethers in the products of the extraction scheme were monitored radiometrically. Technological parameters of the process and the solubility of crown ethers (averaged indicators of a number of experiments) are given in table.16.

Table 16 Extraction of cesium by the method according to the invention Extraction Scheme Product The cesium content in the products of the extraction scheme,% of the initial * The concentration of crown ether in the products of the extraction scheme, mg / l Raffinate 1.35 27 Reextract 94.5 53 Regenerate 4.15 eighteen * taking into account the costs of products

From table 16 it is seen that the extraction of cesium is more than 98% when the release of cesium about 95% in the salt-free product. Cesium-free regenerated extractant with minimal losses can be returned to the production cycle.

7.3. A method for the joint extraction of strontium and cesium according to the invention in a dynamic mode from waste from Russian radiochemical plants.

A solution of radioactive waste was used as the initial solution, the composition of which is given in Table 3, solution No. 1. The process scheme and extraction conditions are similar to those described in 7.1, but a mixture of 0.06 mol / L DB21C7 with 0.08 mol / l of DCH18C6 in a solvent containing syntanol is 13% by volume and fluoroheptanol n ₃ is 87% by volume. The compositions and costs of the components of the extraction scheme are given in table.17.

Table 17 Composition and consumption of components Product Flow rate, ml / hour Structure Stock solution 57.3 See the solution of example 7.1 Extractant 59.0 0.06 mol / L DB21C7 + 0.08 mol / L DCH18C6 + solvent: syntanol - 13% by volume and fluoroheptanol n ₃ - 87% by volume Wash solution 5.66 Deionized water Reextracting Solution 33.3 Deionized water Regenerating solution 5.66 0.025 mol / L aqueous solution
potassium ethylenediaminetetraacetate + potassium hydroxide to a pH of from about 8.0 to about 9.0

During the operation of the installation, the concentrations of strontium and cesium in the raffinates, reextracts and regenerates, as well as the concentration of crown ethers in the products of the extraction scheme were monitored. Technological parameters of the process and the solubility of crown ethers (averaged indicators of a number of experiments) are given in table 18.

Table 18 Extraction of cesium and strontium by the method according to the invention from waste from Russian radiochemical plants Extraction Scheme Product The content in the products of the extraction scheme,% of the initial * The concentration of crown ether in the products of the extraction scheme, mg / l cesium strontium Raffinate 1,63 1.87 180 Reextract 95.1 97.4 152 Regenerate 3.2 0.7 70 * taking into account the costs of products

From the results shown in table 18, it is seen that the combined extraction of strontium and cesium is over 98% with an average concentration of about 1.7 times with 95-97% yield in the final product. The residual content of extractable elements is completely extracted by the regenerating solution, which allows returning the circulating extractant to the cycle and making the process continuous. A study of the composition of the extraction mixture after 50 cycles of circulation of the extractant showed that insignificant losses of the organic phase with aqueous products of the technological scheme allow for continuous continuous processes without adjusting the composition of the organic phase of the extractant according to the invention.

7.4. A method for the joint extraction of strontium and cesium according to the invention in dynamic mode from waste from radiochemical plants INEEL (USA).

The initial aqueous solution, an INEEL waste simulator (Idaho, USA), the composition of which is shown in Table 19, is contacted with an extractant according to the invention containing a mixture of DB21C7 at a concentration of 0.095 mol / L and DCH18C6 at a concentration of 0.095 mol / L in a solvent containing fluoroheptanol n ₃ , in a continuous, countercurrent mode at the installation of extractors of the mixer-settler type with pulsating mixing and phase transport.

Table 19 The composition of the initial solution Element Concentration Element Concentration Mol / l g / l Mol / l g / l Al 0.75 20.25 TO 0.19 7.43 AT 0.03 0.32 Na 1.44 12/33 Cd 0.0038 0.43 Zr 0.01 0.9 Sa 0.065 2.6 Sr 1.7 × 10 ^-4 4.8 × 10 ^-3 Cr 0.005 0.26 Cs 7.5 × 10 ^-5 9.97 × 10 ^-3 Fe 0.021 1.17 Ni 1.7 × 10 ^-3 0.1 Hg 0.004 0.8 Mn 1.4 × 10 ^-3 0.1 Pb 1.45 × 10 ^-3 0.17 HNO ₃ 1.63 103

The extraction scheme includes eight stages of extraction, two stages of washing, ten stages of stripping and four stages of regeneration of the circulating extractant. The compositions and costs of the products are given in table.20.

