XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 2419
gangue minerals. However, coarse particles tend to be
poorly liberated, resulting in poor flotation performance as
there may be a low degree of surface exposure of the min-
erals targeted by the collector. Furthermore, conventional
cells are less effective for coarse particle flotation because
particles with sizes above 150 µm detach easily from the air
bubbles (Kohmuench et al., 2018 Kromah et al., 2022).
The bubble-particle detachment is caused by the turbu-
lence of the rotating impellers of the mechanical cells. As
such, fluidized bed technologies such as Reflux Flotation
Cell (RFC), NovaCell, and HydroFloat have been intro-
duced as one approach to this issue (Kohmuench et al.,
2018 Jameson et al., 2020 Sutherland et al., 2020). They
use high-pressure fluids instead of the rotating impellers in
conventional mechanical cells. In the fluidized bed tech-
nologies, the upward fluidized water contacts the down-
ward feed sample, creating a stream of suspended particles
in proximity to the air bubbles. The presence of pulp agita-
tion and buoyancy creates particle-bubble aggregates with
a reduced settling rate (Kromah et al., 2022). As a result,
bubble-particle detachment is reduced in the system.
Emulsified oil droplets have mainly been applied for
the recovery of fine particles in the open literature (Peng
et al., 2017 Zhou et al., 2020 Hornn et al., 2021 Li et
al., 2022). The basic approach involves the agglomeration
of fine particles under high shear or mixing. The oil (typi-
cally kerosene or diesel) mainly serves as a bridging fluid in
the process. This approach has been used for the flotation
of various minerals including molybdenite, coal, graphite,
sphalerite, and chalcopyrite (Hornn et al., 2021). However,
this technique is faced with several challenges such as the oil
dosage and energy needed to create 1–3 micron emulsion
droplets. Hence, a new system is proposed for the flotation
of coarse chalcopyrite ore, using 10-micron-sized kerosene-
in-water emulsion.
Coarse particle flotation can also be achieved by apply-
ing hydrophobicity modifiers i.e., emulsified oil droplets
(Gao et al., 2022). The application of emulsion would
improve bubble-particle attachment by creating an oil layer
or film on the particle. This is expected to improve the
hydrophobicity of the coarse particle, thereby reducing the
probability of detachment from the air bubbles and leading
to an increase in recovery. In this study, a mechanical flota-
tion cell was used for coarse particle flotation with natural
copper ore samples using kerosene-in-water emulsion as a
novel collector. Subsequently, the copper grade and recov-
ery with the emulsion were compared with those of a con-
ventional potassium amyl xanthate collector.
MATERIALS AND APPARATUS
The chemicals used in the study are provided in Table 1.
RO water containing 0.01 M KCl as a background elec-
trolyte was used throughout the study. 1 M NaOH(aq) was
used as the pH modifier. Kerosene was selected as the oil
phase for the emulsion and also acts as a non-ionic col-
lector. Potassium amyl xanthate (PAX) was selected as the
emulsifier and baseline collector for comparison with the
kerosene-in-water emulsion.
The flotation test was conducted with a West Australian
copper-gold ore. The compositions of the main elements
are reported in Table 2 based on X-ray fluorescence (XRF)
analysis with calibration standards. The feed sample con-
tains approximately 0.9% copper. Mineral Liberation
Analysis (MLA) was also carried out to understand the lib-
eration classes of the feed. Five representative samples (5 g
each) were sent to the University of Queensland for the
MLA.
The apparatus used in the study includes a high-speed
mixer (IKA Ultra Turrax T45) for homogenization and
emulsion formulation, a Mastersizer 3000 laser diffraction
particle size analyzer (Malvern Panalytical) for size distri-
bution measurement, a riffle splitter, a sieve shaker using
sieves with different sizes (2 mm to 25 μm), chrome steel
balls of varying diameters (1.5 cm to 4 cm), a 2 L mill jar,
Table 1. Purities and suppliers of chemicals used in the study
Material Grade/Purity (%)Supplier
Potassium chloride (KCl) AR, ≥99 Chem-Supply
Sodium hydroxide (NaOH) AR, ≥99 Merck
4-Methyl-2-pentanol (MIBC) AR, 98 Sigma Aldrich
Potassium amyl xanthate (PAX) AR, 97 Tokyo Chemical Industry
Kerosene AR, ≈100 Sigma Aldrich
Table 2. The XRF assay of the main elements in the feed sample
Element Cu Fe S Si Al K
Composition (%)0.9 6.6 2.0 32.9 4.7 5.1
gangue minerals. However, coarse particles tend to be
poorly liberated, resulting in poor flotation performance as
there may be a low degree of surface exposure of the min-
erals targeted by the collector. Furthermore, conventional
cells are less effective for coarse particle flotation because
particles with sizes above 150 µm detach easily from the air
bubbles (Kohmuench et al., 2018 Kromah et al., 2022).
