952 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
curves presented in Figure 3a show indeed that coarse par-
ticle recoveries were substantially increased by switching to
a Super Collector.
Improving Throughput and Recovery
In most sulfide mineral flotation plants, the slowest-float-
ing materials congregate in the cleaner-scavenger tails
(CSTs), as shown in Figure 2. The particles are typically
20 µm in size. Therefore, mill operators return them to the
rougher flotation bank as circulating loads (CLs) to help
recover the target minerals, e.g., chalcopyrite, by allowing
longer retention times. It has been found, however, that
much of the target are found as composite particles in a
CST stream and/or superficially oxidized while being recir-
culated repeatedly, both of which would make it difficult to
recover them efficiently. In the present work, we conducted
plant simulations on a porphyry copper ore flotation plant
using a SC and compared the results with those obtained
previously using KAX (Gupta et al., 2023).
Table 2 shows that a simple substitution of the con-
ventional collector with a CS in a closed-circuit configura-
tion increased the copper recovery from 86.6 to 95.86%.
No other changes in operating conditions were necessary to
increase the recovery by 9.21%, which can be attributed to
the substantial increase in the flotation rate constants (ki)
as shown in Figure 3a. Of course, the main reason for the
increase ki is the large contact angles brought out from the
use of a SC.
Circulating loads usually account for 20–25% of
the volumetric flows through rougher flotation banks.
Recognizing that the materials in a CST flow represent the
slowest-floating copper-bearing minerals, their flotation
rates are much slower than those present in freshly mined
ore feeds and, hence, entail a significant decrease in through-
put. In this regard, CLs represent a costly exercise in plant
operation. With the advent of a series of Super Collectors,
it may be worthwhile to open the flotation circuit. The sim-
ulation results obtained under open circuit configurations
are presented in Table 2. As shown, the throughput was
increased to from 5,000 to 6,239 tph, which represented a
24.8% increase in throughput for the cases of using KAX
and SC. When using an SC, copper recovery was increased
from 86.65 to 93.32%. These improvements can be trans-
lated to an increase in the yearly copper production by
34.4% from 78,658.3 tons to 105,701.2 tons.
With KAX as a collector, opening the rougher circuit
increases the throughput similarly but at a loss of copper
recovery from 86.65 to 85.3%. Companies are aware of the
substantial increase in throughput by opening the circuit
but are hesitant to implement the concept due to the loss
of copper recovery by 1.35%. When SCs become available
commercially, this barrier may be eliminated.
SUMMARY AND CONCLUSIONS
A flotation model has been derived by considering both the
forward and backward reactions in bubble-particle interac-
tion. The model can be used to predict the rate constants
using a simple Arrhenius-type equation as functions of
collision frequency, energy barriers due to surface forces,
hydrodynamic resistance, work of adhesion, and energy
dissipation rate. It can accurately predict the intrinsic
flotation rate constants that can be used to design flota-
tion plants and simulate plant operations without using
assumed scaleup factors.
The model has been used to simulate the performance
of the super collectors that can create contact angles nearly
twice as large as those obtained using conventional collec-
tors. The simulation results show that the super collectors
are useful for the flotation of composite particles and hence
can improve the recovery of coarse particles. The super col-
lectors are also useful to increase the both throughput and
recovery of a copper flotation plant by improving the recov-
ery of the composite particles present in cleaner-scavenger
tails.
A user-friendly computer simulator has been devel-
oped to make it easier for process engineers to design flota-
tion circuits for different ore types and for plant operators
to optimize plant operations by varying both the hydrody-
namic and surface chemistry parameters as input.
Table 2. Comparison of plant simulations conducted on a low-grade porphyry copper ore flotation plant using KAX and a SC
Reagents
Closed Circuit Open Circuit
Throughput,
tph
Con
Grade,
%Cu
Tails
Grade,
%Cu
Recovery,
%
Throughput,
tph
Grade,
%Cu
Tails
Grade,
%Cu
Recovery,
%
KAX 5,000 25.68 0.0305 86.65 6,239 26.84 0.0325 85.30
SC 5,000 23.72 0.0095 95.86 6,239 25.01 0.0152 93.32
curves presented in Figure 3a show indeed that coarse par-
ticle recoveries were substantially increased by switching to
a Super Collector.
