1
25-075
Process Intensification by Resonant Vibratory Mixing for the
Recyclable Samarium -Cobalt Magnets after Chemical Leaching
with Deep Eutectic Solvents
Zainab Nasrullah
Dept. of Metallurgical and Materials Engineering,
Montana Technological University, Butte, Montana
Frank Agyemang
Dept. of Metallurgical and Materials Engineering,
Montana Technological University, Butte, Montana
Mehran Saddat
Dept. of Metallurgical and Materials Engineering,
Montana Technological University, Butte, Montana
Richard LaDouceur
Dept. of Metallurgical and Materials Engineering,
Montana Technological University, Butte, Montana
ABSTRACT
To sustain the circular economy, defence applications, and
other renewable technologies, recycling rare earth elements
(REEs) and other critical elements from their secondary
resources is important. This cause has resulted in rigorous
research and development for viable extraction and separa-
tion of REEs. Previously, Sm-Co recycling has been done
with technologies, which fall under the categories of pyro-
metallurgy, physical separation, and hydrometallurgy. All
these methods have limitations associated with energy, cost,
and environment. Reportedly, the chemical leaching tech-
nology has successfully recovered and separated Sm-Co.
Still, it has limitations associated with slow mass transfer
and leaching kinetics, and there is a need to intensify the
process to make it time efficient. This approach has also
adversely impacted the environment by an extensive use
of toxic, corrosive, non-selective, and expensive reagents.
In this research study, chemical leaching of Sm-Co was
performed using this new class of solvents, Deep Eutectic
Solvents (DESs), which fall under the category of ion met-
allurgy. Four different DESs were used, proven to be green,
non-toxic, biodegradable, cheap, and selective for cobalt
over samarium by 82% leaching conversion. To improve
the slow mass transfer and leaching time, this new technol-
ogy of resonant vibratory mixing (RVM) was also tested.
RVM intensifies mixing by establishing near instanta-
neous, low energy mixing conditions through resonance.
It has been shown to improve the adsorption kinetics and
was tested for the leaching kinetics. Four combinations of
DESs were prepared, which are made up of two quater-
nary salts: Choline Chloride and Tetra Butyl Ammonium
Chloride, and three organic compounds: Oxalic Acid,
Urea, and Ethylene Glycol. These combinations were used
for chemical leaching of Sm-Co with leaching factors of
time, temperature, and type of DESs. After leaching, the
samples were tested with and without resonant vibratory
mixing with conditions of time, intensity (%),and type
of DESs. Samples were analysed with Induced Coupled
Plasma -Optical Spectroscopy (ICP -OES). Future work
will involve a life-cycle assessment to assess the RVM tech-
nology with other conventional mixers, and an extensive
study of DES properties to improve selective leaching.
INTRODUCTION
Together with yttrium (Y), scandium (Sc), and lanthanides,
the rare earth elements (REE) are a collection of 17 chemi-
cally related elements [1]. Due to their distinctive physical
and chemical characteristics, rare earth elements (REEs) are
valuable resources that are necessary for a wide range of
modern technological applications, including metallurgy,
machine building, radio electronics, instrument engineer-
ing, nuclear engineering, and manufacturing [1], [2], [3].
Many nations’ economic growth and national security
depend on the reliable supply and durability of these vital
25-075
Process Intensification by Resonant Vibratory Mixing for the
Recyclable Samarium -Cobalt Magnets after Chemical Leaching
with Deep Eutectic Solvents
Zainab Nasrullah
Dept. of Metallurgical and Materials Engineering,
Montana Technological University, Butte, Montana
Frank Agyemang
Dept. of Metallurgical and Materials Engineering,
Montana Technological University, Butte, Montana
Mehran Saddat
Dept. of Metallurgical and Materials Engineering,
Montana Technological University, Butte, Montana
Richard LaDouceur
Dept. of Metallurgical and Materials Engineering,
Montana Technological University, Butte, Montana
ABSTRACT
To sustain the circular economy, defence applications, and
other renewable technologies, recycling rare earth elements
(REEs) and other critical elements from their secondary
resources is important. This cause has resulted in rigorous
research and development for viable extraction and separa-
tion of REEs. Previously, Sm-Co recycling has been done
with technologies, which fall under the categories of pyro-
metallurgy, physical separation, and hydrometallurgy. All
these methods have limitations associated with energy, cost,
and environment. Reportedly, the chemical leaching tech-
nology has successfully recovered and separated Sm-Co.
Still, it has limitations associated with slow mass transfer
and leaching kinetics, and there is a need to intensify the
process to make it time efficient. This approach has also
adversely impacted the environment by an extensive use
of toxic, corrosive, non-selective, and expensive reagents.
In this research study, chemical leaching of Sm-Co was
performed using this new class of solvents, Deep Eutectic
Solvents (DESs), which fall under the category of ion met-
allurgy. Four different DESs were used, proven to be green,
non-toxic, biodegradable, cheap, and selective for cobalt
over samarium by 82% leaching conversion. To improve
the slow mass transfer and leaching time, this new technol-
ogy of resonant vibratory mixing (RVM) was also tested.
RVM intensifies mixing by establishing near instanta-
neous, low energy mixing conditions through resonance.
It has been shown to improve the adsorption kinetics and
was tested for the leaching kinetics. Four combinations of
DESs were prepared, which are made up of two quater-
nary salts: Choline Chloride and Tetra Butyl Ammonium
Chloride, and three organic compounds: Oxalic Acid,
Urea, and Ethylene Glycol. These combinations were used
for chemical leaching of Sm-Co with leaching factors of
time, temperature, and type of DESs. After leaching, the
samples were tested with and without resonant vibratory
mixing with conditions of time, intensity (%),and type
of DESs. Samples were analysed with Induced Coupled
Plasma -Optical Spectroscopy (ICP -OES). Future work
will involve a life-cycle assessment to assess the RVM tech-
nology with other conventional mixers, and an extensive
study of DES properties to improve selective leaching.
INTRODUCTION
Together with yttrium (Y), scandium (Sc), and lanthanides,
the rare earth elements (REE) are a collection of 17 chemi-
cally related elements [1]. Due to their distinctive physical
and chemical characteristics, rare earth elements (REEs) are
valuable resources that are necessary for a wide range of
modern technological applications, including metallurgy,
machine building, radio electronics, instrument engineer-
ing, nuclear engineering, and manufacturing [1], [2], [3].
Many nations’ economic growth and national security
depend on the reliable supply and durability of these vital