2882 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
while maintaining a higher selectivity. This shows that for
the low copper grade tailings stream, the use of a crowder
improves the scavenging effect of the Concorde Cell.
Air-to-Pulp Ratio
The Concorde Cell operates with pressurized air. In general,
the ability to control the air flowrate into a flotation cell
allows the operator to maximize metallurgical performance
(Dahlke et al., 2004 Gorain, 2005 Yáñez et al., 2009).
Indeed, increasing the air flowrate leads to higher mass pull
and lower concentrate grade through higher entrainment
(Barbian et al., 2005 Zheng et al., 2006). It should be
noted that controlling the air flowrate allows increasing the
kinetics of the particles, but these kinetics will always reach
an asymptote and as such, increasing the flowrate indefi-
nitely will not lead to faster and better flotation (Hoang et
al., 2018 Wills &Finch, 2016). In the Concorde Cell, the
air flowrate is controlled through the so-called Air-to-Pulp
Ratio. An APR of 1 means that there is 1 m3/h of air for
1 m3/h of pulp in the feed.
For HGT and LGT, low APRs of 0,6 and 0,8 were
tested as there was a need to maintain a high grade. The
copper grade-recoveries are presented in Figure 6, the
kinetic curves in Figure 7 and the selectivity curves against
silica in Figure 8.
For both streams, the slight increase in APR provided
no difference in performance, with a possible minimal
difference in grade with lower selectivity against silica.
Recovery did not change whatsoever, and the kinetics did
not increase unlike what was expected. This could indi-
cate that the change in APR was not significant enough to
impact the flotation.
Froth Washing
The concept of wash water into the froth was developed
together with flotation columns to create a downward liq-
uid flow through the froth (Finch et al., 2007). Froth wash-
ing fulfils three functions in flotation: cleaning of the froth
(reducing the entrainment of gangue), dilution of the pulp
and breakdown of the froth for thicker froths (Farrokhpay,
2011). This is especially important when dealing with fine
and ultrafine particles, as they are more easily entrained.
HGT and LGT were tested with and without froth
washing in order to test a possible increase in grade. The
copper grade-recoveries are presented in Figure 9, the
kinetic curves in Figure 10 and the selectivity curves against
silica in Figure 11.
For the high-grade tailings stream, the addition of
froth washing has had a strong impact on the metallurgi-
cal performance, the grade is highly increased (+10%) by
sacrificing 12% of the recovery. The kinetics are heavily
slowed and yet the selectivity against silica remains identi-
cal. Investigating the rest of the data (not presented here
for length reasons) shows that the selectivity against Fe and
Mg is largely increased, which allows for the higher cop-
per grade in spite of silica. Given that chalcocite contains
79,8% Cu, the fact that 57,1% Cu was the highest grade
achievable across the test work might point to mineralogical
0
10
20
30
40
50
60
0 1 2 3 4 5 6 7 8 9
Si recovery, %
HGT
1 2
0
5
10
15
20
25
30
0 1 2 3 4 5 6 7 8
SiO2 recovery, %
LGT
2 3
Figure 5. Copper – silica recovery for HGT and LGT tests with (HGT-2 and LGT-3) and without crowder
(HGT-1 and LGT-2)
Cu
r
overy,
%
Cu
r
overy,
%
while maintaining a higher selectivity. This shows that for
the low copper grade tailings stream, the use of a crowder
improves the scavenging effect of the Concorde Cell.
Air-to-Pulp Ratio
The Concorde Cell operates with pressurized air. In general,
the ability to control the air flowrate into a flotation cell
allows the operator to maximize metallurgical performance
(Dahlke et al., 2004 Gorain, 2005 Yáñez et al., 2009).
Indeed, increasing the air flowrate leads to higher mass pull
and lower concentrate grade through higher entrainment
(Barbian et al., 2005 Zheng et al., 2006). It should be
noted that controlling the air flowrate allows increasing the
kinetics of the particles, but these kinetics will always reach
an asymptote and as such, increasing the flowrate indefi-
nitely will not lead to faster and better flotation (Hoang et
al., 2018 Wills &Finch, 2016). In the Concorde Cell, the
air flowrate is controlled through the so-called Air-to-Pulp
Ratio. An APR of 1 means that there is 1 m3/h of air for
1 m3/h of pulp in the feed.
For HGT and LGT, low APRs of 0,6 and 0,8 were
tested as there was a need to maintain a high grade. The
copper grade-recoveries are presented in Figure 6, the
kinetic curves in Figure 7 and the selectivity curves against
silica in Figure 8.
For both streams, the slight increase in APR provided
no difference in performance, with a possible minimal
difference in grade with lower selectivity against silica.
Recovery did not change whatsoever, and the kinetics did
not increase unlike what was expected. This could indi-
cate that the change in APR was not significant enough to
impact the flotation.
Froth Washing
The concept of wash water into the froth was developed
together with flotation columns to create a downward liq-
uid flow through the froth (Finch et al., 2007). Froth wash-
ing fulfils three functions in flotation: cleaning of the froth
(reducing the entrainment of gangue), dilution of the pulp
and breakdown of the froth for thicker froths (Farrokhpay,
2011). This is especially important when dealing with fine
and ultrafine particles, as they are more easily entrained.
HGT and LGT were tested with and without froth
washing in order to test a possible increase in grade. The
copper grade-recoveries are presented in Figure 9, the
kinetic curves in Figure 10 and the selectivity curves against
silica in Figure 11.
For the high-grade tailings stream, the addition of
froth washing has had a strong impact on the metallurgi-
cal performance, the grade is highly increased (+10%) by
sacrificing 12% of the recovery. The kinetics are heavily
slowed and yet the selectivity against silica remains identi-
cal. Investigating the rest of the data (not presented here
for length reasons) shows that the selectivity against Fe and
Mg is largely increased, which allows for the higher cop-
per grade in spite of silica. Given that chalcocite contains
79,8% Cu, the fact that 57,1% Cu was the highest grade
achievable across the test work might point to mineralogical
0
10
20
30
40
50
60
0 1 2 3 4 5 6 7 8 9
Si recovery, %
HGT
1 2
0
5
10
15
20
25
30
0 1 2 3 4 5 6 7 8
SiO2 recovery, %
LGT
2 3
Figure 5. Copper – silica recovery for HGT and LGT tests with (HGT-2 and LGT-3) and without crowder
(HGT-1 and LGT-2)
Cu
r
overy,
%
Cu
r
overy,
%