XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 949
in the froth phase using the following relationship (Park et
al., 2018),
exp^-axh R d2,t
d2,b
f =[6]
and
.46n
d
d
J t
h 0 .5
g c
f f
2,t
2,b
0
=oG =expe- [7]
In Eqs. [6] and [7], d2,b and d2,t represent the bubble sizes
at the base and top of a froth phase, respectively, nf the
number of faces of a bubble rupturing during coalescence,
hf the froth height, tc is the critical rupture time of a lamella
film varies with the contact angles of the particles in froth
phase.
Substituting Eq. [6] into the following relationship
(Finch and Dobby, 1990),
k k R
p f =[8]
one can determine the flotation rate constant (k) for the
pulp and froth phase recovery steps combined in a flotation
cell.
Note here that Eq. [6] does not include the froth phase
recovery due to entrainment, which has been given by
Huang et al., (2022).
RESULTS
Laboratory Tests Using Super Collector
Laboratory flotation tests were conducted on a low-grade
porphyry copper ore sample assaying ~0.3%Cu. In each
test, 1,000 g sample (–10 mesh) was wet-ground in a rod
mill for 10 min to d80 =280 µm. In control tests, the mill
products were floated in a 2-L Denver cell with 40–100
g/t potassium amyl xanthate (KAX) as collector and methyl
isobutyl carbinol (MIBC) as frother. All tests were con-
ducted for 5 min at 1,000 r.p.m. while taking timed-cut
samples at 1, 3, and 5 min. The water contact angles (θ)
measured on polished chalcopyrite specimens were in the
range of 65–75°. In comparison tests, a Super Collector
(SC) was added to the cell after a 2-min conditioning time
with 50 g/t KAX, which further increased θ to the 150–
160° range.
Figure 1 shows the results of the flotation tests con-
ducted on the porphyry copper ore samples that had been
ground to d80 =280 µm in a rod mill. The size-by-size recov-
eries obtained after the 5-min flotation time obtained using
KAX and Super Collector did not appear to show substan-
tial improvements. However, using SC showed significant
benefits with the flotation of coarse and fine particles (see
Figure 1a). On the other hand, the grade vs. recovery curves
plotted in Figure 1b showed substantial benefits of using
SC. As shown, the use of SC substantially improved the
selectivity, which can be attributed to the large increase in
contact angles. The reason that the size-by-size recoveries
did not show significant differences was because the flota-
tion tests were conducted at a high energy dissipation rate (
f) at a long flotation time (5 min). As is well known, flota-
tion rates increase with increasing f due to increased Z12
(see Eq, [2]).
CIRCUIT SIMULATION
Using the model summarily presented in this communica-
tion, a flotation circuit has been simulated with and with-
out using SC. Further details of the model equations and
Figure 1. a) Size-by-size recovery and b) grade vs. recovery curves obtained in lab tests using SC and KAX as collectors
in the froth phase using the following relationship (Park et
al., 2018),
exp^-axh R d2,t
d2,b
f =[6]
and
.46n
d
d
J t
h 0 .5
g c
f f
2,t
2,b
0
=oG =expe- [7]
In Eqs. [6] and [7], d2,b and d2,t represent the bubble sizes
at the base and top of a froth phase, respectively, nf the
number of faces of a bubble rupturing during coalescence,
hf the froth height, tc is the critical rupture time of a lamella
film varies with the contact angles of the particles in froth
phase.
Substituting Eq. [6] into the following relationship
(Finch and Dobby, 1990),
k k R
p f =[8]
one can determine the flotation rate constant (k) for the
pulp and froth phase recovery steps combined in a flotation
cell.
Note here that Eq. [6] does not include the froth phase
recovery due to entrainment, which has been given by
Huang et al., (2022).
RESULTS
Laboratory Tests Using Super Collector
Laboratory flotation tests were conducted on a low-grade
porphyry copper ore sample assaying ~0.3%Cu. In each
test, 1,000 g sample (–10 mesh) was wet-ground in a rod
mill for 10 min to d80 =280 µm. In control tests, the mill
products were floated in a 2-L Denver cell with 40–100
g/t potassium amyl xanthate (KAX) as collector and methyl
isobutyl carbinol (MIBC) as frother. All tests were con-
ducted for 5 min at 1,000 r.p.m. while taking timed-cut
samples at 1, 3, and 5 min. The water contact angles (θ)
measured on polished chalcopyrite specimens were in the
range of 65–75°. In comparison tests, a Super Collector
(SC) was added to the cell after a 2-min conditioning time
with 50 g/t KAX, which further increased θ to the 150–
160° range.
Figure 1 shows the results of the flotation tests con-
ducted on the porphyry copper ore samples that had been
ground to d80 =280 µm in a rod mill. The size-by-size recov-
eries obtained after the 5-min flotation time obtained using
KAX and Super Collector did not appear to show substan-
tial improvements. However, using SC showed significant
benefits with the flotation of coarse and fine particles (see
Figure 1a). On the other hand, the grade vs. recovery curves
plotted in Figure 1b showed substantial benefits of using
SC. As shown, the use of SC substantially improved the
selectivity, which can be attributed to the large increase in
contact angles. The reason that the size-by-size recoveries
did not show significant differences was because the flota-
tion tests were conducted at a high energy dissipation rate (
f) at a long flotation time (5 min). As is well known, flota-
tion rates increase with increasing f due to increased Z12
(see Eq, [2]).
CIRCUIT SIMULATION
Using the model summarily presented in this communica-
tion, a flotation circuit has been simulated with and with-
out using SC. Further details of the model equations and
Figure 1. a) Size-by-size recovery and b) grade vs. recovery curves obtained in lab tests using SC and KAX as collectors