2808 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
density fall to the inclined surface by gravity and glide
along the surface of the inclined channel towards the bot-
tom while the air bubbles with or without particles rise to
the fluidized bed (Chen et al., 2022 Cole et al., 2020 Cole
et al., 2021 Galvin, 2012 Jiang et al., 2019). This bubble-
particle separation is what is termed as the Boycott effect
(Boycott, 1920 Peacock, 2005).
Previous studies have provided comprehensive insights
by outlining the flotation performance of the RFC, spe-
cifically for particles within the size range of 24.5 μm to
0.35 mm (Cole et al., 2020 Dickinson et al., 2015 Iveson
et al., 2022 Jiang, 2017). Although the mineral recovery
data obtained within the mentioned particle size class are
promising, there is a paucity of data on the flotation perfor-
mance of the RFC in the ultrafine size range (–20 microns).
The current work intends to ascertain and optimize the
hydrodynamic parameters that may affect the performance
of the RFC at ultrafine particle sizes.
EXPERIMENTAL
Materials
Pentlandite employed in this study was obtained from
Ward’s Natural Science Establishment, Inc., Ontario,
Canada, and quartz from Unimin, Adelaide, Australia.
Inductively coupled plasma mass spectrometry (ICP-MS)
and Inductively Coupled Plasma Atomic Emission
Spectroscopy (ICP-AES) were carried out on both sam-
ples to determine the elemental composition. The results
are presented in Table 1. Potassium amyl xanthate (PAX)
obtained from Sinoz Chemicals &Commodities Pty in
Australia was used as a collector. Methyl isobutyl carbonyl
(MIBC) of industry grade with purity greater than 96%
was used as frother. Sodium hydroxide and hydrochloric
acid were used as pH-modifiers during the flotation stud-
ies. CMC was used as a dispersant. Demineralised water
was used throughout the experiments. The particle size
distribution of both pentlandite and quartz, depicted in
Figure 2 were obtained using the Malvern Mastersizer 2000
Particle Size Analyser. In the context of this research, the
term ‘ultrafine particle size’ is used to characterize –20 µm
particle size samples.
Flotation Test Using the Reflux Flotation Cell
A laboratory-scale Reflux Flotation Cell was employed to
conduct a mixed mineral flotation study on pentlandite
and quartz in a ratio of 1:20 by mass. A 0.06 m3 tank with
an impeller attached to the base was employed as the slurry
conditioning tank. A Verderflex VF15 peristaltic pump with
a maximum head of 12 bar was used to circulate feed from
the conditioning tank to the RFC. The pump is connected
to a MagMaster electromagnetic flowmeter to monitor and
measure the feed rate. An Ebara CDXM 120/70 hydrofloat
pump with a maximum head of 4 bar was used to pump
fluidization water into the cell. The wash water flowrate
was measured using a Sensus iPERL Smart Water Meter.
To maintain a steady-state operation, the tailings stream
(underflow) was recirculated back to the feed tank, creating
a pseudo-continuous process. A magnetic flow meter was
employed to measure the underflow rate before the stream
was returned to the feed tank, allowing for flow rate control
through the underflow valves.
A previous study by the authors, a precursor to the cur-
rent work, investigated the entrainment behaviour of quartz
in pentlandite flotation (Ayedzi et al., 2024). Quartz which
has inherent hydrophilic properties was used as an entrain-
ment monitor. The optimal parameters for low entrain-
ment of quartz were also determined in the previous study
and used as the baseline condition for the current investi-
gation. The pulp pH was adjusted using dilute HCl and
dilute NaOH. Subsequently, PAX and MIBC were added
and given 5 mins and 3 mins conditioning time, respec-
tively. Each flotation test was carried out for 20 min and
concentrates were recovered at cumulative times of 1, 3,
6, 10, 15, and 20 min. The concentrates and tailings from
each test were dried, weighed, and assayed to determine the
flotation recovery.
Effect of Pulp Density
Pulp density, a physical variable of flotation, has been
determined to directly influence the mineral recovery and
entrainment during flotation (Çilek and Yılmazer, 2003).
Thus, four pulp densities were tested using the RFC to
determine its hydrodynamic response, specifically in ultra-
fine flotation. The pulp densities that were considered in
the flotation study were 17 wt.%, 2 wt.%, 1 wt.% and
0.1 wt.%. The highest (17 wt.%) was selected based on a
Table 1. Chemical composition of mineral samples used,
obtained via ICP-MS measurements
Element Pentlandite [%]Quartz [%]
Nickel (Ni) 9.6 –
Copper (Cu) 5.3 –
Sulphur (S) 34.1 –
Lead (Pb) 0.1 –
Iron (Fe) 45.5 0.23
Silicon (Si) 0.3 45.3
Aluminium (Al) 0.1 0.4
density fall to the inclined surface by gravity and glide
along the surface of the inclined channel towards the bot-
tom while the air bubbles with or without particles rise to
the fluidized bed (Chen et al., 2022 Cole et al., 2020 Cole
et al., 2021 Galvin, 2012 Jiang et al., 2019). This bubble-
particle separation is what is termed as the Boycott effect
(Boycott, 1920 Peacock, 2005).
