3208 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
incidence of LFP particles coating the graphite surfaces,
thus enhancing the probability that air bubbles will attach
to the graphite particles and improve their recovery.
When the PAM dosage is increased to 100g/t, there
is an observed surge in recovery rate to 90.6% C however,
this is accompanied by a substantial reduction in grade to
71.1% C. The microscopic images in Figure 5 suggest that
this high recovery coupled with a lower grade is indicative
of an excessive aggregation of graphite and LFP particles,
which leads to higher recovery but also entrains a greater
quantity of impurities, diminishing the grade. With dos-
ages of 150 g/t and 200 g/t of PAM, the selectivity dimin-
ishes almost entirely, which may indicate a saturation
point where PAM’s effectiveness as a selective flocculant is
outweighed by the non-selective aggregation of particles,
reducing the differential attachment to air bubbles that is
essential for effective separation.
Flotation Industrial Black Mass (IBM)
Figure 6 presents the obtained results for IBM flotation
employing diverse reagent combinations and attrition
pre-treatment. In study, the use of attrition pre-treatment
aimed to refresh particle surfaces by removing residual
binders or pyrolytic oils, which affect flotation efficiency
negatively by increasing the hydrophobicity of CAMs
particles. Contrary to this hypothesis, the high intensity
attrition pre-treatment resulted in lower selectivity and
reduced graphite recovery. This outcome deviates from
typical expectations of improved liberation and selectiv-
ity post-attrition observed in previous studies with LCO/
NMC black mass (Salces et al., 2022 Vanderbruggen et
al., 2022). The observed decrease in selectivity might be
due to the liberation of more ultra-fine particles of LFP
and also increasing slime coating phenomenon where LFP
particles adhere to graphite surfaces, which contradicts
conventional understanding and highlights the need for
additional research. The effect of attrition pre-treatment
is observed when tested at 10,000 rpm for 5 minutes, in
which a slight decline in grade was noted in comparison
to the no-attrition condition, from 81.4%C decreasing to
72.9–73.6%C. This suggests that while attrition may clean
particle surfaces, it can also lead to a modest decrease in
the purity of the recovered material, possibly due to the
partial liberation of fines that can contaminate the con-
centrate due to entrainment mechanisms. When attrition
is performed at higher speed, 16,000 rpm for also 5 min,
the graphite recovery remains around 90%C but the grade
drops drastically to 59.8%C. This outcome suggests that
more aggressive attrition may lead to over-liberation of fine
particles, which, despite improving liberation, ultimately
lowers the grade due to increased fines entrainment. These
insights were further compounded by the finding that both
0
10
20
30
40
50
60
70
80
90
100
0 10 20 30 40 50 60 70 80 90 100
Cumulative graphite recovery (%)
MIBC +ESCAID MIBC +ESCAID +50g/t PAM
MIBC +ESCAID +100gpt PAM MIBC +ESCAID +PAM 150g/t
MIBC +ESCAID +PAM 200g/t
Figure 4. Graphite grade and recovery curve for MBM in the overflow product with different reagent combinations and
dosages
Cumulative
graphite
grades
(%)
incidence of LFP particles coating the graphite surfaces,
thus enhancing the probability that air bubbles will attach
to the graphite particles and improve their recovery.
When the PAM dosage is increased to 100g/t, there
is an observed surge in recovery rate to 90.6% C however,
this is accompanied by a substantial reduction in grade to
71.1% C. The microscopic images in Figure 5 suggest that
this high recovery coupled with a lower grade is indicative
of an excessive aggregation of graphite and LFP particles,
which leads to higher recovery but also entrains a greater
quantity of impurities, diminishing the grade. With dos-
ages of 150 g/t and 200 g/t of PAM, the selectivity dimin-
ishes almost entirely, which may indicate a saturation
point where PAM’s effectiveness as a selective flocculant is
outweighed by the non-selective aggregation of particles,
reducing the differential attachment to air bubbles that is
essential for effective separation.
Flotation Industrial Black Mass (IBM)
Figure 6 presents the obtained results for IBM flotation
employing diverse reagent combinations and attrition
pre-treatment. In study, the use of attrition pre-treatment
aimed to refresh particle surfaces by removing residual
binders or pyrolytic oils, which affect flotation efficiency
negatively by increasing the hydrophobicity of CAMs
particles. Contrary to this hypothesis, the high intensity
attrition pre-treatment resulted in lower selectivity and
reduced graphite recovery. This outcome deviates from
typical expectations of improved liberation and selectiv-
ity post-attrition observed in previous studies with LCO/
NMC black mass (Salces et al., 2022 Vanderbruggen et
al., 2022). The observed decrease in selectivity might be
due to the liberation of more ultra-fine particles of LFP
and also increasing slime coating phenomenon where LFP
particles adhere to graphite surfaces, which contradicts
conventional understanding and highlights the need for
additional research. The effect of attrition pre-treatment
is observed when tested at 10,000 rpm for 5 minutes, in
which a slight decline in grade was noted in comparison
to the no-attrition condition, from 81.4%C decreasing to
72.9–73.6%C. This suggests that while attrition may clean
particle surfaces, it can also lead to a modest decrease in
the purity of the recovered material, possibly due to the
partial liberation of fines that can contaminate the con-
centrate due to entrainment mechanisms. When attrition
is performed at higher speed, 16,000 rpm for also 5 min,
the graphite recovery remains around 90%C but the grade
drops drastically to 59.8%C. This outcome suggests that
more aggressive attrition may lead to over-liberation of fine
particles, which, despite improving liberation, ultimately
lowers the grade due to increased fines entrainment. These
insights were further compounded by the finding that both
0
10
20
30
40
50
60
70
80
90
100
0 10 20 30 40 50 60 70 80 90 100
Cumulative graphite recovery (%)
MIBC +ESCAID MIBC +ESCAID +50g/t PAM
MIBC +ESCAID +100gpt PAM MIBC +ESCAID +PAM 150g/t
MIBC +ESCAID +PAM 200g/t
Figure 4. Graphite grade and recovery curve for MBM in the overflow product with different reagent combinations and
dosages
Cumulative
graphite
grades
(%)