XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 1913
showed that alanine formed bonds with gold predominantly
through its amine and carboxylic ends, with deprotonated
alanine exhibiting more pronounced bonding compared to
its neutral counterpart.DFT analysis further corroborated
these findings, emphasizing the stability of the N-Au-N
bonding configuration, which proved to be the most stable
for both deprotonated and zwitterionic alanine. Notably,
the deprotonated alanine complex displayed the highest
complexation energy, indicating a high intensity of interac-
tion for gold-alanine formation in its deprotonated state.
Upon dissolution, the study revealed that at deprotonation
pH, alanine exhibited high gold dissolution compared to its
neutral form. This suggests a potential correlation between
FTIR, DFT predictions, and the actual gold dissolution
behavior of alanine. In a practical feasibility study, deprot-
onated alanine proved to be a promising green lixiviant for
gold leaching.
ACKNOWLEDGMENTS
The authors thank and acknowledge the Royal Society and
the African Academy of Sciences for funding through the
FLAIR fellowship grant number FLRR119154.
Lastly, special thanks to the Centre for High
Performance Computing (CHPC) in Cape Town for the
provision of resources that enabled the execution of the
DFT calculations.
DECLARATION OF INTERESTS
• The authors declare that they have no known com-
peting financial interests or personal relationships
that could have appeared to influence the work
reported in this paper.
• The authors declare the following financial interests/
personal relationships which may be considered as
potential competing interests:
Margreth Tadie reports financial support was provided by
Royal Society and the African Academy of Sciences.
REFERENCES
Abdalmoneam, M.H., Waters, K., Saikia, N. and
Pandey, R., 2017. Amino-acid-conjugated gold clus-
ters: interaction of alanine and tryptophan with Au8
and Au20. The Journal of Physical Chemistry C,
121(45), pp.25585–25593.
Altinkaya, P., Wang, Z., Korolev, I., Hamuyuni, J.,
Haapalainen, M., Kolehmainen, E., Yliniemi, K.
and Lundström, M., 2020. Leaching and recovery of
gold from ore in cyanide-free glycine media. Minerals
Engineering, 158, p.106610.
Akram, M., Asif, H.M., Uzair, M., Akhtar, N., Madni, A.,
Shah, S.A., Hasan, Z.U. and Ullah, A., 2011. Amino
acids: A review article. Journal of Medicinal Plants
Research, 5(17), pp.3997–4000.
0
10
20
30
40
50
60
70
80
90
100
Conditions :amino concentration -pulp density- preoxidation time-copper ion concentration
Figure 7. The leaching of a Witwatersrand tailings using deprotonated alanine (pH 12), room temperature at varoius leach
conditions
Maximum
goldextracti
(%)
af te r
24
hr
showed that alanine formed bonds with gold predominantly
through its amine and carboxylic ends, with deprotonated
alanine exhibiting more pronounced bonding compared to
its neutral counterpart.DFT analysis further corroborated
these findings, emphasizing the stability of the N-Au-N
bonding configuration, which proved to be the most stable
for both deprotonated and zwitterionic alanine. Notably,
the deprotonated alanine complex displayed the highest
complexation energy, indicating a high intensity of interac-
tion for gold-alanine formation in its deprotonated state.
Upon dissolution, the study revealed that at deprotonation
pH, alanine exhibited high gold dissolution compared to its
neutral form. This suggests a potential correlation between
FTIR, DFT predictions, and the actual gold dissolution
behavior of alanine. In a practical feasibility study, deprot-
onated alanine proved to be a promising green lixiviant for
gold leaching.
ACKNOWLEDGMENTS
The authors thank and acknowledge the Royal Society and
the African Academy of Sciences for funding through the
FLAIR fellowship grant number FLRR119154.
Lastly, special thanks to the Centre for High
Performance Computing (CHPC) in Cape Town for the
provision of resources that enabled the execution of the
DFT calculations.
DECLARATION OF INTERESTS
• The authors declare that they have no known com-
peting financial interests or personal relationships
that could have appeared to influence the work
reported in this paper.
• The authors declare the following financial interests/
personal relationships which may be considered as
potential competing interests:
Margreth Tadie reports financial support was provided by
Royal Society and the African Academy of Sciences.
REFERENCES
Abdalmoneam, M.H., Waters, K., Saikia, N. and
Pandey, R., 2017. Amino-acid-conjugated gold clus-
ters: interaction of alanine and tryptophan with Au8
and Au20. The Journal of Physical Chemistry C,
121(45), pp.25585–25593.
Altinkaya, P., Wang, Z., Korolev, I., Hamuyuni, J.,
Haapalainen, M., Kolehmainen, E., Yliniemi, K.
and Lundström, M., 2020. Leaching and recovery of
gold from ore in cyanide-free glycine media. Minerals
Engineering, 158, p.106610.
Akram, M., Asif, H.M., Uzair, M., Akhtar, N., Madni, A.,
Shah, S.A., Hasan, Z.U. and Ullah, A., 2011. Amino
acids: A review article. Journal of Medicinal Plants
Research, 5(17), pp.3997–4000.
0
10
20
30
40
50
60
70
80
90
100
Conditions :amino concentration -pulp density- preoxidation time-copper ion concentration
Figure 7. The leaching of a Witwatersrand tailings using deprotonated alanine (pH 12), room temperature at varoius leach
conditions
Maximum
goldextracti
(%)
af te r
24
hr