666 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
J.S. Laskowski et al., 2007 Estrada et al., 2020 Scott et
al., 1996).
The fast natural flotability of molybdenite is originated
by its well-defined crystalline structure, and in its amor-
phous variety the flotation of this mineral can be very
inefficient (Zanin et al., 2009). High or low molybdenum
recovery in flotation is the product of several factors related
to some typical ore characteristics, such as particle mor-
phology in relation to hydrodynamics, inherent particle
hydrophobicity controlled by the face/edge ratio, interac-
tions between molybdenite particles and gangue miner-
als, and particle recovery in the froth phase (Ametov et al.,
2008 Castro et al., 2016 Zanin et al., 2009).
Researchers in recent years have studied anionic and
cationic polyacrylamide by varying its pH, concentration,
mechanical degradation, degree of anionicity, molecular
weight, and showed different effects on metal recovery
(Wang et al., 2012 Echeverry et al., 2021). In the flota-
tion of copper molybdenum minerals, cationic PAM was
evaluated and demonstrated that it is a potential depressant
of chalcopyrite and can be separated from molybdenite in
the presence of kerosene as a collector (Zhang et al., 2022).
Anionic polyacrylamides at 8.15% and 11.9% anionicity
present in molybdenite flotation have demonstrated that
their long chains increase the depressant effect on molybde-
nite (Echeverry et al., 2021 Estrada et al., 2020).
Due to the considerable consumption of fresh water
in the flotation process, it is crucial to investigate the use
of alternative water sources, such as groundwater, recycled
water, and seawater. These water sources contain various
inorganic electrolytes, such as KCl, NaCl, Na2SO4, MgSO4
and CaCl2, which can cause various effects on mineral flo-
tation due to the presence of divalent ions. For example,
the formation of colloidal precipitates has been observed
under alkaline conditions, generating adverse effects on the
flotation process (Suyantara et al., 2018). However, it is
important to note that beneficial effects can also arise, such
as inhibition of bubble coalescence and froth layer stabili-
zation, according to previous research (Castro et al., 2014
Suyantara et al., 2018 Zhu et al., 2020).
Although some research has been carried out on these
topics, the effect of these polymers on the flotation of sul-
fide minerals of mining relevance such as molybdenite has
not yet been reported in the literature. In this work, the
effect of an anionic polyacrylamide of medium low anionic
degree (LPAM) on molybdenite in aqueous media of vary-
ing ionic strength is analyzed. The flotation of the minerals
was studied as a function of their pH and at different PAM
concentrations.
METHODOLOGY
Materials and Reagents
In this research work, a sample of molybdenite is used as
raw material, obtained from a molybdenum concentrate
from a Chilean concentrator plant. The particle size of the
molybdenite sample was in the range of –150 +45 μm
with a d80 of 49.78 micrometers. For its study, washing
of the mineral is carried out with ethyl ether and sodium
sulfhydrate (NaSH) to remove residual reactive and organic
agents. The purity of the molybdenite sample reached
99.14%, with molybdenum and sulfur concentrations of
59.2% and 39.94%, respectively. X-Ray Diffraction (XRD)
analyses also confirmed the high purity of the sample, as
evidenced by the peaks in the diffractogram presented in
Figure 1, which are characteristic of pure molybdenite.
The PAM used in this work was provided by SNF-Chile
(of 99.99%) purity specified by provider) This, was labeled
as SNF2030. The sample was received in dry white gran-
ules and was used without any treatment or purification.
According to the information provided by the manufac-
turer, this flocculant was anionic in nature of a high molec-
ular weight of around 16×106 Da, and a low DA. Methyl
isobutyl carbinol (MIBC) obtained from Merck was used as
frother. Milli-Q water of a resistivity of 18.4 MΩ∙cm at 25
°C was used in all the experiments. pH was adjusted using
sodium hydroxide of analytical grade obtained from Merck
in all the tests. The aqueous medium for the experiments
was 0.05 M MgCl2 and MgSO4 and 0.01 M CaCl2 and
CaSO4. The solutions were prepared using Milli-Q water
with a resistivity of 18.4 MΩ∙cm at 25 °C.
Procedures
Flocculant Preparation
LPAM solutions were made daily by preparing stock solu-
tions of 2000 g/L at 20°C of flocculant, mechanically agi-
tating the suspension at 400 rpm for 4 hours, and then
diluted and mixed to the required concentrations. To
ensure the integrity of the solutions, the beaker was covered
with parafilm and opaque foil, thus avoiding exposure to
light and possible degradation (Arinaitwe and Pawlik 2013)
.The stock solutions were kept for up to 12 h, after which
they were discarded. From the stock solution, dilute solu-
tions were prepared for LPAM concentrations of 2.5,5.0,
7.5 and 10.
Microflotation Process
Minerals flotation was assessed using microflotation tests
in a 150 mL Partridge and Smith glass cell, as shown in
J.S. Laskowski et al., 2007 Estrada et al., 2020 Scott et
al., 1996).
