Deciphering the Third Phase Structure in Uranium Extraction with Aliphatic Amines Using Combined Small-Angle X-ray
E Guerinoni1, T Zemb1, R Motokawa2
1ICSM, Univ Montpellier, CEA, CNRS, ENSCM, Bagnol sur Cèze 30207, France.
The Journal of Physical Chemistry. B
|August 4, 2025
Summary
Organic phase demixing in uranium extraction is clarified. Uranium-loaded aggregates cause phase separation, forming clusters in the third phase, impacting liquid-liquid extraction efficiency.
Area of Science:
- Chemical Engineering
- Materials Science
- Nuclear Chemistry
Background:
- Organic phase demixing hinders liquid-liquid extraction efficiency.
- Understanding demixing mechanisms is crucial for process optimization.
- Uranium extraction using aliphatic amines is sensitive to phase behavior.
Purpose of the Study:
- Investigate the mechanisms of organic phase demixing in uranium extraction.
- Characterize the multiscale structure of demixed organic phases.
- Determine the extractant phase stability threshold.
Main Methods:
- Small-angle X-ray scattering (SAXS) for structural analysis.
- Small-angle neutron scattering (SANS) for microstructure characterization.
- Determination of extractant phase stability threshold.
Main Results:
- The third phase consists of water-in-oil (w/o) aggregates with interdigitated hydrocarbon chains.
- The lighter phase contains monomeric amines and amine-water aggregates.
- Uranium-loaded aggregates exhibit stronger attractive interactions, leading to segregation and cluster formation.
Conclusions:
- Phase demixing results from the segregation of uranium-loaded aggregates into large clusters.
- SAXS detects this clustering via a Porod-type decay at low q-values.
- This study elucidates key mechanisms of phase separation in uranium extraction systems.
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