XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 2365
FLOTATION TESTS
Batch Flotation Tests
The batch flotation tests were performed using a mechani-
cal flotation cell (Agitair-type 1.75 L flotation cell). After
the conditioning for agglomeration, the slurry was kept
agitated by an impeller at 900 rpm. Methyl isobutyl carbi-
nol (MIBC) was added as frother, and 5 L/min of air was
introduced for flotation. The froth was recovered at 1, 3, 5,
and 10 min and dried in an oven at 90°C for more than 12
h. The dried froth samples were analyzed by AAS to obtain
copper grade. The flotation results were analyzed using the
following equation based on the first-order kinetic model
(Sutherland 1948):
R R e
max =--kit ^th ^1 h
where R(t) is the recovery, Rmax is the maximum recovery,
ki is the flotation rate constant, t is the flotation time. This
equation was fitted to the flotation data using the least
squares method, and the maximum recovery Rmax and the
flotation rate constant ki were calculated and evaluated.
Continuous flotation tests
The continuous flotation tests were carried out with the
conditions in Table 6. “Fine sample” and water were added
into a conditioning tank, and agglomeration conditioning
(Table 5) was conducted. The slurry was transferred into
the upper part of column cell by using a peristaltic pump.
The residence time of the slurry in a column cell was set by
changing the slurry flow rate. The froth and tailing samples
continuously produced were sampled into measuring cylin-
ders at a predetermined time, and the slurry volumes were
recorded to calculate the volumetric flow rates. Both sam-
ples were dried in an oven, and the weight of dried samples
were recorded to calculate the solid flow rates. The dried
samples were analyzed by AAS to obtain copper grade, and
the copper recovery was calculated. The calculated data
were analyzed using following equation (Wills 2016):
R Rmax k
kix
1
i
)d x =+^th n
where R(t) is the recovery, Rmax is the maximum recovery,
ki is the flotation rate constant, τ is the residence time. This
equation was fitted to the flotation data using the least
squares method, and the maximum recovery Rmax and the
flotation rate constant ki were calculated and evaluated.
RESULTS AND DISCUSSIONS
Agglomeration Tests
Agglomeration tests were conducted for the fine sample,
and the effects of collector dosage and pulp density on par-
ticle size (D80) were investigated (Figures 1(i) and (ii)). As
shown in Figure 1(i), particle size (D80) increased drasti-
cally when collector dosage increased: when comparing
the agglomerate size with dispersed particle size, the par-
ticle size of the agglomerate with 2000 g/t of collector was
over 2 times of that for dispersed particles, and it became
about 3 times with 4,000 g/t of collector. This indicates
that the increase in particle surface hydrophobicity induced
by adsorption of collector on the surface is an important
factor for agglomeration. As shown in Figure 1(ii), the par-
ticle size also increased with increasing pulp density, while
the effect was limited. Even at the maximum pulp density
(15 wt%), the value of D80 of agglomerate was less than
two times of that for dispersed particles.
These results can be explained by the effect of the
potential energy of the particle surface (i.e., the hydropho-
bicity) and the pulp density on agglomeration (Takamori
1985). On the other hand, the limited effect of increasing
pulp density on agglomeration might be because the basic
condition of 100 g/t of collector was insufficient for the
surface hydrophobicity to agglomerate. This was indicated
by the result that the effect of condition of 100 g/t of col-
lector on the particle size was not significant, as shown in
Figures 1(i).
Figure 2 (i), (ii), and (iii) shows the effects of carrier par-
ticle (coarse sample) addition on the volumetric frequency
of the dispersed and agglomerated particle size. As shown
in Figure 2(i), when comparing the results for dispersed
particles and agglomerated particles, the frequency of the
fine particles become slightly lower, and the frequency of
coarse particles become slightly larger for agglomerates.
This may be because of the attachment of fine particles to
course particles. These agglomeration by the carrier particle
can be indicated as according to the reports of Chia and
Somasundaran 1983, Valderrama and Rubio 1998 and
Ateşok et al. 2001. On the other hand, when increasing
the carrier particle to fine particle ratio, there were no clear
Table 6. The continuous flotation tests’ conditions
Flotation
Cell Type
Compact Lab Column
(Eriez Manufacturing Co.)
