2126 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
MATERIALS AND METHODS
Materials
Pyrite mineral was purchased from Ward’s Science,
Huanzala, Peru. The initial pyrite samples were approxi-
mately 13 × 15 mm in size. The samples were crushed using
a jaw crusher Retsch (BB 250XL) with a faw width of 120 ×
90 mm and a gap width of setting 0–30 mm, until particles
reached sizes around 700 μm. Then, this coarse fraction was
stored to be used in the flotation and adsorption test. Prior
to each microflotation and adsorption test, the necessary
amount of this fraction was grounded in an automatic in a
RETSCH-StaLab RM 200 mortar mill, before each test to
get a fresh fraction –75 +150 µm. Potassium amyl xanthate
(PAX) and Sodium Dialkyl DithioPhosphate (DTP) were
the collectors used to run the microflotation and adsorption
experiments with a nominal purity of ≥ 95% and ≥ 90%,
respectively. The DTP was used as alternative collector to
float pyrite, since this collector has a better HSE (health,
safety and environmental) profile compare PAX collector
(Tercero et al., 2019). Deionized water was used to conduct
the experiments and prepare the solutions. Hydrogen per-
oxide 30% was used to conduct the oxidation experiments.
Methods
After the review of the literature, different methods were
designed to examine the problems identified in the previ-
ous section. The methodology begins with the character-
ization of the pyrite, to meet this objective the purity of
the pyrite will be determined by X-ray diffraction (XRD)
and Fourier transform infrared FT-IR. The adsorption test
was conducted, followed by the regrinding, ultrasonic, and
hydrogen peroxide treatments to assess the adsorption/
desorption mechanism of collector onto pyrite surface.
These findings enable to identify the optimal parameters
and conditions to conduct the pyrite flotation, followed
by the depression of pyrite that has already been floated.
Regrinding is work in progress, reason why in this man-
uscript version, it was provided the results related to the
effect of regrinding on pyrite flotation/depression, the anal-
ysis about the adsorption mechanisms is still in progress.
Then, the microflotation process (activation/depression of
the pyrite) was carried out in a Hallimond tube. Different
characterization techniques such as (FT-IR), SEM-EDS,
atomic absorption (AA) and photoelectron spectrometry
(XPS), in addition the Z potential, will be used to analyze
the data collected from the microflotation and ultrasonic,
regrinding and hydrogen peroxide treatments. Here it was
presenting only FT-IR.
Pyrite Characterization
The mineralogical phase of pyrite was identified by X-ray
diffraction (XRD) in a Bruker X-ray diffractometer,
model D8 Advance, equipped with an X-ray source (Cu)
and detector (Scintillation, 40 kV, 30 mA). The analysis
was carried out in a 2θ range from 5 to 70° degrees. The
adsorption tests, ultrasonic treatment and hydrogen perox-
ide treatment were studied by FT-IR on a JASCO model
FT-IR-4600, with a resolution of 0.7 cm −1, and ATR-IR
accessory, in a spectral range of 4000–400 cm −1 using a
germanium crystal for opaque minerals.
Adsorption Test
Adsorption tests were carried out to study the physical-
chemical interaction between the pyrite surface and each
collector. 1 g of fine fraction pyrite (-20 um) was mixed
with a solution of each collector (PAX or DTP), prepared
at a concentration of 1 × 10–3 mol/L, at natural pH. After
15 minutes of stirring, the slurry was washed once with
deionized water, filtered, and dried at 40° C in an oven for
24 h. The powder obtained was analyzed by FT-IR to iden-
tify the collector’s adsorption onto pyrite surface.
Ultrasonic Treatment
An ultrasonic device, brand VCX 500 ultrasonic proces-
sor with an amplitude of 40%, frequency of 20 kHz, and
total power 500 W was used to study the effect of ultra-
sonic on the collector’s removal from pyrite surface. 1g of
fine fraction pyrite (-20 um) was prepared with the col-
lector as was mentioned in the adsorption test. Then, the
slurry was filtered, and the pyrite treated was mixed with
150 ml of deionized water followed by the ultrasonic treat-
ment. Eight different times were assessed (2, 4, 6, 8, 10,
12, 14 and 20 minutes). After each time the treated slurry
was subsequently filtered and dried at 40° C in an oven for
24 h. Then, the powders obtained was analyzed by FT-IR.
Also, the effect of ultrasonic on pulp oxygen content was
assessed. These results enable to understand the relationship
between the oxygen content, the oxidation of pyrite surface
and decomposition of collectors over time, which comple-
ment the FT-IR results.
Hydrogen Peroxide Treatment
Hydrogen peroxide 30% was used to conduct the decom-
position of collectors adsorbed onto pyrite surface. 1 g of
fine fraction pyrite (-20 um) was prepared with the col-
lector as was mentioned in the adsorption test. Then, the
slurry was filtered, and the pyrite treated was mixed with
150 ml of a solution prepared with three different hydrogen
peroxide concentrations (0.001 M, 0.01 M, and 0.1M).
