XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 1691
It can be seen from the result that Ethaline does not
show a high selectivity for either Co or Sm over each other
even though the conversion is not proportional for both Co
and Sm. It can also be seen that time significantly affects
the Sm and Co dissolution process. The difference between
the Co and Sm conversion is not huge as compared to the
results obtained for Oxaline and Reline. Ethaline is a weak
acid [36] and since cobalt dissolves slowly in a weak acid,
this could be a reason why the conversion of cobalt is lower
in Ethaline as compared to Oxaline which is a strong acid.
Samarium (Sm) and Cobalt (Co) Conversion (%)from
SmCo Magnet Leaching in EG- TBAC.
Figure 6 compares the conversion of Sm and Co during the
leaching of the SmCo magnet in EG-TBAC. The results
show that the Sm conversion is not proportional to the Co
conversion. As can be seen, the conversion of Sm is very
low and is about 12% and the Co conversion is higher
about 60% indicating a high selectivity of EG-TBAC to
Co over Sm. Also, the conversion for both Sm and Co
increases with increasing time. Rare earth metals react, but
slowly, with strong bases [15], and since EG-TBAC is a
strong alkaline [41] the low conversion of Sm in Urea can
be attributed to it.
Comparison of Sm and Co Conversion (%)in Different
DES Media
Sm and Co conversion in different DES media is compared
and presented in Figure 7 The highest conversion for Co
was obtained in Oxaline leaching. While Oxaline leaching
achieved 82% conversion, Ethaline, Reline, and EG-TBAC
showed lower conversion. The order of conversion of Co
in the leaching media is in the order of Oxaline Reline
EG-TBAC Ethaline. For the Sm conversion, the order
is Ethaline Reline EG-TBAC Oxaline. The acidity
of the studied DES is in the following order: Oxaline
Ethaline EG-TBAC Reline [28], [41], [42]. This reason
supports why the conversion of Sm is higher in Ethaline
because Ethaline is a weak acid and REE reacts slowly in
strong acids and bases.
The higher conversion of Co in Oxaline is due to its
acidic nature [42] and the presence of H+ ions. Another rea-
son could be the high chloride and oxalate concentration
which may have had a significant influence on the stabil-
ity of Co complexes in the solution [43]. From the results
in Figure 7 the DES Oxaline, Reline and, EG-TBAC are
selective for Co over Sm while Ethaline is not selective for
either Co or Sm over each other.
CONCLUSION
The effectiveness of DESs as leachate for extraction of Sm
and Co from waste SmCo magnet and the use of RAM
for intensifying leaching was investigated in this study. The
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
Figure 6. Samarium (Sm) and Cobalt (Co) dissolution from
SmCo magnet leaching in EG-TBAC
Figure 7. Comparison of Sm and Co Conversion in different
DES media
It can be seen from the result that Ethaline does not
show a high selectivity for either Co or Sm over each other
even though the conversion is not proportional for both Co
and Sm. It can also be seen that time significantly affects
the Sm and Co dissolution process. The difference between
the Co and Sm conversion is not huge as compared to the
results obtained for Oxaline and Reline. Ethaline is a weak
acid [36] and since cobalt dissolves slowly in a weak acid,
this could be a reason why the conversion of cobalt is lower
in Ethaline as compared to Oxaline which is a strong acid.
Samarium (Sm) and Cobalt (Co) Conversion (%)from
SmCo Magnet Leaching in EG- TBAC.
Figure 6 compares the conversion of Sm and Co during the
leaching of the SmCo magnet in EG-TBAC. The results
show that the Sm conversion is not proportional to the Co
conversion. As can be seen, the conversion of Sm is very
low and is about 12% and the Co conversion is higher
about 60% indicating a high selectivity of EG-TBAC to
Co over Sm. Also, the conversion for both Sm and Co
increases with increasing time. Rare earth metals react, but
slowly, with strong bases [15], and since EG-TBAC is a
strong alkaline [41] the low conversion of Sm in Urea can
be attributed to it.
Comparison of Sm and Co Conversion (%)in Different
DES Media
Sm and Co conversion in different DES media is compared
and presented in Figure 7 The highest conversion for Co
was obtained in Oxaline leaching. While Oxaline leaching
achieved 82% conversion, Ethaline, Reline, and EG-TBAC
showed lower conversion. The order of conversion of Co
in the leaching media is in the order of Oxaline Reline
EG-TBAC Ethaline. For the Sm conversion, the order
is Ethaline Reline EG-TBAC Oxaline. The acidity
of the studied DES is in the following order: Oxaline
Ethaline EG-TBAC Reline [28], [41], [42]. This reason
supports why the conversion of Sm is higher in Ethaline
because Ethaline is a weak acid and REE reacts slowly in
strong acids and bases.
The higher conversion of Co in Oxaline is due to its
acidic nature [42] and the presence of H+ ions. Another rea-
son could be the high chloride and oxalate concentration
which may have had a significant influence on the stabil-
ity of Co complexes in the solution [43]. From the results
in Figure 7 the DES Oxaline, Reline and, EG-TBAC are
selective for Co over Sm while Ethaline is not selective for
either Co or Sm over each other.
CONCLUSION
The effectiveness of DESs as leachate for extraction of Sm
and Co from waste SmCo magnet and the use of RAM
for intensifying leaching was investigated in this study. The
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
Figure 6. Samarium (Sm) and Cobalt (Co) dissolution from
SmCo magnet leaching in EG-TBAC
Figure 7. Comparison of Sm and Co Conversion in different
DES media