Table 20 Composition and consumption of components Extraction Scheme Component Flow rate, ml / hour Structure Stock solution 57.3 See table 19. Extractant 59.0 DB21C7 in concentration 0.095 mol / L + DCH18C6 at a concentration of 0.095 mol / L in a solvent - fluoroheptanol n ₃ - 100% by volume Wash solution 5.66 Deionized water Reextracting Solution 33.3 Deionized water Regenerating solution 33.3 0.025 mol / L aqueous solution
potassium ethylenediaminetetraacetate + potassium hydroxide to pH ~ 8

During the operation of the installation, the concentrations of strontium and cesium in the raffinates, reextracts and regenerates, as well as the concentration of crown ethers in the products of the extraction scheme were monitored. Technological process indicators and the solubility of crown ethers (averaged indicators of a number of experiments) are given in table.21.

Table 21 Extraction of strontium and cesium from waste products manufactured by INEEL, USA Extraction Scheme Product The content in the products of the extraction scheme,% of the initial * The concentration of crown ether in the products of the extraction scheme, mg / l cesium strontium Raffinate 1.93 1.88 36 Reextract 94.87 94.42 19 Regenerate 3.2 3,7 eleven * taking into account the costs of products

From table 21 it is seen that the combined extraction of strontium and cesium is over 98%, with an average concentration of about 1.2 times and about 95% yield in the final product. Loss of extractant with aqueous solutions in this process is minimal.

According to the test results of the method according to the invention, it was found that:

- the use of the extractant according to the invention containing a mixture of crown ethers DB21C7 and DCH18C6 allows you to extract more than 98% strontium and cesium in one extraction cycle,

- concentrated strontium was achieved more than 1.8 times, the resulting salt-free aqueous strips contained less than 0.1 mol / l of nitric acid,

- loss of extractant was less than 1.0 ml per 1 liter of the processed solution.

Thus, extractants based on crown ethers with a high selective ability to radionuclides and methods for the extraction of radionuclides from acidic aqueous solutions of highly active wastes of radiochemical plants containing macronutrients, including significant amounts of sodium, were developed.

The advantages of the methods according to the invention for the extraction of radionuclides should also include:

- the possibility of processing liquid radioactive waste of any composition without prior adjustment,

- the possibility of re-extraction of radionuclides with aqueous solutions, and, as a result,

- the possibility of directing the strips to the vitrification furnace to increase the specific activity of the glass,

- the versatility of the methods according to the invention, as evidenced by the possibility of obtaining a joint strontium-cesium reextract, or separate reextracts both in one technological scheme, and in separate technological schemes, using individual extractants.

An experimental determination of the thermal stability of extractants mixed with nitric acid of various concentrations showed that the operations of extraction and re-extraction, as well as the subsequent evaporation of aqueous products of the extraction scheme, are explosion and fireproof.

The possibility of using according to the invention fluoroheptanol n ₃ as a diluent of macrocyclic compounds, for example crown ethers, which has the ability to retain crown ethers and their associates with recoverable ions, has allowed the development of various extractants for extraction, for example, radionuclides, and methods for their extraction, which are safe and technological.

As economic advantages of the use of extractants according to the invention based on crown ethers, one can note a reduction in the costs of crown ethers due to the possibility of regenerating the extractant, saving hydrazine and nitric acid, as well as saving the extractant itself due to less loss of extractant components during water contacts.

The extractants according to the invention can be obtained using known technologies. Methods of regenerating extractants for subsequent reusable use and methods for extracting radionuclides according to the invention, using extractants according to the invention, can be implemented in various industrial plants, with the choice of the composition and quantitative ratio of the components of the extraction scheme and processing conditions in accordance with the composition of the processed solutions.

The compactness of the technological scheme of the methods according to the invention allows the use of technology for the separation of radionuclides, in particular strontium and cesium, in both chamber and canyon equipment placement variants.

