1272 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
copper refining. Although nearly undetectable in Bingham
Canyon ore, in 2019 through advances in analytical tech-
niques, we were able to measure sufficient concentrations of
Te in the ore to begin construction of a Te circuit. In 2021,
Rio Tinto invested $2.9 million to build a Te recovery cir-
cuit (Figure 4) for extracting this valuable mineral from the
waste streams.
Through innovation and implementation of new
processes, Rio Tinto established one of only two domes-
tic value streams for producing copper telluride, essential
to the manufacturing of ultra-high purity semiconductor
materials and thin film photovoltaic solar panels. The cir-
cuit is designed to produce roughly 20 tonnes of Te as cop-
per telluride per year, contributing approximately 5% of
U.S. annual production and a new North American supply
for this critical mineral. New efforts are underway to fur-
ther increase annual Te production targets.
Before the Te circuit was built, waste from electrore-
fining copper was treated with reagents and sent for dis-
posal. Now, after the copper ore is smelted and refined, the
extracted slimes are processed through the Te circuit. First,
the solution is moved into a reactor where it is heated and
agitated in the presence of copper chips. The solution is
then cooled and filtered to produce copper telluride. The
copper telluride product is then sent to 5N Plus, a global
semiconductor manufacturer, for conversion to cadmium
telluride and refinement before being returned to Utah and
First Solar, a global photovoltaic company, for domestic
production of solar panels.
Rhenium
Rhenium (Re) is an important strategic metal in a class
of high-performance alloys known as “superalloys.” These
alloys are resistant to oxidation and creep at extreme tem-
peratures, rendering them ideal for fabrication into turbine
blades for jet engines or steam turbine generators.
In Bingham Canyon ore, Re is known to be present
in molybdenite, some of which is recovered in the final
copper concentrate that feeds the smelter. Rhenium in the
concentrate is volatilized in the flash-smelting furnace, with
most of it captured in the gas scrubbers. In 2009, Rio Tinto
invested $5.5 million to build a recovery plant to capture
the Re.
The recovery plant uses continuous ion exchange
(CIX) technology to recover and concentrate Re from the
scrubber acid plant blowdown (APB). This APB requires
pre-treatment before it is suitable for CIX. Pretreatments
include removal of dissolved selenium, which would co-
extract, and filtration to remove suspended solids. The
treated APB is pumped through a series of resin columns
that extract the Re selectively. The loaded columns are then
subjected to an automated regeneration sequence that pro-
duces a concentrated solution of sodium perrhenate, and
then returns the eluted columns to the loading, or recovery,
Figure 4. Rio Tinto process for recovery and production of copper-telluride as a copper production co-product
copper refining. Although nearly undetectable in Bingham
Canyon ore, in 2019 through advances in analytical tech-
niques, we were able to measure sufficient concentrations of
Te in the ore to begin construction of a Te circuit. In 2021,
Rio Tinto invested $2.9 million to build a Te recovery cir-
cuit (Figure 4) for extracting this valuable mineral from the
waste streams.
Through innovation and implementation of new
processes, Rio Tinto established one of only two domes-
tic value streams for producing copper telluride, essential
to the manufacturing of ultra-high purity semiconductor
materials and thin film photovoltaic solar panels. The cir-
cuit is designed to produce roughly 20 tonnes of Te as cop-
per telluride per year, contributing approximately 5% of
U.S. annual production and a new North American supply
for this critical mineral. New efforts are underway to fur-
ther increase annual Te production targets.
Before the Te circuit was built, waste from electrore-
fining copper was treated with reagents and sent for dis-
posal. Now, after the copper ore is smelted and refined, the
extracted slimes are processed through the Te circuit. First,
the solution is moved into a reactor where it is heated and
agitated in the presence of copper chips. The solution is
then cooled and filtered to produce copper telluride. The
copper telluride product is then sent to 5N Plus, a global
semiconductor manufacturer, for conversion to cadmium
telluride and refinement before being returned to Utah and
First Solar, a global photovoltaic company, for domestic
production of solar panels.
Rhenium
Rhenium (Re) is an important strategic metal in a class
of high-performance alloys known as “superalloys.” These
alloys are resistant to oxidation and creep at extreme tem-
peratures, rendering them ideal for fabrication into turbine
blades for jet engines or steam turbine generators.
In Bingham Canyon ore, Re is known to be present
in molybdenite, some of which is recovered in the final
copper concentrate that feeds the smelter. Rhenium in the
concentrate is volatilized in the flash-smelting furnace, with
most of it captured in the gas scrubbers. In 2009, Rio Tinto
invested $5.5 million to build a recovery plant to capture
the Re.
The recovery plant uses continuous ion exchange
(CIX) technology to recover and concentrate Re from the
scrubber acid plant blowdown (APB). This APB requires
pre-treatment before it is suitable for CIX. Pretreatments
include removal of dissolved selenium, which would co-
extract, and filtration to remove suspended solids. The
treated APB is pumped through a series of resin columns
that extract the Re selectively. The loaded columns are then
subjected to an automated regeneration sequence that pro-
duces a concentrated solution of sodium perrhenate, and
then returns the eluted columns to the loading, or recovery,
Figure 4. Rio Tinto process for recovery and production of copper-telluride as a copper production co-product