3110 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
value was taken as the final result. The measured solubility
of AIBTC in water was 3.63×10–3 M and 2.98×10–3 M
in borate buffer. The solubility determined for IPETC was
2.24×10–2 M and 1.93×10–2 M in water and borate buffer,
respectively. The results for IPETC were close to the value
measured in 0.01 M KCl at a pH of 7.7 by Fairthorne et
al. (1996).
The solubility of AIBTC was found to be lower than
that of IPETC in both borate and water solutions, the rea-
sons for which may include the longer hydrocarbon chain
length of AIBTC (two carbons more than IPETC) and the
existence of the ally group. Furthermore, when the ionic
strength increased, both ligands’ solubilities decreased,
reducing by roughly 18% for AIBTC and 8% for IPETC.
The reduced solubility might suggest that AIBTC and
IPETC molecules can be ionized at elevated pH. Further
investigation on their pKa will be conducted.
The surface tension of aqueous solutions versus the
ligand concentration is depicted in Figure 4. The drop in
surface tension was more significant with the concentra-
tion of AIBTC, suggesting a more surface-active nature of
AIBTC. Interestingly, within the range of their maximal
concentration in water, the surface tension did not reach a
steady state, where surface tension would marginally change
with increasing concentration, thereby indicating micelle
formation. Micelle formation was not detected with either
AIBTC or IPETC over the concentration range study. This
differs from dithiocarbonates (aka, xanthates) and other
collectors (Han et al., 2018). This is probably due to the
limited solubility of the thionocarbamates.
Figure 3. (a)-(d). Ligand concentration vs. UV/VIS Absorbance for AIBTC-borate, AIBTC-water, IPETC-borate, and IPETC-
water
value was taken as the final result. The measured solubility
of AIBTC in water was 3.63×10–3 M and 2.98×10–3 M
in borate buffer. The solubility determined for IPETC was
2.24×10–2 M and 1.93×10–2 M in water and borate buffer,
respectively. The results for IPETC were close to the value
measured in 0.01 M KCl at a pH of 7.7 by Fairthorne et
al. (1996).
The solubility of AIBTC was found to be lower than
that of IPETC in both borate and water solutions, the rea-
sons for which may include the longer hydrocarbon chain
length of AIBTC (two carbons more than IPETC) and the
existence of the ally group. Furthermore, when the ionic
strength increased, both ligands’ solubilities decreased,
reducing by roughly 18% for AIBTC and 8% for IPETC.
The reduced solubility might suggest that AIBTC and
IPETC molecules can be ionized at elevated pH. Further
investigation on their pKa will be conducted.
The surface tension of aqueous solutions versus the
ligand concentration is depicted in Figure 4. The drop in
surface tension was more significant with the concentra-
tion of AIBTC, suggesting a more surface-active nature of
AIBTC. Interestingly, within the range of their maximal
concentration in water, the surface tension did not reach a
steady state, where surface tension would marginally change
with increasing concentration, thereby indicating micelle
formation. Micelle formation was not detected with either
AIBTC or IPETC over the concentration range study. This
differs from dithiocarbonates (aka, xanthates) and other
collectors (Han et al., 2018). This is probably due to the
limited solubility of the thionocarbamates.
Figure 3. (a)-(d). Ligand concentration vs. UV/VIS Absorbance for AIBTC-borate, AIBTC-water, IPETC-borate, and IPETC-
water