1810
A Novel Process of Cascade Suspension Roasting-Acid Leaching
for Vanadium Extraction from Carbonaceous Shale
Zhe Bai, Yuexin Han, Jianping Jin, Yongsheng Sun, Zhenya Zhou
School of Resources and Civil Engineering, Northeastern University, Shenyang, China
National-local Joint Engineering Research Center of High-efficient Exploitation Technology for Refractory Iron Ore
Resources, Shenyang, China
ABSTRACT: The cascade suspension roasting-acid leaching process was proposed, which was additive-free and
effectively improved the leaching efficiency with preliminary oxidation and further high-temperature reoxidation.
The best V2O5 leaching rate of roasted product reached 68.89%, which was 36.23 percent higher than that
of raw ore. It innovatively discovered that the carbonaceous shale can withstand high temperatures without
sintering after preliminary roasting. High-temperature reoxidation was the prerequisite for destroying the lattice
of vanadium-bearing minerals and promoting vanadium release. Meanwhile, the loose and porous honeycomb
particle products promoted reactions. This study provided a novel and effective method for vanadium extraction
from carbonaceous shale.
Keywords: Carbonaceous shale Gradient oxidation Fluidized roasting Vanadium Acid leaching
INTRODUCTION
Vanadium-bearing carbonaceous shale is a shale ore with
high vanadium content, which is also called Vanadium-
bearing black shale (Hu and Zhang, 2022). Its vanadium
content is generally less than 1%(Anjum et al., 2012 Yang
et al., 2018). China has the richest resources of vanadium-
bearing carbonaceous shale in the world. The composition
and properties of carbonaceous shale are complex, so the
vanadium extraction process is also complex (Liu et al.,
2021 Zou et al., 2021). Vanadium-bearing carbonaceous
shale can be roughly divided into oxidation type and pri-
mary type. V in oxidized carbonaceous shale mainly exists
as V(IV), which is easy to extract vanadium. V(III) mainly
exists in primary carbonaceous shale, which is very difficult
to extract vanadium (Yuan et al., 2016).
The current vanadium extraction processes mainly
include direct leaching and oxidation roasting-leaching
(He et al., 2022 Huang et al., 2020). Direct leaching is
widely used. It extracts vanadium from oxidized carbona-
ceous shale by acid leaching. To improve the recovery rate
of vanadium, researchers optimized the process parameters,
added leaching aids, and heated or pressurized them (Li
et al., 2023). Oxidation roasting with and without addi-
tives has been studied. The effect of various additives on
vanadium leaching has been studied, including Na2SO4,
NaCl, CaCO3, Na2CO3, CaF2, and CaO(Wang et al.,
2017 Wang et al., 2011). Additives can greatly improve
the leaching rate of vanadium. Because they destroy the lat-
tice structure of vanadium-bearing minerals and react with
them (Cai et al., 2016). However, many shortcomings of
A Novel Process of Cascade Suspension Roasting-Acid Leaching
for Vanadium Extraction from Carbonaceous Shale
Zhe Bai, Yuexin Han, Jianping Jin, Yongsheng Sun, Zhenya Zhou
School of Resources and Civil Engineering, Northeastern University, Shenyang, China
National-local Joint Engineering Research Center of High-efficient Exploitation Technology for Refractory Iron Ore
Resources, Shenyang, China
ABSTRACT: The cascade suspension roasting-acid leaching process was proposed, which was additive-free and
effectively improved the leaching efficiency with preliminary oxidation and further high-temperature reoxidation.
The best V2O5 leaching rate of roasted product reached 68.89%, which was 36.23 percent higher than that
of raw ore. It innovatively discovered that the carbonaceous shale can withstand high temperatures without
sintering after preliminary roasting. High-temperature reoxidation was the prerequisite for destroying the lattice
of vanadium-bearing minerals and promoting vanadium release. Meanwhile, the loose and porous honeycomb
particle products promoted reactions. This study provided a novel and effective method for vanadium extraction
from carbonaceous shale.
Keywords: Carbonaceous shale Gradient oxidation Fluidized roasting Vanadium Acid leaching
INTRODUCTION
Vanadium-bearing carbonaceous shale is a shale ore with
high vanadium content, which is also called Vanadium-
bearing black shale (Hu and Zhang, 2022). Its vanadium
content is generally less than 1%(Anjum et al., 2012 Yang
et al., 2018). China has the richest resources of vanadium-
bearing carbonaceous shale in the world. The composition
and properties of carbonaceous shale are complex, so the
vanadium extraction process is also complex (Liu et al.,
2021 Zou et al., 2021). Vanadium-bearing carbonaceous
shale can be roughly divided into oxidation type and pri-
mary type. V in oxidized carbonaceous shale mainly exists
as V(IV), which is easy to extract vanadium. V(III) mainly
exists in primary carbonaceous shale, which is very difficult
to extract vanadium (Yuan et al., 2016).
The current vanadium extraction processes mainly
include direct leaching and oxidation roasting-leaching
(He et al., 2022 Huang et al., 2020). Direct leaching is
widely used. It extracts vanadium from oxidized carbona-
ceous shale by acid leaching. To improve the recovery rate
of vanadium, researchers optimized the process parameters,
added leaching aids, and heated or pressurized them (Li
et al., 2023). Oxidation roasting with and without addi-
tives has been studied. The effect of various additives on
vanadium leaching has been studied, including Na2SO4,
NaCl, CaCO3, Na2CO3, CaF2, and CaO(Wang et al.,
2017 Wang et al., 2011). Additives can greatly improve
the leaching rate of vanadium. Because they destroy the lat-
tice structure of vanadium-bearing minerals and react with
them (Cai et al., 2016). However, many shortcomings of