Claims (26)

1. The use of a mixture containing polyfluorinated alcohol-telomer 1,1,7-trihydrodeodefluoroheptanol-1, having the chemical formula H (CF ₂ CF ₂ ) _n CH ₂ OH, where n = 3, and polyoxyethylene glycol esters of synthetic primary higher fatty alcohols fraction C ₁₂ -C _{14 of the} general formula C _n H _{2n + 1} O (C ₂ H ₄ O) _m H, where n = 12 ÷ 14, m = 2, as a diluent for solutions containing macrocyclic compounds selected from the group including crown ethers having unsubstituted aromatic moieties; crown ethers having substituted aromatic moieties containing linear and / or branched alkyl and / or hydroxyalkyl substituents; crown ethers having unsubstituted cyclohexane moieties; crown ethers having substituted cyclohexane moieties containing linear and / or branched alkyl and / or hydroxyalkyl substituents; crown ethers having substituted —O — CHR — CH ₂ O— moieties where R is straight or branched alkyl or hydroxyalkyl. 2. Extractant for the extraction of radionuclides from acidic aqueous solutions of high-level waste from radiochemical industries, also containing other macroproducts, including sodium, containing macrocyclic compounds selected from the group including crown ethers having unsubstituted aromatic moieties; crown ethers having substituted aromatic moieties containing linear and / or branched alkyl and / or hydroxyalkyl substituents; crown ethers having unsubstituted cyclohexane moieties; crown ethers having substituted cyclohexane moieties containing linear and / or branched alkyl and / or hydroxyalkyl substituents; crown ethers having substituted —O — CHR — CH ₂ O— moieties, where R is straight or branched alkyl or hydroxyalkyl in an organic solvent containing a polyfluorinated telomeric alcohol 1,1,7-trihydrodeodecafluoroheptanol-1 and a mixture of synthetic polyoxyethylene glycol ethers primary higher fatty alcohols of the C ₁₂ -C ₁₄ fraction of the general formula C _n H _{2n + 1} O (C ₂ H ₄ O) _m H, where n = 12 ÷ 14, m = 2. 3. The extractant according to claim 2, characterized in that the organic solvent has the following ratio of components, vol.%: polyfluorinated telomere alcohol 1,1,7-trihydrododecafluoroheptanol-1 80-99 a mixture of polyoxyethylene glycol ethers synthetic primary higher fatty alcohols fraction C ₁₂ -C ₁₄ 20-1 4. An extractant for the extraction of cesium radionuclides from acidic aqueous solutions of highly radioactive waste from radiochemical plants containing cesium cations, as well as other macroimpurities, including sodium containing crown ether selected from the group consisting of di-tert.butyl dibenzo-18-crown-6 ( DTBDB18C6), di-isooctyl dibenzo-18-crown-6 (DIODB18C6), dibenzo-21-crown-7 (DB21C7), bis-4,4 '(5') [1-hydroxy-2-ethylhexyl] benzo-18- crown-6 (Crown XVII) in an organic solvent containing polyfluorinated telomeric alcohol 1,1,7-trihydrodeodecafluoroheptanol-1 and a mixture of polyoxyethylene glycol synthetic ethers of primary higher fatty alcohols of the fraction C ₁₂ -C ₁₄ of the general formula C _n H _{2n + 1} O (C ₂ H ₄ O) _m H, where n = 12 ÷ 14, m = 2, with the following ratio of components, vol.% : polyfluorinated telomere alcohol 1,1,7-trihydrododecafluoroheptanol-1 80-99 a mixture of polyoxyethylene glycol ethers synthetic primary higher fatty alcohols fraction C ₁₂ -C ₁₄ 20-1 5. The extractant according to claim 4, characterized in that it contains crown ether dibenzo-21-crown-7 (DB21C7) in a concentration of from 0.04 mol / l to 0.095 mol / l of extractant. 6. An extractant for the extraction of strontium radionuclides from acidic aqueous solutions of highly radioactive waste from radiochemical plants containing strontium cations, as well as other macroimpurities, including sodium, containing crown ether, selected from the group consisting of di-tert.butyl dicyclohexano-18-crown-6 ( DTBDCH18C6), di-isooctyl dicyclohexano-18-crown-6 (DIODCH18C6), dicyclohexano-18-crown-6 (DCH18C6), bis-4,4 '(5') [1-hydroxyheptyl] cyclohexo-18-crown-6 ( Crown XVI) in an organic solvent containing polyfluorinated telomeric alcohol 1,1,7-trihydrodeodecafluoroheptanol-1 and with es polyoxyethylene glycol ethers of synthetic primary higher fatty alcohols of the fraction C ₁₂ -C ₁₄ of the general formula C _n H _{2n + 1} O (C ₂ H ₄ O) _m H, where n = 12 ÷ 14, m = 2, with the following component ratio, about .