The bubble-particle detachment is caused by the turbu-
lence of the rotating impellers of the mechanical cells. As
such, fluidized bed technologies such as Reflux Flotation
Cell (RFC), NovaCell, and HydroFloat have been intro-
duced as one approach to this issue (Kohmuench et al.,
2018 Jameson et al., 2020 Sutherland et al., 2020). They
use high-pressure fluids instead of the rotating impellers in
conventional mechanical cells. In the fluidized bed tech-
nologies, the upward fluidized water contacts the down-
ward feed sample, creating a stream of suspended particles
in proximity to the air bubbles. The presence of pulp agita-
tion and buoyancy creates particle-bubble aggregates with
a reduced settling rate (Kromah et al., 2022). As a result,
bubble-particle detachment is reduced in the system.
Emulsified oil droplets have mainly been applied for
the recovery of fine particles in the open literature (Peng
et al., 2017 Zhou et al., 2020 Hornn et al., 2021 Li et
al., 2022). The basic approach involves the agglomeration
of fine particles under high shear or mixing. The oil (typi-
cally kerosene or diesel) mainly serves as a bridging fluid in
the process. This approach has been used for the flotation
of various minerals including molybdenite, coal, graphite,
sphalerite, and chalcopyrite (Hornn et al., 2021). However,
this technique is faced with several challenges such as the oil
dosage and energy needed to create 1–3 micron emulsion
droplets. Hence, a new system is proposed for the flotation
of coarse chalcopyrite ore, using 10-micron-sized kerosene-
in-water emulsion.
Coarse particle flotation can also be achieved by apply-
ing hydrophobicity modifiers i.e., emulsified oil droplets
(Gao et al., 2022). The application of emulsion would
improve bubble-particle attachment by creating an oil layer
or film on the particle. This is expected to improve the
hydrophobicity of the coarse particle, thereby reducing the
probability of detachment from the air bubbles and leading
to an increase in recovery. In this study, a mechanical flota-
tion cell was used for coarse particle flotation with natural
copper ore samples using kerosene-in-water emulsion as a
novel collector. Subsequently, the copper grade and recov-
ery with the emulsion were compared with those of a con-
ventional potassium amyl xanthate collector.
MATERIALS AND APPARATUS
The chemicals used in the study are provided in Table 1.
RO water containing 0.01 M KCl as a background elec-
trolyte was used throughout the study. 1 M NaOH(aq) was
used as the pH modifier. Kerosene was selected as the oil
phase for the emulsion and also acts as a non-ionic col-
lector. Potassium amyl xanthate (PAX) was selected as the
emulsifier and baseline collector for comparison with the
kerosene-in-water emulsion.
The flotation test was conducted with a West Australian
copper-gold ore. The compositions of the main elements
are reported in Table 2 based on X-ray fluorescence (XRF)
analysis with calibration standards. The feed sample con-
tains approximately 0.9% copper. Mineral Liberation
Analysis (MLA) was also carried out to understand the lib-
eration classes of the feed. Five representative samples (5 g
each) were sent to the University of Queensland for the
MLA.
The apparatus used in the study includes a high-speed
mixer (IKA Ultra Turrax T45) for homogenization and
emulsion formulation, a Mastersizer 3000 laser diffraction
particle size analyzer (Malvern Panalytical) for size distri-
bution measurement, a riffle splitter, a sieve shaker using
sieves with different sizes (2 mm to 25 μm), chrome steel
balls of varying diameters (1.5 cm to 4 cm), a 2 L mill jar,
Table 1. Purities and suppliers of chemicals used in the study
Material Grade/Purity (%)Supplier
Potassium chloride (KCl) AR, ≥99 Chem-Supply
Sodium hydroxide (NaOH) AR, ≥99 Merck
4-Methyl-2-pentanol (MIBC) AR, 98 Sigma Aldrich
Potassium amyl xanthate (PAX) AR, 97 Tokyo Chemical Industry
Kerosene AR, ≈100 Sigma Aldrich
Table 2. The XRF assay of the main elements in the feed sample
Element Cu Fe S Si Al K
Composition (%)0.9 6.6 2.0 32.9 4.7 5.1