XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 943
BUILDING FLOTATION FUNDAMENTALS
IN DIGITAL ONE
Bubble Characteristics Control—Optimizing
Hydrodynamics of Flotation
Air and MIBC form the foundation of kinetic control
inside the flotation cells. The quantity of bubbles and the
quality of bubble loading are clearly critical for recovery.
Digital One adjusts air and MIBC with XRF readings and
bubble characteristics as soft sensors towards reaching tar-
get rougher and final concentrate grades.
Low bubble loading however can be caused by two
separate scenarios: too many bubbles or not enough min-
eral availability. The on-line XRF can be used to distinguish
these two conditions by observing the targeted metal going
to the tails. By using both sensors, the fundamental limita-
tion of only using assays or surface bubble characteristics
is overcome, enabling advanced control of both air and
MIBC for the float cells.
Buick Mill’s operations historically have not controlled
air to this extent, so this also provides a new way to maxi-
mize the effectiveness of otherwise aging flotation cells.
Modern Reagents and Control—Thermodynamics,
Kinetics and Phase Equilibria of Flotation
Reagents besides bubbles influence thermodynamics and
kinetics of flotation which are difficult to define and con-
trol. Buick Mill built an automatic second reagent sys-
tem of highly selective and potent modern collectors and
depressants (Mang et al., 2024a, 2024c). As illustrated in
Tables 10 and 11, Digital One can regulate these reagents
in DCS using XRF readings, now as phase equilibria of flo-
tation, to guide and optimize thermodynamics and kinetics
of flotation, reaching control targets.
Automatic reagent addition can be set to “Basic” or
“Advanced” modes. The “Basic” mode is an on-off control
meant to reliably add a minimal effective dose of the chemi-
cal as needed. The “Advanced” mode dynamically changes
the reagent addition rate, adding more when XRF assay
readings are far from the shut-off target. The “Advanced”
mode therefore enhances the thermodynamics and kinet-
ics of flotation and improves flotation phase equilibria and
metal recoveries more and faster than the “Basic” mode.
As the result, Buick mill has deactivated the “Basic” mode
since the “Advanced” mode includes the “Basic” mode, see
Table 11.
Froth Velocity Control and Removal—Bubble and
Froth Optimization
Froth velocity control is the core of the VisioFroth ™ sys-
tem, and Digital One enables removing froth by exact
amount at exact time reaching target concentrate grades
while improving recoveries, with rapidly varying ore grades.
XRF assays can be used as soft sensors to guide this system,
so that velocity can be adjusted to exploit the phase equilib-
ria designed in the previous sections.
Digital One builds on top of these to minimize distur-
bances due to changing feed grades. By monitoring spikes
in feed content, the system uses machine learning to prime
itself for an associated spike in process loading. When that
subsequent spike is detected, the exact amount of excess
froth can be removed to stabilize the process. This is key
to managing the dynamic feed grades often presented by
complex ores.
Digital One further optimizes bubbles and froth hydro-
dynamically using air and MIBC, thermodynamically using
Table 10. Specialized reagents controlled based on on-line XRF analyzer readings
Chemical Control Target Reagent Started Reagent Stopped
Pb Collector %Pb in Zn Conc. 4.0% 3.0%
Zn Collector %Zn in Zn Tailings 0.15% 0.1%
Cu Collector %Cu in Pb Conc. 1.2% 0.9%
Fe Depressant in Zn Conditioner %Fe in Zn Conc. 3.0% 2.5%
Pb Depressant in Cu Absorber %Pb in Cu Conc. 4.5% 4.0%
Table 11. Reagents dosage and limits editable in DCS
Chemical “Basic” Flow Rate, CCM
“Advanced”
Low Limit, CCM
“Advanced”
High Limit, CCM
Pb Collector 20 20 35
Zn Collector 25 25 40
Cu Collector 20 20 40
Fe Depressant to Zn Conditioner 20 20 50
Pb Depressant to Cu Absorber 20 20 60
BUILDING FLOTATION FUNDAMENTALS
IN DIGITAL ONE
Bubble Characteristics Control—Optimizing
Hydrodynamics of Flotation
Air and MIBC form the foundation of kinetic control
inside the flotation cells. The quantity of bubbles and the
quality of bubble loading are clearly critical for recovery.