Improving Throughput and Recovery
In most sulfide mineral flotation plants, the slowest-float-
ing materials congregate in the cleaner-scavenger tails
(CSTs), as shown in Figure 2. The particles are typically
20 µm in size. Therefore, mill operators return them to the
rougher flotation bank as circulating loads (CLs) to help
recover the target minerals, e.g., chalcopyrite, by allowing
longer retention times. It has been found, however, that
much of the target are found as composite particles in a
CST stream and/or superficially oxidized while being recir-
culated repeatedly, both of which would make it difficult to
recover them efficiently. In the present work, we conducted
plant simulations on a porphyry copper ore flotation plant
using a SC and compared the results with those obtained
previously using KAX (Gupta et al., 2023).
Table 2 shows that a simple substitution of the con-
ventional collector with a CS in a closed-circuit configura-
tion increased the copper recovery from 86.6 to 95.86%.
No other changes in operating conditions were necessary to
increase the recovery by 9.21%, which can be attributed to
the substantial increase in the flotation rate constants (ki)
as shown in Figure 3a. Of course, the main reason for the
increase ki is the large contact angles brought out from the
use of a SC.
Circulating loads usually account for 20–25% of
the volumetric flows through rougher flotation banks.
Recognizing that the materials in a CST flow represent the
slowest-floating copper-bearing minerals, their flotation
rates are much slower than those present in freshly mined
ore feeds and, hence, entail a significant decrease in through-
put. In this regard, CLs represent a costly exercise in plant
operation. With the advent of a series of Super Collectors,
it may be worthwhile to open the flotation circuit. The sim-
ulation results obtained under open circuit configurations
are presented in Table 2. As shown, the throughput was
increased to from 5,000 to 6,239 tph, which represented a
24.8% increase in throughput for the cases of using KAX
and SC. When using an SC, copper recovery was increased
from 86.65 to 93.32%. These improvements can be trans-
lated to an increase in the yearly copper production by
34.4% from 78,658.3 tons to 105,701.2 tons.
With KAX as a collector, opening the rougher circuit
increases the throughput similarly but at a loss of copper
recovery from 86.65 to 85.3%. Companies are aware of the
substantial increase in throughput by opening the circuit
but are hesitant to implement the concept due to the loss
of copper recovery by 1.35%. When SCs become available
commercially, this barrier may be eliminated.
SUMMARY AND CONCLUSIONS
A flotation model has been derived by considering both the
forward and backward reactions in bubble-particle interac-
tion. The model can be used to predict the rate constants
using a simple Arrhenius-type equation as functions of
collision frequency, energy barriers due to surface forces,
hydrodynamic resistance, work of adhesion, and energy
dissipation rate. It can accurately predict the intrinsic
flotation rate constants that can be used to design flota-
tion plants and simulate plant operations without using
assumed scaleup factors.
The model has been used to simulate the performance
of the super collectors that can create contact angles nearly
twice as large as those obtained using conventional collec-
tors. The simulation results show that the super collectors
are useful for the flotation of composite particles and hence
can improve the recovery of coarse particles. The super col-
lectors are also useful to increase the both throughput and
recovery of a copper flotation plant by improving the recov-
ery of the composite particles present in cleaner-scavenger
tails.
A user-friendly computer simulator has been devel-
oped to make it easier for process engineers to design flota-
tion circuits for different ore types and for plant operators
to optimize plant operations by varying both the hydrody-
namic and surface chemistry parameters as input.
Table 2. Comparison of plant simulations conducted on a low-grade porphyry copper ore flotation plant using KAX and a SC
Reagents
Closed Circuit Open Circuit
Throughput,
tph
Con
Grade,
%Cu
Tails
Grade,
%Cu
Recovery,
%
Throughput,
tph
Grade,
%Cu
Tails
Grade,
%Cu
Recovery,
%
KAX 5,000 25.68 0.0305 86.65 6,239 26.84 0.0325 85.30
SC 5,000 23.72 0.0095 95.86 6,239 25.01 0.0152 93.32