XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 2125
alternative in the flotation process. It is worth mentioning
that all these methods of pyrite depression have been car-
ried out considering flotation circuits in which pyrite is first
depressed in the concentration process. Therefore, imple-
menting this traditional pyrite depression process would be
not feasible for desulfurization process, followed by selec-
tive separation, since the pyrite would already be activated
due to the initial bulk concentration stage. This is why,
in addition to the use of chemical reagents in the depres-
sion of pyrite, it may also be useful to consider the use of
physical methods such as ultrasonic and regrinding. These
methods would help to have a new fresh surface, clean and
ready to react, either by oxidizing, adsorbing depressant
reagents, using oxidants such as peroxide or a mixture of
both. For instance, Chen et al. (2020), explains from the
perspective of ultrasonic theory the effects and applications
of ultrasonic in the flotation process. They identified that
ultrasonic generates a mechanical or physical effect (such
as surface cleaning effect and breaking effect) and a chemi-
cal effect such as sonochemical reactions. The times and
frequencies of ultrasonic depend on the type of treatment
sought, whether physical or chemical. Despite ultrasonic is
used in several areas of industry, few works have been car-
ried out that show the effect of ultrasonic on the recovery of
minerals in flotation. For example, ultrasonic has been used
before flotation (during reagent conditioning time), and
during flotation. An effect has been observed on the size
and distribution of bubbles when ultrasonic is applied dur-
ing flotation, which allows obtaining a significant increase
in the recovery of minerals of interest (Bagheri et al., 2020
Filippov et al., 2021 Horasan et al., 2020). These works
allowed us to understand the role that ultrasonic plays in
the physicochemical interactions of minerals and reagents
during flotation. However, the effect of ultrasonic on sulfide
mineral surfaces and reagents interactions such as, adsorp-
tion/desorption of collectors or depressants, degradation,
reduction, and oxidation have not yet been assessed.
Regarding the effect of regrinding, these have been
extensively studied in the flotation of sulfide minerals,
since they give rise to changes in the surface properties of
the minerals (Huang &Grano, 2006 Martin et al., 1991
Moslemi &Gharabaghi, 2017 Mu &Peng, 2019 Peng
et al., 2017 and 2003). The type of regrinding media is
a critical factor in determining the chemistry of the flota-
tion feed pulp. The interaction mechanisms between the
mineral and the grinding medium are complex and lead
to galvanic interactions (Chen et al., 2014). These galvanic
interactions are weaker when grinding is used since the par-
ticle size is coarser, which causes the mineral of interest to
be blocked by another sulfide mineral or gangue mineral,
which decreases its exposed surface to react. This is why
regrinding the rougher concentrate and subsequent flo-
tation in a cleaning stage is a methodology that has been
implemented since it allows the release of the mineral and
has a new exposed surface to interact with either collec-
tors, activators, or depressants, and thus improve mineral
recovery. Therefore, it has been shown that, by controlling
oxygen concentration, the pulp potential, and the type of
grinding media, it is possible to obtain the optimal condi-
tions for a sulfide mineral to be floated or depressed (Agheli
et al., 2020 Ye et al. al., 2010). For instance, Chen et al.
(2013) studied the effect of regrinding on pyrite in the
presence of copper ions and subsequent flotation of pyrite
in the cleaning stage. They determined that although steel
generates a more oxidizing medium, by introducing copper
and collector ions it is possible to reverse the depression
of pyrite, apparently generating both active sites (adsorp-
tion of collectors and copper ions) and desorption of the
depressor or elimination of oxidized species from the sur-
face of the mineral, which allow its floatability. Therefore,
the flotation efficiency is influenced in regrinding not only
by the degree of mineral liberation, but also by the level
of oxidation and the competition between adsorption and
desorption of reagents on the mineral surfaces (Chen et al.,
2013 and 2014). In conclusion, this study demonstrates
the importance of controlling the level of oxidation in a flo-
tation process since a certain level is required for the oxida-
tion of the reagents to occur whether to float or depress. In
the case of depressing, it is also required that the regrinding
promotes surface oxidation.
According to this analysis we believe we can control
the adsorption/desorption mechanism by using regrinding,
ultrasonic, and hydrogen peroxide treatment, either to pro-
mote the oxidation of the pyrite surface, and/or decompo-
sition of the collectors, and thus improve the depression
of the pyrite which has already been floated. Therefore,
the objective of this work is obtaining a tailing that has
a low content of sulfide species. To reach this purpose it
is proposed first to obtain a bulk concentrate, followed by
the selective separation of the pyrite mineral. We look to
answer the following questions: What effect have ultra-
sonic, regrinding, and hydrogen peroxide treatment on the
characteristics of pyrite sulfide once they have been active
with collectors? What levels of pyrite depression can be
obtained by ultrasonic, regrinding, and hydrogen perox-
ide treatment? What operational conditions allows pyrite
that has been activated in a porphyry copper mineral to be
extracted?
