2904 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
are removed from the float feed. Frother was added directly
to the flotation cell through the fluidisation water lines.
Five samples were collected during each survey: hydro-
cyclone feed (2nd nest), hydrocyclone overflow (2nd nest),
hydrocyclone underflow (HydroFloat feed), HydroFloat
concentrate and HydroFloat tailings. At the end of the sur-
veys, the samples were weighed, filtered, dried and prepared
for assay.
RESULTS AND DISCUSSIONS
Repeatability Flotation Tests
Because the small-scale fluidised bed cell is new and has not
been extensively characterized, it is essential to establish the
reproducibility of both the testing methodology and the
flotation results within these tests. The center point runs in
the factorial design were used to measure the repeatability
of the flotation results. Figure 3 shows the feed size dis-
tributions of the center point runs, indicating similar P80
values.
The results for overall copper recoveries and enrichment
ratios for all three tests are presented in Figure 4. The results
show that all three tests exhibit recoveries and enrichment
ratios that are in close agreement, demonstrating a high
degree of reproducibility. The average copper recovery was
76.9 ± 2.6% the error estimate represents the 95% confi-
dence interval. The enrichment ratio was 2.3 for the three
center point tests. The enrichment ratios observed in these
tests are relatively low. Nevertheless, it is crucial to note
that the flotation feed for these tests was low-grade tailings
from a conventional flotation circuit. The small-scale flui-
dised bed device produced remarkably reproducible results
due to the lack of a froth phase and no requirement for
an operator to scrape periodic concentrate samples, which
could potentially introduce errors.
The results for copper recoveries as a function of time
for all three tests are presented in Figure 5. The recovery-
time curves for the three tests show highly repeatable overall
recovery results, with the recoveries reaching a plateau at the
four-minute mark. Close observation of the curves reveals
variations in recovery within the first and second concen-
trates. This variation could be attributed to experimental
error or variations in the feed characteristics. Variations
in recovery in the initial seconds of flotation are common
even in conventional batch flotation testing. Nonetheless,
the overall flotation results and the general shape of the
recovery as a function of time showed high repeatability
and proved that the test procedure was robust.
Modelling Copper Recovery in the Small-Scale
Fluidised Bed Device
The tests were performed with the objective of deter-
mining the effects of the operational parameters on the per-
formance of the small-scale fluidised bed flotation device.
A linear regression analysis was performed using the full
factorial data to determine the relationship between flu-
idisation air, fluidisation water and copper recovery. The
confidence level was set at 95% (two-sided), and a stepwise
elimination method was applied to remove terms with a
P-Value higher than 0.05. The derived model is shown in
100
80
60
40
20
0
Particle Size, μm
T6 Feed
T10 Feed
T11 Feed
10 100 1000
Figure 3. Feed particle size distributions of the center point runs (see Table 1 for test details)
Cumulative%
Passing
are removed from the float feed. Frother was added directly
to the flotation cell through the fluidisation water lines.
Five samples were collected during each survey: hydro-
cyclone feed (2nd nest), hydrocyclone overflow (2nd nest),
hydrocyclone underflow (HydroFloat feed), HydroFloat
concentrate and HydroFloat tailings. At the end of the sur-
veys, the samples were weighed, filtered, dried and prepared
for assay.
RESULTS AND DISCUSSIONS
Repeatability Flotation Tests
Because the small-scale fluidised bed cell is new and has not
been extensively characterized, it is essential to establish the
reproducibility of both the testing methodology and the
flotation results within these tests. The center point runs in
the factorial design were used to measure the repeatability
of the flotation results. Figure 3 shows the feed size dis-
tributions of the center point runs, indicating similar P80
values.
The results for overall copper recoveries and enrichment
ratios for all three tests are presented in Figure 4. The results
show that all three tests exhibit recoveries and enrichment
ratios that are in close agreement, demonstrating a high
degree of reproducibility. The average copper recovery was
76.9 ± 2.6% the error estimate represents the 95% confi-
dence interval. The enrichment ratio was 2.3 for the three
center point tests. The enrichment ratios observed in these
tests are relatively low. Nevertheless, it is crucial to note
that the flotation feed for these tests was low-grade tailings
from a conventional flotation circuit. The small-scale flui-
dised bed device produced remarkably reproducible results
due to the lack of a froth phase and no requirement for
an operator to scrape periodic concentrate samples, which
could potentially introduce errors.
The results for copper recoveries as a function of time
for all three tests are presented in Figure 5. The recovery-
time curves for the three tests show highly repeatable overall
recovery results, with the recoveries reaching a plateau at the
four-minute mark. Close observation of the curves reveals
variations in recovery within the first and second concen-
trates. This variation could be attributed to experimental
error or variations in the feed characteristics. Variations
in recovery in the initial seconds of flotation are common
even in conventional batch flotation testing. Nonetheless,
the overall flotation results and the general shape of the
recovery as a function of time showed high repeatability
and proved that the test procedure was robust.
Modelling Copper Recovery in the Small-Scale
Fluidised Bed Device
The tests were performed with the objective of deter-
mining the effects of the operational parameters on the per-
formance of the small-scale fluidised bed flotation device.
A linear regression analysis was performed using the full
factorial data to determine the relationship between flu-
idisation air, fluidisation water and copper recovery. The
confidence level was set at 95% (two-sided), and a stepwise
elimination method was applied to remove terms with a
P-Value higher than 0.05. The derived model is shown in
100
80
60
40
20
0
Particle Size, μm
T6 Feed
T10 Feed
T11 Feed
10 100 1000
Figure 3. Feed particle size distributions of the center point runs (see Table 1 for test details)
Cumulative%
Passing