The fast natural flotability of molybdenite is originated
by its well-defined crystalline structure, and in its amor-
phous variety the flotation of this mineral can be very
inefficient (Zanin et al., 2009). High or low molybdenum
recovery in flotation is the product of several factors related
to some typical ore characteristics, such as particle mor-
phology in relation to hydrodynamics, inherent particle
hydrophobicity controlled by the face/edge ratio, interac-
tions between molybdenite particles and gangue miner-
als, and particle recovery in the froth phase (Ametov et al.,
2008 Castro et al., 2016 Zanin et al., 2009).
Researchers in recent years have studied anionic and
cationic polyacrylamide by varying its pH, concentration,
mechanical degradation, degree of anionicity, molecular
weight, and showed different effects on metal recovery
(Wang et al., 2012 Echeverry et al., 2021). In the flota-
tion of copper molybdenum minerals, cationic PAM was
evaluated and demonstrated that it is a potential depressant
of chalcopyrite and can be separated from molybdenite in
the presence of kerosene as a collector (Zhang et al., 2022).
Anionic polyacrylamides at 8.15% and 11.9% anionicity
present in molybdenite flotation have demonstrated that
their long chains increase the depressant effect on molybde-
nite (Echeverry et al., 2021 Estrada et al., 2020).
Due to the considerable consumption of fresh water
in the flotation process, it is crucial to investigate the use
of alternative water sources, such as groundwater, recycled
water, and seawater. These water sources contain various
inorganic electrolytes, such as KCl, NaCl, Na2SO4, MgSO4
and CaCl2, which can cause various effects on mineral flo-
tation due to the presence of divalent ions. For example,
the formation of colloidal precipitates has been observed
under alkaline conditions, generating adverse effects on the
flotation process (Suyantara et al., 2018). However, it is
important to note that beneficial effects can also arise, such
as inhibition of bubble coalescence and froth layer stabili-
zation, according to previous research (Castro et al., 2014
Suyantara et al., 2018 Zhu et al., 2020).
Although some research has been carried out on these
topics, the effect of these polymers on the flotation of sul-
fide minerals of mining relevance such as molybdenite has
not yet been reported in the literature. In this work, the
effect of an anionic polyacrylamide of medium low anionic
degree (LPAM) on molybdenite in aqueous media of vary-
ing ionic strength is analyzed. The flotation of the minerals
was studied as a function of their pH and at different PAM
concentrations.
METHODOLOGY
Materials and Reagents
In this research work, a sample of molybdenite is used as
raw material, obtained from a molybdenum concentrate
from a Chilean concentrator plant. The particle size of the
molybdenite sample was in the range of –150 +45 μm
with a d80 of 49.78 micrometers. For its study, washing
of the mineral is carried out with ethyl ether and sodium
sulfhydrate (NaSH) to remove residual reactive and organic
agents. The purity of the molybdenite sample reached
99.14%, with molybdenum and sulfur concentrations of
59.2% and 39.94%, respectively. X-Ray Diffraction (XRD)
analyses also confirmed the high purity of the sample, as
evidenced by the peaks in the diffractogram presented in
Figure 1, which are characteristic of pure molybdenite.
The PAM used in this work was provided by SNF-Chile
(of 99.99%) purity specified by provider) This, was labeled
as SNF2030. The sample was received in dry white gran-
ules and was used without any treatment or purification.
According to the information provided by the manufac-
turer, this flocculant was anionic in nature of a high molec-
ular weight of around 16×106 Da, and a low DA. Methyl
isobutyl carbinol (MIBC) obtained from Merck was used as
frother. Milli-Q water of a resistivity of 18.4 MΩ∙cm at 25
°C was used in all the experiments. pH was adjusted using
sodium hydroxide of analytical grade obtained from Merck
in all the tests. The aqueous medium for the experiments
was 0.05 M MgCl2 and MgSO4 and 0.01 M CaCl2 and
CaSO4. The solutions were prepared using Milli-Q water
with a resistivity of 18.4 MΩ∙cm at 25 °C.
Procedures
Flocculant Preparation
LPAM solutions were made daily by preparing stock solu-
tions of 2000 g/L at 20°C of flocculant, mechanically agi-
tating the suspension at 400 rpm for 4 hours, and then
diluted and mixed to the required concentrations. To
ensure the integrity of the solutions, the beaker was covered
with parafilm and opaque foil, thus avoiding exposure to
light and possible degradation (Arinaitwe and Pawlik 2013)
.The stock solutions were kept for up to 12 h, after which
they were discarded. From the stock solution, dilute solu-
tions were prepared for LPAM concentrations of 2.5,5.0,
7.5 and 10.
Microflotation Process
Minerals flotation was assessed using microflotation tests
in a 150 mL Partridge and Smith glass cell, as shown in