An overview of solvent extraction processes developed in Europe for advanced nuclear fuel recycling, Part 2 — homogeneous recycling

Authen, Thea Lyseid; Adnet, Jean-Marc; Bourg, Stéphane; Carrott, Michael; Ekberg, Christian; Galán, Hitos; Geist, Andreas; Guilbaud, Philippe; Miguirditchian, Manuel; Modolo, Giuseppe; Rhodes, Chris; Wilden, Andreas; Taylor, Robin

doi:10.1080/01496395.2021.2001531

Cited by 35 publications

(17 citation statements)

References 97 publications

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“…Such a vision has boosted the development of several processes for the recovery of MAs from high-level waste, and a large number of hydrophilic and lipophilic extractants have been developed to achieve this challenging goal. − …”

Section: Introductionmentioning

confidence: 99%

Insights into the Complexation Mechanism of a Promising Lipophilic PyTri Ligand for Actinide Partitioning from Spent Nuclear Fuel

et al. 2022

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The challenging issue of spent nuclear fuel (SNF) management is being tackled by developing advanced technologies that point to reduce environmental footprint, long-term radiotoxicity, volumes and residual heat of the final waste, and to increase the proliferation resistance. The advanced recycling strategy provides several promising processes for a safer reprocessing of SNF. Advanced hydrometallurgical processes can extract minor actinides directly from Plutonium and Uranium Reduction Extraction raffinate by using selective hydrophilic and lipophilic ligands. This research is focused on a recently developed N-heterocyclic selective lipophilic ligand for actinides separation to be exploited in advanced Selective ActiNide EXtraction (SANEX)-like processes: 2,6-bis(1-(2-ethylhexyl)-1H-1,2,3-triazol-4-yl)pyridine (PyTri-Ethyl-Hexyl-PTEH). The formation and stability of metal–ligand complexes have been investigated by different techniques. Preliminary studies carried out by electrospray ionization mass spectrometry (ESI–MS) analysis enabled to qualitatively explore the PTEH complexes with La(III) and Eu(III) ions as representatives of lanthanides. Time-resolved laser fluorescence spectroscopy (TRLFS) experiments have been carried out to determine the ligand stability constants with Cm(III) and Eu(III) and to better investigate the ligand complexes involved in the extraction process. The contribution of a 1:3 M/L complex, barely identified by ESI–MS analyses, was confirmed as the dominant species by TRLFS experiments. To shed light on ligand selectivity toward actinides over lanthanides, NMR investigations have been performed on PTEH complexes with Lu(III) and Am(III) ions, thereby showing significant differences in chemical shifts of the coordinating nitrogen atoms providing proof of a different bond nature between actinides and lanthanides. These scientific achievements encourage consideration of this PyTri ligand for a potential large-scale implementation.

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Section: Introductionmentioning

confidence: 99%

Insights into the Complexation Mechanism of a Promising Lipophilic PyTri Ligand for Actinide Partitioning from Spent Nuclear Fuel

et al. 2022

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“…This has since been attributed to the short residence time of the centrifugal contactors and the need for more contacting stages dedicated to scrubbing the solvent. 19 Most prior literature and both tests on irradiated fuel utilized 1.0 M DEHiBA; however, this concentration of DEHiBA did not achieve an organic phase loading (0.14 M for JRC test), 27 which is on par with the traditional PUREX process (0.33−0.40 M). 28 Thus, while these tests were extremely useful in the demonstration that DEHiBA is a practical extractant to use with real irradiated fuel, it would be beneficial to have a solvent formulation that allows for a higher U loading, and thus less secondary radioactive waste generation.…”

Section: ■ Introductionmentioning

confidence: 99%

“…The test at JRC had a small amount of Np in the U organic stream, and a high amount of Tc. This has since been attributed to the short residence time of the centrifugal contactors and the need for more contacting stages dedicated to scrubbing the solvent . Most prior literature and both tests on irradiated fuel utilized 1.0 M DEHiBA; however, this concentration of DEHiBA did not achieve an organic phase loading (0.14 M for JRC test), which is on par with the traditional PUREX process (0.33–0.40 M) .…”

Section: Introductionmentioning

confidence: 99%

Extraction of Nitric Acid and Uranium with DEHiBA under High Loading Conditions

et al. 2023

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The mechanism by which high concentrations (1.5 M in n-dodecane) of N,N-di-2-ethylhexyl-isobutyramide (DEHiBA) extracts HNO3 and UO2(NO3)2 is under examination. Most prior studies have examined the extractant and the mechanism at a concentration of 1.0 M in n-dodecane; however, under the higher loading conditions that can be achieved by a higher concentration of extractant, this mechanism could change. Increased extraction of both nitric acid and uranium is observed with an increased concentration of DEHiBA. The mechanisms are examined by thermodynamic modeling of distribution ratios, 15N nuclear magnetic resonance (NMR) spectroscopy, and Fourier transform infrared (FTIR) spectroscopy coupled with principal component analysis (PCA). Speciation diagrams produced through thermodynamic modeling have been qualitatively reproduced through PCA of the FTIR spectra. The predominant extracted species of HNO3(DEHiBA), HNO3(DEHiBA)2, and UO2(NO3)2(DEHiBA)2 are in good agreement with prior literature reports for 1.0 M DEHiBA systems. Evidence for an additional species of either UO2(NO3)2(DEHiBA) or UO2(NO3)2(DEHiBA)2(HNO3) also contributing to the extraction of uranium species is given.

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“…Research continues to improve hydrometallurgical technologies for uranium handling. New processes and extraction systems are being developed for these purposes. − One of the most promising approaches is the GANEX process, which is designed to simultaneously extract all actinides (U, Np, Pu, Am, and Cm) from nitric acid solutions of SNF providing a proliferation-resistant fuel cycle. The organic phase in such a process should possess high capacity for the macrocomponent of SNF, which is U(VI).…”

Section: Introductionmentioning

confidence: 99%

Solvation-Anionic Exchange Mechanism of Solvent Extraction: Enhanced U(VI) Uptake by Tetradentate Phenanthroline Ligands

et al. 2022

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Phenanthroline diamides (L) demonstrated a unique ability to extract uranium from nitric acid solutions into a polar organic solvent forming complexes of 1:2 stoichiometry as tight ion pairs {[UO2 LNO3]+[UO2(NO3)3]−} by a novel extraction mechanism, which is a combination of two already well-known mechanisms: solvation and ion-pair anion exchange. A UV–vis study was used to confirm the formation of such complexes directly in the organic phase. Moreover, chemical synthesis and single crystal growth were performed to confirm unambiguously the structure of the complexes in the solid state.

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An overview of solvent extraction processes developed in Europe for advanced nuclear fuel recycling, Part 2 — homogeneous recycling

Cited by 35 publications

References 97 publications

Insights into the Complexation Mechanism of a Promising Lipophilic PyTri Ligand for Actinide Partitioning from Spent Nuclear Fuel

Insights into the Complexation Mechanism of a Promising Lipophilic PyTri Ligand for Actinide Partitioning from Spent Nuclear Fuel

Extraction of Nitric Acid and Uranium with DEHiBA under High Loading Conditions

Solvation-Anionic Exchange Mechanism of Solvent Extraction: Enhanced U(VI) Uptake by Tetradentate Phenanthroline Ligands

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