XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 2133
the depression process was conducted (see Figure 7, bottom
part), the depression of pyrite without any pre-treatment
shows similar recoveries from those obtained in the pyrite
flotation PAX (68%) and DTP (54%), demonstrating that
once the pyrite is floated is challenging to be depressed,
as has been reported in the literature. Nevertheless, when
the floated pyrite was pretreated, the recovery slowed
down drastically for all the procedures, demonstrating that
applying these mythologies are feasible for depression of
activated pyrite. The treatment with H2O2 was the most
effective procedure to depressed activated pyrite since the
recovery went down around 7% for PAX (68% less) and
around 5.4% for DTP (70% less). Followed by the ultra-
sonic and regrinding. Finally, both collectors behave almost
the same when the recoveries were compared between the
different treatments used. Therefore, either PAX or DTP
can be used to conduct these methodologies.
CONCLUSIONS
The ultrasonic findings enable to conclude that PAX collec-
tor could be decomposed from pyrite surface using 20 min-
utes of ultrasonic time. The formation of species C=O and
O=S=O identified by FT-IR analysis explain the interaction
mechanisms between PAX, H2O2 and Pyrite surface. Then,
for the DTP, there was not observed an effect of ultra-
sonic treatment on DTP decomposition from pyrite sur-
face, even using 20 minutes of ultrasonic. Complementary
characterization techniques are required to get a complete
analysis of the behavior of the pyrite with this treatment.
Regarding the hydrogen peroxide treatment, it was possible
to decompose both collectors. In the case of PAX collec-
tor, the interaction mechanism was proposed through the
oxidation of PAX with H2O2 and subsequent formation
of carbonate and sulfate species. Then, DTP elimination
from pyrite surface was evident according to FT-IR results
because the peaks identified for DTP adsorption disappears
after H2O2 treatment. Nevertheless, not species were iden-
tified such as oxidized species from pyrite surface, or sulfate
species from the DTP decomposition. Therefore, the inter-
action mechanism between DTP and pyrite surface is still
unknown, then more characterization techniques and tests
must be conducted to complement FT-IR results and pro-
pose an interaction mechanism between DTP and pyrite
surface. Finally, flotation results allowed us to get the opti-
mal parameters to run the depression of activated pyrite.
All the procedures propose seems to work. Nevertheless,
the most suitable methodology was the H2O2 treatment.
All these information give us insights on the depression of
pyrite that has been first activated, could be successfully
depressed which enables to face the future challenges to
integrate the desulfurization process in the flotation circuit
plant.
ACKNOWLEDGMENTS
This publication was supported by the Agencia Nacional de
Investigación y Desarrollo de Chile, ANID/ACT210027,
AMTC Basal Project—Basal Financing Program for
Scientific and Technological Centers—grant number
AFB230001, and Fondecyt 1211498.
Figure 7. Flotation results depression of activated pyrite
the depression process was conducted (see Figure 7, bottom
part), the depression of pyrite without any pre-treatment
shows similar recoveries from those obtained in the pyrite
flotation PAX (68%) and DTP (54%), demonstrating that
once the pyrite is floated is challenging to be depressed,
as has been reported in the literature. Nevertheless, when
the floated pyrite was pretreated, the recovery slowed
down drastically for all the procedures, demonstrating that
applying these mythologies are feasible for depression of
activated pyrite. The treatment with H2O2 was the most
effective procedure to depressed activated pyrite since the
recovery went down around 7% for PAX (68% less) and
around 5.4% for DTP (70% less). Followed by the ultra-
sonic and regrinding. Finally, both collectors behave almost
the same when the recoveries were compared between the
different treatments used. Therefore, either PAX or DTP
can be used to conduct these methodologies.
CONCLUSIONS
The ultrasonic findings enable to conclude that PAX collec-
tor could be decomposed from pyrite surface using 20 min-
utes of ultrasonic time. The formation of species C=O and
O=S=O identified by FT-IR analysis explain the interaction
mechanisms between PAX, H2O2 and Pyrite surface. Then,
for the DTP, there was not observed an effect of ultra-
sonic treatment on DTP decomposition from pyrite sur-
face, even using 20 minutes of ultrasonic. Complementary
characterization techniques are required to get a complete
analysis of the behavior of the pyrite with this treatment.
Regarding the hydrogen peroxide treatment, it was possible
to decompose both collectors. In the case of PAX collec-
tor, the interaction mechanism was proposed through the
oxidation of PAX with H2O2 and subsequent formation
of carbonate and sulfate species. Then, DTP elimination
from pyrite surface was evident according to FT-IR results
because the peaks identified for DTP adsorption disappears
after H2O2 treatment. Nevertheless, not species were iden-
tified such as oxidized species from pyrite surface, or sulfate
species from the DTP decomposition. Therefore, the inter-
action mechanism between DTP and pyrite surface is still
unknown, then more characterization techniques and tests
must be conducted to complement FT-IR results and pro-
pose an interaction mechanism between DTP and pyrite
surface. Finally, flotation results allowed us to get the opti-
mal parameters to run the depression of activated pyrite.
All the procedures propose seems to work. Nevertheless,
the most suitable methodology was the H2O2 treatment.
All these information give us insights on the depression of
pyrite that has been first activated, could be successfully
depressed which enables to face the future challenges to
integrate the desulfurization process in the flotation circuit
plant.
ACKNOWLEDGMENTS
This publication was supported by the Agencia Nacional de
Investigación y Desarrollo de Chile, ANID/ACT210027,
AMTC Basal Project—Basal Financing Program for
Scientific and Technological Centers—grant number
AFB230001, and Fondecyt 1211498.
Figure 7. Flotation results depression of activated pyrite