1276 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
Ge and most of it seems to be reporting to the smelter
streams. Here concentration reach around 20 ppm for Ge
and slightly higher values for In and Ga concentrations
in the downstream processing stream across concentrator,
smelter and refinery reach around 20 ppm. Indium and Ga
occur in similar concentration and appear to concentrate in
similar streams.
Complex leaching and separation chemistry for each
of the elements and different process streams require dif-
ferent processing approaches. We are therefore prioritizing
streams with elements that are prospective targets based
on their concentration, stream tonnage, extraction effort,
price, and strategic factors.
Despite its relatively low concentration, Ge’s low global
supply, high value of typically 1000 $/kg (Statista Research
Department 2024) and its strategic significance makes it an
attractive target for recovery. Figure 9 shows that Ge is pres-
ent in similar concentration in various streams general mill
tailings as well as mechanical scavenger tails show higher
concentrations. However, these are considerable amounts of
material that would need substantial investment in process-
ing facilities to separate and enrich Ge. Due to their signifi-
cantly lower annual volume, flash smelting and converting
furnaces (FSF and FCF) waste heat boiler and electrostatic
separator (ESP) dusts as well as slag have been identified as
prospective target streams. Combined these streams have
the potential to deliver several tons of Ge per year.
Germanium containing FSF and FCF dusts are
an attractive target due to their low volume and lim-
ited pre-processing requirements. In addition, RTKC
Hydrometallurgical plant already has water and acid leach
processing infrastructure in place to leach FSF ESP dusts.
González, Font, Moreno et al. (2016) achieved 100% recov-
ery of Ge using a water leaching approach on FSF dusts.
While the ore characteristics in the Chilean flue dust used
in their study are likely different from Bingham Canyon
ore, this indicates that Ge might be associated with highly
soluble minerals. Several other leaching studies have dem-
onstrated Ge leachability with various lixiviants including
sulfuric acid (H2SO4) (Drzazga, Prajsnar, Chmielarz et al.,
2018), Oxalic Acid (C2H2O4) (Arroyo, Font, Chimenos
et al., 2014), Nitric acid (HNO3) (Potysz and Kierczak
2019). Therefore, we are investigating different lixiviants
that could prove viable for other streams such as slag, offer
better selectivity, or co-dissolution of In and Ga. We are
currently investigating effective leaching conditions for
dust and slag waste streams with various partners including
Missouri University of Science &Technology and Arcadis.
We are also actively investigating possible extraction
solutions including solvent extraction and ion exchange
methods. Ion exchange could be a promising option due
to its relatively low implementation effort. There are sev-
eral studies that have shown the efficacy of commercial ion
exchange resins to selectively extract Ge (Nguyen and Lee
2021). A possible location within the current flowsheet
Figure 9. Concentration of indium, gallium, and germanium across different process locations
Ge and most of it seems to be reporting to the smelter
streams. Here concentration reach around 20 ppm for Ge
and slightly higher values for In and Ga concentrations
in the downstream processing stream across concentrator,
smelter and refinery reach around 20 ppm. Indium and Ga
occur in similar concentration and appear to concentrate in
similar streams.
Complex leaching and separation chemistry for each
of the elements and different process streams require dif-
ferent processing approaches. We are therefore prioritizing
streams with elements that are prospective targets based
on their concentration, stream tonnage, extraction effort,
price, and strategic factors.
Despite its relatively low concentration, Ge’s low global
supply, high value of typically 1000 $/kg (Statista Research
Department 2024) and its strategic significance makes it an
attractive target for recovery. Figure 9 shows that Ge is pres-
ent in similar concentration in various streams general mill
tailings as well as mechanical scavenger tails show higher
concentrations. However, these are considerable amounts of
material that would need substantial investment in process-
ing facilities to separate and enrich Ge. Due to their signifi-
cantly lower annual volume, flash smelting and converting
furnaces (FSF and FCF) waste heat boiler and electrostatic
separator (ESP) dusts as well as slag have been identified as
prospective target streams. Combined these streams have
the potential to deliver several tons of Ge per year.
Germanium containing FSF and FCF dusts are
an attractive target due to their low volume and lim-
ited pre-processing requirements. In addition, RTKC
Hydrometallurgical plant already has water and acid leach
processing infrastructure in place to leach FSF ESP dusts.
González, Font, Moreno et al. (2016) achieved 100% recov-
ery of Ge using a water leaching approach on FSF dusts.
While the ore characteristics in the Chilean flue dust used
in their study are likely different from Bingham Canyon
ore, this indicates that Ge might be associated with highly
soluble minerals. Several other leaching studies have dem-
onstrated Ge leachability with various lixiviants including
sulfuric acid (H2SO4) (Drzazga, Prajsnar, Chmielarz et al.,
2018), Oxalic Acid (C2H2O4) (Arroyo, Font, Chimenos
et al., 2014), Nitric acid (HNO3) (Potysz and Kierczak
2019). Therefore, we are investigating different lixiviants
that could prove viable for other streams such as slag, offer
better selectivity, or co-dissolution of In and Ga. We are
currently investigating effective leaching conditions for
dust and slag waste streams with various partners including
Missouri University of Science &Technology and Arcadis.
We are also actively investigating possible extraction
solutions including solvent extraction and ion exchange
methods. Ion exchange could be a promising option due
to its relatively low implementation effort. There are sev-
eral studies that have shown the efficacy of commercial ion
exchange resins to selectively extract Ge (Nguyen and Lee
2021). A possible location within the current flowsheet
Figure 9. Concentration of indium, gallium, and germanium across different process locations