8
replacement (EDRR) technique has recently gained atten-
tion for the recovery of Te with lower concentrations.
Rhee et al. [52] outlined a process for the extraction
of Te including leaching, precipitation, and electrowinning
stages. Initially, more than 95% of the Te was recovered
in the form of TeO32– in alkaline leaching solution, while
the remaining impurities, such as Cu and Pb, were primar-
ily precipitated using Na2S. Subsequently, nearly 99.9% of
the Te was recovered through electrowinning from the rela-
tively purified pregnant solution. The cathodic and anodic
reactions within the electrowinning of Te in an alkaline
solution were stated as follows: pH of 14, temperature of
25°C, TeO32– concentration of 1 mol/L, and oxygen pres-
sure of 1 atm):
Cathode: TeO32–(aq) +3H2O(aq) +4e– Te(s)
+6OH–(aq) E° =–0.413 V (6)
Anode: 4OH–(aq)– 4e– ↔ 2H2O(aq)
+O2(g) E° =0.401 V (7)
To address the limitations associated with high reagent
dosage and low recovery efficiency in traditional methods,
Jin et al. [68] introduced an innovative and effective elec-
trochemical extraction technique for Te and Cu from HCl
solutions using stainless steel electrodes. The high mobility
of Te in HCl solutions led to favorable electrodeposition
behavior of Te (IV) based on both thermodynamic and
kinetic considerations.
The conventional electrolytic extraction process
involved an initial Te concentration of 100–300 g/L and a
current density of 50–60 A m2, yielding a current efficiency
of 70–80% over a period of approximately 25 days [69].
Various efforts have been carried out towards the develop-
ment of novel electrowinning methods. Cyclone electro-
winning has been invented to effectively recover Te from
electrolytes with substantially lower concentrations and
higher impurity levels. Cyclone electrowinning achieves
efficient electrowinning by facilitating high-speed liquid
injection, increasing mass transfer near the electrode sur-
face, and enhancing current density [70].
A number of research studies have concentrated on
the recovery of Te from aqueous solutions using cyclone
electrowinning. One of these studies, conducted by Jin et
al. [68], successfully produced fine Te powder from a HCl
system including 2 g/L Te, with a cathode current effi-
ciency of only 84.3%. Another study, conducted by Xu et
al. [70], demonstrated that the efficient electro-deposition
of 99.94% pure Te from a sodium tellurite alkaline solution
with a current efficiency of 95.25%. The Te concentration
in the solution was notably high at 100 g·L–1, and the solu-
tion contained almost no impurities.
Tian et al. [69] primarily examined the utilization of
cyclone electrowinning to extract Te from alkaline solu-
tions. Their findings indicated that optimal conditions
involved an electrolysis time of 24 hours, a current den-
sity of 60 Am2, and an electrolyte flow speed of 300 Lh–1.
Approximately 82.89% of Te was extracted with a purity of
99.90% and a current efficiency of 95.61%. The results of
the pilot-scale experiments indicated that Te was achieved
with a purity of 99.99% with a current efficiency of 97.1%
[71]. Nonetheless, some challenges persist in the practi-
cal application of cyclone electrowinning, including issues
concerning test conditions and equipment for large scale
production.
CONCLUSIONS AND
RECOMMENDATIONS FOR
FUTURE RESEARCH
The demand for tellurium (Te) is on the rise due to its
extensive applications ranging from traditional metallurgy
to emerging electronics. The disparity between the limited
reserves and yield of Te and the growing market demand
underscores the need for the development of highly effi-
cient and large-scale recovery technologies. The recovery of
Te from tailings and metallurgical wastes of copper sulfide
processing holds promise in offsetting a significant portion
of primary Te extraction, thus helping to alleviate poten-
tial supply risks in the future. This comprehensive review
offered insights into recent advancements in Te recovery
from these resources and indicated a heightened focus on
research endeavors aimed at devising effective recovery
technologies. Given that currently over 90% of the global
Te supply originates from anode slimes, a byproduct of
copper electrorefining, various promising hydrometallurgy
techniques that are commonly utilized for Te recovery, were
discussed in this review including leaching, precipitation,
and electrolysis. Successful extraction of Te can be achieved
from both acidic and alkaline solutions. Despite their
reduced energy consumption and diminished air pollu-
tion, the proposed methods are still plagued by prolonged
processes, elevated equipment corrosion, and challenging
liquid-solid separation. Efforts are underway to enhance
leaching efficiency and selectivity through the utilization
of eco-friendly oxidants, the incorporation of organic sol-
vents and resins, and the optimization of effective param-
eters. Overall, efficient Te recovery mandates the creation
of environmentally sustainable, economically feasible, fully
integrated, and logistically streamlined recovery flowsheets.
