XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 2625
flotation has the advantages of easy control, low cost, good
selectivity and anti-breaking ability, and is widely used in
the flotation of fine minerals[10, 11]. The process is to add
collector and non-polar oil to the pulp in sequence, under
high-speed stirring, the hydrophobic fine particles form
large size agglomerates, and then the agglomerates are effi-
ciently recovered by flotation.
In this study, we investigated the effect of NaOL and
kerosene on inducing hydrophobic agglomeration of fine
cassiterite. Through the agglomeration test we found that
either NaOL alone or NaOL with kerosene can induce
hydrophobic agglomeration of fine cassiterite. Then, the
effect of the reagent on the surface potential and wettabil-
ity of cassiterite was analyzed by zeta potential and contact
angle measurements. Finally, the flotation test shown that
the agglomerates induced by adding kerosene before NaOL
can obtain the highest recovery.
Experimental
Materials
The cassiterite used in this study was came from Guangxi,
China, which was crushed, ground and sieved to –19 μm
for the experiments. The SnO2 content of the sample was
97.87%, and the d50 and d90 of the sample were 6.17 μm
and 19.32 μm, respectively. The sodium oleate (NaOL) and
kerosene used in the experiments were of analytical grade,
and all water was deionised.
Methods
The agglomeration test was carried out in a beaker with
a mechanical agitator. 1.0 g of cassiterite and 100 ml of
water were placed into a 250 mL of beaker, and the pulp
pH was adjusted to 8.0, then 40 mg/L NaOL or kerosene
were added to react for 10 min respectively. Samples were
taken for particle size analysis after the reaction. The cas-
siterite pulp after the agglomeration test was transferred to
a Hallimond tube for flotation test. The flotation test used
a peristaltic pump to inject air into the flotation tube, col-
lecting concentrate and tailings respectively after flotation
for 5 min to calculate recovery.
Characterization
The apparent particle size of the test samples was detected
by the Malvern Mastersizer 2000 particle size analyser to
determine whether the cassiterite particles were aggregated.
The Zetasizer Nano-ZS ZEN3600 was used to measure the
zeta potential of the cassiterite surface before and after the
reaction with the reagent. The contact angles were mea-
sured by a contact angle detector to analyse the change of
the surface wettability of cassiterite.
Results and Discussion
Effect of NaOL and Kerosene on the Apparent Particle
Size of Fine Cassiterite
The apparent particle size of cassiterite under different
reagent was detected to investigate the effect of NaOL and
kerosene addition method on the agglomeration behaviour
of fine cassiterite. As shown in Figure 1, when kerosene was
added alone, the d50 of cassiterite particles increased from
6.17 μm to 7.27 μm, and the d90 increased from 19.32 μm
to 23.21 μm, the particle size of cassiterite increased very
slightly. When NaOL was added alone, the d50 and d90 of
cassiterite particles increased to 15.74 μm and 75.70 μm,
respectively, indicating that NaOL can induce fine cassit-
erite agglomeration[12]. Adding kerosene after the reaction
of NaOL, the d50 and d90 of cassiterite particles further
increased to 21.95 μm and 85.50 μm, respectively. Adding
NaOL after the reaction of kerosene, the d50 and d90 of cas-
siterite particles showed the greatest increase, increasing to
27.63 μm and 92.22 μm, respectively. The results indicated
that the combination use of NaOL and kerosene can fur-
ther promote the growth of aggregates, and added kerosene
first followed by NaOL had the most significant promoting
effect.
Effect of NaOL and Kerosene on the Surface Potential
of Fine Cassiterite
The adsorption behaviour of reagent on mineral surface can
be inferred by the change of zeta potential[13]. The agglom-
eration test was carried out at pulp pH of 8.0, so the zeta
potential of cassiterite surface before and after the reaction
6.17 7.27
15.74
21.95
27.63
19.32
23.21
75.70
85.50
92.22
0
20
40
60
80
100
d
50
d90
Without
reagent
Kerosene NaOL Kerosene
+NaOL
NaOL+
Kerosene
Figure 1. Apparent particle size of cassiterite under different
reagent
flotation has the advantages of easy control, low cost, good
selectivity and anti-breaking ability, and is widely used in
the flotation of fine minerals[10, 11]. The process is to add
collector and non-polar oil to the pulp in sequence, under
high-speed stirring, the hydrophobic fine particles form
large size agglomerates, and then the agglomerates are effi-
ciently recovered by flotation.
