Development of an f-element separation chemistry using solid electrolytes

145 Pages·2017·3.12 MB·English

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Doctoral Dissertations Graduate School
12-2016
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Kristian Guy Myhre
University of Tennessee, Knoxville, [email protected]
Follow this and additional works at: https://trace.tennessee.edu/utk_graddiss
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Myhre, Kristian Guy, "Development of an f-element separation chemistry using solid electrolytes. " PhD
diss., University of Tennessee, 2016.
https://trace.tennessee.edu/utk_graddiss/4155
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To the Graduate Council:
I am submitting herewith a dissertation written by Kristian Guy Myhre entitled "Development of
an f-element separation chemistry using solid electrolytes." I have examined the final electronic
copy of this dissertation for form and content and recommend that it be accepted in partial
fulfillment of the requirements for the degree of Doctor of Philosophy, with a major in Energy
Science and Engineering.
Thomas A. Zawodzinski, Major Professor
We have read this dissertation and recommend its acceptance:
Miting Du, Rose A. Boll, Claudia J. Rawn, Adam J. Rondinone, David W. DePaoli
Accepted for the Council:
Carolyn R. Hodges
Vice Provost and Dean of the Graduate School
(Original signatures are on file with official student records.)
Development of an f‒element separation chemistry using solid electrolytes

A Dissertation Presented for the
Doctor of Philosophy
Degree
The University of Tennessee, Knoxville

Kristian Guy Myhre
December 2016
ii
Copyright © 2016 by Kristian Guy Myhre
All rights reserved.
iii
Dedication

To my beautiful and precious wife, whom I adore endlessly:
I have never loved you so much and I will never love you so little again, Bethany.
iv
Acknowledgements

It is a nearly impossible task to decide where to start in thanking those who have
helped me get to this point. Certainly, it is truly impossible to decide where to end, as
there have been too many people that have helped me along the way to count.
First and foremost, I want to thank my wife and family. Bethany, you are the most
amazing wife and more than I deserve. I have been and continue to be extremely blessed
by your supportive and endless love. I am beyond excited to continue sharing every day
of my life with you. Mom, thank you for enabling and encouraging me to pursue an
education that I enjoyed. Dad, thank you for showing me that family comes first and that
hard work coupled with integrity is its own reward. Kameron and Kjasa, thank you for
keeping me humble in the way only siblings can. I want to also thank my in‒laws, who
have been an immensely important part of my life in Tennessee.
I want to sincerely thank those at the University of Tennessee and Oak Ridge
National Laboratory for giving me so many wonderful opportunities during my time in
graduate school. I am especially thankful to Dr. Lee Riedinger for accepting me into the
Bredesen Center for my graduate studies as well as personally ensuring my time as a
graduate student was successful. The Radiochemical Engineering Development Center
has been an extremely exciting place to carry out my dissertation research. The
opportunities and support I have been provided as a member of the Nuclear Materials
Processing group have been unbelievable. I am also extremely thankful to all of my
graduate committee members, each of which has been instrumental in my graduate
education. I look forward to continuing to work with all of them.
I want to also thank those that encouraged me throughout the pursuit of my
undergraduate degree and helped grow my passion for chemistry, particularly in the areas
of separation chemistry, radiochemistry, and electrochemistry.
v
Abstract
The f‒elements (lanthanides and actinides) have numerous applications and are
critically important to many industries, including the energy, security, and medical
industries. One of the barriers to increased use and availability of the f‒elements is the
difficulty in separating them from each other due to their similar chemistries. This is
especially true of the trivalent f‒elements (lanthanides and minor actinides). The
development of separation techniques that maximize the differences in the
physicochemical properties of the f‒elements is therefore an important area of research.
For these reasons, an effort was undertaken to explore the use of solid electrolyte
materials to accomplish separations of the f‒elements. The results of this work have led
to the development of a novel separation method at Oak Ridge National Laboratory for
accomplishing f‒element separations using inorganic solid electrolyte materials,
specifically beta´´‒alumina. The use of beta´´‒alumina was both investigated both as an
ion exchanger and selective membrane. Given the large dependence of superionic
conductivity upon the valence of mobile ions, oxidation state control of the ions to be
separated was explored. The high‒temperature regimes (greater than 300°C) required for
superionic conduction of multivalent metal ions in beta´´‒alumina necessitated the use of
molten salts as a medium to contain ions to interact with the solid electrolyte. These
studies also included the development of Laser Induced Breakdown Spectroscopy for
determining the concentrations of f‒elements in the alumina based materials.
vi
Preface

“Captain, you almost make me believe in luck.” – Spock
vii
Table of Contents

Chapter 1 Introduction and motivation .............................................................................. 1
1.1 Use of f‒elements in society ..................................................................................... 2
1.2 Project motivation ..................................................................................................... 3
1.3 Scope of work ........................................................................................................... 4
1.4 References ................................................................................................................. 8
Chapter 2 Background ..................................................................................................... 11
2.1 Separation of the f‒elements ................................................................................... 12
2.2 Separations using solid electrolytes ........................................................................ 17
2.3 References ............................................................................................................... 22
Chapter 3 Quantification of rare earths in alumina matrix via laser induced breakdown
spectroscopy ...................................................................................................................... 27
3.1 Disclosure ............................................................................................................... 28
3.2 Abstract ................................................................................................................... 28
3.3 Introduction ............................................................................................................. 29
3.4 Materials and characterization ................................................................................ 32
3.5 Results and discussion ............................................................................................ 36
3.6 Conclusion .............................................................................................................. 40
3.7 Acknowledgements ................................................................................................. 41
3.8 References ............................................................................................................... 43
Chapter 4 Oxidation state behavior of rare earths in beta´´‒alumina by x‒ray
photoelectron spectroscopy ............................................................................................... 45
4.1 Disclosure ............................................................................................................... 46
4.2 Abstract ................................................................................................................... 46
4.3 Introduction ............................................................................................................. 47
4.4 Materials and characterization ................................................................................ 48
4.5 Results and discussion ............................................................................................ 50
4.6 Conclusion .............................................................................................................. 53
4.7 Acknowledgements ................................................................................................. 54
4.8 References ............................................................................................................... 55
viii
Chapter 5 Separation of f‒elements by ion exchange reactions between molten salts and
beta´´‒alumina .................................................................................................................. 57
5.1 Disclosure ............................................................................................................... 58
5.2 Abstract ................................................................................................................... 58
5.3 Introduction ............................................................................................................. 59
5.4 Materials and characterization ................................................................................ 60
5.5 Results and discussion ............................................................................................ 63
5.6 Conclusion .............................................................................................................. 71
5.7 Acknowledgements ................................................................................................. 72
5.8 References ............................................................................................................... 73
Chapter 6 Reduction of Eu in molten CsCl‒MgCl and subsequent separation from Sm
2
using a beta´´‒alumina membrane .................................................................................... 76
6.1 Disclosure ............................................................................................................... 77
6.2 Abstract ................................................................................................................... 77
6.3 Introduction ............................................................................................................. 77
6.4 Materials and characterization ................................................................................ 79
6.5 Results and discussion ............................................................................................ 81
6.6 Conclusion .............................................................................................................. 82
6.7 Acknowledgements ................................................................................................. 82
6.8 References ............................................................................................................... 84
Chapter 7 Conclusions and recommendations ................................................................. 86
7.1 Important conclusions ............................................................................................. 87
7.2 Recommendations for future work ......................................................................... 87
7.3 References ............................................................................................................... 90
Appendix ........................................................................................................................... 91
Vita .................................................................................................................................. 131