3
with the 1L cell and the 2-7/8 in. diameter impeller attach-
ment. These experiments were performed using procedures
published in the literature for similar systems[30,31]. The
flotation feed (P80 =135µm, P50 =42 µm) was prepared in
tap water at 30 wt.% solids. The prepared slurry was agi-
tated at 900 RPM for 3 mins. The slurry’s pH was modified
to pH 9 using NaOH. The frother’s dosage was fixed at 50
g/t for all experiments. Table 1 shows the parameters and
conditions used in this set of feasibility experiments. The
experiments were performed with pH conditioning, fol-
lowed by collector addition, and lastly, the frother at the
specified dosages.
Concentrates were collected over 5 min. of flotation
time. The concentrate and tailing products were dried,
weighed, and assayed using ICP-MS. Recovery was calcu-
lated using Equation 1.
**R^% c Tth
Cc 100 element or compoundh =+^C (1)
In Equation 1, C is the mass of the concentrates, c is the
grade of valuable element or compound in the concentrates,
T is the mass of the tailings, and t is the grade of valuable
element or compound in the tailings. Flotation enrichment
was calculated using concentrate grade over feed grade.
Preconcentration and Flotation Experiments
Based on the results from the baseline experiments, pre-
concentration experiments were conducted using a Wilfley
Table by Outotec (Equation 1). Preconcentration experi-
ments used the Wilfley Table for gravity separation (GS)
and production of three streams: concentrate, middlings,
and tailings. The preconcentration experiments aimed to
deslime the CT (as-received material). The process con-
sisted of performing 3 GS experiments by increasing the
solid-liquid ratio from 1:15, 1:10, and 1:5. The remaining
GS parameters were consistent at 11 cm stroke, 0° tilt (flat),
slurry flow of 1.2 L/min. and wash water flow 1 L/min. The
middlings and the concentrate streams were combined to
generate a preconcentration product used in the flotation
experiments using the most efficient collector and frother
combination from the baseline experiments. Figure 1 shows
the proposed telluride concentration strategies.
All the grades for these streams were quantified using
XRF. The recoveries for the flotation and preconcentration
experiments were calculated using Equation 1. Flotation
enrichment was calculated using concentrate grade over
feed grade.
RESULTS
Characterization of Copper Tailings
Chemical Composition of Copper Tailings
The average concentration of tellurium, gold, and silver
in CT was determined using ICP-MS. Tellurium, gold,
and silver grades were 0.4 ppm, 61.7 ppb, and 0.66 ppm,
respectively. The name “valuable elements” was given to
commodities that would positively impact the process
if these elements were concentrated with Te by flotation.
Furthermore, other elements were placed in the valuable
elements list because they are part of the U.S.A. critical
mineral list. The remaining grades for valuables considered
are shown in Table 2.
Additionally, XRF analysis was performed on CT sam-
ples and averaged to obtain a general distribution of major
elements that contribute to the composition of CT. Major
elements have 1 wt.%, minor elements have a 0.1 wt.% to
1 wt.%, and trace elements have 0.1 wt.% composition.
Table 1. Baseline Flotation Experiment Design
Description Collector Dosage (g/ton)
EXP300422 +MIBC 30, 60, 90, 120,
150 &180
EXP300422 +OREPREP X-237 90 &150
EXP 300422 +terpineol 90 &150
SPIX +MIBC 30, 60, 90, 120,
150 &180
SPIX +OREPREP X-237 90 &150
SPIX +terpineol 90 &150
Figure 1. Copper tailings preconcentration strategies
followed by flotation of concentrate and middling mix to
produce an Au-Ag-Te rich concentrate
with the 1L cell and the 2-7/8 in. diameter impeller attach-
ment. These experiments were performed using procedures
published in the literature for similar systems[30,31]. The
flotation feed (P80 =135µm, P50 =42 µm) was prepared in
tap water at 30 wt.% solids. The prepared slurry was agi-
tated at 900 RPM for 3 mins. The slurry’s pH was modified
to pH 9 using NaOH. The frother’s dosage was fixed at 50
g/t for all experiments. Table 1 shows the parameters and
conditions used in this set of feasibility experiments. The
experiments were performed with pH conditioning, fol-
lowed by collector addition, and lastly, the frother at the
specified dosages.
Concentrates were collected over 5 min. of flotation
time. The concentrate and tailing products were dried,
weighed, and assayed using ICP-MS. Recovery was calcu-
lated using Equation 1.
**R^% c Tth
Cc 100 element or compoundh =+^C (1)
In Equation 1, C is the mass of the concentrates, c is the
grade of valuable element or compound in the concentrates,
T is the mass of the tailings, and t is the grade of valuable
element or compound in the tailings. Flotation enrichment
was calculated using concentrate grade over feed grade.
Preconcentration and Flotation Experiments
Based on the results from the baseline experiments, pre-
concentration experiments were conducted using a Wilfley
Table by Outotec (Equation 1). Preconcentration experi-
ments used the Wilfley Table for gravity separation (GS)
and production of three streams: concentrate, middlings,
and tailings. The preconcentration experiments aimed to
deslime the CT (as-received material). The process con-
sisted of performing 3 GS experiments by increasing the
solid-liquid ratio from 1:15, 1:10, and 1:5. The remaining
GS parameters were consistent at 11 cm stroke, 0° tilt (flat),
slurry flow of 1.2 L/min. and wash water flow 1 L/min. The
middlings and the concentrate streams were combined to
generate a preconcentration product used in the flotation
experiments using the most efficient collector and frother
combination from the baseline experiments. Figure 1 shows
the proposed telluride concentration strategies.
All the grades for these streams were quantified using
XRF. The recoveries for the flotation and preconcentration
experiments were calculated using Equation 1. Flotation
enrichment was calculated using concentrate grade over
feed grade.
RESULTS
Characterization of Copper Tailings
Chemical Composition of Copper Tailings
The average concentration of tellurium, gold, and silver
in CT was determined using ICP-MS. Tellurium, gold,
and silver grades were 0.4 ppm, 61.7 ppb, and 0.66 ppm,
respectively. The name “valuable elements” was given to
commodities that would positively impact the process
if these elements were concentrated with Te by flotation.
Furthermore, other elements were placed in the valuable
elements list because they are part of the U.S.A. critical
mineral list. The remaining grades for valuables considered
are shown in Table 2.
Additionally, XRF analysis was performed on CT sam-
ples and averaged to obtain a general distribution of major
elements that contribute to the composition of CT. Major
elements have 1 wt.%, minor elements have a 0.1 wt.% to
1 wt.%, and trace elements have 0.1 wt.% composition.
Table 1. Baseline Flotation Experiment Design
Description Collector Dosage (g/ton)
EXP300422 +MIBC 30, 60, 90, 120,
150 &180
EXP300422 +OREPREP X-237 90 &150
EXP 300422 +terpineol 90 &150
SPIX +MIBC 30, 60, 90, 120,
150 &180
SPIX +OREPREP X-237 90 &150
SPIX +terpineol 90 &150
Figure 1. Copper tailings preconcentration strategies
followed by flotation of concentrate and middling mix to
produce an Au-Ag-Te rich concentrate