2138 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
MATERIALS
Tailing Samples
The copper tailings (CT) samples were taken from the
rougher flotation tailings at a major copper producer in the
U.S.A. Two batch samples were provided with a time differ-
ence of one year the first batch received was called Tailings
1, and the second batch was called Tailings 2. The samples
were air-dried and subsequently divided into representative
portions for mineralogical and chemical characterization.
Flotation Reagents
Conventional flotation reagents were obtained and pur-
chased from multiple suppliers, but all were prepared in-
house. The carbamate (EXP300422) collector was obtained
from NeoSolutions. Thiophosphate (AERO 8989) and thi-
azole (AERO 412) collectors and glycol (OREPREP X-237)
frother were obtained from Cytec Industries (Solvay).
Xanthate (SIPX) collector was obtained from the Doe Run
Co. Frothers such as methyl isobutyl carbinol (MIBC), and
terpineol were purchased from Fisher Scientific. Stock solu-
tions for all collectors and frothers were prepared at 1g/L.
Sodium hydroxide (NaOH) and hydrochloric acid (HCl)
were purchased from Fisher Scientific and used for pH
modification from prepared stock solutions of 10 g/L and
9.12 g/L solutions, respectively.
METHODOLOGY
Analysis and Characterization
Inductively Coupled Plasma Mass Spectrometry Studies
The inductively coupled plasma mass spectrometry
(ICP-MS) was performed to identify Te and other elements
in the CT (flotation feed), flotation concentrates, and flota-
tion tailings samples. ICP-MS “total” digestion process was
used to test digested powdered mineral samples in a four-
step dilution process beginning with hydrochloric acid,
second nitric acid, third perchloric acid, and lastly, hydro-
fluoric acid. The digestion produced a stable ionic solution
for ICP-MS analysis (Actlabs 2023).
TESCAN’S Integrated Mineral Analysis studies.
Automated mineralogical analysis using TESCAN’s
Integrated Mineral Analysis (TIMA) was performed on CT
to identify the mineral associations and locking behavior
for different Te mineral phases. To prepare for TIMA, the
materials are sieved into size fractions of +150 µm, +75 µm,
+38 µm, and –38 µm, and then mounted onto an epoxy.
The mounted materials are then ground and polished until
they have a 0.3 µm finish and coated with carbon to ensure
the conductivity of electrons. The CT samples are then
rasterized using a scanning electron microscope (SEM)
equipped with energy-dispersive X-ray spectroscopy (EDS)
and backscatter electron (BSE) imaging. Mineral phases
are differentiated through a watershed transform algorithm
that analyzes variation in the BSE image and EDS spec-
tra between adjacent pixels. Mineral identification is car-
ried out using spectral identification protocols based on
phase-specific X-ray profiles and elemental intensity selec-
tion rules for qualitative mineral identification. Finally, sur-
face area data and density for individual phases are used to
quantify the results. TIMA experiments were performed at
Montana Technological University’s Center for Advanced
Materials Processing (CAMP).
Flotation Experiments
Bench flotation experiments were conducted to establish a
baseline and feasibility of concentrating Te minerals from
the CT samples. Flotation experiments were carried out in
a Denver D12 flotation machine with the 1L cell and the
2-7/8 in. diameter impeller.
This study tested the as-received CT, now considered
the flotation feed, and prepared a slurry in tap water at 30
wt.% solids. The prepared slurry was agitated at 900 RPM,
and the pH was modified to pH 8 using NaOH for 2 mins.
These experiments tested the collector type using the con-
ditions presented in Table 1 and mixed for 3 mins. after
addition to the slurry. These experiments used MIBC as a
frother at 50 g/t and conditioned for 1 min. Airflow rate
was 5 L/min.
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 %element or compoundh Ff
Cc *100 =^(1)
In Equation 1, “R” is the recovery of element or com-
pound, “C” is the mass of the concentrates, “c” is the grade
of valuable element or compound in the concentrates, “F”
is the mass of the feed/head, and “f” is the grade of valuable
Table 1. List of reagents used as collectors in CT flotation
studies
Collector Type
As-Received
CT
Collector Dosage
(g/ton)
EXP300422 (carbamate) Tailings 1 150
SIPX (xanthate) 150
AERO 8989
(thiophosphate)
Tailings 2 150
AERO 412 (thiazole) 150
MATERIALS
Tailing Samples
The copper tailings (CT) samples were taken from the
rougher flotation tailings at a major copper producer in the
U.S.A. Two batch samples were provided with a time differ-
ence of one year the first batch received was called Tailings
1, and the second batch was called Tailings 2. The samples
were air-dried and subsequently divided into representative
portions for mineralogical and chemical characterization.
