XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 3109
the higher dissolution rate of IPETC. Interaction kinetics
between ligands and value minerals, mainly chalcopyrite in
this ore system, are not deemed to be the reason for the dif-
ference in recovery in the first 30 seconds. In single mineral
micro-flotation studies (not reported here), results showed
that when ligands were added as fully dissolved aqueous
solution at pH 9, AIBTC reached an apparently higher
recovery in the first flotation stage in 30 seconds.
When flotation concentrate collection time was 1 min-
ute, Cu and Mo recoveries with AIBTC almost caught up
with those with IPETC, with around 55 to 57% Cu recov-
ery and 16 to 17% Mo recovery. After 2 minutes of flota-
tion, both Cu and Mo recoveries with AIBTC started to
surpass those with IPETC.
Cu recovery increased rapidly in the first two minutes
of flotation, after which recoveries with AIBTC continued
to increase steadily during the 2 to 4 minutes of flotation
and then gradually increased to a final recovery of 86%.
Similarly, Mo recovery risen fast in the first 7 minutes and
then gently increased to 41% when the flotation was com-
pleted. On the contrary, the initial fast recovery rate with
IPETC significantly slowed down after a 2-minute flota-
tion, and the final Cu and Mo recoveries were lower than
those with AIBTC, suggesting a more efficient recovery
performance of AIBTC. In real ore flotation, collectors
were dosed at the same grams per ton of ore. Considering
that AIBTC has a greater molar mass than IPETC and thus
a lesser number of molecules per sample weight, its higher
recovery capacity can be explained by its greater adsorption
onto the value mineral surface and greater surface-active
nature, which will be elaborated in the following sections,
resulting in an increased surface hydrophobicity.
Similar observations were made for Mo recovery,
except that Mo recovery with AIBTC increased signifi-
cantly at the later flotation stages, e.g., 4 to 10 minutes.
This is believed to be due to the substantially lower head
Mo concentration (about 300 g/t) compared to the head
grade of Cu (about 0.5%), and ligand molecules had a sig-
nificantly higher possibility of adsorbing onto the surface
of Cu minerals. Thus, Cu minerals were more floatable and
more favorable regarding flotation kinetics. Most Cu recov-
ery was accomplished in the first 4-minute flotation, after
which residual ligand molecules would go to Mo minerals.
An upward shift in Mo recovery versus time was noticeable
in the case of AIBTC while less evident for IPETC. Again,
this demonstrated a greater recovery efficiency and capacity
of AIBTC.
Solution Property Study
The assigned UV-Vis peak coincides well with the previ-
ous report for IPETC by Fairthorne et al. (1996), which
was recorded at 241.5 nm. The remarkable closeness of
the characteristic peaks observed for both AIBTC and
IPETC implies that an allylic double bond in AIBTC did
not significantly affect the C=S bond. This contrasts with
IBECTC, as reported in the same study by Fairthorne et al.
(1996), which displayed an absorption peak at 253.3 nm.
This discrepancy indicates that the alkoxycarbonyl group in
IBECTC effectively alters the functional group, resulting in
distinct spectroscopic characteristics.
Ligand concentration vs. absorbance diagrams for
AIBTC-borate, AIBTC-water, IPETC-borate, and IPETC-
water were plotted in Figure 3 (a)-(d). Solubility for each
ligand-solvent pair was measured four or six times with a
standard deviation of 0.11% to 3.97%, and the average
Figure 2. Cumulative recovery vs. cumulative flotation time of a) Cu, b) Mo
the higher dissolution rate of IPETC. Interaction kinetics
between ligands and value minerals, mainly chalcopyrite in
this ore system, are not deemed to be the reason for the dif-
ference in recovery in the first 30 seconds. In single mineral
micro-flotation studies (not reported here), results showed
that when ligands were added as fully dissolved aqueous
solution at pH 9, AIBTC reached an apparently higher
recovery in the first flotation stage in 30 seconds.
When flotation concentrate collection time was 1 min-
ute, Cu and Mo recoveries with AIBTC almost caught up
with those with IPETC, with around 55 to 57% Cu recov-
ery and 16 to 17% Mo recovery. After 2 minutes of flota-
tion, both Cu and Mo recoveries with AIBTC started to
surpass those with IPETC.
Cu recovery increased rapidly in the first two minutes
of flotation, after which recoveries with AIBTC continued
to increase steadily during the 2 to 4 minutes of flotation
and then gradually increased to a final recovery of 86%.
Similarly, Mo recovery risen fast in the first 7 minutes and
then gently increased to 41% when the flotation was com-
pleted. On the contrary, the initial fast recovery rate with
IPETC significantly slowed down after a 2-minute flota-
tion, and the final Cu and Mo recoveries were lower than
those with AIBTC, suggesting a more efficient recovery
performance of AIBTC. In real ore flotation, collectors
were dosed at the same grams per ton of ore. Considering
that AIBTC has a greater molar mass than IPETC and thus
a lesser number of molecules per sample weight, its higher
recovery capacity can be explained by its greater adsorption
onto the value mineral surface and greater surface-active
nature, which will be elaborated in the following sections,
resulting in an increased surface hydrophobicity.
Similar observations were made for Mo recovery,
except that Mo recovery with AIBTC increased signifi-
cantly at the later flotation stages, e.g., 4 to 10 minutes.
This is believed to be due to the substantially lower head
Mo concentration (about 300 g/t) compared to the head
grade of Cu (about 0.5%), and ligand molecules had a sig-
nificantly higher possibility of adsorbing onto the surface
of Cu minerals. Thus, Cu minerals were more floatable and
more favorable regarding flotation kinetics. Most Cu recov-
ery was accomplished in the first 4-minute flotation, after
which residual ligand molecules would go to Mo minerals.
An upward shift in Mo recovery versus time was noticeable
in the case of AIBTC while less evident for IPETC. Again,
this demonstrated a greater recovery efficiency and capacity
of AIBTC.
Solution Property Study
The assigned UV-Vis peak coincides well with the previ-
ous report for IPETC by Fairthorne et al. (1996), which
was recorded at 241.5 nm. The remarkable closeness of
the characteristic peaks observed for both AIBTC and
IPETC implies that an allylic double bond in AIBTC did
not significantly affect the C=S bond. This contrasts with
IBECTC, as reported in the same study by Fairthorne et al.
(1996), which displayed an absorption peak at 253.3 nm.
This discrepancy indicates that the alkoxycarbonyl group in
IBECTC effectively alters the functional group, resulting in
distinct spectroscopic characteristics.
Ligand concentration vs. absorbance diagrams for
AIBTC-borate, AIBTC-water, IPETC-borate, and IPETC-
water were plotted in Figure 3 (a)-(d). Solubility for each
ligand-solvent pair was measured four or six times with a
standard deviation of 0.11% to 3.97%, and the average
Figure 2. Cumulative recovery vs. cumulative flotation time of a) Cu, b) Mo