3234 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
sufficiently fine grinding there still may be difficulties in
separating the Co and SmFeO3 as SmFeO3 is somewhat
magnetic (Tripathi et al. 2023).
CONCLUSIONS
The selective oxidation of SmCo magnets to Sm2O3 and
Co was partially successful. Magnets were oxidized to Co,
Co0.7Fe0.3, and SmFeO3, but magnetic separation of these
products was not feasible due to the small size of the oxide
particles and a resulting lack of liberation after grinding.
Annealing treatments or oxidation at different tempera-
tures may produce a coarser microstructure which is more
amenable to magnetic separation. Additionally, roasting at
a lower pO2 may prevent formation SmFeO3 and instead
produce the desired Co, CoFe, and Sm2O3. Further inves-
tigation on oxidation of the magnets at different tempera-
tures and pO2s is ongoing.
ACKNOWLEDGMENTS
Research was sponsored by the DEVCOM Combat
Capabilities Development Command Army Research
Laboratory and was accomplished under Cooperative
Agreement Number W911NF-22-2-0015. The views
and conclusions contained in this document are those of
the authors, and should not be interpreted as represent-
ing the official policies, either expressed or implied, of the
DEVCOM Combat Capabilities Development Command
Army Research Laboratory or the U.S. Government. The
U.S. Government is authorized to reproduce and distrib-
ute reprints for Government purposes notwithstanding any
copyright notation herein.
REFERENCES
2022. 2022 Final List of Critical Minerals. United States
Geological Survey.
2023. Cobalt (Mineral Commodity Summaries). United
States Geological Survey.
2023. Critical Materials Assessment Draft Report. United
States Department of Energy.
Barin, I., Platzki, G. 1995. Thermochemical Data of Pure
Substances, 3rd ed. VCH.
Baker, I. 1997. Thayer School of Engineering, Dartmouth
College, NH, USA. ICDD Grant-in-Aid.
Bartlett, R.W., and Jorgensen, P.J. 1974. Microstructure and
Growth Kinetics of the Fibrous Composite Subscale
formed by Internal Oxdiation of SmCo5. Metallurgical
Transactions, 5:355–361.
Hedrick, J.B. 2004. Rare Earths in Selected U.S. Defense
Applications. 40th Forum on the Geology of Industrial
Minerals.
Kharko, O.V., Vasylechko, L.O., Ubizskii, S.B., Pashuk,
A., Prots, Y. 2014. Structural behaviour of continuous
solid solution SmCo1-xFexO3. Functional Materials,
21(2):226.
Kupcis, O. A., &Ramaswami, B. 1969. A new method for
internal oxidation at low oxygen pressures. Materials
Science and Engineering, 5(1):43–44.
Lyman, J., and Palmer, G. (1993). Recycling of Neodymium
Iron Boron Magnet Scrap. Report of Investigations
9481. United States Department of the Interior,
Bureau of Mines.
Martin, K., McCarthy, G. 1991. North Dakota State
University, Fargo, North Dakota, USA. ICDD
Grant-in-Aid.
Ojima, T., Tomizawa, S., Yoneyama, T., &Hori, T. 1977.
Magnetic properties of a new type of rare-earth cobalt
magnets Sm2(Co, Cu, Fe, M)17. IEEE Transactions on
Magnetics 13(5):1317–1319.
Rhines, F. 1940. A Metallographic Study of Internal
Oxidation in the Alpha Solid Solutions of Copper.
AIME.
Swanson, H.E., Morris, M.C., and Evans, E.H. 1996.
Standard X-ray Diffraction Patterns. Monograph 25
Section 4. National Bureau of Standards.
Song, X., Lu, N., Xu, W., Zhang, Z., Zhang, J. 2009. Phase
transformation in nanocrystalline Sm2Co17 permanent
magnet material. Journal of Applied Crystallography
42(4):691.
Sucksmith, W., and Pearce, R.R. The paramagnetism of the
ferromagnetic elements. 1938. Proceedings of the Royal
Society of London. Series A. Mathematical and Physical
Sciences 167(929):189–204.
Swanson, H.E., Morris, M.C., Evans, E.H. 1966. Standard
X-ray Diffraction Powder Patterns. Monograph 25
Section 4. National Bureau of Standards.
Tripathi, A., Nigam, A., &Pawar, S. J. 2023. Rare Earth
Metal Samarium Doped Ferrite and Its Structural,
Morphological, Magnetic, and Optical Studies for
Biomedical Applications. Integrated Ferroelectrics,
237(1):170–185.
Williams, E. H. 1918. The Magnetic Properties of some
rare Earth Oxides as a Function of the Temperature.
Physical Review 12(2):158–166.
Yuan, Y., Yi, J., Borzone, G., and Watson, A. 2011.
Thermodynamic modeling of the Co–Sm system.
