8
leaching investigation showed clearly that Sm and Co disso-
lution in DES was successful and effectively increased with
increasing time. The use of RAM increased the leaching
efficiency for both Sm and Co dissolution with an increase
in time.
Reline, Oxaline, and EG-TBAC DES were selective
to Co over Sm. The optimum media for the conversion of
Co was Oxaline at 82% while the lowest recovery was in
Ethaline leaching media. The highest recovery for Sm was
in Ethaline leaching media at 14% while the lowest recov-
ery was in Oxaline leaching media. Leaching in Ethaline
was not selective for either Co or Sm over each other. This
implies that the effectiveness of leaching is rather depen-
dent on the chemical properties of each of the DESs.
RECOMMENDATIONS
• Further work should be done to ascertain why
the leaching of SmCo using Reline, Oxaline, and
EG-TBAC was selective to Co over Sm while
Ethaline showed little difference between Co or Sm
over other leaching conversions.
• Work should be done to have a better understand-
ing of the leaching kinetics in the DESs medium by
increasing time and varying leaching parameters.
• Work should be done to know why Oxaline with a
higher viscosity is shown to be the best reagent for
the leaching of Co with 82% conversion.
• More work should be done by increasing RAM
operating time and varying operating parameters to
improve on recovery efficiency.
REFERENCES
[1] S. Peelman, Z. H. I. Sun, J. Sietsma, and Y. Yang,
“Leaching of Rare Earth Elements: Review of Past
and Present Technologies,” in Rare Earths Industry:
Technological, Economic, and Environmental
Implications, Elsevier Inc., 2015, pp. 319–334. DOI:
10.1016/B978-0-12-802328-0.00021-8.
[2] T. Dutta et al., “Global demand for rare earth
resources and strategies for green mining.,” Environ
Res, vol. 150, pp. 182–190, Oct. 2016, DOI: 10.1016
/J.ENVRES.2016.05.052.
[3] H. X. Mai et al., “High-quality sodium rare-earth flu-
oride nanocrystals: Controlled synthesis and optical
properties,” J Am Chem Soc, vol. 128, no. 19, pp. 6426–
6436, May 2006, DOI: 10.1021/JA060212H
/SUPPL_FILE/JA060212HSI20060414_124908
.PDF.
[4] U. States Department of Energy, “Critical Materials
Rare Earths Supply Chain: A Situational White
Paper,” 2020.
[5] G. Inman, I. C. Nlebedim, and D. Prodius,
“Application of Ionic Liquids for the Recycling and
Recovery of Technologically Critical and Valuable
Metals,” Energies, vol. 15, no. 2. MDPI, Jan. 01,
2022. DOI: 10.3390/en15020628.
[6] M. Irina et al., “Electrochemical leaching of rare-
earth elements from spent NdFeB magnets,” 2020,
DOI: 10.1016/j.hydromet.2020.105264.
[7] J. Z. Wang, Y. C. Tang, and Y. H. Shen, “Leaching
of Sm, Co, Fe, and Cu from Spent SmCo Magnets
Using Organic Acid,” Metals (Basel), vol. 13, no. 2,
Feb. 2023, DOI: 10.3390/met13020233.
[8] R. Herrington, “Mining our green future,” DOI:
10.1038/s41578-021-00325-9.
[9] N. T. Nassar and S. M. Fortier, “ofr20211045.pdf
-Methodology and Technical Input for the 2021
Review and Revision of the U.S. Critical Minerals
List,” 2021.
[10] S. Prusty, S. Pradhan, and S. Mishra, “Extraction
and separation studies of Nd/Fe and Sm/Co by deep
eutectic solvent containing Aliquat 336 and glycerol,”
Journal of Chemical Technology and Biotechnology, vol.
98, no. 7, pp. 1631–1641, Jul. 2023, DOI: 10.1002
/jctb.7381.
[11] M. H. Severson, R. T. Nguyen, J. Ormerod, A.
Palasyuk, and J. Cui, “A preliminary feasibility study
of potential market applications for non-commercial
technology magnets,” Heliyon, vol. 8, no. 12, Dec.
2022, DOI: 10.1016/J.HELIYON.2022.E11773.
[12] X. Li, Z. Li, M. Orefice, and K. Binnemans, “Metal
Recovery from Spent Samarium-Cobalt Magnets
Using a Trichloride Ionic Liquid,” ACS Sustain Chem
Eng, vol. 7, no. 2, pp. 2578–2584, Jan. 2019, DOI:
10.1021/acssuschemeng.8b05604.
[13] S. Sobekova Foltova, T. Vander Hoogerstraete, D.
Banerjee, and K. Binnemans, “Samarium/cobalt
separation by solvent extraction with undiluted qua-
ternary ammonium ionic liquids,” Sep Purif Technol,
vol. 210, pp. 209–218, Feb. 2019, DOI: 10.1016
/j.seppur.2018.07.069.
[14] J. M. D. Coey, “Perspective and Prospects for Rare
Earth Permanent Magnets,” Engineering, vol. 6,
no. 2, pp. 119–131, Feb. 2020, DOI: 10.1016
/J.ENG.2018.11.034.
