XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 2721
average gas holdup for with and without wash water and
NaCl is presented in Figure 7.
Figure 7 shows that the addition of wash increased the
gas holdup for both with and without NaCl. The addition
of wash water reduces the rise velocity of bubbles in the
vertical section of the column. This increases the average
residence time of the bubbles, allowing for a denser accu-
mulation of bubbles in the cell. The effect of salt on the gas
holdup is negligible when wash water is used however, a
marginal increase in gas holdup is observed in cases with-
out wash. This effect can be linked to the inhibition of
bubble coalescence, as demonstrated in Figure 6. The pres-
ence of the salt concentration leads to smaller bubbles due
to reduced coalescence. These smaller bubbles rise more
slowly, which contributes to their increased accumulation
and, therefore, a higher gas holdup. In conventional flota-
tion gas holdup typically ranges from 3% to 20% (Schwarz
&Alexander, 2006), whereas the RFC, as demonstrated,
achieves much higher values. As shown in Figure 6(B), this
results in a significantly higher bubble surface flux, which is
a key parameter in flotation.
CONCLUSIONS
This work demonstrates the effectiveness of counter-cur-
rent washing on the removal of hydrophilic silica particles
in the presence of salt in a Reflux Flotation Cell. The find-
ings offer promising prospects for the use of saline water
in mineral processing plants, potentially contributing to
global efforts in addressing freshwater scarcity through
water recycling. To further elucidate the implications of
these findings, additional research involving various salts at
higher concentrations is recommended.
ACKNOWLEDGMENTS
The authors would like to acknowledge the financial sup-
port from the Australian Research Council (ARC) through
the ARC Centre of Excellence for Enabling Eco-efficient
Beneficiation of Minerals, grant number CE200100009.
REFERENCES
Castro, S., &Laskowski, J. S. (2011). Froth Flotation
in Saline Water. KONA Powder and Particle Journal
No.29, 4–15.
Crompton, L. J., Islam, T. M., &Galvin, K. P. (2022).
Investigation of Internal Classification in Coarse
Particle Flotation of Chalcopyrite Using the CoarseAIR.
Minerals.
Dickinson, J. E., &Galvin, K. P. (2014). Fluidized bed
desliming in fine particle flotation – Part I. Chemical
Engineering Science 108, 283–298.
Firouzi, M., &Nguyen, A. V. (2014). On the effect of van
der Waals attractions on the critical salt concentration
for inhibiting bubble coalescence. Minerals Engineering
58, 108–112.
Firouzi, M., &Nguyen, A. V. (2017). The Gibbs-Marangoni
stress and nonDLVO forces are equally important for
modeling bubble coalescence in salt solutions. Colloids
and Surfaces A: Physicochemical and Engineering Aspects
515, 62–68.
Figure 7. Gas Holdup for each NaCl feed concentration and wash rate
average gas holdup for with and without wash water and
NaCl is presented in Figure 7.
Figure 7 shows that the addition of wash increased the
gas holdup for both with and without NaCl. The addition
of wash water reduces the rise velocity of bubbles in the
vertical section of the column. This increases the average
residence time of the bubbles, allowing for a denser accu-
mulation of bubbles in the cell. The effect of salt on the gas
holdup is negligible when wash water is used however, a
marginal increase in gas holdup is observed in cases with-
out wash. This effect can be linked to the inhibition of
bubble coalescence, as demonstrated in Figure 6. The pres-
ence of the salt concentration leads to smaller bubbles due
to reduced coalescence. These smaller bubbles rise more
slowly, which contributes to their increased accumulation
and, therefore, a higher gas holdup. In conventional flota-
tion gas holdup typically ranges from 3% to 20% (Schwarz
&Alexander, 2006), whereas the RFC, as demonstrated,
achieves much higher values. As shown in Figure 6(B), this
results in a significantly higher bubble surface flux, which is
a key parameter in flotation.
CONCLUSIONS
This work demonstrates the effectiveness of counter-cur-
rent washing on the removal of hydrophilic silica particles
in the presence of salt in a Reflux Flotation Cell. The find-
ings offer promising prospects for the use of saline water
in mineral processing plants, potentially contributing to
global efforts in addressing freshwater scarcity through
water recycling. To further elucidate the implications of
these findings, additional research involving various salts at
higher concentrations is recommended.
ACKNOWLEDGMENTS
The authors would like to acknowledge the financial sup-
port from the Australian Research Council (ARC) through
the ARC Centre of Excellence for Enabling Eco-efficient
Beneficiation of Minerals, grant number CE200100009.
REFERENCES
Castro, S., &Laskowski, J. S. (2011). Froth Flotation
in Saline Water. KONA Powder and Particle Journal
No.29, 4–15.
Crompton, L. J., Islam, T. M., &Galvin, K. P. (2022).
Investigation of Internal Classification in Coarse
Particle Flotation of Chalcopyrite Using the CoarseAIR.
Minerals.
Dickinson, J. E., &Galvin, K. P. (2014). Fluidized bed
desliming in fine particle flotation – Part I. Chemical
Engineering Science 108, 283–298.
Firouzi, M., &Nguyen, A. V. (2014). On the effect of van
der Waals attractions on the critical salt concentration
for inhibiting bubble coalescence. Minerals Engineering
58, 108–112.
Firouzi, M., &Nguyen, A. V. (2017). The Gibbs-Marangoni
stress and nonDLVO forces are equally important for
modeling bubble coalescence in salt solutions. Colloids
and Surfaces A: Physicochemical and Engineering Aspects
515, 62–68.
Figure 7. Gas Holdup for each NaCl feed concentration and wash rate