Previous studies have provided comprehensive insights
by outlining the flotation performance of the RFC, spe-
cifically for particles within the size range of 24.5 μm to
0.35 mm (Cole et al., 2020 Dickinson et al., 2015 Iveson
et al., 2022 Jiang, 2017). Although the mineral recovery
data obtained within the mentioned particle size class are
promising, there is a paucity of data on the flotation perfor-
mance of the RFC in the ultrafine size range (–20 microns).
The current work intends to ascertain and optimize the
hydrodynamic parameters that may affect the performance
of the RFC at ultrafine particle sizes.
EXPERIMENTAL
Materials
Pentlandite employed in this study was obtained from
Ward’s Natural Science Establishment, Inc., Ontario,
Canada, and quartz from Unimin, Adelaide, Australia.
Inductively coupled plasma mass spectrometry (ICP-MS)
and Inductively Coupled Plasma Atomic Emission
Spectroscopy (ICP-AES) were carried out on both sam-
ples to determine the elemental composition. The results
are presented in Table 1. Potassium amyl xanthate (PAX)
obtained from Sinoz Chemicals &Commodities Pty in
Australia was used as a collector. Methyl isobutyl carbonyl
(MIBC) of industry grade with purity greater than 96%
was used as frother. Sodium hydroxide and hydrochloric
acid were used as pH-modifiers during the flotation stud-
ies. CMC was used as a dispersant. Demineralised water
was used throughout the experiments. The particle size
distribution of both pentlandite and quartz, depicted in
Figure 2 were obtained using the Malvern Mastersizer 2000
Particle Size Analyser. In the context of this research, the
term ‘ultrafine particle size’ is used to characterize –20 µm
particle size samples.
Flotation Test Using the Reflux Flotation Cell
A laboratory-scale Reflux Flotation Cell was employed to
conduct a mixed mineral flotation study on pentlandite
and quartz in a ratio of 1:20 by mass. A 0.06 m3 tank with
an impeller attached to the base was employed as the slurry
conditioning tank. A Verderflex VF15 peristaltic pump with
a maximum head of 12 bar was used to circulate feed from
the conditioning tank to the RFC. The pump is connected
to a MagMaster electromagnetic flowmeter to monitor and
measure the feed rate. An Ebara CDXM 120/70 hydrofloat
pump with a maximum head of 4 bar was used to pump
fluidization water into the cell. The wash water flowrate
was measured using a Sensus iPERL Smart Water Meter.
To maintain a steady-state operation, the tailings stream
(underflow) was recirculated back to the feed tank, creating
a pseudo-continuous process. A magnetic flow meter was
employed to measure the underflow rate before the stream
was returned to the feed tank, allowing for flow rate control
through the underflow valves.
A previous study by the authors, a precursor to the cur-
rent work, investigated the entrainment behaviour of quartz
in pentlandite flotation (Ayedzi et al., 2024). Quartz which
has inherent hydrophilic properties was used as an entrain-
ment monitor. The optimal parameters for low entrain-
ment of quartz were also determined in the previous study
and used as the baseline condition for the current investi-
gation. The pulp pH was adjusted using dilute HCl and
dilute NaOH. Subsequently, PAX and MIBC were added
and given 5 mins and 3 mins conditioning time, respec-
tively. Each flotation test was carried out for 20 min and
concentrates were recovered at cumulative times of 1, 3,
6, 10, 15, and 20 min. The concentrates and tailings from
each test were dried, weighed, and assayed to determine the
flotation recovery.
Effect of Pulp Density
Pulp density, a physical variable of flotation, has been
determined to directly influence the mineral recovery and
entrainment during flotation (Çilek and Yılmazer, 2003).
Thus, four pulp densities were tested using the RFC to
determine its hydrodynamic response, specifically in ultra-
fine flotation. The pulp densities that were considered in
the flotation study were 17 wt.%, 2 wt.%, 1 wt.% and
0.1 wt.%. The highest (17 wt.%) was selected based on a
Table 1. Chemical composition of mineral samples used,
obtained via ICP-MS measurements
Element Pentlandite [%]Quartz [%]
Nickel (Ni) 9.6 –
Copper (Cu) 5.3 –
Sulphur (S) 34.1 –
Lead (Pb) 0.1 –
Iron (Fe) 45.5 0.23
Silicon (Si) 0.3 45.3
Aluminium (Al) 0.1 0.4