Methods Development: Nickel Purification and Recovery Project
There is interest in recovering and recycling the nickel, although there are many
regulatory issues associated with any use of such material outside of the nuclear
industry. The current separation technologies for the Ni/Tc pair; ion exchange,
solvent extraction, melt refining, inductoslag refining, and electrolysis, do not
meet the release criteria for radioactive materials. The best available electrolysis
process still leaves about 1 Bequerel of technetium activity per gram for materials
starting at 320 Bequerels. Other radioactive materials can be separated from
nickel via electrolysis processes. This project will obtain the data necessary
to evaluate a new alternative separation method that is based on the differences
between the vapor pressures of nickel and technetium over solid and liquid solutions
of the pair.
This project seeks to develop and demonstrate a technically effective and cost-efficient
process using physical vapor deposition to recover pure nickel with no detectable
traces of technetium. The slag left behind will be composed of technetium
with small levels of nickel. Several separation systems can be envisioned:
batch separation in which nickel is preferentially evaporated from solid or liquid
solutions of Ni/Tc and condensed on cold surfaces for recovery and continuous distillation
in which a specially designed, insulated and instrumented column is used for the
separation (similar in concept to the separation of organic liquids by boiling point).
Dr. Eric Grulke has experience in industrial process design and separations.
A physical vapor-deposition process can be designed only after the project obtains
fundamental data on the vapor-liquid-solid phase equilibria of the metal mixtures
in question. A unique MS (mass spectrometer) system designed for metal vapor
service will be constructed to obtain the needed data. Similar systems were
constructed at Lawrence Livermore National Laboratory (1969) and Los Alamos National Laboratory (1983), but are no longer
available. A University of Kentucky expert on MS, Bert Lynn, has designed other specialized MS
instruments and will collaborate on design, construction, validation, and commissioning
of the new MS.
The data obtained with the GC/MS will redefine the phase diagrams for metallic mixtures,
and will permit thermodynamic phase equilibria models to be developed and applied
to the process design. The data necessary to proceed with process design includes
vapor pressures, heat of vaporizations, heats of sublimation, activity coefficients,
and separation factors for the nickel-technetium pair at different temperatures.
The data will be incorporated into phase diagrams that include the vapor phases.
Dr. Tony Zhai will apply metallurgy principles to process applications of
The proposed research will investigate the physiochemical system of nickel-technetium.
There are no phase diagrams that relate metal vapor compositions to their liquid-solid
phase compositions. This approach is relatively unexplored, and has
applications for many non-radioactive systems as well, such as scrap metal recycling
and alloy purification. The nickel-rhenium system has been chosen to be a
model system to validate the performance of the new MS because its liquid phase
diagram behaves similarly to that of Ni/Tc and rhenium is not radioactive.
- Finalize design and build specially adapted MS for metal vapor study.
- Obtain vapor-liquid-solid phase equilibria data
- Provide written summary of equilibria data collection findings
- Apply equilibria findings for prototype design
- Build and test bench-scale pilot reactor
- Provide summary report for prototype design and bench scale study
Project 9: Purification and Recovery of Radiologically Contaminated Metals
- Project Manager
Steve Hampson, Associate Director/Co-Principal
Investigator, University of Kentucky, Kentucky Research Consortium for Energy &
- Principal Investigators
Dr. Tony Zhai, Ph.D., Professor University
of Kentucky, College of Engineering
Eric Grulke, Ph.D., Professor University
of Kentucky, College of Engineering
- Team Members
- Louie El-Asami
Dr. John Volpe
- Bert Lynn, University of Kentucky