Digital One adjusts air and MIBC with XRF readings and
bubble characteristics as soft sensors towards reaching tar-
get rougher and final concentrate grades.
Low bubble loading however can be caused by two
separate scenarios: too many bubbles or not enough min-
eral availability. The on-line XRF can be used to distinguish
these two conditions by observing the targeted metal going
to the tails. By using both sensors, the fundamental limita-
tion of only using assays or surface bubble characteristics
is overcome, enabling advanced control of both air and
MIBC for the float cells.
Buick Mill’s operations historically have not controlled
air to this extent, so this also provides a new way to maxi-
mize the effectiveness of otherwise aging flotation cells.
Modern Reagents and Control—Thermodynamics,
Kinetics and Phase Equilibria of Flotation
Reagents besides bubbles influence thermodynamics and
kinetics of flotation which are difficult to define and con-
trol. Buick Mill built an automatic second reagent sys-
tem of highly selective and potent modern collectors and
depressants (Mang et al., 2024a, 2024c). As illustrated in
Tables 10 and 11, Digital One can regulate these reagents
in DCS using XRF readings, now as phase equilibria of flo-
tation, to guide and optimize thermodynamics and kinetics
of flotation, reaching control targets.
Automatic reagent addition can be set to “Basic” or
“Advanced” modes. The “Basic” mode is an on-off control
meant to reliably add a minimal effective dose of the chemi-
cal as needed. The “Advanced” mode dynamically changes
the reagent addition rate, adding more when XRF assay
readings are far from the shut-off target. The “Advanced”
mode therefore enhances the thermodynamics and kinet-
ics of flotation and improves flotation phase equilibria and
metal recoveries more and faster than the “Basic” mode.
As the result, Buick mill has deactivated the “Basic” mode
since the “Advanced” mode includes the “Basic” mode, see
Table 11.
Froth Velocity Control and Removal—Bubble and
Froth Optimization
Froth velocity control is the core of the VisioFroth ™ sys-
tem, and Digital One enables removing froth by exact
amount at exact time reaching target concentrate grades
while improving recoveries, with rapidly varying ore grades.
XRF assays can be used as soft sensors to guide this system,
so that velocity can be adjusted to exploit the phase equilib-
ria designed in the previous sections.
Digital One builds on top of these to minimize distur-
bances due to changing feed grades. By monitoring spikes
in feed content, the system uses machine learning to prime
itself for an associated spike in process loading. When that
subsequent spike is detected, the exact amount of excess
froth can be removed to stabilize the process. This is key
to managing the dynamic feed grades often presented by
complex ores.
Digital One further optimizes bubbles and froth hydro-
dynamically using air and MIBC, thermodynamically using
Table 10. Specialized reagents controlled based on on-line XRF analyzer readings
Chemical Control Target Reagent Started Reagent Stopped
Pb Collector %Pb in Zn Conc. 4.0% 3.0%
Zn Collector %Zn in Zn Tailings 0.15% 0.1%
Cu Collector %Cu in Pb Conc. 1.2% 0.9%
Fe Depressant in Zn Conditioner %Fe in Zn Conc. 3.0% 2.5%
Pb Depressant in Cu Absorber %Pb in Cu Conc. 4.5% 4.0%
Table 11. Reagents dosage and limits editable in DCS
Chemical “Basic” Flow Rate, CCM
“Advanced”
Low Limit, CCM
“Advanced”
High Limit, CCM
Pb Collector 20 20 35
Zn Collector 25 25 40
Cu Collector 20 20 40
Fe Depressant to Zn Conditioner 20 20 50
Pb Depressant to Cu Absorber 20 20 60