In this study, we investigated the effect of NaOL and
kerosene on inducing hydrophobic agglomeration of fine
cassiterite. Through the agglomeration test we found that
either NaOL alone or NaOL with kerosene can induce
hydrophobic agglomeration of fine cassiterite. Then, the
effect of the reagent on the surface potential and wettabil-
ity of cassiterite was analyzed by zeta potential and contact
angle measurements. Finally, the flotation test shown that
the agglomerates induced by adding kerosene before NaOL
can obtain the highest recovery.
Experimental
Materials
The cassiterite used in this study was came from Guangxi,
China, which was crushed, ground and sieved to –19 μm
for the experiments. The SnO2 content of the sample was
97.87%, and the d50 and d90 of the sample were 6.17 μm
and 19.32 μm, respectively. The sodium oleate (NaOL) and
kerosene used in the experiments were of analytical grade,
and all water was deionised.
Methods
The agglomeration test was carried out in a beaker with
a mechanical agitator. 1.0 g of cassiterite and 100 ml of
water were placed into a 250 mL of beaker, and the pulp
pH was adjusted to 8.0, then 40 mg/L NaOL or kerosene
were added to react for 10 min respectively. Samples were
taken for particle size analysis after the reaction. The cas-
siterite pulp after the agglomeration test was transferred to
a Hallimond tube for flotation test. The flotation test used
a peristaltic pump to inject air into the flotation tube, col-
lecting concentrate and tailings respectively after flotation
for 5 min to calculate recovery.
Characterization
The apparent particle size of the test samples was detected
by the Malvern Mastersizer 2000 particle size analyser to
determine whether the cassiterite particles were aggregated.
The Zetasizer Nano-ZS ZEN3600 was used to measure the
zeta potential of the cassiterite surface before and after the
reaction with the reagent. The contact angles were mea-
sured by a contact angle detector to analyse the change of
the surface wettability of cassiterite.
Results and Discussion
Effect of NaOL and Kerosene on the Apparent Particle
Size of Fine Cassiterite
The apparent particle size of cassiterite under different
reagent was detected to investigate the effect of NaOL and
kerosene addition method on the agglomeration behaviour
of fine cassiterite. As shown in Figure 1, when kerosene was
added alone, the d50 of cassiterite particles increased from
6.17 μm to 7.27 μm, and the d90 increased from 19.32 μm
to 23.21 μm, the particle size of cassiterite increased very
slightly. When NaOL was added alone, the d50 and d90 of
cassiterite particles increased to 15.74 μm and 75.70 μm,
respectively, indicating that NaOL can induce fine cassit-
erite agglomeration[12]. Adding kerosene after the reaction
of NaOL, the d50 and d90 of cassiterite particles further
increased to 21.95 μm and 85.50 μm, respectively. Adding
NaOL after the reaction of kerosene, the d50 and d90 of cas-
siterite particles showed the greatest increase, increasing to
27.63 μm and 92.22 μm, respectively. The results indicated
that the combination use of NaOL and kerosene can fur-
ther promote the growth of aggregates, and added kerosene
first followed by NaOL had the most significant promoting
effect.
Effect of NaOL and Kerosene on the Surface Potential
of Fine Cassiterite
The adsorption behaviour of reagent on mineral surface can
be inferred by the change of zeta potential[13]. The agglom-
eration test was carried out at pulp pH of 8.0, so the zeta
potential of cassiterite surface before and after the reaction
6.17 7.27
15.74
21.95
27.63
19.32
23.21
75.70
85.50
92.22
0
20
40
60
80
100
d
50
d90
Without
reagent
Kerosene NaOL Kerosene
+NaOL
NaOL+
Kerosene
Figure 1. Apparent particle size of cassiterite under different
reagent