Magnetics Business & Technology - September/October 2022 - 23

RESEARCH & DEVELOPMENT
be arranged into different structural configurations. For example,
their length and shape can be altered, branches created or linear
chains transformed into cyclic arrangements.
The ORNL team passed the trial ligands off to Lyon to test under
industrial operating conditions using a counter-current solvent
extraction system - a series of vessels that mix and settle the
materials to separate out REE compounds through a sequence of
liquid-liquid extraction stages.
During the mixing, the ligands attract the metal ions using
electron-rich donor groups, binding the metal ions in a coordinated
manner. Extracting certain lanthanides over others depends
on ligands having the right number and arrangement of functional
groups - atoms within a molecule that can maintain functionality
independently of other atoms in the molecule - as well as the size
of the ligands and their ability to mix with the oily organic solvent.
The ORNL team designed, synthesized and tested a library of
chemically modified ligands, in collaboration with Lyon, narrowing
the field of novel agents for industrial application that could
potentially outperform state-of-the-art technology in REE selectivity.
Each agent performs differently based on its physical arrangement
and the electronic activity it prompts.
" The TODGA extractant, when saturated with REE ions, would
rapidly transform from the liquid phase into a gel or precipitate, "
Jansone-Popova said. " The new DGA ligands allow the system to
remain homogenous even at higher extractant concentrations and
maintain good selectivity. "
In separating REEs, the new ligands achieved a
selectivity range of 2.5-3.1, a staggering improvement
for these critical materials.
The team then took on the challenge of scaling up
the process to be viable for industry use.
" The process was very iterative; minute changes
in the structures of these molecules have impact, "
Lyon said. " The bottom line is that a new technology
has to be economically viable. We're very driven
by input from industry and the methods they use. "
" Most REE extractants have a separation factor
of about 1.5 for adjacent lanthanides across the
series - if we get to 2, that's good. If we get to 2.5,
that's really starting to save some money. If we can
get to 3, we're really happy. We've gotten to 6.7
with one of Santa's ligands, " said ORNL's Bruce
Moyer, who leads the CMI focus area for diversifying
supply and is a collaborator on the licensed
technology.
The work of the CMI team was outlined in Inorganic
Chemistry. Co-authors include ORNL's
Santa Jansone-Popova, Bruce Moyer, Ilja Popovs,
Camille Albisser, Vyacheslav Bryantsev, Mary
Healy and Diana Stamberga; INL's Lyon; Argonne
National Laboratory's Benjamin Reinhart; Foster
of Marshallton Research Laboratories; and Alena
Paulenova and Yana Karslyan, Oregon State
University.
www.MagneticsMag.com
September/October 2022 * Magnetics Business & Technology 23
In his role at CMI, Moyer oversees a portfolio of research projects
investigating how to expand the supply of REEs through innovative
processes.
" CMI's goal is to provide the best separation technology to industry.
We've selected these DGAs because they have the potential
to reduce the consumption of chemicals and production of waste,
thereby lowering costs. They're more selective, which reduces
the number of stages needed, reducing the overall capital cost of
building a plant, " he said.
" We're creating better technology that will make the production of
purified rare earths cheaper. By doing that, the U.S. industry will
get more competitive and be able to deliver purified rare earths for
magnet production and other applications. "
ORNL's Technology Transfer Office led the commercialization,
working alongside INL under an inter-institutional agreement.
ORNL built upon existing collaborations with Marshallton Research
Laboratories under CMI to further develop this partnership
with an exclusive field of use patent license agreement
ORNL is managed by UT-Battelle for the U.S. Department of
Energy's Office of Science, the single largest supporter of basic
research in the physical sciences in the United States. DOE's
Office of Science is working to address some of the most pressing
challenges of our time.
For more information, please visit energy.gov/science.
http://energy.gov/science http://meda.com http://www.MagneticsMag.com
Magnetics Business & Technology - September/October 2022

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