XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 2413
Ore Flotation
Cu Ore
The flotation results for a porphyry Cu ore are shown in
Figure 12. In comparison to sodium di-isobutyl dithio-
phosphate (DIBDTP), when BCBDTC or BCBTC (the
O-analogue of BCBDTC) are used instead at the same dos-
age, a difference in selectivity between Cu and S (used as
a proxy for pyrite) can be seen between the three ligands.
The order of selectivity against pyrite is BCBTC
BCBDTC DIBDTP. The high overall S recoveries for all
three ligands can be attributed to inadvertent Cu-activation
of pyrite during the grinding stage. The interesting feature
is that while BCBDTC and BCBTC show strong differ-
ences in selectivity against pyrite, their respective Cu grade-
recovery curves nearly overlap with each other this can be
attributed to differing affinities between the two for various
Cu species.
Nagaraj et al., 1989 noted that the differing affinities
between ACATCs and ACATUs for secondary Cu sulfides
and chalcopyrite respectively is kinetically based, and as
such the equilibrium recoveries of these minerals could
be the same. This is likely also the case in comparing the
ACADTCs with its analogues. ToF-SIMS results demon-
strated they can form Cu complexes on both chalcopyrite
and chalcocite surfaces, but this does not demonstrate a
clear difference in their propensity to interact with different
Cu-containing species.
Au Ore
Primary Au ores can host Au in the form of auriferous iron
sulfides, native Au, electrum, and various Au-Ag tellurides.
In the case of this ore, Au is both associated with pyrite and
as free species. Potassium amyl xanthate (PAX) at high dos-
ages is typically used, but even this is not always adequate.
When BCBDTC is used alone, more than 70% of the Au is
recovered at low S recovery, as seen in Figure 13.
This behavior of BCBDTC is a strong justification
for the use of Pearson’s HSAB principle, that it is selective
towards soft acids like Au as opposed to harder ones like
Fe2+ in pyrite. This is further justified in comparing the
voltammograms for Au and pyrite, and in view of the ToF-
SIMS results.
An additional striking feature is that when BCBDTC
is added with PAX (Figure 13), the recoveries of both Au
and S increase relative to either collector on its own. This
synergistic performance provided by the combination of
these ligands demonstrates that BCBDTC can also interact
with pyrite. As previously noted from ToF-SIMS, a mecha-
nism for this interaction is still not fully understood, but it
can likely be attributed to differing mineralogical features
across various ore systems.
Pb-Zn-Ag Ore and Tailings
In Pb-Zn-Ag ores, Ag is often associated with galena and
differential flotation is used to sequentially recover Pb and
Figure 12. Cu flotation performance for DIBDTP, BCBDTC, and BCBTC P80 -212 µm, pH -10.5, flotation time -10 min
Ore Flotation
Cu Ore
The flotation results for a porphyry Cu ore are shown in
Figure 12. In comparison to sodium di-isobutyl dithio-
phosphate (DIBDTP), when BCBDTC or BCBTC (the
O-analogue of BCBDTC) are used instead at the same dos-
age, a difference in selectivity between Cu and S (used as
a proxy for pyrite) can be seen between the three ligands.
The order of selectivity against pyrite is BCBTC
BCBDTC DIBDTP. The high overall S recoveries for all
three ligands can be attributed to inadvertent Cu-activation
of pyrite during the grinding stage. The interesting feature
is that while BCBDTC and BCBTC show strong differ-
ences in selectivity against pyrite, their respective Cu grade-
recovery curves nearly overlap with each other this can be
attributed to differing affinities between the two for various
Cu species.
Nagaraj et al., 1989 noted that the differing affinities
between ACATCs and ACATUs for secondary Cu sulfides
and chalcopyrite respectively is kinetically based, and as
such the equilibrium recoveries of these minerals could
be the same. This is likely also the case in comparing the
ACADTCs with its analogues. ToF-SIMS results demon-
strated they can form Cu complexes on both chalcopyrite
and chalcocite surfaces, but this does not demonstrate a
clear difference in their propensity to interact with different
Cu-containing species.
Au Ore
Primary Au ores can host Au in the form of auriferous iron
sulfides, native Au, electrum, and various Au-Ag tellurides.
In the case of this ore, Au is both associated with pyrite and
as free species. Potassium amyl xanthate (PAX) at high dos-
ages is typically used, but even this is not always adequate.
When BCBDTC is used alone, more than 70% of the Au is
recovered at low S recovery, as seen in Figure 13.
This behavior of BCBDTC is a strong justification
for the use of Pearson’s HSAB principle, that it is selective
towards soft acids like Au as opposed to harder ones like
Fe2+ in pyrite. This is further justified in comparing the
voltammograms for Au and pyrite, and in view of the ToF-
SIMS results.
An additional striking feature is that when BCBDTC
is added with PAX (Figure 13), the recoveries of both Au
and S increase relative to either collector on its own. This
synergistic performance provided by the combination of
these ligands demonstrates that BCBDTC can also interact
with pyrite. As previously noted from ToF-SIMS, a mecha-
nism for this interaction is still not fully understood, but it
can likely be attributed to differing mineralogical features
across various ore systems.
Pb-Zn-Ag Ore and Tailings
In Pb-Zn-Ag ores, Ag is often associated with galena and
differential flotation is used to sequentially recover Pb and
Figure 12. Cu flotation performance for DIBDTP, BCBDTC, and BCBTC P80 -212 µm, pH -10.5, flotation time -10 min