1620 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
peaks of muscovite in the leaching residues in these two
systems are weaker than that in the raw vanadium-bear-
ing shale, which is more obvious in the UAL process. The
results imply that the destruction of structure of muscovite
is more serious in the UAL system, which is beneficial for
the release of the vanadium (Xue et al., 2020). It is worth
noting that there are no pyrite phases detected in the UAL
residues, indicating that Fe(II) in pyrite is also been oxi-
dized and entered into the leachate as Fe(III) with the com-
bination of ultrasound and NaClO3.
Particle Size Distribution of Vanadium-Bearing Shale
The particle size differential distribution of the leaching
residues collected from CL and UAL process are displayed
in Figure 7. As is observed from Figure 7, the distribution
percentage in the particle size range of [0.11, 9.98] μm for
the UAL residues is slightly higher than that for the CL
residues. Nevertheless, the distribution percentage in the
particle size range of [11.11, 76.33] μm for the UAL resi-
dues is obviously lower than that for the CL residues. In
particular, the Characteristic particle size of D10, D50 and
D90 for the UAL residues is apparently smaller than that for
the CL residues. The results imply that the ultrasound will
induce the breaking of the vanadium-bearing shale particles
(Li et al., 2018), which in turn intensify the leaching reac-
tion of vanadium.
Microstructure Transformation of Vanadium-Bearing
Shale
The microstructure of these two leaching residues obtained
from CL and UAL process were comparatively observed
by SEM-EDS, the outcome is shown in Figure 8. From
Figure 8(a) and (d), it is apparent that the particles in the
UAL residues are more uniform with fine size than that for
the CL residues, and the agglomeration between particles is
serious in the CL residues. In the meanwhile, the particles
in the CL residues are dense (Figure 8(b)), which is incon-
ducive to the diffusion of the lixiviant. On the contrary,
there are lots of holes and cracks on the surface of
the particles in the UAL residues after ultrasound treatment
(Figure 8(e)) (Zhang et al., 2016), which is conducive to
the dissolution of the vanadium-bearing muscovite. From
Figure 4. Effect of leaching time on the leaching ratio of vanadium (NaClO
3 dosage of 9 wt.%,
H
2 SO
4 concentration of 20 vol.%, leaching temperature of 95°C, ultrasound power of 150 W,
liquid to solid ratio of 3:1 mL/g)
Table 2. Fitting parameters of the leaching kinetics of vanadium by SCM model
Leaching Systems
R2
kp, min–1 Product Diffusion Chemical Rection Mixed
CL 0.99 0.97 0.92 5.8×10–4
UAL 0.99 0.91 0.93 2.89×10–3
peaks of muscovite in the leaching residues in these two
systems are weaker than that in the raw vanadium-bear-
ing shale, which is more obvious in the UAL process. The
results imply that the destruction of structure of muscovite
is more serious in the UAL system, which is beneficial for
the release of the vanadium (Xue et al., 2020). It is worth
noting that there are no pyrite phases detected in the UAL
residues, indicating that Fe(II) in pyrite is also been oxi-
dized and entered into the leachate as Fe(III) with the com-
bination of ultrasound and NaClO3.
Particle Size Distribution of Vanadium-Bearing Shale
The particle size differential distribution of the leaching
residues collected from CL and UAL process are displayed
in Figure 7. As is observed from Figure 7, the distribution
percentage in the particle size range of [0.11, 9.98] μm for
the UAL residues is slightly higher than that for the CL
residues. Nevertheless, the distribution percentage in the
particle size range of [11.11, 76.33] μm for the UAL resi-
dues is obviously lower than that for the CL residues. In
particular, the Characteristic particle size of D10, D50 and
D90 for the UAL residues is apparently smaller than that for
the CL residues. The results imply that the ultrasound will
induce the breaking of the vanadium-bearing shale particles
(Li et al., 2018), which in turn intensify the leaching reac-
tion of vanadium.
Microstructure Transformation of Vanadium-Bearing
Shale
The microstructure of these two leaching residues obtained
from CL and UAL process were comparatively observed
by SEM-EDS, the outcome is shown in Figure 8. From
Figure 8(a) and (d), it is apparent that the particles in the
UAL residues are more uniform with fine size than that for
the CL residues, and the agglomeration between particles is
serious in the CL residues. In the meanwhile, the particles
in the CL residues are dense (Figure 8(b)), which is incon-
ducive to the diffusion of the lixiviant. On the contrary,
there are lots of holes and cracks on the surface of
the particles in the UAL residues after ultrasound treatment
(Figure 8(e)) (Zhang et al., 2016), which is conducive to
the dissolution of the vanadium-bearing muscovite. From
Figure 4. Effect of leaching time on the leaching ratio of vanadium (NaClO
3 dosage of 9 wt.%,
H
2 SO
4 concentration of 20 vol.%, leaching temperature of 95°C, ultrasound power of 150 W,
liquid to solid ratio of 3:1 mL/g)
Table 2. Fitting parameters of the leaching kinetics of vanadium by SCM model
Leaching Systems
R2
kp, min–1 Product Diffusion Chemical Rection Mixed
CL 0.99 0.97 0.92 5.8×10–4
UAL 0.99 0.91 0.93 2.89×10–3