XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 2953
fine bubble production, but with much lower energy con-
sumption. Conditioned feed pulp is mixed with air in an
external self-aeration unit above the flotation cell. The air–
slurry mixture descends a downcomer pipe and is intro-
duced to the separation vessel through a distributor box
and ring pipe with nozzles that redirect the flow upward
in the cell. The separation vessel is fitted with an adjustable
froth crowding cone which can be used to control mass
pull. The concentrate overflows to an external froth laun-
der, while the tailings stream exits at the base of the vessel.
Several machines have been offered under the Imhoflot
name. The V-Cell, in which the feed was introduced verti-
cally, has been superseded by the G-Cell, shown in Figure 9.
In the G-Cell, the tangential introduction of the feed accel-
erates the froth for quicker separation. Imhoflot also offers
the hybrid H-Cell and the VC-Cell, designed for coarser
particles.
SKIMAIR® CELL
The SkimAir ® cell, a flash flotation* cell offered by Metso,
is designed to produce a high-grade concentrate by recover-
ing liberated coarse particles from the circulating load of
the grinding process. The SkimAir ® was designed to avoid
over-grinding of valuable dense materials, especially gold
and sulfide minerals, in the circulating loads of primary
milling circuits. It allows floating of coarse particles with
*The early development of flash flotation is described by Lynch
et al. (2010)
high grades in early flotation stages. The SkimAir ® cell
is unique because it operates as a flotation cell, and as a
classifier, separating the coarse feed particles from finer,
floatable particles. One advantage of the SkimAir ®, often
overlooked, is that it provides a buffer for the conventional
flotation circuit to produce a more stable feed when the
feed grade is highly. Figure 10 shows a schematic and an
image of a SkimAir ® machine.
Since the first SkimAir ® cell was installed in the 1980s,
improved wear technology has allowed its operation
directly in the grinding circuit, and several design modifi-
cations have made it suitable for a variety of ore types and
plants. The Top-Outlet design allows SkimAir ® to operate
with minimum impact on the water balance in the grind-
ing circuit. It can also be used downstream of the grinding
circuit to achieve high recovery without compromising on
concentrate grade.
ERIEZ CELLS
Stack Cell®
The Eriez StackCell ®, shown in Figure 11, was developed to
combine the metallurgical performance of a column with
the footprint of a mechanical cell (Nelson and Lelinski
2019).
Feed is introduced into an internal mixing and aera-
tion canister in the cell. Intensely mixed, aerated slurry is
discharged under pressure from the mixing canister into
the larger cell, which operates under conditions designed to
allow bubble-particle aggregates to rise into the froth and
Figure 9. Imhoflot G-Cell, Schematic and Image (Maelgwyn 2024)
fine bubble production, but with much lower energy con-
sumption. Conditioned feed pulp is mixed with air in an
external self-aeration unit above the flotation cell. The air–
slurry mixture descends a downcomer pipe and is intro-
duced to the separation vessel through a distributor box
and ring pipe with nozzles that redirect the flow upward
in the cell. The separation vessel is fitted with an adjustable
froth crowding cone which can be used to control mass
pull. The concentrate overflows to an external froth laun-
der, while the tailings stream exits at the base of the vessel.
Several machines have been offered under the Imhoflot
name. The V-Cell, in which the feed was introduced verti-
cally, has been superseded by the G-Cell, shown in Figure 9.
In the G-Cell, the tangential introduction of the feed accel-
erates the froth for quicker separation. Imhoflot also offers
the hybrid H-Cell and the VC-Cell, designed for coarser
particles.
SKIMAIR® CELL
The SkimAir ® cell, a flash flotation* cell offered by Metso,
is designed to produce a high-grade concentrate by recover-
ing liberated coarse particles from the circulating load of
the grinding process. The SkimAir ® was designed to avoid
over-grinding of valuable dense materials, especially gold
and sulfide minerals, in the circulating loads of primary
milling circuits. It allows floating of coarse particles with
*The early development of flash flotation is described by Lynch
et al. (2010)
high grades in early flotation stages. The SkimAir ® cell
is unique because it operates as a flotation cell, and as a
classifier, separating the coarse feed particles from finer,
floatable particles. One advantage of the SkimAir ®, often
overlooked, is that it provides a buffer for the conventional
flotation circuit to produce a more stable feed when the
feed grade is highly. Figure 10 shows a schematic and an
image of a SkimAir ® machine.
Since the first SkimAir ® cell was installed in the 1980s,
improved wear technology has allowed its operation
directly in the grinding circuit, and several design modifi-
cations have made it suitable for a variety of ore types and
plants. The Top-Outlet design allows SkimAir ® to operate
with minimum impact on the water balance in the grind-
ing circuit. It can also be used downstream of the grinding
circuit to achieve high recovery without compromising on
concentrate grade.
ERIEZ CELLS
Stack Cell®
The Eriez StackCell ®, shown in Figure 11, was developed to
combine the metallurgical performance of a column with
the footprint of a mechanical cell (Nelson and Lelinski
2019).
Feed is introduced into an internal mixing and aera-
tion canister in the cell. Intensely mixed, aerated slurry is
discharged under pressure from the mixing canister into
the larger cell, which operates under conditions designed to
allow bubble-particle aggregates to rise into the froth and
Figure 9. Imhoflot G-Cell, Schematic and Image (Maelgwyn 2024)