%: polyfluorinated telomere alcohol 1,1,7-trihydrododecafluoroheptanol-1 80-99 a mixture of polyoxyethylene glycol ethers synthetic primary higher fatty alcohols fractions C ₁₂ -C ₁₄ 20-1 7. The extractant according to claim 6, characterized in that it contains dicyclohexano-18-crown-6 in a concentration of from 0.04 to 0.095 mol / l of extractant. 8. An extractant for the joint extraction of strontium and cesium from acidic aqueous solutions of high-level waste from radiochemical industries containing strontium and cesium cations, as well as other macroimpurities, including sodium, containing a mixture of crown ethers in which at least one crown ether is selected from the group consisting of di-tert-butyl dibenzo-18-crown-6 (DTBDB18C6), di-isooctyl dibenzo-18-crown-6 (DIODB18C6), dibenzo-21-crown-7 (DB21C7), bis-4.4 '( 5 ') [1-hydroxy-2-ethylhexyl] benzo-18-crown-6 (Crown XVII), and at least one crown ether is selected from the group consisting of di-tert. tildicyclohexano-18-crown-6 (DTBDCH18C6), di-isooctyl dicyclohexano-18-crown-6 (DIODCH18C6), dicyclohexano-18-crown-6 (DCH18C6), bis-4,4 '(5') [1-hydroxyheptyl] cyclohexo-18-crown-6 (Crown XVI) in an organic solvent containing a polyfluorinated telomeric alcohol 1,1,7-trihydrodeodecafluoroheptanol-1 and a mixture of polyoxyethylene glycol esters of synthetic primary higher fatty alcohols fraction C ₁₂ -C _{14 of the} general formula C _n H _{2n +1} O (C ₂ H ₄ O) _m H, where n = 12 ÷ 14, m = 2, in the following ratio of components, vol.%: polyfluorinated telomere alcohol 1,1,7-trihydrododecafluoroheptanol-1 80-99 a mixture of polyoxyethylene glycol ethers synthetic primary higher fatty alcohols fractions C ₁₂ -C ₁₄ 20-1 9. The extractant according to claim 8, characterized in that preferably the organic solvent has the following ratio of components, vol.%: polyfluorinated telomere alcohol 1,1,7-trihydrododecafluoroheptanol-1 87 a mixture of polyoxyethylene glycol ethers synthetic primary higher fatty alcohols fraction C ₁₂ -C ₁₄ 13 10. The extractant according to claim 9, characterized in that it contains a mixture of crown ethers of dicyclohexyl-18-crown-6 and dibenzo-21-crown-7 at a concentration of each of the crown ethers from 0.04 to 0.095 mol / L extractant. 11. The method of regeneration of the spent extractant containing complexes of macrocyclic compounds selected from the group comprising crown ethers having unsubstituted aromatic fragments; crown ethers having substituted aromatic moieties containing linear and / or branched alkyl and / or hydroxyalkyl substituents; crown ethers having unsubstituted cyclohexane moieties; crown ethers having substituted cyclohexane moieties containing linear and / or branched alkyl and / or hydroxyalkyl substituents; crown ethers having substituted —O — CHR — CH ₂ O— moieties, where R is straight or branched alkyl or hydroxyalkyl, with recoverable cations of radionuclides in an organic solvent containing a polyfluorinated telomeric alcohol 1,1,7-trihydrodeodecafluoroheptanol-1 and polyoxyethylene glycol ethers of synthetic primary higher fatty alcohols of the C ₁₂ -C ₁₄ fraction of the general formula C _n H _{2n + 1} O (C ₂ H ₄ O) _m H, where n = 12 ÷ 14, m = 2, by treating the spent extractant with an aqueous solution of potassium ethylene diamine tetra acetate at pH from 8.0 to 9.0. 