alternative in the flotation process. It is worth mentioning
that all these methods of pyrite depression have been car-
ried out considering flotation circuits in which pyrite is first
depressed in the concentration process. Therefore, imple-
menting this traditional pyrite depression process would be
not feasible for desulfurization process, followed by selec-
tive separation, since the pyrite would already be activated
due to the initial bulk concentration stage. This is why,
in addition to the use of chemical reagents in the depres-
sion of pyrite, it may also be useful to consider the use of
physical methods such as ultrasonic and regrinding. These
methods would help to have a new fresh surface, clean and
ready to react, either by oxidizing, adsorbing depressant
reagents, using oxidants such as peroxide or a mixture of
both. For instance, Chen et al. (2020), explains from the
perspective of ultrasonic theory the effects and applications
of ultrasonic in the flotation process. They identified that
ultrasonic generates a mechanical or physical effect (such
as surface cleaning effect and breaking effect) and a chemi-
cal effect such as sonochemical reactions. The times and
frequencies of ultrasonic depend on the type of treatment
sought, whether physical or chemical. Despite ultrasonic is
used in several areas of industry, few works have been car-
ried out that show the effect of ultrasonic on the recovery of
minerals in flotation. For example, ultrasonic has been used
before flotation (during reagent conditioning time), and
during flotation. An effect has been observed on the size
and distribution of bubbles when ultrasonic is applied dur-
ing flotation, which allows obtaining a significant increase
in the recovery of minerals of interest (Bagheri et al., 2020
Filippov et al., 2021 Horasan et al., 2020). These works
allowed us to understand the role that ultrasonic plays in
the physicochemical interactions of minerals and reagents
during flotation. However, the effect of ultrasonic on sulfide
mineral surfaces and reagents interactions such as, adsorp-
tion/desorption of collectors or depressants, degradation,
reduction, and oxidation have not yet been assessed.
Regarding the effect of regrinding, these have been
extensively studied in the flotation of sulfide minerals,
since they give rise to changes in the surface properties of
the minerals (Huang &Grano, 2006 Martin et al., 1991
Moslemi &Gharabaghi, 2017 Mu &Peng, 2019 Peng
et al., 2017 and 2003). The type of regrinding media is
a critical factor in determining the chemistry of the flota-
tion feed pulp. The interaction mechanisms between the
mineral and the grinding medium are complex and lead
to galvanic interactions (Chen et al., 2014). These galvanic
interactions are weaker when grinding is used since the par-
ticle size is coarser, which causes the mineral of interest to
be blocked by another sulfide mineral or gangue mineral,
which decreases its exposed surface to react. This is why
regrinding the rougher concentrate and subsequent flo-
tation in a cleaning stage is a methodology that has been
implemented since it allows the release of the mineral and
has a new exposed surface to interact with either collec-
tors, activators, or depressants, and thus improve mineral
recovery. Therefore, it has been shown that, by controlling
oxygen concentration, the pulp potential, and the type of
grinding media, it is possible to obtain the optimal condi-
tions for a sulfide mineral to be floated or depressed (Agheli
et al., 2020 Ye et al. al., 2010). For instance, Chen et al.
(2013) studied the effect of regrinding on pyrite in the
presence of copper ions and subsequent flotation of pyrite
in the cleaning stage. They determined that although steel
generates a more oxidizing medium, by introducing copper
and collector ions it is possible to reverse the depression
of pyrite, apparently generating both active sites (adsorp-
tion of collectors and copper ions) and desorption of the
depressor or elimination of oxidized species from the sur-
face of the mineral, which allow its floatability. Therefore,
the flotation efficiency is influenced in regrinding not only
by the degree of mineral liberation, but also by the level
of oxidation and the competition between adsorption and
desorption of reagents on the mineral surfaces (Chen et al.,
2013 and 2014). In conclusion, this study demonstrates
the importance of controlling the level of oxidation in a flo-
tation process since a certain level is required for the oxida-
tion of the reagents to occur whether to float or depress. In
the case of depressing, it is also required that the regrinding
promotes surface oxidation.
According to this analysis we believe we can control
the adsorption/desorption mechanism by using regrinding,
ultrasonic, and hydrogen peroxide treatment, either to pro-
mote the oxidation of the pyrite surface, and/or decompo-
sition of the collectors, and thus improve the depression
of the pyrite which has already been floated. Therefore,
the objective of this work is obtaining a tailing that has
a low content of sulfide species. To reach this purpose it
is proposed first to obtain a bulk concentrate, followed by
the selective separation of the pyrite mineral. We look to
answer the following questions: What effect have ultra-
sonic, regrinding, and hydrogen peroxide treatment on the
characteristics of pyrite sulfide once they have been active
with collectors? What levels of pyrite depression can be
obtained by ultrasonic, regrinding, and hydrogen perox-
ide treatment? What operational conditions allows pyrite
that has been activated in a porphyry copper mineral to be
extracted?