XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 675
Additionally, it was observed that the solids recovery
trends for DI tests are generally higher than those for 5SPW.
However, this trend is not entirely typical of the results of
FS-DI at pH 4, which show significantly lower solids and
water recoveries compared to FS-5SPW, and even more so
when compared to the Cer media. This observation persists,
albeit less significantly, at natural pH (6–8) conditions. The
process selectivity, in terms of gangue entrainment control,
for sulfide minerals may be greatest when dissolved Fe ions
from FS media are present in the system.
As indicated by Figure 1, the system FS-DI at pH 4
has the most positive Eh of the results obtained using FS
media, and the resultant slurry is electrochemically favour-
able for the formation of hydrophobic dixanthogen spe-
cies. However, it should be noted that, at pH 4, all milling
media-water type combinations have a final Eh greater than
200 mV. Therefore, it is plausible that a combination of fac-
tors, such as the absence of dissolved salts from plant water
and the presence of dissolved Fe ions in the FS-DI system
at pH 4, leads to less entrainment in the system.
The experimental results show that the presence of dis-
solved salts in the plant water promotes water recovery but
may increase the likelihood of entrainment of minerals in
the froth phase. This is consistent with the well-known fact
that the presence of ions in a system promotes the stability
of a froth. Furthermore, the presence of dissolved Fe ions in
the FS media may enhance the selectivity of the process for
sulfide minerals. However, the analysis of grade-recovery
data is necessary to fully identify and understand the under-
lying mechanisms.
Grade-Recovery Analysis
When considering which milling media and water options
to use in a metallurgical circuit, it is essential to optimise
grade-recovery performance, cost-effectiveness, and envi-
ronmental sustainability. This section attempts to identify
the experimental conditions most favourable to achieve
the optimal. Since a mixed ore was used in this study, the
grade-recovery responses of Py and Gn are considered indi-
vidually, while at the same time investigating any galvanic
interactions between the sulfide minerals, the milling sys-
tem, and the xanthate collector added.
Fe Grade vs Recovery
Figure 3 shows the variations in Fe grade and recovery at
the different pH levels, milling media, and water types uti-
lised in the present study.
When analysing Figure 3, it is essential to note that the
recovery of Fe is directly linked to the Py component of
the composite ore as well as the Fe originating from the FS
media used in some experiments. The rejection of Fe associ-
ated with Py is of significant importance from a metallurgi-
cal standpoint since Py depression is a major objective in
many flotation operations.
Across all pHs, the Fe grade ranged from 15–24 wt.%.
At pH 4, where a higher concentration of dissolved Fe is
0
20
40
60
80
100
120
140
160
180
200
0 200 400 600 800 1000
Water recovery (g)
FS-DI
FS-5SPW
Cer-DI
Cer-5SPW
0
20
40
60
80
100
120
140
160
180
200
0 200 400 600 800 1000
Water recovery (g)
FS-DI
FS-5SPW
Cer-DI
Cer-5SPW
pH 4 pH 6 -8
Figure 2. Effect of pH control on different milling media and water type variation
Solids
recovery
(g)
Solids
recovery
(
Additionally, it was observed that the solids recovery
trends for DI tests are generally higher than those for 5SPW.
However, this trend is not entirely typical of the results of
FS-DI at pH 4, which show significantly lower solids and
water recoveries compared to FS-5SPW, and even more so
when compared to the Cer media. This observation persists,
albeit less significantly, at natural pH (6–8) conditions. The
process selectivity, in terms of gangue entrainment control,
for sulfide minerals may be greatest when dissolved Fe ions
from FS media are present in the system.
As indicated by Figure 1, the system FS-DI at pH 4
has the most positive Eh of the results obtained using FS
media, and the resultant slurry is electrochemically favour-
able for the formation of hydrophobic dixanthogen spe-
cies. However, it should be noted that, at pH 4, all milling
media-water type combinations have a final Eh greater than
200 mV. Therefore, it is plausible that a combination of fac-
tors, such as the absence of dissolved salts from plant water
and the presence of dissolved Fe ions in the FS-DI system
at pH 4, leads to less entrainment in the system.
The experimental results show that the presence of dis-
solved salts in the plant water promotes water recovery but
may increase the likelihood of entrainment of minerals in
the froth phase. This is consistent with the well-known fact
that the presence of ions in a system promotes the stability
of a froth. Furthermore, the presence of dissolved Fe ions in
the FS media may enhance the selectivity of the process for
sulfide minerals. However, the analysis of grade-recovery
data is necessary to fully identify and understand the under-
lying mechanisms.
Grade-Recovery Analysis
When considering which milling media and water options
to use in a metallurgical circuit, it is essential to optimise
grade-recovery performance, cost-effectiveness, and envi-
ronmental sustainability. This section attempts to identify
the experimental conditions most favourable to achieve
the optimal. Since a mixed ore was used in this study, the
grade-recovery responses of Py and Gn are considered indi-
vidually, while at the same time investigating any galvanic
interactions between the sulfide minerals, the milling sys-
tem, and the xanthate collector added.
Fe Grade vs Recovery
Figure 3 shows the variations in Fe grade and recovery at
the different pH levels, milling media, and water types uti-
lised in the present study.
When analysing Figure 3, it is essential to note that the
recovery of Fe is directly linked to the Py component of
the composite ore as well as the Fe originating from the FS
media used in some experiments. The rejection of Fe associ-
ated with Py is of significant importance from a metallurgi-
cal standpoint since Py depression is a major objective in
many flotation operations.
Across all pHs, the Fe grade ranged from 15–24 wt.%.
At pH 4, where a higher concentration of dissolved Fe is
0
20
40
60
80
100
120
140
160
180
200
0 200 400 600 800 1000
Water recovery (g)
FS-DI
FS-5SPW
Cer-DI
Cer-5SPW
0
20
40
60
80
100
120
140
160
180
200
0 200 400 600 800 1000
Water recovery (g)
FS-DI
FS-5SPW
Cer-DI
Cer-5SPW
pH 4 pH 6 -8
Figure 2. Effect of pH control on different milling media and water type variation
Solids
recovery
(g)
Solids
recovery
(