A technology for the extraction of zirconium (IV) from solutions of high-level waste, adapted to the existing equipment scheme of the PUREX process, has been developed using the example of model solutions in tributyl phosphate in a hydrocarbon diluent. An experimental simulation of the calculated 5-stage counter-current cascade was carried out, and good agreement between the calculated and experimental results was shown. The methods for re-extraction of Zr4+ from the loaded organic phase were selected, the number of stages of exhaustion of Zr4+ from the loaded organic phase under the selected conditions was calculated. A fundamental technological scheme for the extraction method of zirconium recovery from Eastern Administrative Okrug is proposed which does not require a radical reconstruction of existing high-level nuclear fuel reprocessing facilities.

A new hydrophilic DAPhen derivative, N2,N9-bis(2-morpholinoethyl)-1,10-phenanthroline-2,9-dicarboxamide (L), was synthesized and investigated as a selective aqueous-phase complexing agent for the separation of Am(III) from lanthanides in phosphine oxide-based extraction systems. Potentiometric and spectrophotometric titrations with Eu(III) demonstrated the formation of 1 : 1 and 1 : 2 complexes. X-ray crystallography revealed a unique coordination pattern with progressive substitution of nitrate anions by water molecules across the lanthanide series (La-Er), as well as protonation of morpholine nitrogen atoms under crystallization conditions. Solvent extraction experiments showed that the addition of L to aqueous nitric acid solutions reduces the distribution ratio of Am(III), thereby enhancing separation from Eu(III) and other lanthanides when combined with TOPO in kerosene or F-3. Separation factors SF(Eu/Am) of up to 26 were achieved. Although insufficient selectivity was observed for Am(III)/La(III) separation, the system demonstrates the potential for group separation of An(III) from Ln(III) with subsequent back-extraction of Am(III).

The efficiency of the extraction of lanthanide(III), americium(III), and thorium(IV) ions from nitric acid solutions with tetraoctyldiglycolamide significantly increases in the presence of an ionic liquid, didecylammonium di-2-ethylhexyl sulfosuccinate, in the organic phase. The effect of the aqueous phase acidity on the distribution ratios of the extracted elements was considered, and the stoichiometry of the extractable complexes was determined.

The influence of metal corrosion products on the thermal effects of reactions in nitric acid solutions with hydrazine nitrate, carbohydrazide, acetohydroxamic acid before and after irradiation has been studied. For this purpose, the onset temperature of exothermic processes (Tst), their duration (τ), specific thermal effect of reactions (Qsp), self-heating value of the solution (ΔT), and also the increase in pressure during the reaction (ΔP) were determined by the method of thermal analysis in crucibles of different compositions. It has been established that in the presence of corrosion products (Fe, Cr, Ni), an increase in self-heating value of the sample, pressure and thermal effects of the reaction is observed. Irradiation of mixtures to the doses of 100 and 500 kGy leads to a change in the characteristics of the exothermic process, with the most significant increase in parameters observed for solutions in hastelloy crucibles.

The extraction of U(VI), Th(IV), Am(III), and Eu(III) with solutions of phosphorylated pyridines from nitric acid solutions has been studied. The stoichiometry of the extractable complexes was established. In terms of their extraction ability, these compounds are inferior to bis(diphenylphosphinyl)methane, but they are significantly superior to carbamoylmethylphosphine oxides. An increase in the number of phosphine oxide groups in the molecules of phosphorylated pyridines leads to a significant decrease in their extraction ability and selectivity in the extraction of Am(III) and Eu(III) from nitric acid solutions.

Phase formation in cast stone matrices (CSMs) fabricated through the interaction of comelted basalt with ZrO2 at 1623 K for 5 h on air was studied. Basalt melted under the above conditions contains two spinels (relict and newly formed), clinopyroxene of the composition Mg0.66Ca0.60Fe0.26Ti0.05Al0.66Si1.80O6, and glass as the major phases. When basalt is comelted with ZrO2, taken in a weight ratio of 1 : 1, CSMs containing zircon (ZrSiO4), glass, and baddeleyite (ZrO2) as the major phases are formed. Zirconium is concentrated mainly in two phases, zircon and baddeleyite. The rate of Zr leaching from the synthesized CSMs into H2O after 28 days is 1.0 × 10–9 g/(cm2 day).

