XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 3243
component in the product (mi,Product) was divided by the
mass of the component in the air classifier feed (mi,Feed
ZZS ).
R m
m
,Feed
,Product
c ZZS
=(2)
For the calculation of the cumulative component recov-
ery (Rc,cum) at different settling velocities Equation (4) was
used. The cumulative sum of the masses of the individual
component in the light fraction of the different settling
velocities (Σmi,SV) was divided by the mass of the compo-
nent in the air classifier feed (mi,Feed
ZZS ).
Rc,cum m
m
,Feed
,SV
ZZS
SV
n
0 ==
/
(3)
The black mass yield (YBM) was obtained by dividing the
mass of the produced fraction (mBM), for black mass 1
(1000 µm) and for black mass 2 (500 µm), by the origi-
nal cell mass (mCell).
Y m
m
BM
Cell
BM =(4)
The metal recovery (RMe) was calculated for Co, Li and Ni
and compared to the aims of the European legislation for
the recycling efficiencies. The mass of the respective metal
in the black mass was related to the mass of the respective
metal in the cell. Therefore, the measured concentration of
the metal (cBM,Me) in the black mass and in the whole cell
(cCell,Me) was used to calculate the masses in the black mass.
Only the anode Cu was considered for Cu recovery as the
exact amount of Cu in the casing could not be accurately
determined and it was also not expected that the casing Cu
would end up in the black mass to a greater extent.
,Me
,
·
,,,
·
BM BM
Me
cell Cell Me
m c
R withMe Co Cu Li Ni
m c
==
(5)
For more details and assumptions of the calculation see
Wilke et al. (BM).
RESULTS AND DISCUSSION
Prior to the mechanical treatment of the batteries the
depollution in form of discharging plays an important role
as shown by Kaas eta al. (Kaas et al., 2023). To avoid the
phenomena of discharging into pole reversal, the authors
made sure, that the batteries were only discharged to a SoC
of 0%.
Comminution
Dealing with the recycling of LIB the composition of the
batteries is of interest. From the investigated cells a good
overview of the components in the cells can be found in
(Wilke et al., 2023a). Moreover, the required specific stress
energy is already discussed. The authors conclude that the
investigated prismatic cells (P1, P2 and P6) show a similar
specific stress energy, due to the same casing material (Fig..
1a), cell type and thickness of current collector. The cylin-
dric cells show small differences. The C3 required higher
specific stress energy than the C2, although the casing of
C2 is made of steel. Possible reasons for that may be the
greater thickness of the current collector foils of the C3. As
this battery is of an older generation than the C2, greater
thickness of the aluminium and copper foil were used back
then. Next, C3 has a more complex inner structure. As the
jelly roll is wound onto a plastic tube and at both ends of
the roll are strong metal plates a greater energy could be
required (Wilke et al., 2023a).
First Air Classification
During the first air classification a separator product
is formed by the light fraction separated at 2.0 m/s air
speed. The composition of the separator product as well
as the recovery of the separator in this fraction is shown
in Figure 3a-b. The recovery varies greatly between 37%
(P6) and 85% (C2). To explain the different recoveries of
the separator the principle of the zig-zag air classifier must
be taken into account. The separation is based on the set-
tling velocity which is a function of size, shape and density
(Kaas et al., 2022). Therefore, the possible reasons for the
different recoveries are diverse. The material of the separa-
tor and further additives form one part of the explanation.
The C2 separator is the only one coated with a ceramic
layer. Although the density is increased, the material also
gets more brittle thus more susceptible to crushing. The
smaller party can be better transferred to the light product.
Furthermore, the batteries being pre-crushed and not cylin-
dric (P1-P6) show lower recoveries. The influence of auto-
genic crushing by the different thicknesses and shapes of
the casing should be further investigated. Concentrating on
the composition of the separator product, C2 shows again
the best result with 94% share of the separator whereby
C3 with 91% is performing well too (Figure 3a). The bat-
teries with minor decoating of the cathode (C3) respec-
tively cathode and anode (C2) after the first crushing have
smaller impurities in the separator product. The coating in
the separator fraction results from cathode and anode. As
the cathode of the prismatic is better decoated than for the
cylindric units, more coating and aluminium is transferred
to the fraction. Generally, it should be questioned whether
a separator fraction is efficient in the battery recycling as
the recoveries and compositions are too various. Other pos-
sibilities could be a later removal by float sink separation
component in the product (mi,Product) was divided by the
mass of the component in the air classifier feed (mi,Feed
ZZS ).
