XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 2331
of the molecule because of the donor inductive effect that
will be more important. When the oxygen was located far
from the amine head (ETA4), the adsorption energy was
almost the same as the one of the fatty amines. However,
dispersion energies were twice higher than for the FA, due
to the long-distance interactions between the oxygen of the
molecule and the surface.
CONCLUSION
In this work the adsorption mechanisms of dodecylamine
hydrochloride and an etheramine salt on kaolinite were
investigated using DFT and experimental techniques.
Etheramines were known to be efficient, soluble collec-
tors for the flotation of iron ores. Now, it is shown that
the mechanisms of adsorption are the same as classical
fatty amines, but the adsorption behaviour difference (high
adsorption capacity) is due to the presence of the oxygen
within the hydrophobic chain that allows the formation of
close packed monolayer on top of kaolinite surface. These
results are of uttermost importance as they highlight the
mechanisms of the formation of amine surfactant mono-
layers. Similar investigations on other collectors which led
researchers to be able to design more selective reagents for
more efficient flotation processes.
ACKNOWLEDGMENTS
This work has been conducted in the frame of the indus-
trial chair MULTIMINE funded by ArcelorMittal, Région
Grand Est, Metz Métropole and Université de Lorraine.
REFERENCES
Araujo, A.C., Viana, P.R.M., Peres, A.E.C., 2005. Reagents
in iron ores flotation. Minerals Engineering, Reagents
’04 18, 219–224. doi: 10.1016/j.mineng.2004.08.023.
Barani, K., Kalantari, M., 2018. Recovery of kaolin-
ite from tailings of Zonouz kaolin-washing plant by
flotation-flocculation method. Journal of Materials
Research and Technology 7, 142–148. doi: 10.1016/j.
jmrt.2017.05.010.
Figure 4. Configuration of adsorption of the amine molecules (FA, ETA1, ETA3 and ETA4) onto the octahedral surface
Table 7. Influence of the oxygen and its position within the carbon chain on the adsorption energies (kJ·mol-1) of amine
molecules onto kaolinite basal surfaces calculated using DFT at 0 K
Adsorption Energies (kJ·mol–1)
(and Dispersion Contribution) ETA1 ETA3 ETA4 FA
Octahedral -61.0 (38%) -64.2 (41%) -69.6 (37%) -71.8 (14%)
Tetrahedral -14.8 (108%) -15.1 (110%) — -29.2 (70%)
of the molecule because of the donor inductive effect that
will be more important. When the oxygen was located far
from the amine head (ETA4), the adsorption energy was
almost the same as the one of the fatty amines. However,
dispersion energies were twice higher than for the FA, due
to the long-distance interactions between the oxygen of the
molecule and the surface.
CONCLUSION
In this work the adsorption mechanisms of dodecylamine
hydrochloride and an etheramine salt on kaolinite were
investigated using DFT and experimental techniques.
Etheramines were known to be efficient, soluble collec-
tors for the flotation of iron ores. Now, it is shown that
the mechanisms of adsorption are the same as classical
fatty amines, but the adsorption behaviour difference (high
adsorption capacity) is due to the presence of the oxygen
within the hydrophobic chain that allows the formation of
close packed monolayer on top of kaolinite surface. These
results are of uttermost importance as they highlight the
mechanisms of the formation of amine surfactant mono-
layers. Similar investigations on other collectors which led
researchers to be able to design more selective reagents for
more efficient flotation processes.
ACKNOWLEDGMENTS
This work has been conducted in the frame of the indus-
trial chair MULTIMINE funded by ArcelorMittal, Région
Grand Est, Metz Métropole and Université de Lorraine.
REFERENCES
Araujo, A.C., Viana, P.R.M., Peres, A.E.C., 2005. Reagents
in iron ores flotation. Minerals Engineering, Reagents
’04 18, 219–224. doi: 10.1016/j.mineng.2004.08.023.
Barani, K., Kalantari, M., 2018. Recovery of kaolin-
ite from tailings of Zonouz kaolin-washing plant by
flotation-flocculation method. Journal of Materials
Research and Technology 7, 142–148. doi: 10.1016/j.
jmrt.2017.05.010.
Figure 4. Configuration of adsorption of the amine molecules (FA, ETA1, ETA3 and ETA4) onto the octahedral surface
Table 7. Influence of the oxygen and its position within the carbon chain on the adsorption energies (kJ·mol-1) of amine
molecules onto kaolinite basal surfaces calculated using DFT at 0 K
Adsorption Energies (kJ·mol–1)
(and Dispersion Contribution) ETA1 ETA3 ETA4 FA
Octahedral -61.0 (38%) -64.2 (41%) -69.6 (37%) -71.8 (14%)
Tetrahedral -14.8 (108%) -15.1 (110%) — -29.2 (70%)