Cell size 5.3 L
Cell height 2.0 m
Cell diameter 52 mm (2 inch)
Air flow rate 0.80 L/min
Froth depth 21 cm
Flow rate at tailing automatically adjust froth depth to 21 cm
Residence time 5, 15, 30, 45 min
Frother dosage 15 ppm
FLOTATION TESTS
Batch Flotation Tests
The batch flotation tests were performed using a mechani-
cal flotation cell (Agitair-type 1.75 L flotation cell). After
the conditioning for agglomeration, the slurry was kept
agitated by an impeller at 900 rpm. Methyl isobutyl carbi-
nol (MIBC) was added as frother, and 5 L/min of air was
introduced for flotation. The froth was recovered at 1, 3, 5,
and 10 min and dried in an oven at 90°C for more than 12
h. The dried froth samples were analyzed by AAS to obtain
copper grade. The flotation results were analyzed using the
following equation based on the first-order kinetic model
(Sutherland 1948):
R R e
max =--kit ^th ^1 h
where R(t) is the recovery, Rmax is the maximum recovery,
ki is the flotation rate constant, t is the flotation time. This
equation was fitted to the flotation data using the least
squares method, and the maximum recovery Rmax and the
flotation rate constant ki were calculated and evaluated.
Continuous flotation tests
The continuous flotation tests were carried out with the
conditions in Table 6. “Fine sample” and water were added
into a conditioning tank, and agglomeration conditioning
(Table 5) was conducted. The slurry was transferred into
the upper part of column cell by using a peristaltic pump.
The residence time of the slurry in a column cell was set by
changing the slurry flow rate. The froth and tailing samples
continuously produced were sampled into measuring cylin-
ders at a predetermined time, and the slurry volumes were
recorded to calculate the volumetric flow rates. Both sam-
ples were dried in an oven, and the weight of dried samples
were recorded to calculate the solid flow rates. The dried
samples were analyzed by AAS to obtain copper grade, and
the copper recovery was calculated. The calculated data
were analyzed using following equation (Wills 2016):
R Rmax k
kix
1
i
)d x =+^th n
where R(t) is the recovery, Rmax is the maximum recovery,
ki is the flotation rate constant, τ is the residence time. This
equation was fitted to the flotation data using the least
squares method, and the maximum recovery Rmax and the
flotation rate constant ki were calculated and evaluated.
RESULTS AND DISCUSSIONS
Agglomeration Tests
Agglomeration tests were conducted for the fine sample,
and the effects of collector dosage and pulp density on par-
ticle size (D80) were investigated (Figures 1(i) and (ii)). As
shown in Figure 1(i), particle size (D80) increased drasti-
cally when collector dosage increased: when comparing
the agglomerate size with dispersed particle size, the par-
ticle size of the agglomerate with 2000 g/t of collector was
over 2 times of that for dispersed particles, and it became
about 3 times with 4,000 g/t of collector. This indicates
that the increase in particle surface hydrophobicity induced
by adsorption of collector on the surface is an important
factor for agglomeration. As shown in Figure 1(ii), the par-
ticle size also increased with increasing pulp density, while
the effect was limited. Even at the maximum pulp density
(15 wt%), the value of D80 of agglomerate was less than
two times of that for dispersed particles.
These results can be explained by the effect of the
potential energy of the particle surface (i.e., the hydropho-
bicity) and the pulp density on agglomeration (Takamori
1985). On the other hand, the limited effect of increasing
pulp density on agglomeration might be because the basic
condition of 100 g/t of collector was insufficient for the
surface hydrophobicity to agglomerate. This was indicated
by the result that the effect of condition of 100 g/t of col-
lector on the particle size was not significant, as shown in
Figures 1(i).
Figure 2 (i), (ii), and (iii) shows the effects of carrier par-
ticle (coarse sample) addition on the volumetric frequency
of the dispersed and agglomerated particle size. As shown
in Figure 2(i), when comparing the results for dispersed
particles and agglomerated particles, the frequency of the
fine particles become slightly lower, and the frequency of
coarse particles become slightly larger for agglomerates.
This may be because of the attachment of fine particles to
course particles. These agglomeration by the carrier particle
can be indicated as according to the reports of Chia and
Somasundaran 1983, Valderrama and Rubio 1998 and
Ateşok et al. 2001. On the other hand, when increasing
the carrier particle to fine particle ratio, there were no clear
Table 6. The continuous flotation tests’ conditions
Flotation
Cell Type
Compact Lab Column
(Eriez Manufacturing Co.)
Cell size 5.3 L
Cell height 2.0 m
Cell diameter 52 mm (2 inch)
Air flow rate 0.80 L/min
Froth depth 21 cm
Flow rate at tailing automatically adjust froth depth to 21 cm
Residence time 5, 15, 30, 45 min
Frother dosage 15 ppm