R m
m
,Feed
,Product
c ZZS
=(2)
For the calculation of the cumulative component recov-
ery (Rc,cum) at different settling velocities Equation (4) was
used. The cumulative sum of the masses of the individual
component in the light fraction of the different settling
velocities (Σmi,SV) was divided by the mass of the compo-
nent in the air classifier feed (mi,Feed
ZZS ).
Rc,cum m
m
,Feed
,SV
ZZS
SV
n
0 ==
/
(3)
The black mass yield (YBM) was obtained by dividing the
mass of the produced fraction (mBM), for black mass 1
(1000 µm) and for black mass 2 (500 µm), by the origi-
nal cell mass (mCell).
Y m
m
BM
Cell
BM =(4)
The metal recovery (RMe) was calculated for Co, Li and Ni
and compared to the aims of the European legislation for
the recycling efficiencies. The mass of the respective metal
in the black mass was related to the mass of the respective
metal in the cell. Therefore, the measured concentration of
the metal (cBM,Me) in the black mass and in the whole cell
(cCell,Me) was used to calculate the masses in the black mass.
Only the anode Cu was considered for Cu recovery as the
exact amount of Cu in the casing could not be accurately
determined and it was also not expected that the casing Cu
would end up in the black mass to a greater extent.
,Me
,
·
,,,
·
BM BM
Me
cell Cell Me
m c
R withMe Co Cu Li Ni
m c
==
(5)
For more details and assumptions of the calculation see
Wilke et al. (BM).
RESULTS AND DISCUSSION
Prior to the mechanical treatment of the batteries the
depollution in form of discharging plays an important role
as shown by Kaas eta al. (Kaas et al., 2023). To avoid the
phenomena of discharging into pole reversal, the authors
made sure, that the batteries were only discharged to a SoC
of 0%.
Comminution
Dealing with the recycling of LIB the composition of the
batteries is of interest. From the investigated cells a good
overview of the components in the cells can be found in
(Wilke et al., 2023a). Moreover, the required specific stress
energy is already discussed. The authors conclude that the
investigated prismatic cells (P1, P2 and P6) show a similar
specific stress energy, due to the same casing material (Fig..
1a), cell type and thickness of current collector. The cylin-
dric cells show small differences. The C3 required higher
specific stress energy than the C2, although the casing of
C2 is made of steel. Possible reasons for that may be the
greater thickness of the current collector foils of the C3. As
this battery is of an older generation than the C2, greater
thickness of the aluminium and copper foil were used back
then. Next, C3 has a more complex inner structure. As the
jelly roll is wound onto a plastic tube and at both ends of
the roll are strong metal plates a greater energy could be
required (Wilke et al., 2023a).
First Air Classification
During the first air classification a separator product
is formed by the light fraction separated at 2.0 m/s air
speed. The composition of the separator product as well
as the recovery of the separator in this fraction is shown
in Figure 3a-b. The recovery varies greatly between 37%
(P6) and 85% (C2). To explain the different recoveries of
the separator the principle of the zig-zag air classifier must
be taken into account. The separation is based on the set-
tling velocity which is a function of size, shape and density
(Kaas et al., 2022). Therefore, the possible reasons for the
different recoveries are diverse. The material of the separa-
tor and further additives form one part of the explanation.
The C2 separator is the only one coated with a ceramic
layer. Although the density is increased, the material also
gets more brittle thus more susceptible to crushing. The
smaller party can be better transferred to the light product.
Furthermore, the batteries being pre-crushed and not cylin-
dric (P1-P6) show lower recoveries. The influence of auto-
genic crushing by the different thicknesses and shapes of
the casing should be further investigated. Concentrating on
the composition of the separator product, C2 shows again
the best result with 94% share of the separator whereby
C3 with 91% is performing well too (Figure 3a). The bat-
teries with minor decoating of the cathode (C3) respec-
tively cathode and anode (C2) after the first crushing have
smaller impurities in the separator product. The coating in
the separator fraction results from cathode and anode. As
the cathode of the prismatic is better decoated than for the
cylindric units, more coating and aluminium is transferred
to the fraction. Generally, it should be questioned whether
a separator fraction is efficient in the battery recycling as
the recoveries and compositions are too various. Other pos-
sibilities could be a later removal by float sink separation