XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 1869
the main impurity, in NdFeB magnets in the two types
of DESs (EG-MA, GUC-LA) were investigated, and the
results are shown in Figure 1.
Figure 1 demonstrates that both DESs are effective
in leaching Nd2O3. The leaching efficiency of Fe2O3 was
0.07% in EG-MA and 5.63% in GUC-LA, indicating it
is near insoluble in both DESs. On the other hand, Fe3O4
showed opposite leaching behavior for the two DESs,
with 99% leaching in GUC-LA whereas it was insoluble
in EG-MA. This suggests selective leaching of Nd is pos-
sible once the elements in NdFeB magnets exist as Nd2O3
and Fe2O3 in both DESs. However, GUC-LA has a higher
leaching efficiency of Fe2O3 than EG-MA, and the pres-
ence of Fe3O4 may impede selectivity, so EG-MA is consid-
ered a more suitable lixiviant for selective leaching of Nd.
Leaching of Oxidative Roasted Magnet
Oxidative roasting is the most common pretreatment
method used to convert the elements of magnets to their
oxide forms. Although the magnet was expected to be con-
verted into selectively leachable forms Nd2O3 and Fe2O3,
the XRD pattern shown in Figure 2 demonstrates that Nd
exists as NdFeO3 after oxidative roasting.
Figure 1. Leaching efficiency of Nd
2 O
3 ,Fe
3 O
4 and Fe
2 O
3 in EG-MA and GUC-LA DESs
Figure 2. XRD patterns of NdFeB magnet and oxidative roasted NdFeB magnet
the main impurity, in NdFeB magnets in the two types
of DESs (EG-MA, GUC-LA) were investigated, and the
results are shown in Figure 1.
Figure 1 demonstrates that both DESs are effective
in leaching Nd2O3. The leaching efficiency of Fe2O3 was
0.07% in EG-MA and 5.63% in GUC-LA, indicating it
is near insoluble in both DESs. On the other hand, Fe3O4
showed opposite leaching behavior for the two DESs,
with 99% leaching in GUC-LA whereas it was insoluble
in EG-MA. This suggests selective leaching of Nd is pos-
sible once the elements in NdFeB magnets exist as Nd2O3
and Fe2O3 in both DESs. However, GUC-LA has a higher
leaching efficiency of Fe2O3 than EG-MA, and the pres-
ence of Fe3O4 may impede selectivity, so EG-MA is consid-
ered a more suitable lixiviant for selective leaching of Nd.
Leaching of Oxidative Roasted Magnet
Oxidative roasting is the most common pretreatment
method used to convert the elements of magnets to their
oxide forms. Although the magnet was expected to be con-
verted into selectively leachable forms Nd2O3 and Fe2O3,
the XRD pattern shown in Figure 2 demonstrates that Nd
exists as NdFeO3 after oxidative roasting.
Figure 1. Leaching efficiency of Nd
2 O
3 ,Fe
3 O
4 and Fe
2 O
3 in EG-MA and GUC-LA DESs
Figure 2. XRD patterns of NdFeB magnet and oxidative roasted NdFeB magnet