2
experiments, a comprehensive mineralogical and elemental
analysis of the tailing sample was conducted. Quantitative
X-ray diffraction (XRD) inductively coupled plasma-mass
spectrometry (ICP-MS) and TESCAN integrated min-
eral analysis (TIMA) with Scanning Electron Microscopy
(SEM) were utilized for these analyses. The mineral phases
within the tailing sample were identified through quantita-
tive XRD. Concentrations of Zn, Ga and Ge were mea-
sured using the ICP-MS. Additionally, TIMA provided
valuable information about the zinc mineral liberation
and associations. Flotation studies were performed using
potassium amyl xanthate as a collector, sodium sulfide as
a sulfidizing agent, lead nitrate as an activator, and methyl
isobutyl carbinol as a frother. The sulfidizer and activator
were specifically used to activate the surface of zinc minerals
to promote the collector’s adsorption and therefore enhance
their floatability.
MATERIALS AND METHODS
Tailing Sample
The zinc tailing sample was obtained from the Tri-State
Superfund Site in the U.S. The samples were mixed,
homogenized and then divided into 2–3 kg representative
portions using a rotary splitter and riffle. Then, representa-
tive samples were dried in an oven at 60⁰C prior to charac-
terization studies.
Flotation Reagents
Potassium amyl xanthate (PAX), used as a collector, was
obtained from TCI America, U.S. Sodium sulfide (Na2S)
used as a sulfidizer reagent and methyl isobutyl carbinol
(MIBC) used as a frother were obtained from Thermo
Fisher Scientific, U.S. Lead nitrate (Pb(NO3)2) was pur-
chased from Sigma-Aldrich, U.S. and used as an activator.
All tests were performed using distilled water to avoid the
interference of dissolved species with the adsorption of flo-
tation reagents on mineral surfaces.
Quantitative X-Ray Diffraction
Quantitative X-ray diffraction (XRD) analysis was used to
characterize the mineral composition of the tailing samples
and flotation concentrates. The XRD analysis was deter-
mined using an XPERT-PRO PANAlytical diffractometer
with a PIXCel detector and CuKα radiation generated at
angular interval 2θ from 5° to 90° and a speed of 2°/min,
with Cu Kα radiation (k=0.15418 nm, X-ray tube voltage
45 kV, 40 mA) in the Materials Research Center at Missouri
S&T University. The Rietveld method was performed for
the determination of amounts of different mineral phases
in multi-phase mineral samples.
Inductively Coupled Plasma-Mass Spectrometry
Inductively coupled plasma-mass spectrometry (ICP-MS)
analyses were performed at Activation Laboratories in
Canada. The sodium peroxide fusion method was used to
measure the total concentrations of Zn, Ga, and Ge in the
different size fractions of the bulk tailing sample, flotation
concentrates, and tailings.
TESCAN Integrated Mineral Analysis
TESCAN integrated mineral analysis (TIMA) was used
for the identification of mineral locking characteristics and
degree of liberation which are important for the design of
flotation experiments. TIMA characterization studies were
carried out at Montana Technological University’s Center
for Advanced Materials Processing (CAMP). A representa-
tive bulk sample was wet sieved and then polished epoxy
mounts using sieve fraction were prepared for analysis.
Flotation Experiments
A representative tailings sample was subjected to bench-
scale froth flotation tests to evaluate the floatability of zinc
minerals, which serve as the primary potential hosts for Ga
and Ge elements.
Preliminary experiments were performed in a 1-liter
Denver cell (D12). In each test, a 400 g sample was mixed
with 900 mL of distilled water to achieve a pulp density
of 30%. The flotation experiments were carried out at
the pH~8. The pulp was mixed at an agitation speed of
1200 rpm for 2 minutes before the reagents were added.
The pulp was conditioned sequentially by the addition of
Na₂S, Pb(NO₃)₂, and PAX, with a conditioning period
of 4 minutes allocated for each reagent to allow sufficient
time for the surface of the mineral particles to react with
the reagents. Before the air was turned on, the pulp was
conditioned for 3 minutes with MIBC. The total dura-
tion of the flotation process was 7 minutes. Following the
completion of flotation, the concentrates and tailings were
dried, weighed, and subsequently analyzed using ICP-MS
to determine the recoveries of Zn, Ga, and Ge.
The types and dosages of chemical reagents utilized
in the flotation experiments are presented in Table 1. The
values were selected based on a comprehensive review of
relevant literature [8–12].