Calphad 35(3):416–420.
sufficiently fine grinding there still may be difficulties in
separating the Co and SmFeO3 as SmFeO3 is somewhat
magnetic (Tripathi et al. 2023).
CONCLUSIONS
The selective oxidation of SmCo magnets to Sm2O3 and
Co was partially successful. Magnets were oxidized to Co,
Co0.7Fe0.3, and SmFeO3, but magnetic separation of these
products was not feasible due to the small size of the oxide
particles and a resulting lack of liberation after grinding.
Annealing treatments or oxidation at different tempera-
tures may produce a coarser microstructure which is more
amenable to magnetic separation. Additionally, roasting at
a lower pO2 may prevent formation SmFeO3 and instead
produce the desired Co, CoFe, and Sm2O3. Further inves-
tigation on oxidation of the magnets at different tempera-
tures and pO2s is ongoing.
ACKNOWLEDGMENTS
Research was sponsored by the DEVCOM Combat
Capabilities Development Command Army Research
Laboratory and was accomplished under Cooperative
Agreement Number W911NF-22-2-0015. The views
and conclusions contained in this document are those of
the authors, and should not be interpreted as represent-
ing the official policies, either expressed or implied, of the
DEVCOM Combat Capabilities Development Command
Army Research Laboratory or the U.S. Government. The
U.S. Government is authorized to reproduce and distrib-
ute reprints for Government purposes notwithstanding any
copyright notation herein.
REFERENCES
2022. 2022 Final List of Critical Minerals. United States
Geological Survey.
2023. Cobalt (Mineral Commodity Summaries). United
States Geological Survey.
2023. Critical Materials Assessment Draft Report. United
States Department of Energy.
Barin, I., Platzki, G. 1995. Thermochemical Data of Pure
Substances, 3rd ed. VCH.
Baker, I. 1997. Thayer School of Engineering, Dartmouth
College, NH, USA. ICDD Grant-in-Aid.
Bartlett, R.W., and Jorgensen, P.J. 1974. Microstructure and
Growth Kinetics of the Fibrous Composite Subscale
formed by Internal Oxdiation of SmCo5. Metallurgical
Transactions, 5:355–361.
Hedrick, J.B. 2004. Rare Earths in Selected U.S. Defense
Applications. 40th Forum on the Geology of Industrial
Minerals.
Kharko, O.V., Vasylechko, L.O., Ubizskii, S.B., Pashuk,
A., Prots, Y. 2014. Structural behaviour of continuous
solid solution SmCo1-xFexO3. Functional Materials,
21(2):226.
Kupcis, O. A., &Ramaswami, B. 1969. A new method for
internal oxidation at low oxygen pressures. Materials
Science and Engineering, 5(1):43–44.
Lyman, J., and Palmer, G. (1993). Recycling of Neodymium
Iron Boron Magnet Scrap. Report of Investigations
9481. United States Department of the Interior,
Bureau of Mines.
Martin, K., McCarthy, G. 1991. North Dakota State
University, Fargo, North Dakota, USA. ICDD
Grant-in-Aid.
Ojima, T., Tomizawa, S., Yoneyama, T., &Hori, T. 1977.
Magnetic properties of a new type of rare-earth cobalt
magnets Sm2(Co, Cu, Fe, M)17. IEEE Transactions on
Magnetics 13(5):1317–1319.
Rhines, F. 1940. A Metallographic Study of Internal
Oxidation in the Alpha Solid Solutions of Copper.
AIME.
Swanson, H.E., Morris, M.C., and Evans, E.H. 1996.
Standard X-ray Diffraction Patterns. Monograph 25
Section 4. National Bureau of Standards.
Song, X., Lu, N., Xu, W., Zhang, Z., Zhang, J. 2009. Phase
transformation in nanocrystalline Sm2Co17 permanent
magnet material. Journal of Applied Crystallography
42(4):691.
Sucksmith, W., and Pearce, R.R. The paramagnetism of the
ferromagnetic elements. 1938. Proceedings of the Royal
Society of London. Series A. Mathematical and Physical
Sciences 167(929):189–204.
Swanson, H.E., Morris, M.C., Evans, E.H. 1966. Standard
X-ray Diffraction Powder Patterns. Monograph 25
Section 4. National Bureau of Standards.
Tripathi, A., Nigam, A., &Pawar, S. J. 2023. Rare Earth
Metal Samarium Doped Ferrite and Its Structural,
Morphological, Magnetic, and Optical Studies for
Biomedical Applications. Integrated Ferroelectrics,
237(1):170–185.
Williams, E. H. 1918. The Magnetic Properties of some
rare Earth Oxides as a Function of the Temperature.
Physical Review 12(2):158–166.
Yuan, Y., Yi, J., Borzone, G., and Watson, A. 2011.
Thermodynamic modeling of the Co–Sm system.
Calphad 35(3):416–420.