XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 2467
condition, whereas the AECI collectors followed with the
PGE arsenides and PGE tellurides.
The data for the secondary grind rougher flotation
concentrates preferentially upgrades the PGE sulphides
(cooperite/braggite and laurite), followed by other PGE
(alloys, etc.), PGE tellurides and PGE arsenides for the
standard condition (Figure 6C). The AECI collectors on
the other hand, preferentially upgrade the PGE arsenides
followed by the PGE tellurides and other PGE (alloys, etc.)
for the SGRF 2, whereas the SGRF 3 and 4 preferentially
upgrade the PGE tellurides, followed by the PGE arsenides
(Figure 7C).
Overall, the AECI collectors evaluated show a higher
PGM (total) minerals upgrade ratio for both the primary
and secondary grind rougher flotation concentrates com-
pared to the standard (Figures 7B and C).
Grain sizes are expressed in equivalent circle diameter
(ECD), which is defined as the diameter of a circle with the
same area as the measured grain. The grains size distribu-
tion (GSD) of all the samples suggests that the PGM grains
present are fine-grained, however, some larger grains were
detected. It should be noted that these larger grains can
skew the mineralogical data as seen in the case for laurite
(Figures 7A and B). The primary grind feed showed that
the PGM grain sizes predominantly ranged between 0 and
9 μm, in terms of number %,with grains in the 0–3 μm
size class being the most abundant.
Figure 8A shows the PGE minerals GSD for the total
PGE for the primary and secondary grind rougher flota-
tion. Figures 8B, C and D show the individual data for
the three main PGE minerals species (PGE tellurides, sul-
phides and arsenides) for the primary and secondary grind
rougher flotation. The data shows that the 5.00 μm PGE
grains reporting to the concentrates are much lower in the
primary grind rougher flotation compared to the secondary
grind rougher flotation which is most likely due to libera-
tion of the fine grained PGE during the secondary grind
(Figure 8A). The same is true for the ≥5.0015.00 size class,
however, the ≥25.0050.00 and ≥50.00 size class shows a
different trend with higher amounts of these grains sizes
reporting to the primary grind rougher flotation compared
to the secondary grind flotation.
When comparing the individual PGE minerals species
(PGE tellurides, sulphides and arsenides) grain size classes,
a similar trend is observed when compared to the total
PGE minerals GSD (Figures 8B, C and D). It’s interesting
to note that the standard condition (PGRF 1 and SGRF
1) preferentially upgrades the 5.00 μm PGE sulphides
while the AECI collector conditions (PGRF 3 and SGRF
3 and SGRF 4) upgrade the 5.00 μm PGE tellurides and
PGE arsenides (Figures 8B, C and D) compared to the
standard (PGRF 1 and SGRF 1). The same is true for the
≥5.0015.00 size class for the PGE tellurides for both the
primary and secondary grind rougher flotation, whereas,
the PGE sulphides and arsenides follow a similar trend but
only for the secondary grind rougher flotation condition.
The PGE arsenides are mostly collected during the second-
ary grind rougher flotation for all size classes.
The PGM liberation data indicates that the mode of
occurrence of the PGMs in the feed to be ~38 mass %
Figure 4. (A) Ni grade-recovery curves and (B) Ni recovery-concentrate mass pull curves evaluating AECI Mining Chemicals
reagents compared to the standard reagent regime used. The dotted line represents the primary grind rougher flotation and the
solid line the secondary grind rougher flotation
condition, whereas the AECI collectors followed with the
PGE arsenides and PGE tellurides.
The data for the secondary grind rougher flotation
concentrates preferentially upgrades the PGE sulphides
(cooperite/braggite and laurite), followed by other PGE
(alloys, etc.), PGE tellurides and PGE arsenides for the
standard condition (Figure 6C). The AECI collectors on
the other hand, preferentially upgrade the PGE arsenides
followed by the PGE tellurides and other PGE (alloys, etc.)
for the SGRF 2, whereas the SGRF 3 and 4 preferentially
upgrade the PGE tellurides, followed by the PGE arsenides
(Figure 7C).
Overall, the AECI collectors evaluated show a higher
PGM (total) minerals upgrade ratio for both the primary
and secondary grind rougher flotation concentrates com-
pared to the standard (Figures 7B and C).
Grain sizes are expressed in equivalent circle diameter
(ECD), which is defined as the diameter of a circle with the
same area as the measured grain. The grains size distribu-
tion (GSD) of all the samples suggests that the PGM grains
present are fine-grained, however, some larger grains were
detected. It should be noted that these larger grains can
skew the mineralogical data as seen in the case for laurite
(Figures 7A and B). The primary grind feed showed that
the PGM grain sizes predominantly ranged between 0 and
9 μm, in terms of number %,with grains in the 0–3 μm
size class being the most abundant.
Figure 8A shows the PGE minerals GSD for the total
PGE for the primary and secondary grind rougher flota-
tion. Figures 8B, C and D show the individual data for
the three main PGE minerals species (PGE tellurides, sul-
phides and arsenides) for the primary and secondary grind
rougher flotation. The data shows that the 5.00 μm PGE
grains reporting to the concentrates are much lower in the
primary grind rougher flotation compared to the secondary
grind rougher flotation which is most likely due to libera-
tion of the fine grained PGE during the secondary grind
(Figure 8A). The same is true for the ≥5.0015.00 size class,
however, the ≥25.0050.00 and ≥50.00 size class shows a
different trend with higher amounts of these grains sizes
reporting to the primary grind rougher flotation compared
to the secondary grind flotation.
When comparing the individual PGE minerals species
(PGE tellurides, sulphides and arsenides) grain size classes,
a similar trend is observed when compared to the total
PGE minerals GSD (Figures 8B, C and D). It’s interesting
to note that the standard condition (PGRF 1 and SGRF
1) preferentially upgrades the 5.00 μm PGE sulphides
while the AECI collector conditions (PGRF 3 and SGRF
3 and SGRF 4) upgrade the 5.00 μm PGE tellurides and
PGE arsenides (Figures 8B, C and D) compared to the
standard (PGRF 1 and SGRF 1). The same is true for the
≥5.0015.00 size class for the PGE tellurides for both the
primary and secondary grind rougher flotation, whereas,
the PGE sulphides and arsenides follow a similar trend but
only for the secondary grind rougher flotation condition.
The PGE arsenides are mostly collected during the second-
ary grind rougher flotation for all size classes.
The PGM liberation data indicates that the mode of
occurrence of the PGMs in the feed to be ~38 mass %
Figure 4. (A) Ni grade-recovery curves and (B) Ni recovery-concentrate mass pull curves evaluating AECI Mining Chemicals
reagents compared to the standard reagent regime used. The dotted line represents the primary grind rougher flotation and the
solid line the secondary grind rougher flotation