The radiation thermal stability of extraction mixtures based on methyltrioctylammonium (MTOA) carbonate was studied. The volumes and maximum rate of release of gaseous products at atmospheric and elevated pressures were determined. No exothermic processes were shown to occur in the studied mixtures under experimental conditions. Irradiation up to a dose of 1 MGy has little effect on the density, viscosity, and surface tension of mixtures, but significantly reduces the phase separation rate. The distribution coefficients of Am(III) in the system of 50% MTOA carbonate in toluene are practically independent of the absorbed dose; however, irradiation can significantly affect the composition of the extractable americium complexes. The results of the study of extraction systems showed their high radiation thermal stability.

A systematic study of extraction systems for the separation of f-elements using the tetradentate N,O-donor diamide of 1,10-phenanthroline-2,9-dicarboxylic acid (L) in various molecular and ionic solvents was performed. It was demonstrated that the nature of a diluent has a significant impact on solvent extraction of Am(III) and Ln(III) and the stoichiometry of formed complexes with f-elements. The mechanism of complexation and forms of complexes in different diluents were investigated by radiometric methods, UV-vis titration, and XRD.

Sorption of tributyl phosphate (TBP) on a polymer sorbent Polysorb-1 in aqueous solutions and sorption of butylphosphoric acids onto layered Mg-Al double oxides and hydroxides in a 70

This work examines cast stone matrices (CSM) fabricated by comelting of basalt with both uranium-bearing perlite (M150 grade) and U3O8 at a temperature of 1623 K in air for 5 h. As a result of comelting of basalt with uranium-free M150 grade perlite, matrices are obtained containing glass and spinel as the major phases. When basalt is comelted with uranium-bearing perlite (M150 grade) CSMs are formed, the major phases of which are two Cr-spinels of different compositions, uranium-bearing glass, and dendritic aluminosilicate crystals. In the case of fusion of basalt and U3O8 taken in the initial weight ratio of 1 : 1, CSM is generated as the major phases containing UO3, CaU3O10, (Al,Cr,Fe)2U2O9, plagioclase, and uranium-bearing glass. The leaching rate of uranium from a basalt melt with uranium-bearing perlite (M150 grade, 7.2 wt

The influence of temperature on the extraction of Am(III), Eu(III) and Lu(III) by TODGA from nitric, hydrochloric and sulfuric acid solutions has been studied. The compositions of the extracted species were determined and the thermodynamic parameters of the extraction reactions were defined. On the basis of data on thermal effects of extraction processes, a method of Lu(III) concentrating at the stage of back-extraction was proposed. The influence of the nature of acid on the possibility of group separation of REE was evaluated.

In this work, for the first time we proposed a mixture based on 2-nitro-4-nonylphenol as a lithium-selective binary extractant, in which the nitro group simultaneously participates in the formation of a six-membered metallocycle and increases the acidity of the phenolic group. The extraction of alkali metals (Li, Na, K) by a mixture of 2-nitro-4-nonylphenol and trioctylphosphinoxide in dodecane was studied in detail. The extraction of Li from mother liquors after Li2CO3 precipitation was considered as a practical application of the new binary extractant. It was shown that by using only liquid extraction methods, a high degree of concentration and purification of final product can be achieved. Mother liquor of Li2CO3 precipitation was concentrated by Li more than 50 times. Degree of lithium concentrate purification from Na and K was more than 5500 and 100,000 times, correspondingly.

The extraction of Li, Na and K trichloroacetates by benzo-15-crown-5 ether and its lipophilic analog in chloroform has been studied. Extraction isotherms were obtained and the transition of extractants into the equilibrium aqueous phase was determined. The metal: crown ether ratios in the extracted compounds were determined by the slope analysis method. The thermodynamic extraction parameters of Li, Na and K trichloroacetates in systems with benzo-15-crown-5 ether (B15C5) and 3-tert-pentylbenzo-15-crown-5 ether (tPB15C5) were determined. The complexes [Li-3(B15C5)(TCA)(3)], [Na(B15C5)(TCA)] and [K(B15C5)(2)](DCA)H2O were isolated in crystalline form and characterized by IR spectroscopy and X-ray diffraction.

