XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 2909
were lower, possibly due to the other factors affecting its
performance.
Residence time, for instance, plays a vital role in flo-
tation. Demir et al. (2022) observed in their pilot-scale
HydroFloat ® work that Cu recovery increased with increas-
ing residence time. Although the residence time in the
full-scale unit is unknown at this stage, it is expected to be
lower than in the small-scale tests (16 minutes). Perhaps
Cu recovery in the full-scale unit could be improved with
additional flotation time. Further work is required to elu-
cidate the reasons for the higher recoveries observed in the
small-scale fluidised bed device.
Nevertheless, it is important to note that while the
scale-up between the small-scale and full-scale flota-
tion performance was not perfect, it was still remarkably
close—within the range of variation between experimental
conditions.
CONCLUSIONS
This work presented the outcomes of flotation tests con-
ducted in a small-scale fluidised bed flotation device that
uses 1–2 kg of copper ore sample and compared the results
to those obtained from tests conducted in a full-scale indus-
trial unit. Based on the obtained analysis, the following can
be concluded:
• The overall recovery results obtained from the small-
scale fluidised bed device exhibit remarkable repro-
ducibility. This can be attributed to the absence of a
froth phase and the elimination of the need to inter-
mittently scrape concentrate samples, which has the
potential to introduce errors.
• Regression modelling of the data indicates that cop-
per recovery in the small-scale device is a strong
function of air and fluidisation water flow rates, with
air flow rate showing a non-linear relationship with
copper recovery and water flow rate showing a linear
relationship with copper recovery. The relationships
between copper recovery and air and water flow rate
observed in this work were also observed in previous
pilot-scale work by other researchers.
• Copper recovery increased with increasing air flow
rate at all the water flow rates tested, but there
appears to be an optimum beyond which copper
recovery begins to plateau. The leveling off in recov-
ery at the high air flow region indicates the presence
of a competing mechanism, which requires further
work to understand.
• Increasing the water flow rate increased the overall
copper recovery. This was attributed to the expansion
of the fluidised bed as the water flow rate increased,
resulting in higher bed porosity and lower bed den-
sity. This favours high particle-bubble collisions and
attachments. Increasing the water flow rate also
increases the upward forces on the bubble-particle
aggregates, thereby promoting recovery. This was
observed at both low and high air flow rates.
• The small-scale fluidised bed device produced results
of similar magnitude to the full-scale HydroFloat ®
however, the recoveries obtained in the full-scale
HydroFloat ® were lower, possibly due to factors such
as residence time, throughput, and dilution water
addition rate, affecting its performance.
ACKNOWLEDGMENTS
The authors acknowledge the funding support from the
sponsors of the Collaborative Consortium for Coarse
Particle Processing Research Program. The authors
acknowledge the site support provided by the Cadia Valley
Operations team. The authors also acknowledge the support
from the Australian Research Council for the ARC Centre
of Excellence for Enabling Eco-Efficient Beneficiation of
Minerals, grant number CE200100009.
REFERENCES
Awatey, B., Skinner, W. &Zanin, M. 2015. Incorporating
fluidised-bed flotation into a conventional flotation
flowsheet: A focus on energy implications of coarse
particle recovery. Powder Technology, 275, 85–93.
Awatey, B., Thanasekaran, H., Kohmuench, J. N.,
Skinner, W. &Zanin, M. 2013. Optimization of
operating parameters for coarse sphalerite flotation
in the HydroFloat fluidised-bed separator. Minerals
Engineering, 50–51, 99–105.
Ballantyne, G., Powell, M. &Tiang, M. Proportion of
energy attributable to comminution. Proceedings of the
11th Australasian Institute of Mining and Metallurgy
Mill Operator’s Conference, 2012. 25–30.
Barbian, N., Hadler, K. &Cilliers, J. J. 2006. The froth sta-
bility column: Measuring froth stability at an industrial
scale. Minerals Engineering, 19, 713–718.
Dankwah, J. B., Asamoah, R. K., Zanin, M. &Skinner, W.
2022. Influence of water rate, gas rate, and bed particle
size on bed-level and coarse particle flotation perfor-
mance. Minerals Engineering, 183, 107622.
Demir, H. K., Morrison, A., Runge, K., Evans, C. &
Kohmuench, J. The effects of operational param-
eters on HydroFloat ® performance in a metalliferous
application. IMPC Asia-Pacific, 22–24 August 2022
Melbourne, Australia.
were lower, possibly due to the other factors affecting its
performance.