[15] C. K. Gupta and N. (Nagaiyar) Krishnamurthy,
Extractive metallurgy of rare earths. CRC Press, 2005.
leaching investigation showed clearly that Sm and Co disso-
lution in DES was successful and effectively increased with
increasing time. The use of RAM increased the leaching
efficiency for both Sm and Co dissolution with an increase
in time.
Reline, Oxaline, and EG-TBAC DES were selective
to Co over Sm. The optimum media for the conversion of
Co was Oxaline at 82% while the lowest recovery was in
Ethaline leaching media. The highest recovery for Sm was
in Ethaline leaching media at 14% while the lowest recov-
ery was in Oxaline leaching media. Leaching in Ethaline
was not selective for either Co or Sm over each other. This
implies that the effectiveness of leaching is rather depen-
dent on the chemical properties of each of the DESs.
RECOMMENDATIONS
• Further work should be done to ascertain why
the leaching of SmCo using Reline, Oxaline, and
EG-TBAC was selective to Co over Sm while
Ethaline showed little difference between Co or Sm
over other leaching conversions.
• Work should be done to have a better understand-
ing of the leaching kinetics in the DESs medium by
increasing time and varying leaching parameters.
• Work should be done to know why Oxaline with a
higher viscosity is shown to be the best reagent for
the leaching of Co with 82% conversion.
• More work should be done by increasing RAM
operating time and varying operating parameters to
improve on recovery efficiency.
REFERENCES
[1] S. Peelman, Z. H. I. Sun, J. Sietsma, and Y. Yang,
“Leaching of Rare Earth Elements: Review of Past
and Present Technologies,” in Rare Earths Industry:
Technological, Economic, and Environmental
Implications, Elsevier Inc., 2015, pp. 319–334. DOI:
10.1016/B978-0-12-802328-0.00021-8.
[2] T. Dutta et al., “Global demand for rare earth
resources and strategies for green mining.,” Environ
Res, vol. 150, pp. 182–190, Oct. 2016, DOI: 10.1016
/J.ENVRES.2016.05.052.
[3] H. X. Mai et al., “High-quality sodium rare-earth flu-
oride nanocrystals: Controlled synthesis and optical
properties,” J Am Chem Soc, vol. 128, no. 19, pp. 6426–
6436, May 2006, DOI: 10.1021/JA060212H
/SUPPL_FILE/JA060212HSI20060414_124908
.PDF.
[4] U. States Department of Energy, “Critical Materials
Rare Earths Supply Chain: A Situational White
Paper,” 2020.
[5] G. Inman, I. C. Nlebedim, and D. Prodius,
“Application of Ionic Liquids for the Recycling and
Recovery of Technologically Critical and Valuable
Metals,” Energies, vol. 15, no. 2. MDPI, Jan. 01,
2022. DOI: 10.3390/en15020628.
[6] M. Irina et al., “Electrochemical leaching of rare-
earth elements from spent NdFeB magnets,” 2020,
DOI: 10.1016/j.hydromet.2020.105264.
[7] J. Z. Wang, Y. C. Tang, and Y. H. Shen, “Leaching
of Sm, Co, Fe, and Cu from Spent SmCo Magnets
Using Organic Acid,” Metals (Basel), vol. 13, no. 2,
Feb. 2023, DOI: 10.3390/met13020233.
[8] R. Herrington, “Mining our green future,” DOI:
10.1038/s41578-021-00325-9.
[9] N. T. Nassar and S. M. Fortier, “ofr20211045.pdf
-Methodology and Technical Input for the 2021
Review and Revision of the U.S. Critical Minerals
List,” 2021.
[10] S. Prusty, S. Pradhan, and S. Mishra, “Extraction
and separation studies of Nd/Fe and Sm/Co by deep
eutectic solvent containing Aliquat 336 and glycerol,”
Journal of Chemical Technology and Biotechnology, vol.
98, no. 7, pp. 1631–1641, Jul. 2023, DOI: 10.1002
/jctb.7381.
[11] M. H. Severson, R. T. Nguyen, J. Ormerod, A.
Palasyuk, and J. Cui, “A preliminary feasibility study
of potential market applications for non-commercial
technology magnets,” Heliyon, vol. 8, no. 12, Dec.
2022, DOI: 10.1016/J.HELIYON.2022.E11773.
[12] X. Li, Z. Li, M. Orefice, and K. Binnemans, “Metal
Recovery from Spent Samarium-Cobalt Magnets
Using a Trichloride Ionic Liquid,” ACS Sustain Chem
Eng, vol. 7, no. 2, pp. 2578–2584, Jan. 2019, DOI:
10.1021/acssuschemeng.8b05604.
[13] S. Sobekova Foltova, T. Vander Hoogerstraete, D.
Banerjee, and K. Binnemans, “Samarium/cobalt
separation by solvent extraction with undiluted qua-
ternary ammonium ionic liquids,” Sep Purif Technol,
vol. 210, pp. 209–218, Feb. 2019, DOI: 10.1016
/j.seppur.2018.07.069.
[14] J. M. D. Coey, “Perspective and Prospects for Rare
Earth Permanent Magnets,” Engineering, vol. 6,
no. 2, pp. 119–131, Feb. 2020, DOI: 10.1016
/J.ENG.2018.11.034.
[15] C. K. Gupta and N. (Nagaiyar) Krishnamurthy,
Extractive metallurgy of rare earths. CRC Press, 2005.