XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 3281
of the size fraction 315 µm x ≤ 1 mm during ultrasonic
stressing (Figure 4b). Here, all measured distributions are
similar, so there is no comminution of the particles dur-
ing stress, indicating a pure decoating. It is also noticeable
that about 30 %of the mass is larger than 1 mm, although
the mesh size of the sieve was 1 mm. This is because the
particles are platelets due to the small thickness of the cell.
As a result, particles larger than 1 mm in diameter, as deter-
mined by static image analysis, will fit diagonally through a
1 mm square mesh. This can also be seen in the distribution
of the coarser fraction 1 mm. The pre-sonication (t =0
s) particle size distribution does not begin to increase until
about 1.2 mm.
Although the 315 µm x ≤ 1 mm size fraction was only
decoated and no fracture comminution could be detected,
the concentration of perovskites in the detached particle
product and the enrichment is lower than in the 1 mm
size fraction, where a fracture comminution occurred. This
effect can be explained by the fact that a finer fraction, as
mentioned above, has a larger surface area that is affected
by the decoating stress. Furthermore, the perovskite layer to
be removed is only present on one side of the cell particles.
However, the surface gain for smaller particles is predomi-
nantly caused by the fracture perpendicular to this surface
due to the platelet shape. This indicates that there is a greater
surface area available that does not consist of perovskite,
which may result in a reduced selectivity of the decoating
process. In addition, the 315 µm x ≤ 1 mm fraction has a
lower perovskite content than the 1 mm fraction, thereby
further enhancing this effect.
CONCLUSION
This study has shown that ultrasonic decoating can be
applied to comminuted SOC particles. Therefore, a non-
destructive disassembly of cells from SOEL is no longer a
prerequisite for its applicability. Ultrasonic decoating of
particles represents a useful method with a high selectivity
for perovskite liberation and separation in the recycling of
SOC. An upstream comminution of cells to homogenize
the particle size suitable for ultrasonic decoating leads to
an enrichment of perovskite material in the fines, which
can be gained as a preconcentrate with a sieving step.
The coarse particles still contain residual perovskite mate-
rial, which can be cleaned by using ultrasonic decoating,
0
25
50
75
100
0 1 2 3
Particle size x /mm
Q3_0ss Q3_10ss
Q3_20ss Q3_30ss
0
25
50
75
100
0 0.5 1 1.5
Particle size x /mm
Q3_0ss Q3_10ss10=t
Q3_20ss Q3_30ss30=t
b) a)
t =0
t =20
t =10
t =30
t =0
t =20
Figure 4. Particle size distribution of the cell particles after a sonication time t =0 s, 10 s, 20 s and 30 s for the particle size
Table 2. Quantiles of the particle size distribution of the fraction x 1 mm after 0 s, 10 s, 20 s and 30 s sonication time
Sonication time t /s 10 %quantile x10 /mm 50 %quantile x50 /mm 90 %quantile x90 /mm
0 s 1.29 1.68 2.19
10 s 1.07 1.38 1.82
20 s 0.96 1.29 1.60
30 s 0.90 1.21 1.50
Cumulative
sumQ
3
/
%
Cumulative
sumQ
3
/
%
of the size fraction 315 µm x ≤ 1 mm during ultrasonic
stressing (Figure 4b). Here, all measured distributions are
similar, so there is no comminution of the particles dur-
ing stress, indicating a pure decoating. It is also noticeable
that about 30 %of the mass is larger than 1 mm, although
the mesh size of the sieve was 1 mm. This is because the
particles are platelets due to the small thickness of the cell.
As a result, particles larger than 1 mm in diameter, as deter-
mined by static image analysis, will fit diagonally through a
1 mm square mesh. This can also be seen in the distribution
of the coarser fraction 1 mm. The pre-sonication (t =0
s) particle size distribution does not begin to increase until
about 1.2 mm.
Although the 315 µm x ≤ 1 mm size fraction was only
decoated and no fracture comminution could be detected,
the concentration of perovskites in the detached particle
product and the enrichment is lower than in the 1 mm
size fraction, where a fracture comminution occurred. This
effect can be explained by the fact that a finer fraction, as
mentioned above, has a larger surface area that is affected
by the decoating stress. Furthermore, the perovskite layer to
be removed is only present on one side of the cell particles.
However, the surface gain for smaller particles is predomi-
nantly caused by the fracture perpendicular to this surface
due to the platelet shape. This indicates that there is a greater
surface area available that does not consist of perovskite,
which may result in a reduced selectivity of the decoating
process. In addition, the 315 µm x ≤ 1 mm fraction has a
lower perovskite content than the 1 mm fraction, thereby
further enhancing this effect.
CONCLUSION
This study has shown that ultrasonic decoating can be
applied to comminuted SOC particles. Therefore, a non-
destructive disassembly of cells from SOEL is no longer a
prerequisite for its applicability. Ultrasonic decoating of
particles represents a useful method with a high selectivity
for perovskite liberation and separation in the recycling of
SOC. An upstream comminution of cells to homogenize
the particle size suitable for ultrasonic decoating leads to
an enrichment of perovskite material in the fines, which
can be gained as a preconcentrate with a sieving step.
The coarse particles still contain residual perovskite mate-
rial, which can be cleaned by using ultrasonic decoating,
0
25
50
75
100
0 1 2 3
Particle size x /mm
Q3_0ss Q3_10ss
Q3_20ss Q3_30ss
0
25
50
75
100
0 0.5 1 1.5
Particle size x /mm
Q3_0ss Q3_10ss10=t
Q3_20ss Q3_30ss30=t
b) a)
t =0
t =20
t =10
t =30
t =0
t =20
Figure 4. Particle size distribution of the cell particles after a sonication time t =0 s, 10 s, 20 s and 30 s for the particle size
Table 2. Quantiles of the particle size distribution of the fraction x 1 mm after 0 s, 10 s, 20 s and 30 s sonication time
Sonication time t /s 10 %quantile x10 /mm 50 %quantile x50 /mm 90 %quantile x90 /mm
0 s 1.29 1.68 2.19
10 s 1.07 1.38 1.82
20 s 0.96 1.29 1.60
30 s 0.90 1.21 1.50
Cumulative
sumQ
3
/
%
Cumulative
sumQ
3
/
%