2242 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
and it can be seen that NBs makes the particle size of lepid-
olite particles undergo a significant increase, and the D50
changes from 10.76 to 20.42 μm. This suggests that floccu-
lation of lepidolite particles occurs in the presence of NBs.
High-speed camera tests showed flocculation of the
lepidolite after the action of NBs. Figure 8 shows the change
in state of the floc during mixing. As the mixing time
increases, the flocculated mineral particles become progres-
sively fewer, and the size of the mineral particles in the field
of view becomes smaller until more dispersed individual
particles remain. This may be due to the fact that the mix-
ing process generates a small number of bubbles (as can be
seen in Figure 9), and flocs, due to their larger particle size,
are more likely to collide and adhere to the bubbles during
mixing, and thus be carried up to the surface of the slurry.
Figure 9 demonstrates the process of a certain lepidolite
floc adhering to the bubbles and rising with them during
stirring, which proves the above speculation. In addition,
the flocculated particles may be subjected to strong shear
force under the action of stirring, and gradually dispersed
into individual particles, which float in the slurry. Figure 10
illustrates the gradual disintegration of a flocculated par-
ticle during mixing. As can be seen from Figure 10, the floc
breaks down from one part into two small pieces and then
gradually disintegrates into more fragments. In summary,
the presence of NBs causes flocculation of the lepidolite
particles, and the flocculent decreases in the slurry with stir-
ring, and he stability of flocs produced by NBs remains to
be studied in greater depth.
Effect of Flocculation on the Settling of Fine Lepidolite
The results of the sedimentation test (Figure 11) indicate a
significant increase in sedimentation distance after the addi-
tion of collectors. The effect of reagents on the sedimenta-
tion of lepidolite particles was evident, with a significant
increase in sedimentation distance observed after the addi-
tion of both HQ330 and DDA. The sedimentation effi-
ciency of lepidolite particles was found to be greater with
HQ330 than with DDA. Furthermore, the combined use
of HQ330 and DDA resulted in even greater sedimenta-
tion efficiency than when either reagent was used alone.
In all cases, the addition of NBs increased the sedimenta-
tion velocity of the lepidolite particles. The sedimentation
velocity (V) is calculated using the Stokes sedimentation
equation: V=gd2(ρ-ρ0)/18μ. This equation shows that the
sedimentation velocity is affected by the density (ρ) and
diameter (d) of the particles, as well as the density of the
water (ρ0). The addition of NBs caused the flocculation of
lepidolite, which increased its diameter and subsequently
increased the settling velocity. The settling distance may
increase with the addition of collectors due to the occur-
rence of hydrophobic flocculation of lepidolite, on which
NBs can further increase the degree or stability of hydro-
phobic flocculation.[21–23]
Effect of NBs on the Zeta Potential of Lepidolites
Based on the zeta potential test results as Figure 12, it is
evident that lepidolite has a zero electric point of less than
3. Additionally, the zeta potential of lepidolite decreases
gradually as the pH increases. After the combined collec-
tor was added, the zeta potential of lepidolite shifted nega-
tively overall, but the trend with pH remained unchanged.
Following the addition of NBs, the zeta potential of lepido-
lite decreased as the pH increased, eventually stabilizing at
pH 7. The pH did not have any further effect on the zeta
potential. Compared to the zeta potential of lepidolite with
only the addition of a collector, the zeta potential shifted
negatively in the pH range of less than 7 and positively
in the pH range greater than 7 after the addition of NBs.
This indicates a decrease in the absolute value of the zeta
Figure 8. NBs-induced flocs float and disperse during stirring
and it can be seen that NBs makes the particle size of lepid-
olite particles undergo a significant increase, and the D50
changes from 10.76 to 20.42 μm. This suggests that floccu-
lation of lepidolite particles occurs in the presence of NBs.
High-speed camera tests showed flocculation of the
lepidolite after the action of NBs. Figure 8 shows the change
in state of the floc during mixing. As the mixing time
increases, the flocculated mineral particles become progres-
sively fewer, and the size of the mineral particles in the field
of view becomes smaller until more dispersed individual
particles remain. This may be due to the fact that the mix-
ing process generates a small number of bubbles (as can be
seen in Figure 9), and flocs, due to their larger particle size,
are more likely to collide and adhere to the bubbles during
mixing, and thus be carried up to the surface of the slurry.
Figure 9 demonstrates the process of a certain lepidolite
floc adhering to the bubbles and rising with them during
stirring, which proves the above speculation. In addition,
the flocculated particles may be subjected to strong shear
force under the action of stirring, and gradually dispersed
into individual particles, which float in the slurry. Figure 10
illustrates the gradual disintegration of a flocculated par-
ticle during mixing. As can be seen from Figure 10, the floc
breaks down from one part into two small pieces and then
gradually disintegrates into more fragments. In summary,
the presence of NBs causes flocculation of the lepidolite
particles, and the flocculent decreases in the slurry with stir-
ring, and he stability of flocs produced by NBs remains to
be studied in greater depth.
Effect of Flocculation on the Settling of Fine Lepidolite
The results of the sedimentation test (Figure 11) indicate a
significant increase in sedimentation distance after the addi-
tion of collectors. The effect of reagents on the sedimenta-
tion of lepidolite particles was evident, with a significant
increase in sedimentation distance observed after the addi-
tion of both HQ330 and DDA. The sedimentation effi-
ciency of lepidolite particles was found to be greater with
HQ330 than with DDA. Furthermore, the combined use
of HQ330 and DDA resulted in even greater sedimenta-
tion efficiency than when either reagent was used alone.
In all cases, the addition of NBs increased the sedimenta-
tion velocity of the lepidolite particles. The sedimentation
velocity (V) is calculated using the Stokes sedimentation
equation: V=gd2(ρ-ρ0)/18μ. This equation shows that the
sedimentation velocity is affected by the density (ρ) and
diameter (d) of the particles, as well as the density of the
water (ρ0). The addition of NBs caused the flocculation of
lepidolite, which increased its diameter and subsequently
increased the settling velocity. The settling distance may
increase with the addition of collectors due to the occur-
rence of hydrophobic flocculation of lepidolite, on which
NBs can further increase the degree or stability of hydro-
phobic flocculation.[21–23]
Effect of NBs on the Zeta Potential of Lepidolites
Based on the zeta potential test results as Figure 12, it is
evident that lepidolite has a zero electric point of less than
3. Additionally, the zeta potential of lepidolite decreases
gradually as the pH increases. After the combined collec-
tor was added, the zeta potential of lepidolite shifted nega-
tively overall, but the trend with pH remained unchanged.
Following the addition of NBs, the zeta potential of lepido-
lite decreased as the pH increased, eventually stabilizing at
pH 7. The pH did not have any further effect on the zeta
potential. Compared to the zeta potential of lepidolite with
only the addition of a collector, the zeta potential shifted
negatively in the pH range of less than 7 and positively
in the pH range greater than 7 after the addition of NBs.
This indicates a decrease in the absolute value of the zeta
Figure 8. NBs-induced flocs float and disperse during stirring
