1204 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
Leaching of Telluride Flotation Concentrates
Leaching of telluride concentrates to produce tellurium
ingots was conducted at the Emperor Mine in Fiji (Cornwall
&Hisshion, 1976). The treatment circuit included a chem-
ical oxidation stage utilising an alkaline hypochlorite leach
to oxidise the telluride minerals followed by cyanidation to
extract the gold. The now solid tellurium oxide was then
leached with sodium sulphide followed by precipitation of
elemental tellurium using sodium sulphite.
Other options to extract tellurium from gold tellurides
would include roasting in air as gold tellurides readily oxi-
dise to form tellurium dioxide (Padmanaban &Lawson,
1991). Dust losses, incomplete oxidation due to locking in
sulphides and the generation of sulphur dioxide has led to
the preference for leaching circuits (Deschênes et al., 2005).
One option for leaching of low tonnage telluride con-
centrates is intensive cyanidation as used for gravity recov-
erable gold concentrates. Intensive cyanidation units can
include a leach catalyst and have been successful in extract-
ing gold from gold tellurides (Fullam et al., 2016). If an
operation has an existing intensive cyanidation reactor,
there may be the opportunity to combine the low tonnage
telluride concentrate with the gravity gold concentrate. An
additional stage to extract tellurium from the reactor tailing
would need to be developed and implemented.
Tailings Retreatment
The flotation of tailings is also a potential source of tellu-
rium. At the Wright-Hargreaves Mine in Northern Ontario
after treatment with cyanide and lime, the leached tailings
were processed through a flotation stage to scavenge for tel-
luride minerals that had not leached (Singh, 1956). This
indicates that the natural floatability of telluride minerals
may not be affected by cyanide leaching. Recovery of tel-
luride minerals from tailings storage facilities or processing
of leach tailings to recover telluride material may be a viable
future option.
The recovery of tellurium as tellurium oxide from
tailings storage facilities also presents an opportunity to
increase tellurium supply. The oxidation of gold telluride
minerals such as calaverite (AuTe2) recrystallises gold as
gold filaments (Zhao et al., 2009 Zhao &Pring, 2019)
releasing tellurium in solution which then precipitates as
TeO2 (Deschênes et al., 2006 Dyer et al., 2017). Flotation
of TeO2 requires further investigation to determine if a via-
ble treatment route is possible.
CONCLUSIONS
Tellurium is largely produced as a byproduct and tellurium
production is dependent on copper production. Gold tellu-
ride deposits represent a potential source of tellurium from
existing operations.
Co-extraction of tellurium from gold ores is a feasible
option via two processing routes for the same environmen-
tal footprint as gold alone. Both circuits incorporate flota-
tion as the method of separation.
Sequential flotation produces a separate telluride con-
centrate prior to sulphide flotation. This process is capital
intensive as it requires treatment of the entire flotation feed
stream. Potential benefits may include the ability to treat
refractory carbonaceous and copper ores.
Reverse flotation involves the separation of a telluride
concentrate from a bulk concentrate whilst depressing
pyrite. This option is attractive to existing concentrators as it
would be less capital intensive and be able to be retrofitted.
The production of a separate low tonnage telluride
concentrate presents the opportunity to reduce operating
costs by enabling the leaching of the sulphide concentrate
at lower pH values in lower quality water (hypersaline).
This reduces the operating costs by reduced consumption
of lime, cyanide, oxygen and potable water.
Extraction of tellurium from telluride concentrates
may be viable using existing intensive leaching reactors.
There may be unrealised opportunities to recover tel-
lurium from leach tailings and through reprocessing stored
tailings.
ACKNOWLEDGMENTS
The author gratefully acknowledges support from the
Australian Government Research Training Program,
Minerals Research Institute of Western Australia Scholarship
Program and the AusIMM Education Endowment Fund
Postgraduate Scholarship.
REFERENCES
Adams, W.G. (1876). II. On the action of light on tellu-
rium and selenium. Proceedings of the Royal Society of
London, 24(164–170), 163–164.
Agorhom, E.A., Skinner, W., &Zanin, M. (2015).
Post-regrind selective depression of pyrite in pyritic
copper–gold flotation using aeration and diethylenetri-
amine. Minerals Engineering, 72, 36–46. doi: 10.1016
/j.mineng.2014.11.019.
Anderson, S.C. (2022). USGS 2018 Minerals Yearbook
Selenium and Tellurium (Advance Release). USGS.
