XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 2903
(Interfroth F236N) to reach a concentration in excess of
30 ppm. The exact concentration was unknown due to the
unknown quantity of residual frother. No further collector
was added during the small-scale flotation tests, as collec-
tors were added upstream of the sample collection point
during the two-stage classification shown in Figure 2.
Flotation
Small-Scale Fluidised Bed Flotation.
The flotation tests were performed following a statistical
Design of Experiments (DoE) plan, as shown in Table 1.
The variables considered in these tests were air and water
flow rates, the main driving parameters for the batch mode
device. These variables were converted into superficial gas
velocity (Jg, cm/s) and superficial water velocity (SWV,
cm/s). Jg and SWV are parameters independent of the cell
size and are calculated from Equations 1 and 2, respectively.
J A
Q
g
a =(1)
SWV A
Q
w =(2)
where Qa is the air flow rate in cm3/s, Qw is the water flow
rate in cm3/s and A is the cross-sectional area of the cell
in cm2.
A freshly collected sample from the plant was used for
each flotation test. The freshly collected sample was initially
screened to remove the –38 µm material from the feed. This
was done to prevent the fine particles from entering the
column and blocking the pores in the sintered disc. The
+38 µm fraction, weighing approximately 1 kg, was then
carefully added into the top chamber of the device before
setting the desired fluidisation water rate.
The flotation test commenced as soon as the air was
introduced into the column, and the air flow rate was kept
constant for the duration of the test. Five concentrates were
collected at 0.5, 1, 4, 8, and 16 minutes. The concentrates
were collected via screens fixed above a collection tank,
thus enabling the recovery and recycling of the fluidisation
water. The concentrate samples were dried, weighed and
prepared for assay. All the 11 tests were performed within
three (3) days. Samples used for testing on a particular day
were collected all at the same time.
Full-Scale Plant Surveys
Five full-scale plant surveys were completed according to
the experimental plan shown in Table 2. The main param-
eters that were varied during the survey were fluidisation air
and water rates and fluidised bed height, measured as a per-
centage of a length measured by the position of a float sen-
sor. A mixed collector formulation (a mixture of xanthate
and diesel) was added to the flotation feed during the two-
stage hydrocyclone classification, where the fine particles
Table 1. Experimental plan based on a full factorial design with three repeat center point tests
Run Order
Day of Sample
Collection Air Flowrate, lpm Water Flowrate, lpm J
g ,cm/s SWV, cm/s
1 1 0.5 2 0.17 0.66
2 1 0.1 3 0.03 0.99
3 1 0.1 1 0.03 0.33
4 2 0.3 3 0.10 0.99
5 2 0.3 1 0.10 0.33
6 2 0.3 2 0.10 0.66
7 2 0.5 3 0.17 0.99
8 3 0.1 2 0.03 0.66
9 3 0.5 1 0.17 0.33
10 3 0.3 2 0.10 0.66
11 3 0.3 2 0.10 0.66
Table 2. Experimental plan for full-scale plant surveys
Run Order Water Flowrate, m3/h Air Flowrate, m3/h Bed Height, %Jg, cm/s SWV, cm/s
1 280 25 20 0.05 0.54
2 280 55 60 0.11 0.54
3 240 40 40 0.08 0.47
4 200 55 20 0.11 0.39
5 200 25 60 0.05 0.39
(Interfroth F236N) to reach a concentration in excess of
30 ppm. The exact concentration was unknown due to the
unknown quantity of residual frother. No further collector
was added during the small-scale flotation tests, as collec-
tors were added upstream of the sample collection point
during the two-stage classification shown in Figure 2.
Flotation
Small-Scale Fluidised Bed Flotation.
The flotation tests were performed following a statistical
Design of Experiments (DoE) plan, as shown in Table 1.
The variables considered in these tests were air and water
flow rates, the main driving parameters for the batch mode
device. These variables were converted into superficial gas
velocity (Jg, cm/s) and superficial water velocity (SWV,
cm/s). Jg and SWV are parameters independent of the cell
size and are calculated from Equations 1 and 2, respectively.
J A
Q
g
a =(1)
SWV A
Q
w =(2)
where Qa is the air flow rate in cm3/s, Qw is the water flow
rate in cm3/s and A is the cross-sectional area of the cell
in cm2.
A freshly collected sample from the plant was used for
each flotation test. The freshly collected sample was initially
screened to remove the –38 µm material from the feed. This
was done to prevent the fine particles from entering the
column and blocking the pores in the sintered disc. The
+38 µm fraction, weighing approximately 1 kg, was then
carefully added into the top chamber of the device before
setting the desired fluidisation water rate.
The flotation test commenced as soon as the air was
introduced into the column, and the air flow rate was kept
constant for the duration of the test. Five concentrates were
collected at 0.5, 1, 4, 8, and 16 minutes. The concentrates
were collected via screens fixed above a collection tank,
thus enabling the recovery and recycling of the fluidisation
water. The concentrate samples were dried, weighed and
prepared for assay. All the 11 tests were performed within
three (3) days. Samples used for testing on a particular day
were collected all at the same time.
Full-Scale Plant Surveys
Five full-scale plant surveys were completed according to
the experimental plan shown in Table 2. The main param-
eters that were varied during the survey were fluidisation air
and water rates and fluidised bed height, measured as a per-
centage of a length measured by the position of a float sen-
sor. A mixed collector formulation (a mixture of xanthate
and diesel) was added to the flotation feed during the two-
stage hydrocyclone classification, where the fine particles
Table 1. Experimental plan based on a full factorial design with three repeat center point tests
Run Order
Day of Sample
Collection Air Flowrate, lpm Water Flowrate, lpm J
g ,cm/s SWV, cm/s
1 1 0.5 2 0.17 0.66
2 1 0.1 3 0.03 0.99
3 1 0.1 1 0.03 0.33
4 2 0.3 3 0.10 0.99
5 2 0.3 1 0.10 0.33
6 2 0.3 2 0.10 0.66
7 2 0.5 3 0.17 0.99
8 3 0.1 2 0.03 0.66
9 3 0.5 1 0.17 0.33
10 3 0.3 2 0.10 0.66
11 3 0.3 2 0.10 0.66
Table 2. Experimental plan for full-scale plant surveys
Run Order Water Flowrate, m3/h Air Flowrate, m3/h Bed Height, %Jg, cm/s SWV, cm/s
1 280 25 20 0.05 0.54
2 280 55 60 0.11 0.54
3 240 40 40 0.08 0.47
4 200 55 20 0.11 0.39
5 200 25 60 0.05 0.39