Dissertation
INVESTIGATING SOLVENT EXTRACTION: SOLVATING EXTRACTANTS, THE ORGANIC PHASE, THEIR IMPACT ON THE THERMODYNAMICS OF EXTRACTION OF LANTHANIDE SALTS, AND THE SEPARATION OF AMERICIUM FROM CURIUM
Doctor of Philosophy (PhD), Washington State University
01/2020
Handle:
https://hdl.handle.net/2376/111811
Abstract
Solvent extraction can and has been employed for the reprocessing of used nuclear fuels
and the closing of the nuclear fuel cycle. Within the realm of solvent extraction science and
technology, however, there are many different chemical and physical processes occurring in both
the aqueous and organic phase. Each of these processes is governed by unique chemical
thermodynamics and changing any portion of the system has the potential to greatly impact the
thermodynamics of the many sub-processes contributing to the desired separation. The type of
extractant studied within these systems is one of the largest contributors to the complexity of the
thermodynamics of the extraction reaction; extractants that accomplish the desired phase transfer
by solvating an electroneutral salt (e.g., Eu(NO3)3) characteristically pose greater challenges for
total transparency. Most of the thermodynamic features of these processes have been proposed, hypothesized, and explained in the prior literature, but there is very little in the way of actual
experimentation to prove the elaborate schemes of individual “sub-processes” that have been
proposed.
This dissertation focuses on the impact on the thermodynamics of extraction of lanthanide
nitrate salts by solvating extractants by changing the features of the organic phase of the extraction
system. The extractant has the potential to produce the largest shift in how solvent extraction in
nuclear reprocessing is approached. Thus, three of the four main chapters presented in this
dissertation will focus on extractants, their impact to thermodynamics within these complex
systems, and their potential utility for closing the nuclear fuel cycle. The fourth chapter
investigates the impact of mixed diluents on the thermodynamics of extraction of europium nitrate
salts by tetra octyl diglycolamide (TODGA) extractants. The fifth chapter focues on a more exotic
actinide separation challenge, the prospects for developing a solvent extraction process that
supports the concept of extraction of the strongly oxidizing hexavalent americium away from
fission product lanthanides and trivalent curium.
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Details
- Title
- INVESTIGATING SOLVENT EXTRACTION: SOLVATING EXTRACTANTS, THE ORGANIC PHASE, THEIR IMPACT ON THE THERMODYNAMICS OF EXTRACTION OF LANTHANIDE SALTS, AND THE SEPARATION OF AMERICIUM FROM CURIUM
- Creators
- Matthew Allen David RisenHuber
- Contributors
- Kenneth L Nash (Advisor)James A Brozik (Advisor)Robert Ronald (Committee Member)Gregg J. Lumetta (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- Chemistry, Department of
- Theses and Dissertations
- Doctor of Philosophy (PhD), Washington State University
- Number of pages
- 149
- Identifiers
- 99900581500601842
- Language
- English
- Resource Type
- Dissertation