Leaching of Telluride Flotation Concentrates
Leaching of telluride concentrates to produce tellurium
ingots was conducted at the Emperor Mine in Fiji (Cornwall
&Hisshion, 1976). The treatment circuit included a chem-
ical oxidation stage utilising an alkaline hypochlorite leach
to oxidise the telluride minerals followed by cyanidation to
extract the gold. The now solid tellurium oxide was then
leached with sodium sulphide followed by precipitation of
elemental tellurium using sodium sulphite.
Other options to extract tellurium from gold tellurides
would include roasting in air as gold tellurides readily oxi-
dise to form tellurium dioxide (Padmanaban &Lawson,
1991). Dust losses, incomplete oxidation due to locking in
sulphides and the generation of sulphur dioxide has led to
the preference for leaching circuits (Deschênes et al., 2005).
One option for leaching of low tonnage telluride con-
centrates is intensive cyanidation as used for gravity recov-
erable gold concentrates. Intensive cyanidation units can
include a leach catalyst and have been successful in extract-
ing gold from gold tellurides (Fullam et al., 2016). If an
operation has an existing intensive cyanidation reactor,
there may be the opportunity to combine the low tonnage
telluride concentrate with the gravity gold concentrate. An
additional stage to extract tellurium from the reactor tailing
would need to be developed and implemented.
Tailings Retreatment
The flotation of tailings is also a potential source of tellu-
rium. At the Wright-Hargreaves Mine in Northern Ontario
after treatment with cyanide and lime, the leached tailings
were processed through a flotation stage to scavenge for tel-
luride minerals that had not leached (Singh, 1956). This
indicates that the natural floatability of telluride minerals
may not be affected by cyanide leaching. Recovery of tel-
luride minerals from tailings storage facilities or processing
of leach tailings to recover telluride material may be a viable
future option.
The recovery of tellurium as tellurium oxide from
tailings storage facilities also presents an opportunity to
increase tellurium supply. The oxidation of gold telluride
minerals such as calaverite (AuTe2) recrystallises gold as
gold filaments (Zhao et al., 2009 Zhao &Pring, 2019)
releasing tellurium in solution which then precipitates as
TeO2 (Deschênes et al., 2006 Dyer et al., 2017). Flotation
of TeO2 requires further investigation to determine if a via-
ble treatment route is possible.
CONCLUSIONS
Tellurium is largely produced as a byproduct and tellurium
production is dependent on copper production. Gold tellu-
ride deposits represent a potential source of tellurium from
existing operations.
Co-extraction of tellurium from gold ores is a feasible
option via two processing routes for the same environmen-
tal footprint as gold alone. Both circuits incorporate flota-
tion as the method of separation.
Sequential flotation produces a separate telluride con-
centrate prior to sulphide flotation. This process is capital
intensive as it requires treatment of the entire flotation feed
stream. Potential benefits may include the ability to treat
refractory carbonaceous and copper ores.
Reverse flotation involves the separation of a telluride
concentrate from a bulk concentrate whilst depressing
pyrite. This option is attractive to existing concentrators as it
would be less capital intensive and be able to be retrofitted.
The production of a separate low tonnage telluride
concentrate presents the opportunity to reduce operating
costs by enabling the leaching of the sulphide concentrate
at lower pH values in lower quality water (hypersaline).
This reduces the operating costs by reduced consumption
of lime, cyanide, oxygen and potable water.
Extraction of tellurium from telluride concentrates
may be viable using existing intensive leaching reactors.
There may be unrealised opportunities to recover tel-
lurium from leach tailings and through reprocessing stored
tailings.
ACKNOWLEDGMENTS
The author gratefully acknowledges support from the
Australian Government Research Training Program,
Minerals Research Institute of Western Australia Scholarship
Program and the AusIMM Education Endowment Fund
Postgraduate Scholarship.
REFERENCES
Adams, W.G. (1876). II. On the action of light on tellu-
rium and selenium. Proceedings of the Royal Society of
London, 24(164–170), 163–164.
Agorhom, E.A., Skinner, W., &Zanin, M. (2015).
Post-regrind selective depression of pyrite in pyritic
copper–gold flotation using aeration and diethylenetri-
amine. Minerals Engineering, 72, 36–46. doi: 10.1016
/j.mineng.2014.11.019.
Anderson, S.C. (2022). USGS 2018 Minerals Yearbook
Selenium and Tellurium (Advance Release). USGS.