XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 179
content, and XRD analysis showed no aluminum crys-
tallized as mullite or other aluminum silicates, which are
refractory to acid leaching. Aluminum sulfate crystalliza-
tion by leachate evaporation led to the recovery of a white
powder which contained aluminum and calcium in similar
amounts. Therefore, while we were able to produce alumi-
num sulphate from the leached aluminum hyperaccumula-
tors, further work is required to purify the final product,
especially to remove calcium.
AKNOWLEDGEMENTS
The author would like to thank Dr Pascal Boulet from the
Institut Jean Lamour (joint lab Université de Lorraine–
CNRS, Nancy, France) for his help in carrying out the
XRD analysis.
This work was supported by the French National Research
Agency through the national program “Investissements
d’avenir” (ANR-10-LABX-21-RESSOURCES21).
Figure 4. Surface response of the aluminum extraction rate at
90°C at different acid concentrations and leaching durations
Figure 5. SEM-EDX observation of ash residue after 2M
sulfuric acid leaching at 90°C for 2 hours
0.43 0.47
3.16
26.60
3.92
0.54
0
5
10
15
20
25
30
Mg Na Ca S Al K
Figure 6. Elemental composition in weight percentage of the products obtained by evaporation of the leachates after leaching
at 90°C with 0.25M H2SO4 for 30 minutes
Weight
percentage
(%)
content, and XRD analysis showed no aluminum crys-
tallized as mullite or other aluminum silicates, which are
refractory to acid leaching. Aluminum sulfate crystalliza-
tion by leachate evaporation led to the recovery of a white
powder which contained aluminum and calcium in similar
amounts. Therefore, while we were able to produce alumi-
num sulphate from the leached aluminum hyperaccumula-
tors, further work is required to purify the final product,
especially to remove calcium.
AKNOWLEDGEMENTS
The author would like to thank Dr Pascal Boulet from the
Institut Jean Lamour (joint lab Université de Lorraine–
CNRS, Nancy, France) for his help in carrying out the
XRD analysis.
This work was supported by the French National Research
Agency through the national program “Investissements
d’avenir” (ANR-10-LABX-21-RESSOURCES21).
Figure 4. Surface response of the aluminum extraction rate at
90°C at different acid concentrations and leaching durations
Figure 5. SEM-EDX observation of ash residue after 2M
sulfuric acid leaching at 90°C for 2 hours
0.43 0.47
3.16
26.60
3.92
0.54
0
5
10
15
20
25
30
Mg Na Ca S Al K
Figure 6. Elemental composition in weight percentage of the products obtained by evaporation of the leachates after leaching
at 90°C with 0.25M H2SO4 for 30 minutes
Weight
percentage
(%)