XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 3185
processed in a muffle furnace (Thermolyne, Thermo Fisher)
at temperatures of 400–500 °C for 0.5–2 hours to remove
both PVDF binder and carbon additives.
Experimental Protocol
In this work, the separation of anode and cathode active
materials is accomplished by a centrifugal gravity separation
method. Separation of mixed fine powders was conducted
using a Falcon Ultra-Fine (UF) concentrator in a laboratory
setting (Falcon L40). Figure 1 shows a schematic diagram
of two experimental protocols in producing concentrate
product and tailing product after a centrifugal gravity sepa-
ration process. In the conventional operation (a), wet cake
materials collected along the inner wall of the concentrator
are reported as the concentrate (or underflow) products,
while the overflow slurry is collected as the tailing product.
The second method (b) is designed to maximize the purity
(percentage) of heavy materials in the concentrate product.
In using the second protocol, wet cake materials deposited
in the middle and lower sections (1" below the top edge) of
the concentrator are collected as the concentrate product,
while materials collected at the upper section (within 1"
below the top edge) combined with the overflow slurry are
collected as the tailing product.
Single-pass gravity separation experiments were per-
formed with black mass samples using a Falcon L40 ultra-
fine (UF) separator. An overhead agitator (Caframo) was
used to stir the slurry for a few minutes to ensure the slurry
was properly mixed. In each trial, the slurry at different
solid concentrations was slowly fed into a central tube
of the Falcon L40 concentrator at a flow rate of approxi-
mately 2 L/min. The concentrator bowl rotated at a speed
of 1,000–3,000 RPM, during which particles in the slurry
within the rotating bowl were subject to a centrifugal force
of up to 50–300 G. The rotation ceased when the slurry
was no longer flushed into the overflow stream. All samples
were weighed, and a fraction of these samples were analyzed
using thermogravimetric analysis (TGA) to determine the
materials’ composition.
In addition, two process flow diagrams (PFD) were
evaluated. The first PFD consisted of one rougher stage, one
cleaner stage, and one scavenger stage. The rougher, scaven-
ger, and cleaner stages operated at g-forces of 163, 290, and
222, respectively. The wet cake materials collected within
the bowl from two rougher runs were combined and mixed
with water to prepare a 5% by weight slurry. The slurry was
then fed to the cleaner stage. The tailing product from the
rougher stage was dewatered to obtain a 5 wt.% slurry and
fed to the scavenger stage. The second PFD consisted of
one rougher stage, two consecutive cleaner stages, and two
consecutive scavenger stages. The operating parameters for
rougher, cleaner, and scavenger stages were 163, 290, and
222 g-forces, respectively.
Material Characterization
The grade (percentage) of cathode active materials in the
separated products was determined from the remaining
weight at a temperature of 800 °C, at which the graphite
was fully decomposed. Thermogravimetric analysis (TGA)
of the sample was conducted using a thermogravimetric
Figure 1. A schematic diagram of two protocols for selecting concentrate and tailings products after separating feed materials
to both concentrate and tail products
(a) (b)
processed in a muffle furnace (Thermolyne, Thermo Fisher)
at temperatures of 400–500 °C for 0.5–2 hours to remove
both PVDF binder and carbon additives.
Experimental Protocol
In this work, the separation of anode and cathode active
materials is accomplished by a centrifugal gravity separation
method. Separation of mixed fine powders was conducted
using a Falcon Ultra-Fine (UF) concentrator in a laboratory
setting (Falcon L40). Figure 1 shows a schematic diagram
of two experimental protocols in producing concentrate
product and tailing product after a centrifugal gravity sepa-
ration process. In the conventional operation (a), wet cake
materials collected along the inner wall of the concentrator
are reported as the concentrate (or underflow) products,
while the overflow slurry is collected as the tailing product.
The second method (b) is designed to maximize the purity
(percentage) of heavy materials in the concentrate product.
In using the second protocol, wet cake materials deposited
in the middle and lower sections (1" below the top edge) of
the concentrator are collected as the concentrate product,
while materials collected at the upper section (within 1"
below the top edge) combined with the overflow slurry are
collected as the tailing product.
Single-pass gravity separation experiments were per-
formed with black mass samples using a Falcon L40 ultra-
fine (UF) separator. An overhead agitator (Caframo) was
used to stir the slurry for a few minutes to ensure the slurry
was properly mixed. In each trial, the slurry at different
solid concentrations was slowly fed into a central tube
of the Falcon L40 concentrator at a flow rate of approxi-
mately 2 L/min. The concentrator bowl rotated at a speed
of 1,000–3,000 RPM, during which particles in the slurry
within the rotating bowl were subject to a centrifugal force
of up to 50–300 G. The rotation ceased when the slurry
was no longer flushed into the overflow stream. All samples
were weighed, and a fraction of these samples were analyzed
using thermogravimetric analysis (TGA) to determine the
materials’ composition.
In addition, two process flow diagrams (PFD) were
evaluated. The first PFD consisted of one rougher stage, one
cleaner stage, and one scavenger stage. The rougher, scaven-
ger, and cleaner stages operated at g-forces of 163, 290, and
222, respectively. The wet cake materials collected within
the bowl from two rougher runs were combined and mixed
with water to prepare a 5% by weight slurry. The slurry was
then fed to the cleaner stage. The tailing product from the
rougher stage was dewatered to obtain a 5 wt.% slurry and
fed to the scavenger stage. The second PFD consisted of
one rougher stage, two consecutive cleaner stages, and two
consecutive scavenger stages. The operating parameters for
rougher, cleaner, and scavenger stages were 163, 290, and
222 g-forces, respectively.
Material Characterization
The grade (percentage) of cathode active materials in the
separated products was determined from the remaining
weight at a temperature of 800 °C, at which the graphite
was fully decomposed. Thermogravimetric analysis (TGA)
of the sample was conducted using a thermogravimetric
Figure 1. A schematic diagram of two protocols for selecting concentrate and tailings products after separating feed materials
to both concentrate and tail products
(a) (b)