Table 1. Flotation reagents used in this study
Reagent Role Dosage
PAX Collector 70 g/t
Na2S Sulfidizing reagent 70 g/t
Pb(NO3)2 Activator 300 g/t
MIBC Frother 60 g/t
experiments, a comprehensive mineralogical and elemental
analysis of the tailing sample was conducted. Quantitative
X-ray diffraction (XRD) inductively coupled plasma-mass
spectrometry (ICP-MS) and TESCAN integrated min-
eral analysis (TIMA) with Scanning Electron Microscopy
(SEM) were utilized for these analyses. The mineral phases
within the tailing sample were identified through quantita-
tive XRD. Concentrations of Zn, Ga and Ge were mea-
sured using the ICP-MS. Additionally, TIMA provided
valuable information about the zinc mineral liberation
and associations. Flotation studies were performed using
potassium amyl xanthate as a collector, sodium sulfide as
a sulfidizing agent, lead nitrate as an activator, and methyl
isobutyl carbinol as a frother. The sulfidizer and activator
were specifically used to activate the surface of zinc minerals
to promote the collector’s adsorption and therefore enhance
their floatability.
MATERIALS AND METHODS
Tailing Sample
The zinc tailing sample was obtained from the Tri-State
Superfund Site in the U.S. The samples were mixed,
homogenized and then divided into 2–3 kg representative
portions using a rotary splitter and riffle. Then, representa-
tive samples were dried in an oven at 60⁰C prior to charac-
terization studies.
Flotation Reagents
Potassium amyl xanthate (PAX), used as a collector, was
obtained from TCI America, U.S. Sodium sulfide (Na2S)
used as a sulfidizer reagent and methyl isobutyl carbinol
(MIBC) used as a frother were obtained from Thermo
Fisher Scientific, U.S. Lead nitrate (Pb(NO3)2) was pur-
chased from Sigma-Aldrich, U.S. and used as an activator.
All tests were performed using distilled water to avoid the
interference of dissolved species with the adsorption of flo-
tation reagents on mineral surfaces.
Quantitative X-Ray Diffraction
Quantitative X-ray diffraction (XRD) analysis was used to
characterize the mineral composition of the tailing samples
and flotation concentrates. The XRD analysis was deter-
mined using an XPERT-PRO PANAlytical diffractometer
with a PIXCel detector and CuKα radiation generated at
angular interval 2θ from 5° to 90° and a speed of 2°/min,
with Cu Kα radiation (k=0.15418 nm, X-ray tube voltage
45 kV, 40 mA) in the Materials Research Center at Missouri
S&T University. The Rietveld method was performed for
the determination of amounts of different mineral phases
in multi-phase mineral samples.
Inductively Coupled Plasma-Mass Spectrometry
Inductively coupled plasma-mass spectrometry (ICP-MS)
analyses were performed at Activation Laboratories in
Canada. The sodium peroxide fusion method was used to
measure the total concentrations of Zn, Ga, and Ge in the
different size fractions of the bulk tailing sample, flotation
concentrates, and tailings.
TESCAN Integrated Mineral Analysis
TESCAN integrated mineral analysis (TIMA) was used
for the identification of mineral locking characteristics and
degree of liberation which are important for the design of
flotation experiments. TIMA characterization studies were
carried out at Montana Technological University’s Center
for Advanced Materials Processing (CAMP). A representa-
tive bulk sample was wet sieved and then polished epoxy
mounts using sieve fraction were prepared for analysis.
Flotation Experiments
A representative tailings sample was subjected to bench-
scale froth flotation tests to evaluate the floatability of zinc
minerals, which serve as the primary potential hosts for Ga
and Ge elements.
Preliminary experiments were performed in a 1-liter
Denver cell (D12). In each test, a 400 g sample was mixed
with 900 mL of distilled water to achieve a pulp density
of 30%. The flotation experiments were carried out at
the pH~8. The pulp was mixed at an agitation speed of
1200 rpm for 2 minutes before the reagents were added.
The pulp was conditioned sequentially by the addition of
Na₂S, Pb(NO₃)₂, and PAX, with a conditioning period
of 4 minutes allocated for each reagent to allow sufficient
time for the surface of the mineral particles to react with
the reagents. Before the air was turned on, the pulp was
conditioned for 3 minutes with MIBC. The total dura-
tion of the flotation process was 7 minutes. Following the
completion of flotation, the concentrates and tailings were
dried, weighed, and subsequently analyzed using ICP-MS
to determine the recoveries of Zn, Ga, and Ge.
The types and dosages of chemical reagents utilized
in the flotation experiments are presented in Table 1. The
values were selected based on a comprehensive review of
relevant literature [8–12].
Table 1. Flotation reagents used in this study
Reagent Role Dosage
PAX Collector 70 g/t
Na2S Sulfidizing reagent 70 g/t
Pb(NO3)2 Activator 300 g/t
MIBC Frother 60 g/t