Residence time, for instance, plays a vital role in flo-
tation. Demir et al. (2022) observed in their pilot-scale
HydroFloat ® work that Cu recovery increased with increas-
ing residence time. Although the residence time in the
full-scale unit is unknown at this stage, it is expected to be
lower than in the small-scale tests (16 minutes). Perhaps
Cu recovery in the full-scale unit could be improved with
additional flotation time. Further work is required to elu-
cidate the reasons for the higher recoveries observed in the
small-scale fluidised bed device.
Nevertheless, it is important to note that while the
scale-up between the small-scale and full-scale flota-
tion performance was not perfect, it was still remarkably
close—within the range of variation between experimental
conditions.
CONCLUSIONS
This work presented the outcomes of flotation tests con-
ducted in a small-scale fluidised bed flotation device that
uses 1–2 kg of copper ore sample and compared the results
to those obtained from tests conducted in a full-scale indus-
trial unit. Based on the obtained analysis, the following can
be concluded:
• The overall recovery results obtained from the small-
scale fluidised bed device exhibit remarkable repro-
ducibility. This can be attributed to the absence of a
froth phase and the elimination of the need to inter-
mittently scrape concentrate samples, which has the
potential to introduce errors.
• Regression modelling of the data indicates that cop-
per recovery in the small-scale device is a strong
function of air and fluidisation water flow rates, with
air flow rate showing a non-linear relationship with
copper recovery and water flow rate showing a linear
relationship with copper recovery. The relationships
between copper recovery and air and water flow rate
observed in this work were also observed in previous
pilot-scale work by other researchers.
• Copper recovery increased with increasing air flow
rate at all the water flow rates tested, but there
appears to be an optimum beyond which copper
recovery begins to plateau. The leveling off in recov-
ery at the high air flow region indicates the presence
of a competing mechanism, which requires further
work to understand.
• Increasing the water flow rate increased the overall
copper recovery. This was attributed to the expansion
of the fluidised bed as the water flow rate increased,
resulting in higher bed porosity and lower bed den-
sity. This favours high particle-bubble collisions and
attachments. Increasing the water flow rate also
increases the upward forces on the bubble-particle
aggregates, thereby promoting recovery. This was
observed at both low and high air flow rates.
• The small-scale fluidised bed device produced results
of similar magnitude to the full-scale HydroFloat ®
however, the recoveries obtained in the full-scale
HydroFloat ® were lower, possibly due to factors such
as residence time, throughput, and dilution water
addition rate, affecting its performance.
ACKNOWLEDGMENTS
The authors acknowledge the funding support from the
sponsors of the Collaborative Consortium for Coarse
Particle Processing Research Program. The authors
acknowledge the site support provided by the Cadia Valley
Operations team. The authors also acknowledge the support
from the Australian Research Council for the ARC Centre
of Excellence for Enabling Eco-Efficient Beneficiation of
Minerals, grant number CE200100009.
REFERENCES
Awatey, B., Skinner, W. &Zanin, M. 2015. Incorporating
fluidised-bed flotation into a conventional flotation
flowsheet: A focus on energy implications of coarse
particle recovery. Powder Technology, 275, 85–93.
Awatey, B., Thanasekaran, H., Kohmuench, J. N.,
Skinner, W. &Zanin, M. 2013. Optimization of
operating parameters for coarse sphalerite flotation
in the HydroFloat fluidised-bed separator. Minerals
Engineering, 50–51, 99–105.
Ballantyne, G., Powell, M. &Tiang, M. Proportion of
energy attributable to comminution. Proceedings of the
11th Australasian Institute of Mining and Metallurgy
Mill Operator’s Conference, 2012. 25–30.
Barbian, N., Hadler, K. &Cilliers, J. J. 2006. The froth sta-
bility column: Measuring froth stability at an industrial
scale. Minerals Engineering, 19, 713–718.
Dankwah, J. B., Asamoah, R. K., Zanin, M. &Skinner, W.
2022. Influence of water rate, gas rate, and bed particle
size on bed-level and coarse particle flotation perfor-
mance. Minerals Engineering, 183, 107622.
Demir, H. K., Morrison, A., Runge, K., Evans, C. &
Kohmuench, J. The effects of operational param-
eters on HydroFloat ® performance in a metalliferous
application. IMPC Asia-Pacific, 22–24 August 2022
Melbourne, Australia.