1804 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
78.31% (L: S=3:1), and 76.75% (L: S=5:1), respectively,
while it of feed ores were 59.13% (L: S=1.5:1), 55.32% (L:
S=3:1), and 51.19% (L: S=5:1), respectively. It indicated
that the leaching efficiency of vanadium can be accelerated
by properly increasing the liquid-solid ratio at the initial
stage of the reaction. However, with the extension of time,
the decline rate of acid concentration in the leaching solu-
tion will accelerate with the increase of liquid-solid ratio
and lead to the decrease of leaching efficiency(Xue and
Zhang and Liu et al., 2017).
Analysis of Leaching Residues
Phase Transformation
The phase transformation during the acid process was
studied by XRD, and the samples were leaching residues
with a leaching time of 6 h, a liquid-solid ratio of 1.5:1,
and different sulfuric acid dosages. The acid dosage has a
great influence on the phase transformation of feed ore in
the leaching process. When the concentrate was 20 wt.%,
some peaks (yellow area in Figure 8(a)) of muscovite which
was the main vanadium-bearing mineral with a strong dif-
fraction peak intensity. It indicated that the muscovite lat-
tice structure is not obviously damaged. Vanadium atoms
with the substitute of Al(III) with isomorphic cannot be
released from the lattice and result in low vanadium leach-
ing efficiency. The diffraction peak intensity of muscovite
decreased when the acid dosage increased to 30 wt.%. It
demonstrated that high acid dosage can effectively destroy
muscovite lattices. With the dosage increased, the diffrac-
tion peak of limonite disappeared gradually, and no hema-
tite peak (green area in Figure 8(a)). It was speculated that
the high acid concentration in the leaching solution led to
a large amount of iron dissolution. In addition, the calcite
diffraction peak disappeared during the leaching process
(blue area in Figure 8(c)). Calcite reacted with sulfuric acid
and generated CO2 gas. In the process of CO2 escaping, a
foam layer (as shown in Figure 8(b)) is formed on the pulp
surface that is difficult to eliminate. The foam prevented
air from entering the leaching system and further hindered
the oxidation of vanadium. Thus, the vanadium extraction
effect and production continuity were poor.
In the suspension oxidation roasting process, the peaks
of muscovite, limonite, and calcite disappeared. It was
indicated that the lattices were destroyed before leaching.
Vanadium was released from the lattice, which was ben-
eficial to the leaching process. The intensity of the hema-
tite diffraction peak did not decrease with the increase in
acid dosage during the leaching process. It shows that the
Figure 7. The effect of liquid-solid ratio on vanadium leaching efficiency
78.31% (L: S=3:1), and 76.75% (L: S=5:1), respectively,
while it of feed ores were 59.13% (L: S=1.5:1), 55.32% (L:
S=3:1), and 51.19% (L: S=5:1), respectively. It indicated
that the leaching efficiency of vanadium can be accelerated
by properly increasing the liquid-solid ratio at the initial
stage of the reaction. However, with the extension of time,
the decline rate of acid concentration in the leaching solu-
tion will accelerate with the increase of liquid-solid ratio
and lead to the decrease of leaching efficiency(Xue and
Zhang and Liu et al., 2017).
Analysis of Leaching Residues
Phase Transformation
The phase transformation during the acid process was
studied by XRD, and the samples were leaching residues
with a leaching time of 6 h, a liquid-solid ratio of 1.5:1,
and different sulfuric acid dosages. The acid dosage has a
great influence on the phase transformation of feed ore in
the leaching process. When the concentrate was 20 wt.%,
some peaks (yellow area in Figure 8(a)) of muscovite which
was the main vanadium-bearing mineral with a strong dif-
fraction peak intensity. It indicated that the muscovite lat-
tice structure is not obviously damaged. Vanadium atoms
with the substitute of Al(III) with isomorphic cannot be
released from the lattice and result in low vanadium leach-
ing efficiency. The diffraction peak intensity of muscovite
decreased when the acid dosage increased to 30 wt.%. It
demonstrated that high acid dosage can effectively destroy
muscovite lattices. With the dosage increased, the diffrac-
tion peak of limonite disappeared gradually, and no hema-
tite peak (green area in Figure 8(a)). It was speculated that
the high acid concentration in the leaching solution led to
a large amount of iron dissolution. In addition, the calcite
diffraction peak disappeared during the leaching process
(blue area in Figure 8(c)). Calcite reacted with sulfuric acid
and generated CO2 gas. In the process of CO2 escaping, a
foam layer (as shown in Figure 8(b)) is formed on the pulp
surface that is difficult to eliminate. The foam prevented
air from entering the leaching system and further hindered
the oxidation of vanadium. Thus, the vanadium extraction
effect and production continuity were poor.
In the suspension oxidation roasting process, the peaks
of muscovite, limonite, and calcite disappeared. It was
indicated that the lattices were destroyed before leaching.
Vanadium was released from the lattice, which was ben-
eficial to the leaching process. The intensity of the hema-
tite diffraction peak did not decrease with the increase in
acid dosage during the leaching process. It shows that the
Figure 7. The effect of liquid-solid ratio on vanadium leaching efficiency