7
The XRD analyses for flotation feed and concentrate
are given in Table 6. Based on the quantitative XRD anal-
ysis, it was observed that sphalerite and hemimorphite
were effectively recovered in the –212+38 µm particle size
range, while the feed material primarily consisted of quartz
and calcite. Additionally, hemimorphite was present in
higher concentration in the concentrate derived from the
–75+38 µm size fraction, further emphasizing its selective
flotation in this size range.
CONCLUSIONS
This study involved comprehensive mineralogical and ele-
mental analyses to characterize the Tri-State tailings, focus-
ing on the potential enrichment of zinc minerals that may
host Ga and Ge. According to the quantitative XRD results
performed at different size ranges, zinc minerals detected in
the tailing sample were sphalerite (1%) and hemimorphite
(0.8%). For a detailed mineralogical analysis of tailings,
TIMA focused specifically on particles finer than 75 µm,
wherein the concentration of Zn was high. The main zinc
minerals identified by TIMA were hemimorphite (2.27%),
sphalerite (1.19%), and smithsonite (0.83%). The gangue
minerals were predominantly silicates, making up 76%,
with quartz comprising 75% and phyllosilicates accounting
for 1%. Carbonates constituted 16%, with dolomite and
calcite being the primary carbonate minerals. TIMA dem-
onstrated that the liberation of hemimorphite and smith-
sonite significantly improved as particle size decreased. In
contrast, sphalerite showed a decline in liberation with
decreased particle size. Moreover, it was observed that zinc
minerals were mainly locked in quartz particles.
Preliminary flotation experiments were conducted
to examine the bulk flotation of zinc minerals both with
and without the use of an activator and sulfidizing agent,
across different size fractions. For the size fractions of
–180+125 µm and –125+75 µm, no significant difference
in the recoveries and grades of Zn, Ga, and Ge was observed
when neither the activator nor the sulfidizing agent was
used. However, for the –212+38 µm and –75+38 µm par-
ticle size ranges, higher recoveries of Zn, Ga, and Ge were
achieved when the activator and sulfidizing agent were
included in the flotation process. future research will focus
on improving recoveries through optimization studies,
including the selection and dosage of reagents, as well as a
deeper exploration of the fundamental flotation chemistry
of Ga and Ge-bearing zinc minerals in the tailing sample.
In conclusion, the recovery of Ga and Ge from tailings
presents a viable and promising strategy for sourcing these
critical elements, addressing the growing demand for them
in advanced technological applications.
ACKNOWLEDGMENTS
The research team would like to acknowledge the
Critical Materials Innovation Hub for sponsoring this
study. The research was funded by the Critical Materials
Innovation Hub, USA, under Grant #AL‑12-350-001.
Researchers would also like to thank the Quapaw Nation
Environmental Office for their assistance with sample col-
lection. Additionally, we appreciate the support of Actlabs
technical staff, Gary F. Wyss from Montana Tech and Eric
Bohannan from Missouri S&T for their contributions to
the elemental and mineralogical analyses.
REFERENCES
[1] U.S. Department of Energy. (2023). Critical mate-
rials assessment 2023. Office of Energy Efficiency
&Renewable Energy. Retrieved from https://www
.energy.gov/eere.
[2] U.S. Geological Survey. (2023). Mineral commodity
summaries 2023. U.S. Department of the Interior.
Retrieved from https://pubs.usgs.gov/periodicals
/mcs2023/.
[3] Schulz, K. J., DeYoung, J. H., Jr., Seal, R. R., II,
&Bradley, D. C. (Eds.). (2017). Critical mineral
resources of the United States—Economic and envi-
ronmental geology and prospects for future supply
(U.S. Geological Survey Professional Paper 1802).
U.S. Geological Survey.
[4] Sverdrup, H.U., Ragnarsdottir, K.V., Koca, D., 2017.
An assessment of metal supply sustainability as an
input to policy: security of supply extraction rates,
stock-in-use, recycling, and risk of scarcity. J. Clean.
Prod. 140, 359–372.
Table 6. The mineral phases identified using quantitative
XRD analysis for flotation feed and concentrate at -particle
sizes of 212+38 µm and –75+38 µm
–212+38 µm –75+38 µm
Feed Concentrate Feed Concentrate
Quartz
(97.8%)
Quartz
(79%)
Quartz
(83.8%)
Quartz
(73.1%)
Calcite
(2.2%)
Calcite
(8.6%)
Calcite
(7.3%)
Calcite
(3%)
— Dolomite
(6%)
Dolomite
(8.6%)
Dolomite
(11.1%)
— Sphalerite
(3.3%)
Sphalerite
(0.3%)
Pyrite
(6.8%)
— Hemimorphite
(3.1%)
— Hemimorphite
(6%)
The XRD analyses for flotation feed and concentrate
are given in Table 6. Based on the quantitative XRD anal-
ysis, it was observed that sphalerite and hemimorphite
were effectively recovered in the –212+38 µm particle size
range, while the feed material primarily consisted of quartz
and calcite. Additionally, hemimorphite was present in
higher concentration in the concentrate derived from the
–75+38 µm size fraction, further emphasizing its selective
flotation in this size range.