This goal can only be realized by integrating the benefits
replacement (EDRR) technique has recently gained atten-
tion for the recovery of Te with lower concentrations.
Rhee et al. [52] outlined a process for the extraction
of Te including leaching, precipitation, and electrowinning
stages. Initially, more than 95% of the Te was recovered
in the form of TeO32– in alkaline leaching solution, while
the remaining impurities, such as Cu and Pb, were primar-
ily precipitated using Na2S. Subsequently, nearly 99.9% of
the Te was recovered through electrowinning from the rela-
tively purified pregnant solution. The cathodic and anodic
reactions within the electrowinning of Te in an alkaline
solution were stated as follows: pH of 14, temperature of
25°C, TeO32– concentration of 1 mol/L, and oxygen pres-
sure of 1 atm):
Cathode: TeO32–(aq) +3H2O(aq) +4e– Te(s)
+6OH–(aq) E° =–0.413 V (6)
Anode: 4OH–(aq)– 4e– ↔ 2H2O(aq)
+O2(g) E° =0.401 V (7)
To address the limitations associated with high reagent
dosage and low recovery efficiency in traditional methods,
Jin et al. [68] introduced an innovative and effective elec-
trochemical extraction technique for Te and Cu from HCl
solutions using stainless steel electrodes. The high mobility
of Te in HCl solutions led to favorable electrodeposition
behavior of Te (IV) based on both thermodynamic and
kinetic considerations.
The conventional electrolytic extraction process
involved an initial Te concentration of 100–300 g/L and a
current density of 50–60 A m2, yielding a current efficiency
of 70–80% over a period of approximately 25 days [69].
Various efforts have been carried out towards the develop-
ment of novel electrowinning methods. Cyclone electro-
winning has been invented to effectively recover Te from
electrolytes with substantially lower concentrations and
higher impurity levels. Cyclone electrowinning achieves
efficient electrowinning by facilitating high-speed liquid
injection, increasing mass transfer near the electrode sur-
face, and enhancing current density [70].
A number of research studies have concentrated on
the recovery of Te from aqueous solutions using cyclone
electrowinning. One of these studies, conducted by Jin et
al. [68], successfully produced fine Te powder from a HCl
system including 2 g/L Te, with a cathode current effi-
ciency of only 84.3%. Another study, conducted by Xu et
al. [70], demonstrated that the efficient electro-deposition
of 99.94% pure Te from a sodium tellurite alkaline solution
with a current efficiency of 95.25%. The Te concentration
in the solution was notably high at 100 g·L–1, and the solu-
tion contained almost no impurities.
Tian et al. [69] primarily examined the utilization of
cyclone electrowinning to extract Te from alkaline solu-
tions. Their findings indicated that optimal conditions
involved an electrolysis time of 24 hours, a current den-
sity of 60 Am2, and an electrolyte flow speed of 300 Lh–1.
Approximately 82.89% of Te was extracted with a purity of
99.90% and a current efficiency of 95.61%. The results of
the pilot-scale experiments indicated that Te was achieved
with a purity of 99.99% with a current efficiency of 97.1%
[71]. Nonetheless, some challenges persist in the practi-
cal application of cyclone electrowinning, including issues
concerning test conditions and equipment for large scale
production.
CONCLUSIONS AND
RECOMMENDATIONS FOR
FUTURE RESEARCH
The demand for tellurium (Te) is on the rise due to its
extensive applications ranging from traditional metallurgy
to emerging electronics. The disparity between the limited
reserves and yield of Te and the growing market demand
underscores the need for the development of highly effi-
cient and large-scale recovery technologies. The recovery of
Te from tailings and metallurgical wastes of copper sulfide
processing holds promise in offsetting a significant portion
of primary Te extraction, thus helping to alleviate poten-
tial supply risks in the future. This comprehensive review
offered insights into recent advancements in Te recovery
from these resources and indicated a heightened focus on
research endeavors aimed at devising effective recovery
technologies. Given that currently over 90% of the global
Te supply originates from anode slimes, a byproduct of
copper electrorefining, various promising hydrometallurgy
techniques that are commonly utilized for Te recovery, were
discussed in this review including leaching, precipitation,
and electrolysis. Successful extraction of Te can be achieved
from both acidic and alkaline solutions. Despite their
reduced energy consumption and diminished air pollu-
tion, the proposed methods are still plagued by prolonged
processes, elevated equipment corrosion, and challenging
liquid-solid separation. Efforts are underway to enhance
leaching efficiency and selectivity through the utilization
of eco-friendly oxidants, the incorporation of organic sol-
vents and resins, and the optimization of effective param-
eters. Overall, efficient Te recovery mandates the creation
of environmentally sustainable, economically feasible, fully
integrated, and logistically streamlined recovery flowsheets.
This goal can only be realized by integrating the benefits