2432 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
Collection of Ultrafine, Fine, Medium, Coarser, and
Less Liberated Particles
The collection and recovery of ultrafine and fine particles
require an intensive energy dissipation environment where
the particle/bubble aggregates will be very strong and sur-
vive their transport to the concentrate. However, the col-
lection, transport and recovery of medium, coarser, and less
liberated particles requires an optimal compromise between
particles attachment and detachment where a lower energy
dissipation environment will enhance the overall flotation
process. Even so, flotation of particles above 300 microns
have low or negligible recoveries in conventional flota-
tion cells. For this reason, alternative flotation machines
for coarse particles flotation allows for floating particles
significantly larger than in conventional mechanical cells.
Coarse particles flotation requires reducing even more the
detachment forces by decreasing the turbulence. To over-
come this limitation, the fluidized bed flotation technology
applies, which is a combination of gravity separation and
flotation (Anzoom et al., 2024, Jameson, 2023). Sulphide
plant operations have recently incorporated the fluidized
bed flotation in (Vollert et al., 2019 Arburo et al., 2022).
CONCLUSIONS
The effective particles collection time in conventional
mechanical cells is difficult to estimate. Assuming the main
collection occurs around the impeller zone and surround-
ings, an estimation of the local residence time was around
11 s.
The estimation of effective particles collection time in
two industrial intensified flotation cells, showed residence
time of 17–20 s for the mechanical SFR cell and 10–12 s
for the pneumatic Jameson cell.
A pilot RFC cell showed collection residence times of
0.5–2.0 s, with a separation zone that allows for increasing
flowrates but prevents the bubbles and particles entrain-
ment to tailings and overflow, respectively.
From these results, it is clear the effectiveness of the
active collection section (reactor), however it is true that
the intensive collection favours the recovery of fine miner-
als, but for medium and coarser sizes the intensive contact
is not appropriate but requires a more quiescent condition.
The testing and selection of flotation machines depends
on the mineral characteristics and conditioning, e.g., par-
ticle size and liberation, and the optimal circuit design will
be a hybrid arrangement that allows for getting the best
from each technology, from ultrafine to coarse particles.
ACKNOWLEDGMENTS
The authors are grateful to Agencia Nacional de
Investigación y Desarrollo (ANID), FONDECYT Project
1241830, and Universidad Técnica Federico Santa María,
(a) (b) (c)
DB 1.0 mm
JG 10 cm/s
G 30-50%
DB 1.0 mm
JG 6-8 cm/s
G 30%
DB 1.0 mm
JG 5-10 cm/s
G 30%
Figure 2. The effective collection zone in: (a) Jameson cell (Glencore Technology, 2024), (b) self-aerated
mechanical cell (FLSmidth, 2024), and (c) forced air mechanical cell (Grau et al., 2018)
Collection of Ultrafine, Fine, Medium, Coarser, and
Less Liberated Particles
The collection and recovery of ultrafine and fine particles
require an intensive energy dissipation environment where
the particle/bubble aggregates will be very strong and sur-
vive their transport to the concentrate. However, the col-
lection, transport and recovery of medium, coarser, and less
liberated particles requires an optimal compromise between
particles attachment and detachment where a lower energy
dissipation environment will enhance the overall flotation
process. Even so, flotation of particles above 300 microns
have low or negligible recoveries in conventional flota-
tion cells. For this reason, alternative flotation machines
for coarse particles flotation allows for floating particles
significantly larger than in conventional mechanical cells.
Coarse particles flotation requires reducing even more the
detachment forces by decreasing the turbulence. To over-
come this limitation, the fluidized bed flotation technology
applies, which is a combination of gravity separation and
flotation (Anzoom et al., 2024, Jameson, 2023). Sulphide
plant operations have recently incorporated the fluidized
bed flotation in (Vollert et al., 2019 Arburo et al., 2022).
CONCLUSIONS
The effective particles collection time in conventional
mechanical cells is difficult to estimate. Assuming the main
collection occurs around the impeller zone and surround-
ings, an estimation of the local residence time was around
11 s.
The estimation of effective particles collection time in
two industrial intensified flotation cells, showed residence
time of 17–20 s for the mechanical SFR cell and 10–12 s
for the pneumatic Jameson cell.
A pilot RFC cell showed collection residence times of
0.5–2.0 s, with a separation zone that allows for increasing
flowrates but prevents the bubbles and particles entrain-
ment to tailings and overflow, respectively.
From these results, it is clear the effectiveness of the
active collection section (reactor), however it is true that
the intensive collection favours the recovery of fine miner-
als, but for medium and coarser sizes the intensive contact
is not appropriate but requires a more quiescent condition.
The testing and selection of flotation machines depends
on the mineral characteristics and conditioning, e.g., par-
ticle size and liberation, and the optimal circuit design will
be a hybrid arrangement that allows for getting the best
from each technology, from ultrafine to coarse particles.
ACKNOWLEDGMENTS
The authors are grateful to Agencia Nacional de
Investigación y Desarrollo (ANID), FONDECYT Project
1241830, and Universidad Técnica Federico Santa María,
(a) (b) (c)
DB 1.0 mm
JG 10 cm/s
G 30-50%
DB 1.0 mm
JG 6-8 cm/s
G 30%
DB 1.0 mm
JG 5-10 cm/s
G 30%
Figure 2. The effective collection zone in: (a) Jameson cell (Glencore Technology, 2024), (b) self-aerated
mechanical cell (FLSmidth, 2024), and (c) forced air mechanical cell (Grau et al., 2018)