1
25-023
Development of Metso’s FloatForce®+ Flotation
Mixing Mechanism
Christian Cardoso
Metso, Burlington, ON, Canada
Guillermo Bermudez
Metso, Burlington, ON, Canada
Ian Sherrell
Metso, York, PA, USA
Henri Vepsäläinen
Metso, Espoo, Finland
ABSTRACT
Performance of mixing mechanisms in flotation cells is
paramount, as inefficiencies can lead to financial losses
through valuable minerals lost to tailings. Technological
advancements have been implemented in flotation cells to
optimize performance, but regardless of the efficacy of these
developments, room for improvement may persist. Since
its launch in 2005, FloatForce ® has set a high industry
standard for flotation mixing mechanisms. However, cur-
rent mining trends call for sustainability-driven develop-
ments while improving metallurgical performance. Metso
has recently introduced FloatForce ®+, the latest iteration of
FloatForce, developed through extensive laboratory, pilot,
and industrial testing, aligning with mining sustainability
trends. It has been designed to maximize recovery, reduce
power draw and optimize manufacturing materials. This
development stems from a redesigned rotor profile paired
with a harmonizing stator configuration. This paper pres-
ents the development journey of Metso’s latest patented
flotation mixing mechanism, an advancement to improve
metallurgical performance at a high sustainable standard in
flotation cells. The theory, CFD modeling and test work are
discussed in detail.
INTRODUCTION
Froth flotation is a crucial technique in mineral processing,
essential for the efficient separation of valuable minerals
from gangue and its relevance lies on its ability to concen-
trate low-grade ores, significantly upgrading different types
of minerals (Wills and Finch, 2016). The process is uti-
lized in its majority of mineral processing plants where feed
grade needs to be increase to produce a concentrate.
There are different types of machines for most min-
eral flotation applications, which can be classified in differ-
ent ways (Gorain et al., 2000, Gupta et al., 2006). Among
them, mechanical flotation cells, noted by their use of a
rotor-stator mixing mechanism, have been predominant in
the mineral industry since the beginning of flotation. These
machines can be sub-categorized depending on their air
feed system into self-aerated, where the aspiration is gener-
ated by rotation of the rotor, and forced-air cells, where air
is introduced through an external blower (Wills and Finch,
2016).
A mechanical flotation cell consists of a tank equipped
with a mixing mechanism which mainly comprises a rotor/
stator assembly. The rotor agitates the pulp to maintain sol-
ids in suspension, disperses air into small bubbles, and cre-
ates an environment conducive to bubble-particle collision
and their subsequent attachment. This process facilitates
the separation of valuable mineral particles from unwanted
gangue particles. The bubble-particle aggregates rise in the
cell due to buoyancy, forming a froth which is removed
through the cell lip into the launder. Particles that do not
attach to the bubbles are discharged from the bottom of the
cell tank into the discharge box.
Regardless of its type and operating conditions, all
flotation machines are required to promote a multitude
of functions simultaneously (Harris, 1976, Gorain et al.,
2000, Mesa and Brito-Parada, 2019). These functions are
essentially:
1. Keep solids in suspension
2. Disperse gas into bubbles throughout the pulp
3. Provide conditions that increase the probability of
bubble-particle collision and attachment
4. Keep a stable pulp-froth interface
5. Provide adequate froth removal capacity
To create these circumstances, the mixing mechanism plays
a key role for the effective operation of a mechanical flota-
tion cell, as it should ensure optimal interaction among the
main process inputs—pulp, gas, and chemical reagents. The
25-023
Development of Metso’s FloatForce®+ Flotation
Mixing Mechanism
Christian Cardoso
Metso, Burlington, ON, Canada
Guillermo Bermudez
Metso, Burlington, ON, Canada
Ian Sherrell
Metso, York, PA, USA
Henri Vepsäläinen
Metso, Espoo, Finland
ABSTRACT
Performance of mixing mechanisms in flotation cells is
paramount, as inefficiencies can lead to financial losses
through valuable minerals lost to tailings. Technological
advancements have been implemented in flotation cells to
optimize performance, but regardless of the efficacy of these
developments, room for improvement may persist. Since
its launch in 2005, FloatForce ® has set a high industry
standard for flotation mixing mechanisms. However, cur-
rent mining trends call for sustainability-driven develop-
ments while improving metallurgical performance. Metso
has recently introduced FloatForce ®+, the latest iteration of
FloatForce, developed through extensive laboratory, pilot,
and industrial testing, aligning with mining sustainability
trends. It has been designed to maximize recovery, reduce
power draw and optimize manufacturing materials. This
development stems from a redesigned rotor profile paired
with a harmonizing stator configuration. This paper pres-
ents the development journey of Metso’s latest patented
flotation mixing mechanism, an advancement to improve
metallurgical performance at a high sustainable standard in
flotation cells. The theory, CFD modeling and test work are
discussed in detail.
INTRODUCTION
Froth flotation is a crucial technique in mineral processing,
essential for the efficient separation of valuable minerals
from gangue and its relevance lies on its ability to concen-
trate low-grade ores, significantly upgrading different types
of minerals (Wills and Finch, 2016). The process is uti-
lized in its majority of mineral processing plants where feed
grade needs to be increase to produce a concentrate.
There are different types of machines for most min-
eral flotation applications, which can be classified in differ-
ent ways (Gorain et al., 2000, Gupta et al., 2006). Among
them, mechanical flotation cells, noted by their use of a
rotor-stator mixing mechanism, have been predominant in
the mineral industry since the beginning of flotation. These
machines can be sub-categorized depending on their air
feed system into self-aerated, where the aspiration is gener-
ated by rotation of the rotor, and forced-air cells, where air
is introduced through an external blower (Wills and Finch,
2016).
A mechanical flotation cell consists of a tank equipped
with a mixing mechanism which mainly comprises a rotor/
stator assembly. The rotor agitates the pulp to maintain sol-
ids in suspension, disperses air into small bubbles, and cre-
ates an environment conducive to bubble-particle collision
and their subsequent attachment. This process facilitates
the separation of valuable mineral particles from unwanted
gangue particles. The bubble-particle aggregates rise in the
cell due to buoyancy, forming a froth which is removed
through the cell lip into the launder. Particles that do not
attach to the bubbles are discharged from the bottom of the
cell tank into the discharge box.
Regardless of its type and operating conditions, all
flotation machines are required to promote a multitude
of functions simultaneously (Harris, 1976, Gorain et al.,
2000, Mesa and Brito-Parada, 2019). These functions are
essentially:
1. Keep solids in suspension
2. Disperse gas into bubbles throughout the pulp
3. Provide conditions that increase the probability of
bubble-particle collision and attachment
4. Keep a stable pulp-froth interface
5. Provide adequate froth removal capacity
To create these circumstances, the mixing mechanism plays
a key role for the effective operation of a mechanical flota-
tion cell, as it should ensure optimal interaction among the
main process inputs—pulp, gas, and chemical reagents. The