Flotation Reagents
Conventional flotation reagents were obtained and pur-
chased from multiple suppliers, but all were prepared in-
house. The carbamate (EXP300422) collector was obtained
from NeoSolutions. Thiophosphate (AERO 8989) and thi-
azole (AERO 412) collectors and glycol (OREPREP X-237)
frother were obtained from Cytec Industries (Solvay).
Xanthate (SIPX) collector was obtained from the Doe Run
Co. Frothers such as methyl isobutyl carbinol (MIBC), and
terpineol were purchased from Fisher Scientific. Stock solu-
tions for all collectors and frothers were prepared at 1g/L.
Sodium hydroxide (NaOH) and hydrochloric acid (HCl)
were purchased from Fisher Scientific and used for pH
modification from prepared stock solutions of 10 g/L and
9.12 g/L solutions, respectively.
METHODOLOGY
Analysis and Characterization
Inductively Coupled Plasma Mass Spectrometry Studies
The inductively coupled plasma mass spectrometry
(ICP-MS) was performed to identify Te and other elements
in the CT (flotation feed), flotation concentrates, and flota-
tion tailings samples. ICP-MS “total” digestion process was
used to test digested powdered mineral samples in a four-
step dilution process beginning with hydrochloric acid,
second nitric acid, third perchloric acid, and lastly, hydro-
fluoric acid. The digestion produced a stable ionic solution
for ICP-MS analysis (Actlabs 2023).
TESCAN’S Integrated Mineral Analysis studies.
Automated mineralogical analysis using TESCAN’s
Integrated Mineral Analysis (TIMA) was performed on CT
to identify the mineral associations and locking behavior
for different Te mineral phases. To prepare for TIMA, the
materials are sieved into size fractions of +150 µm, +75 µm,
+38 µm, and –38 µm, and then mounted onto an epoxy.
The mounted materials are then ground and polished until
they have a 0.3 µm finish and coated with carbon to ensure
the conductivity of electrons. The CT samples are then
rasterized using a scanning electron microscope (SEM)
equipped with energy-dispersive X-ray spectroscopy (EDS)
and backscatter electron (BSE) imaging. Mineral phases
are differentiated through a watershed transform algorithm
that analyzes variation in the BSE image and EDS spec-
tra between adjacent pixels. Mineral identification is car-
ried out using spectral identification protocols based on
phase-specific X-ray profiles and elemental intensity selec-
tion rules for qualitative mineral identification. Finally, sur-
face area data and density for individual phases are used to
quantify the results. TIMA experiments were performed at
Montana Technological University’s Center for Advanced
Materials Processing (CAMP).
Flotation Experiments
Bench flotation experiments were conducted to establish a
baseline and feasibility of concentrating Te minerals from
the CT samples. Flotation experiments were carried out in
a Denver D12 flotation machine with the 1L cell and the
2-7/8 in. diameter impeller.
This study tested the as-received CT, now considered
the flotation feed, and prepared a slurry in tap water at 30
wt.% solids. The prepared slurry was agitated at 900 RPM,
and the pH was modified to pH 8 using NaOH for 2 mins.
These experiments tested the collector type using the con-
ditions presented in Table 1 and mixed for 3 mins. after
addition to the slurry. These experiments used MIBC as a
frother at 50 g/t and conditioned for 1 min. Airflow rate
was 5 L/min.
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 %element or compoundh Ff
Cc *100 =^(1)
In Equation 1, “R” is the recovery of element or com-
pound, “C” is the mass of the concentrates, “c” is the grade
of valuable element or compound in the concentrates, “F”
is the mass of the feed/head, and “f” is the grade of valuable
Table 1. List of reagents used as collectors in CT flotation
studies
Collector Type
As-Received
CT
Collector Dosage
(g/ton)
EXP300422 (carbamate) Tailings 1 150
SIPX (xanthate) 150
AERO 8989
(thiophosphate)
Tailings 2 150
AERO 412 (thiazole) 150