488 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
3 cm pitches, as well as between the 4.5 cm, 3.6 cm, and
3 cm designs, were not significant. This suggests a balance
point at the 6 cm design for particle-wall area. Moreover,
the 4.5 cm design had a lower particle-wall to particle-par-
ticle contact area ratio and a 32% increase in average par-
ticle residence time compared to the 6 cm design.
In summary, the 6 cm pitch design emerged as the
most balanced, maximising particle-wall contact area and
the ratio of particle-wall to particle-particle contacts, while
also enhancing throughput compared to the 4.5 cm design.
Consequently, the 6 cm pitch design was selected as opti-
mal for this study, and all further simulations and experi-
mental investigations proceeded with this configuration.
Design Transferability
The models employed here utilise large, ideal spheres, a
methodological approach that, while effective, presents
limitations in its applicability to real-world scenarios. In
our previous studies (Rasera et al., 2022b, 2023), we estab-
lished the robustness of our charging model for diverse
sample sizes and compositions and have demonstrated
the efficacy of optimised designs in laboratory settings for
separating granular materials. This section aims to support
these previous findings by extends our analysis to com-
pare the performance of a charger design, initially opti-
mised for PTFE, with other single-material species and
their mixtures. Although the charger may not represent the
optimal design for all species, identifying consistent per-
formance trends across different materials can validate the
broader applicability of an optimised design. Moreover, a
comprehensive understanding of the interaction dynamics
within the tribocharger for varied particle types is instru-
mental in evaluating the design’s versatility and efficiency
in a range of processing environments.
An investigation was conducted to compare trends in
particle-wall and particle-particle contact areas across dif-
ferent material types. Figure 7 compares ratios of net parti-
cle-wall to net particle-particle contact areas for 1.59 mm,
3.18 mm, and 3.97 mm PTFE, PA66 and PVC particles
passed through a simulated tribocharger. The data from this
figure suggests a consistent trend in the relative proportions
of contact areas regardless of particle type. This indicates
that while a tribocharger design may not be optimised for
all materials, the trends in relative proportions of parti-
cle-particle and particle-wall contact are consistent. Such
a trend implies that optimising a design for one material
should enhance the charging performance for other materi-
als as well.
Subsequently, two mixed species, mixed size tests were
conducted. In both cases, equal numbers of 1.59 mm and
3.97 mm particles were used. One sample was comprised
of large PTFE and small PA66 particles, and the other of
small PTFE and large PA66 particles. Each mixture was
passed through a simulated tribocharger. Figure 8 presents
the ratio of net particle-particle and particle-wall contact
areas for each material at each size. Here, the particle-wall
contact area was higher than the net particle-particle con-
tact area for both particle types. The resulting ratios for each
material and size are similar and consistent: larger particles
Figure 6. Summary of the net particle-particle and particle-wall contact area
accumulated per second for each charger design error bars indicate 95% confidence
intervals (Rasera et al., 2022b)
3 cm pitches, as well as between the 4.5 cm, 3.6 cm, and
3 cm designs, were not significant. This suggests a balance
point at the 6 cm design for particle-wall area. Moreover,
the 4.5 cm design had a lower particle-wall to particle-par-
ticle contact area ratio and a 32% increase in average par-
ticle residence time compared to the 6 cm design.
In summary, the 6 cm pitch design emerged as the
most balanced, maximising particle-wall contact area and
the ratio of particle-wall to particle-particle contacts, while
also enhancing throughput compared to the 4.5 cm design.
Consequently, the 6 cm pitch design was selected as opti-
mal for this study, and all further simulations and experi-
mental investigations proceeded with this configuration.
Design Transferability
The models employed here utilise large, ideal spheres, a
methodological approach that, while effective, presents
limitations in its applicability to real-world scenarios. In
our previous studies (Rasera et al., 2022b, 2023), we estab-
lished the robustness of our charging model for diverse
sample sizes and compositions and have demonstrated
the efficacy of optimised designs in laboratory settings for
separating granular materials. This section aims to support
these previous findings by extends our analysis to com-
pare the performance of a charger design, initially opti-
mised for PTFE, with other single-material species and
their mixtures. Although the charger may not represent the
optimal design for all species, identifying consistent per-
formance trends across different materials can validate the
broader applicability of an optimised design. Moreover, a
comprehensive understanding of the interaction dynamics
within the tribocharger for varied particle types is instru-
mental in evaluating the design’s versatility and efficiency
in a range of processing environments.
An investigation was conducted to compare trends in
particle-wall and particle-particle contact areas across dif-
ferent material types. Figure 7 compares ratios of net parti-
cle-wall to net particle-particle contact areas for 1.59 mm,
3.18 mm, and 3.97 mm PTFE, PA66 and PVC particles
passed through a simulated tribocharger. The data from this
figure suggests a consistent trend in the relative proportions
of contact areas regardless of particle type. This indicates
that while a tribocharger design may not be optimised for
all materials, the trends in relative proportions of parti-
cle-particle and particle-wall contact are consistent. Such
a trend implies that optimising a design for one material
should enhance the charging performance for other materi-
als as well.
Subsequently, two mixed species, mixed size tests were
conducted. In both cases, equal numbers of 1.59 mm and
3.97 mm particles were used. One sample was comprised
of large PTFE and small PA66 particles, and the other of
small PTFE and large PA66 particles. Each mixture was
passed through a simulated tribocharger. Figure 8 presents
the ratio of net particle-particle and particle-wall contact
areas for each material at each size. Here, the particle-wall
contact area was higher than the net particle-particle con-
tact area for both particle types. The resulting ratios for each
material and size are similar and consistent: larger particles
Figure 6. Summary of the net particle-particle and particle-wall contact area
accumulated per second for each charger design error bars indicate 95% confidence
intervals (Rasera et al., 2022b)