1256 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
minutes, 60 minutes, and 1440 minutes. The findings indi-
cated that AH effectively adsorbed all REEs, aluminum,
and iron in the system, with the exception of calcium,
which was still fully present in the mixed solution after
24 hours (Figure 12). No adsorption was seen for calcium
at any test condition. This shows the low affinity of the
biochar for calcium ions in solution, showing the adsorbent
prefers higher valency elements. The LREE and HREE in
the mixed system showed similar adsorption and the same
uptake percentage when compared with each other as seen
in Figure 24. The uptake of REEs ranged between 40 to
almost 70%. Lanthanum and yttrium showed the lowest
adsorption compared to cerium, neodymium, terbium, and
gadolinium. This clearly shows that the biochar could not
extract elements selectively but instead will interact and
adsorb every element in the system. This, however, calls for
functionalizing our biochar to achieve selectivity between
metals and other competing ions.
CONCLUSIONS
It can be concluded biochar made from Appalachian
hardwood was utilized to remove La(III) from the aque-
ous solution and showed the maximum adsorption capac-
ity of 129mg/g when compared to the other two biochars
employed in this work, which demonstrated more than
double their adsorption capabilities. After adsorption
tests were done, 0.2M HNO3 showed approximately a
100% desorption rate for La(III) when compared to other
desorbents used in this study. The highest desorption rates
achieved with NaOH and HCl were 3% and 62.5%, respec-
tively. Even though nitric acid desorbed completely La(III)
from biochar, It is also suspected that biochar might lose
its adsorption capacity for subsequent adsorption/desorp-
tion cycles however, more investigations are needed to fully
understand the trend. When the experimental system was
expanded to multiple elements, it was observed that the
biochar has tendency toward higher valence elements (3+)
more than divalent elements (such as Ca, 2+). However,
because no selectivity between 3+ elements were seen, bio-
char surface functionalization can be sought for higher effi-
ciency. Overall, this work provides a proof of concept with
Appalachian hardwood as an alternative adsorbent for REE
processes. Detailed investigations are needed to prove this
approach’s environmental and economic feasibility.
REFERENCES
Abhilash, Sinha, S., Sinha, M. K., &Pandey, B. D. (2014).
Extraction of lanthanum and cerium from Indian red
mud. International Journal of Mineral Processing, 127,
70–73. doi: 10.1016/j.minpro.2013.12.009.
Alcaraz, L., Largo, O. R., Alguacil, F. J., Montes, M.
Á., Baudín, C., &López, F. A. (2022). Extraction
of Lanthanum Oxide from Different Spent Fluid
Catalytic Cracking Catalysts by Nitric Acid Leaching
and Cyanex 923 Solvent Extraction Methods. Metals,
12(3), Article 3. doi: 10.3390/met12030378.
0
20
40
60
80
100
10.00 30.00 60.00 480.00 1440.00
Time taken, t
Yttrium
Lanthanum
Cerium
Neodynum
Aluminum
Calcium
Iron
Figure 12. Adsorption of REEs on AH-biochar in the presence of other critical/impurity
elements
Uptake,
%
minutes, 60 minutes, and 1440 minutes. The findings indi-
cated that AH effectively adsorbed all REEs, aluminum,
and iron in the system, with the exception of calcium,
which was still fully present in the mixed solution after
24 hours (Figure 12). No adsorption was seen for calcium
at any test condition. This shows the low affinity of the
biochar for calcium ions in solution, showing the adsorbent
prefers higher valency elements. The LREE and HREE in
the mixed system showed similar adsorption and the same
uptake percentage when compared with each other as seen
in Figure 24. The uptake of REEs ranged between 40 to
almost 70%. Lanthanum and yttrium showed the lowest
adsorption compared to cerium, neodymium, terbium, and
gadolinium. This clearly shows that the biochar could not
extract elements selectively but instead will interact and
adsorb every element in the system. This, however, calls for
functionalizing our biochar to achieve selectivity between
metals and other competing ions.
CONCLUSIONS
It can be concluded biochar made from Appalachian
hardwood was utilized to remove La(III) from the aque-
ous solution and showed the maximum adsorption capac-
ity of 129mg/g when compared to the other two biochars
employed in this work, which demonstrated more than
double their adsorption capabilities. After adsorption
tests were done, 0.2M HNO3 showed approximately a
100% desorption rate for La(III) when compared to other
desorbents used in this study. The highest desorption rates
achieved with NaOH and HCl were 3% and 62.5%, respec-
tively. Even though nitric acid desorbed completely La(III)
from biochar, It is also suspected that biochar might lose
its adsorption capacity for subsequent adsorption/desorp-
tion cycles however, more investigations are needed to fully
understand the trend. When the experimental system was
expanded to multiple elements, it was observed that the
biochar has tendency toward higher valence elements (3+)
more than divalent elements (such as Ca, 2+). However,
because no selectivity between 3+ elements were seen, bio-
char surface functionalization can be sought for higher effi-
ciency. Overall, this work provides a proof of concept with
Appalachian hardwood as an alternative adsorbent for REE
processes. Detailed investigations are needed to prove this
approach’s environmental and economic feasibility.
REFERENCES
Abhilash, Sinha, S., Sinha, M. K., &Pandey, B. D. (2014).
Extraction of lanthanum and cerium from Indian red
mud. International Journal of Mineral Processing, 127,
70–73. doi: 10.1016/j.minpro.2013.12.009.
Alcaraz, L., Largo, O. R., Alguacil, F. J., Montes, M.
Á., Baudín, C., &López, F. A. (2022). Extraction
of Lanthanum Oxide from Different Spent Fluid
Catalytic Cracking Catalysts by Nitric Acid Leaching
and Cyanex 923 Solvent Extraction Methods. Metals,
12(3), Article 3. doi: 10.3390/met12030378.
0
20
40
60
80
100
10.00 30.00 60.00 480.00 1440.00
Time taken, t
Yttrium
Lanthanum
Cerium
Neodynum
Aluminum
Calcium
Iron
Figure 12. Adsorption of REEs on AH-biochar in the presence of other critical/impurity
elements
Uptake,
%