12. The regeneration method according to claim 11, characterized in that the concentration of potassium ethylene diamine tetraacetate in the aqueous solution is selected in the range from 0.02 mol / L to 0.03 mol / L. 13. The regeneration method according to claim 11, characterized in that the pH is provided by the addition of potassium hydroxide. 14. A method for the extraction of radionuclides from an acidic aqueous solution of high-level waste from radiochemical industries containing other macroprolytes, including sodium, in which the aqueous solution of waste is treated with an extractant containing a macrocyclic compound capable of attaching radionuclide ions to form an extract, and the re-extraction of radionuclides from the extract deionized water, and the extractant contains a macrocyclic compound selected from the group including crown ethers having unsubstituted aromatic moieties; crown ethers having substituted aromatic moieties containing linear and / or branched alkyl and / or hydroxyalkyl substituents; crown ethers having unsubstituted cyclohexane moieties; crown ethers having substituted cyclohexane moieties containing linear and / or branched alkyl and / or hydroxyalkyl substituents; crown ethers having substituted —O — CHR — CH ₂ O— moieties, where R is straight or branched alkyl or hydroxyalkyl in an organic solvent containing a polyfluorinated telomeric alcohol 1,1,7-trihydrodeodecafluoroheptanol-1 and a mixture of synthetic polyoxyethylene glycol ethers primary higher fatty alcohols of the C ₁₂ -C ₁₄ fraction of the general formula C _n H _{2n + 1} O (C ₂ H ₄ O) _m H, where n = 12 ÷ 14, m = 2. 15. The method according to 14, characterized in that the organic solvent has the following ratio of components, vol.%: polyfluorinated telomere alcohol 1,1,7-trihydrododecafluoroheptanol-1 80-99 a mixture of polyoxyethylene glycol ethers synthetic primary higher fatty alcohols fraction C ₁₂ -C ₁₄ 20-1 16. A method for the extraction of cesium radionuclides from acidic aqueous solutions of highly active wastes from radiochemical industries containing cesium cations, as well as other macroproducts, including sodium, in which an aqueous waste solution is treated with an extractant containing at least one macrocyclic compound capable of attaching ions cesium radionuclides, with the formation of the extract, and re-extraction of cesium radionuclides from the extract with deionized water, and the extractant contains crown ether, selected selected from the group consisting of di-tert-butyl dibenzo-18-crown-6 (DTBDB 18C6), di-isooctyl dibenzo-18-crown-6 (DIODB18C6), dibenzo-21-crown-7 (DB21C7), bis-4.4 '(5') [1-hydroxy-2-ethylhexyl] benzo-18-crown-6 (Crown XVII), in an organic solvent containing polyfluorinated telomeric alcohol 1,1,7-trihydrodeodecafluoroheptanol-1 and a mixture of synthetic primary polyoxyethylene glycol esters higher fatty alcohols of the fraction C ₁₂ -C _{14 of the} general formula C _n H _{2n + 1} O (C ₂ H ₄ O) _m H, where n = 12 ÷ 14, m = 2, in the following ratio of components, vol.%: polyfluorinated telomere alcohol 1,1,7-trihydrododecafluoroheptanol-1 80-99 a mixture of polyoxyethylene glycol ethers synthetic primary higher fatty alcohols fraction C ₁₂ -C ₁₄ 20-1 17. The method according to clause 16, wherein the extractant contains crown ether dibenzo-21-crown-7 (DB21C7) in a concentration of from 0.04 to 0.095 mol / l of extractant. 18. A method for the extraction of strontium radionuclides from acidic aqueous solutions of highly radioactive waste from radiochemical industries containing strontium cations, as well as other macroproducts, including sodium, in which an aqueous solution of waste is treated with an extractant containing at least one macrocyclic compound capable of attaching ions strontium radionuclides, with the formation of the extract, and re-extraction of strontium radionuclides from the extract with deionized water, and the extractant contains n-ether selected from the group consisting of di-tert-butyl dicyclohexano-18-crown-6 (DTBDCH18C6), di-isooctyl dicyclohexano-18-crown-6 (DIODCH18C6), dicyclohexano-18-crown-6 (DCH18C6), bis- 4.4 '(5') [1-hydroxyheptyl] cyclohexo-18-crown-6 (Crown XVI) in an organic solvent containing polyfluorinated telomeric alcohol 1,1,7-trihydrodeodecafluoroheptanol-1 and a mixture of synthetic primary higher fatty polyoxyethylene glycol esters alcohols of the fraction C ₁₂ -C _{14 of the} general formula C _n H _{2n + 1} O (C ₂ H ₄ O) _m H, where n = 12 ÷ 14, m = 2, in the following ratio of components, vol.