The extraction of U(VI), Th(IV), Am(III), and lanthanides(III) from nitric acid solutions with solutions of phosphorylated pyrazines in organic solvents was studied. The stoichiometry of the extracted complexes was determined, and the influence of the structure of the extractant and an HNO3 concentration in the aqueous phase on the efficiency of the extraction of metal ions into the organic phase was considered. It was established that among the studied compounds, bis(diphenylphosphine)quinoxaline dioxide has the highest extraction ability with respect to actinides and lanthanides in nitric acid media.

The effect of HNO 3 concentration on the extraction of Eu(III), Am(III), and Cm(III) with N , N , N ', N '-tetrabutyldiglycolamide was studied in 5 different diluents: nitrobenzene, toluene, chloroform, 1,2-dichloroethane, and 1,1,2,2-tetrachloroethane. The distribution coefficients of these metals as a function of the nature of the diluent in the following series of compounds was established: nitrobenzene > m -trifluoromethylnitrobenzene > mixture of n -dodecane with decanol-1 (volume ratio 90 : 10) > carbon tetrachloride > 1,2-dichloroethane > benzene > 1,1,2,2-tetrachloroethane > toluene > chloroform. The conditions for the partioning Eu(III)/Am(III) and Am(III)/Cm(III) pairs were found. An explanation was proposed for the observed increase in the separation factors of the Am(III)/Cm(III) pair with increasing concentration of nitric acid in the equilibrium aqueous phase.

Изучена экстракция азотной кислоты, индикаторных количеств 152 Eu(III), 241 Am(III) и 244 Cm(III) N,N,N',Nꞌ-тетрабутилдигликольамидом в четырех разбавителях: смеси н -додекана с деканолом-1 (объемное отношение 90 : 10), бензоле, тетрахлорметане и м -трифторметилнитробензоле. Для всех исследованных разбавителей коэффициенты распределения металлов увеличиваются с ростом концентрации HNO 3 в равновесной водной фазе. Степень извлечения металла в экстракт увеличивается в ряду Cm(III) DD+Dec-1 > CCl 4 > PhH. Найдены условия разделения пар Eu(III)/Am(III) и Am(III)/Cm(III). Показано увеличение тепловых эффектов реакций экстракции при переходе от An(III) к Eu(III) для всех рассмотренных разбавителей.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

Solvent extraction separation of U(VI), Pu(IV), Pu(VI), Np(V)/Np(VI), Am(III), Ce(IV), rare earth elements (III), Mo(VI), and Cs from carbonate solutions using methyltrioctylammonium carbonate was studied. The separation factors of actinides, rare earth elements, molybdenum, and cesium were calculated.

Стадия растворения уранового и смешанного уран-плутониевого оксидного отработавшего ядерного топлива является ключевой начальной стадией новой альтернативной гидрометаллургической технологии - КАРБЭКС-процесса. В работе рассмотрены карбонатные окислительные системы NaHCO 3 /Na 2 CO 3 -H 2 O 2 /2Na 2 CO 3 ·3H 2 O 2 /М 2 S 2 O 8 , где M = Na + , K + или NH 4 + , для растворения порошков оксидов актиноидов. Определены химические и физические факторы, определяющие скорость окислительного растворения порошков индивидуальных оксидов UO 2 , U 3 O 8 , PuO 2 и NpO 2 в карбонатных средах. Полученные результаты являются важными для разработки вариантов окислительного и сонохимического растворения высокопрокаленных кристаллических образцов оксидов урана, плутония и нептуния, а также отработавшего ядерного топлива в карбонатных средах. Ключевые слова: диоксид урана, октаоксид триурана, диоксид плутония, диоксид нептуния, окислительное растворение, карбонатные среды, пероксид водорода, персульфат

The explosive development of renewable energy in recent years is reshaping the geopolitical picture of the world. Solar panels and wind turbines have become the symbol of the new energy transition, while lithium-ion batteries have become its basis and the driver of development. It was lithium-ion batteries that made it possible to overcome the main problem of renewable energy – inconstancy and uncontrollability. The article highlights the lithium problem, the reasons for the volatility of lithium prices, the main sources of lithium and the difficulties of its production. In addition, the prospects of development of lithium industry in Russia and current domestic developments in lithium mining technology are considered.