CONCLUSIONS
This study involved comprehensive mineralogical and ele-
mental analyses to characterize the Tri-State tailings, focus-
ing on the potential enrichment of zinc minerals that may
host Ga and Ge. According to the quantitative XRD results
performed at different size ranges, zinc minerals detected in
the tailing sample were sphalerite (1%) and hemimorphite
(0.8%). For a detailed mineralogical analysis of tailings,
TIMA focused specifically on particles finer than 75 µm,
wherein the concentration of Zn was high. The main zinc
minerals identified by TIMA were hemimorphite (2.27%),
sphalerite (1.19%), and smithsonite (0.83%). The gangue
minerals were predominantly silicates, making up 76%,
with quartz comprising 75% and phyllosilicates accounting
for 1%. Carbonates constituted 16%, with dolomite and
calcite being the primary carbonate minerals. TIMA dem-
onstrated that the liberation of hemimorphite and smith-
sonite significantly improved as particle size decreased. In
contrast, sphalerite showed a decline in liberation with
decreased particle size. Moreover, it was observed that zinc
minerals were mainly locked in quartz particles.
Preliminary flotation experiments were conducted
to examine the bulk flotation of zinc minerals both with
and without the use of an activator and sulfidizing agent,
across different size fractions. For the size fractions of
–180+125 µm and –125+75 µm, no significant difference
in the recoveries and grades of Zn, Ga, and Ge was observed
when neither the activator nor the sulfidizing agent was
used. However, for the –212+38 µm and –75+38 µm par-
ticle size ranges, higher recoveries of Zn, Ga, and Ge were
achieved when the activator and sulfidizing agent were
included in the flotation process. future research will focus
on improving recoveries through optimization studies,
including the selection and dosage of reagents, as well as a
deeper exploration of the fundamental flotation chemistry
of Ga and Ge-bearing zinc minerals in the tailing sample.
In conclusion, the recovery of Ga and Ge from tailings
presents a viable and promising strategy for sourcing these
critical elements, addressing the growing demand for them
in advanced technological applications.
ACKNOWLEDGMENTS
The research team would like to acknowledge the
Critical Materials Innovation Hub for sponsoring this
study. The research was funded by the Critical Materials
Innovation Hub, USA, under Grant #AL‑12-350-001.
Researchers would also like to thank the Quapaw Nation
Environmental Office for their assistance with sample col-
lection. Additionally, we appreciate the support of Actlabs
technical staff, Gary F. Wyss from Montana Tech and Eric
Bohannan from Missouri S&T for their contributions to
the elemental and mineralogical analyses.
REFERENCES
[1] U.S. Department of Energy. (2023). Critical mate-
rials assessment 2023. Office of Energy Efficiency
&Renewable Energy. Retrieved from https://www
.energy.gov/eere.
[2] U.S. Geological Survey. (2023). Mineral commodity
summaries 2023. U.S. Department of the Interior.
Retrieved from https://pubs.usgs.gov/periodicals
/mcs2023/.
[3] Schulz, K. J., DeYoung, J. H., Jr., Seal, R. R., II,
&Bradley, D. C. (Eds.). (2017). Critical mineral
resources of the United States—Economic and envi-
ronmental geology and prospects for future supply
(U.S. Geological Survey Professional Paper 1802).
U.S. Geological Survey.
[4] Sverdrup, H.U., Ragnarsdottir, K.V., Koca, D., 2017.
An assessment of metal supply sustainability as an
input to policy: security of supply extraction rates,
stock-in-use, recycling, and risk of scarcity. J. Clean.
Prod. 140, 359–372.
Table 6. The mineral phases identified using quantitative
XRD analysis for flotation feed and concentrate at -particle
sizes of 212+38 µm and –75+38 µm
–212+38 µm –75+38 µm
Feed Concentrate Feed Concentrate
Quartz
(97.8%)
Quartz
(79%)
Quartz
(83.8%)
Quartz
(73.1%)
Calcite
(2.2%)
Calcite
(8.6%)
Calcite
(7.3%)
Calcite
(3%)
— Dolomite
(6%)
Dolomite
(8.6%)
Dolomite
(11.1%)
— Sphalerite
(3.3%)
Sphalerite
(0.3%)
Pyrite
(6.8%)
— Hemimorphite
(3.1%)
— Hemimorphite
(6%)