%: polyfluorinated telomere alcohol 1,1,7-trihydrododecafluoroheptanol-1 80-99 a mixture of polyoxyethylene glycol ethers synthetic primary higher fatty alcohols fraction C ₁₂ -C ₁₄ 20-1 19. The method according to p. 18, characterized in that the extractant contains dicyclohexano-18-crown-6 in a concentration of from 0.04 to 0.095 mol / l of extractant. 20. A method for joint extraction extraction of cesium and strontium radionuclides from acidic aqueous solutions of high-level waste from radiochemical plants containing cesium and strontium cations, as well as other macroprocesses, including sodium, in which an aqueous waste solution is treated with an extractant containing macrocyclic compounds capable of attaching radionuclide ions cesium and strontium, with the formation of the extract, and re-extraction of radionuclides of cesium and strontium from the extract with deionized water, and the tragent contains a mixture of crown ethers in which at least one crown ether is selected from the group consisting of di-tert-butyl dibenzo-18-crown-6 (DTBDB18C6), di-isooctyldibenzo-18-crown-6 (DIODB18C6) , dibenzo-21-crown-7 (DB21C7), bis-4.4 '(5') [1-hydroxy-2-ethylhexyl] benzo-18-crown-6 (Crown XVII), and at least one crown ether is selected from the group consisting of di-tert-butyl dicyclohexano-18-crown-6 (DTBDCH18C6), di-isooctyl dicyclohexano-18-crown-6 (DIODCH18C6), dicyclohexano-18-crown-6 (DCH18C6), bis-4 , 4 '(5') [1-hydroxyheptyl] cyclohexo-18-crown-6 (Crown XVI), in an organic solvent containing polyfluorine ovanny telomeric alcohol 1,1,7-trigidrododekaftorgeptanol-1 and synthetic mixture of polyoxyethylene glycol ethers of primary higher fatty alcohols of the fraction C ₁₂ -C ₁₄ of the general formula C _n H _{2n + 1} O (C ₂ H ₄ O) _m H, where n = 12 ÷ 14, m = 2, with the following ratio of components, vol.%: polyfluorinated telomere alcohol 1,1,7-trihydrododecafluoroheptanol-1 80-99 a mixture of polyoxyethylene glycol ethers synthetic primary higher fatty alcohols fraction C ₁₂ -C ₁₄ 20-1 21. The method according to claim 20, characterized in that preferably the organic solvent has the following ratio of components, vol.%: polyfluorinated telomere alcohol 1,1,7-trihydrododecafluoroheptanol-1 87 a mixture of polyoxyethylene glycol synthetic primary esters higher fatty alcohols fraction C ₁₂ -C ₁₄ 13 22. The method according to claim 20, characterized in that the extractant contains a mixture of dicyclohexano-18-crown-6 and dibenzo-21-crown-7 at a concentration of each of the crown ethers in the mixture from 0.04 to 0.095 mol / l extractant. 23. The method according to any one of paragraphs.16, 18, 20, characterized in that they further carry out the isolation of the circulating extractant containing complexes of macrocyclic compounds with cations of radionuclides, and regenerating it for reuse by treating the circulating extractant with an aqueous solution of potassium ethylene diamine tetraacetate at a pH of 8, 0 to 9.0 24. The method according to item 23, wherein the concentration of potassium ethylenediaminetetraacetate in the aqueous solution is selected in the range from 0.02 to 0.03 mol / L. 25. The method according to item 23, wherein the pH of the aqueous solution is provided by the addition of potassium hydroxide. 26. The method according to any one of paragraphs.16, 18, 20, characterized in that all operations of the method are carried out in a dynamic countercurrent mode.