2842 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
The funnels were positioned at the same distance from
the top of the tank (36 mm), in the pulp-froth interface, as
shown in Figure 3. Since the different designs had different
volumes, the effective volume of the tank was different for
each case. To account for this, the volume of pulp used on
each test was calculated to maintain the pulp level constant,
with a froth depth of 35 mm.
Materials and Reagents
Single-Species System
Glass beads were used as the only solids in the single-specie
three-phase system. Deionised water was used to prepare
the pulp. This single-species system has been used before
due to its stability and simplicity (Mesa et al., 2020 Norori-
McCormac et al., 2017). In this type of system, recovery is
estimated using solid mass pull (Jameson, 2010 Norori-
McCormac et al., 2017), while the grade is estimated using
solid content by weight as a proxy (Norori-McCormac et
al., 2017).
A 30% solid content pulp was prepared with glass
beads of two particle size classes: a coarse fraction (–150 µm
+75 µm) sourced from Hodge Clemco Ltd, and a fine frac-
tion (–20 µm), provided by SwarcoForce. Dowfroth 250
(DF250, provided by Nasaco) was the frother used for all
the experiments, added at an initial dosage of 4 µl of frother
per litre of water (4 ppm in volume). The collector used was
Tetradecyltrimethylammonium bromide (TTAB, provided
by Sig-ma Aldrich), added at an initial dosage of 4 g/t and
continuous replacement at a rate of 2 g/t per hour.
Synthetic Two-Species System
A synthetic two-species ore was created, combining 5%w/w
chalcopyrite and 95%w/w glass beads. High-purity chal-
copyrite samples from Ward’s Science were crushed and
ground in a close circuit with 100% under 150 µm, and
a P80 between 90 µm and 100 µm. The 95%w/w glass
bead gangue was composed of 66.5%w/w coarse material
(–150 µm +75 µm) and 28.5%w/w fine material (–20 µm),
as shown in Figure 4.
Potassium amyl xanthate (PAX, supplied by Flottec
LLC) was used as a collector, at a concentration of 50 g/t
of synthetic ore. Dowfroth 250 (Nasaco International Ltd.)
was the frother used, added at an initial dosage of 6 ppm
by volume, with a re-dose of 2 ppm per hour. All operating
conditions are summarised in Table 1.
Experimental Procedure
Experiments were performed using the single-species sys-
tems to quantify the effect of funnel retrofit designs on froth
stability, quantified in terms of air recovery, and defined the
optimal operating conditions for the two-species system.
Randomised tests were performed varying Jg between 0.66,
0.98 and 1.31 cm/s (10, 15 and 20 lpm, respectively) mea-
suring air recovery. Each airflow was repeated three times
on each run, with duplicated runs for each design. The
optimal airflow in terms of air recovery was then selected
for metallurgical testing using the synthetic chalcopyrite-
glass system.
Concentrate samples were obtained in triplicate for
each case in the two-species system and analysed in terms
Figure 2. Schematic of the rotor system used (left), and its position on the tank, fitted with a
stator (right)
The funnels were positioned at the same distance from
the top of the tank (36 mm), in the pulp-froth interface, as
shown in Figure 3. Since the different designs had different
volumes, the effective volume of the tank was different for
each case. To account for this, the volume of pulp used on
each test was calculated to maintain the pulp level constant,
with a froth depth of 35 mm.
Materials and Reagents
Single-Species System
Glass beads were used as the only solids in the single-specie
three-phase system. Deionised water was used to prepare
the pulp. This single-species system has been used before
due to its stability and simplicity (Mesa et al., 2020 Norori-
McCormac et al., 2017). In this type of system, recovery is
estimated using solid mass pull (Jameson, 2010 Norori-
McCormac et al., 2017), while the grade is estimated using
solid content by weight as a proxy (Norori-McCormac et
al., 2017).
A 30% solid content pulp was prepared with glass
beads of two particle size classes: a coarse fraction (–150 µm
+75 µm) sourced from Hodge Clemco Ltd, and a fine frac-
tion (–20 µm), provided by SwarcoForce. Dowfroth 250
(DF250, provided by Nasaco) was the frother used for all
the experiments, added at an initial dosage of 4 µl of frother
per litre of water (4 ppm in volume). The collector used was
Tetradecyltrimethylammonium bromide (TTAB, provided
by Sig-ma Aldrich), added at an initial dosage of 4 g/t and
continuous replacement at a rate of 2 g/t per hour.
Synthetic Two-Species System
A synthetic two-species ore was created, combining 5%w/w
chalcopyrite and 95%w/w glass beads. High-purity chal-
copyrite samples from Ward’s Science were crushed and
ground in a close circuit with 100% under 150 µm, and
a P80 between 90 µm and 100 µm. The 95%w/w glass
bead gangue was composed of 66.5%w/w coarse material
(–150 µm +75 µm) and 28.5%w/w fine material (–20 µm),
as shown in Figure 4.
Potassium amyl xanthate (PAX, supplied by Flottec
LLC) was used as a collector, at a concentration of 50 g/t
of synthetic ore. Dowfroth 250 (Nasaco International Ltd.)
was the frother used, added at an initial dosage of 6 ppm
by volume, with a re-dose of 2 ppm per hour. All operating
conditions are summarised in Table 1.
Experimental Procedure
Experiments were performed using the single-species sys-
tems to quantify the effect of funnel retrofit designs on froth
stability, quantified in terms of air recovery, and defined the
optimal operating conditions for the two-species system.
Randomised tests were performed varying Jg between 0.66,
0.98 and 1.31 cm/s (10, 15 and 20 lpm, respectively) mea-
suring air recovery. Each airflow was repeated three times
on each run, with duplicated runs for each design. The
optimal airflow in terms of air recovery was then selected
for metallurgical testing using the synthetic chalcopyrite-
glass system.
Concentrate samples were obtained in triplicate for
each case in the two-species system and analysed in terms
Figure 2. Schematic of the rotor system used (left), and its position on the tank, fitted with a
stator (right)