MATERIALS AND METHODS
Materials
Pyrite mineral was purchased from Ward’s Science,
Huanzala, Peru. The initial pyrite samples were approxi-
mately 13 × 15 mm in size. The samples were crushed using
a jaw crusher Retsch (BB 250XL) with a faw width of 120 ×
90 mm and a gap width of setting 0–30 mm, until particles
reached sizes around 700 μm. Then, this coarse fraction was
stored to be used in the flotation and adsorption test. Prior
to each microflotation and adsorption test, the necessary
amount of this fraction was grounded in an automatic in a
RETSCH-StaLab RM 200 mortar mill, before each test to
get a fresh fraction –75 +150 µm. Potassium amyl xanthate
(PAX) and Sodium Dialkyl DithioPhosphate (DTP) were
the collectors used to run the microflotation and adsorption
experiments with a nominal purity of ≥ 95% and ≥ 90%,
respectively. The DTP was used as alternative collector to
float pyrite, since this collector has a better HSE (health,
safety and environmental) profile compare PAX collector
(Tercero et al., 2019). Deionized water was used to conduct
the experiments and prepare the solutions. Hydrogen per-
oxide 30% was used to conduct the oxidation experiments.
Methods
After the review of the literature, different methods were
designed to examine the problems identified in the previ-
ous section. The methodology begins with the character-
ization of the pyrite, to meet this objective the purity of
the pyrite will be determined by X-ray diffraction (XRD)
and Fourier transform infrared FT-IR. The adsorption test
was conducted, followed by the regrinding, ultrasonic, and
hydrogen peroxide treatments to assess the adsorption/
desorption mechanism of collector onto pyrite surface.
These findings enable to identify the optimal parameters
and conditions to conduct the pyrite flotation, followed
by the depression of pyrite that has already been floated.
Regrinding is work in progress, reason why in this man-
uscript version, it was provided the results related to the
effect of regrinding on pyrite flotation/depression, the anal-
ysis about the adsorption mechanisms is still in progress.
Then, the microflotation process (activation/depression of
the pyrite) was carried out in a Hallimond tube. Different
characterization techniques such as (FT-IR), SEM-EDS,
atomic absorption (AA) and photoelectron spectrometry
(XPS), in addition the Z potential, will be used to analyze
the data collected from the microflotation and ultrasonic,
regrinding and hydrogen peroxide treatments. Here it was
presenting only FT-IR.
Pyrite Characterization
The mineralogical phase of pyrite was identified by X-ray
diffraction (XRD) in a Bruker X-ray diffractometer,
model D8 Advance, equipped with an X-ray source (Cu)
and detector (Scintillation, 40 kV, 30 mA). The analysis
was carried out in a 2θ range from 5 to 70° degrees. The
adsorption tests, ultrasonic treatment and hydrogen perox-
ide treatment were studied by FT-IR on a JASCO model
FT-IR-4600, with a resolution of 0.7 cm −1, and ATR-IR
accessory, in a spectral range of 4000–400 cm −1 using a
germanium crystal for opaque minerals.
Adsorption Test
Adsorption tests were carried out to study the physical-
chemical interaction between the pyrite surface and each
collector. 1 g of fine fraction pyrite (-20 um) was mixed
with a solution of each collector (PAX or DTP), prepared
at a concentration of 1 × 10–3 mol/L, at natural pH. After
15 minutes of stirring, the slurry was washed once with
deionized water, filtered, and dried at 40° C in an oven for
24 h. The powder obtained was analyzed by FT-IR to iden-
tify the collector’s adsorption onto pyrite surface.
Ultrasonic Treatment
An ultrasonic device, brand VCX 500 ultrasonic proces-
sor with an amplitude of 40%, frequency of 20 kHz, and
total power 500 W was used to study the effect of ultra-
sonic on the collector’s removal from pyrite surface. 1g of
fine fraction pyrite (-20 um) was prepared with the col-
lector as was mentioned in the adsorption test. Then, the
slurry was filtered, and the pyrite treated was mixed with
150 ml of deionized water followed by the ultrasonic treat-
ment. Eight different times were assessed (2, 4, 6, 8, 10,
12, 14 and 20 minutes). After each time the treated slurry
was subsequently filtered and dried at 40° C in an oven for
24 h. Then, the powders obtained was analyzed by FT-IR.
Also, the effect of ultrasonic on pulp oxygen content was
assessed. These results enable to understand the relationship
between the oxygen content, the oxidation of pyrite surface
and decomposition of collectors over time, which comple-
ment the FT-IR results.
Hydrogen Peroxide Treatment
Hydrogen peroxide 30% was used to conduct the decom-
position of collectors adsorbed onto pyrite surface. 1 g of
fine fraction pyrite (-20 um) was prepared with the col-
lector as was mentioned in the adsorption test. Then, the
slurry was filtered, and the pyrite treated was mixed with
150 ml of a solution prepared with three different hydrogen
peroxide concentrations (0.001 M, 0.01 M, and 0.1M).