XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 2955
There are three functional zones in the vessel—the free
settling zone with low solids concentration, the fluidized
bed with a nearly plug-flow mixing regime, and the dewa-
tering zone with higher solids density of about 60%. This
design maximizes particle-bubble collision frequency and
particle residence time and minimizes axial mixing, parti-
cle-bubble detachment rate, turbulence, air consumption,
and froth buoyancy restrictions.
HydroFloat ™ cells are used in scavenging tailings,
where selective recovery of semi-liberated and fully-liber-
ated minerals within the coarse size fraction increases global
recovery. They can also be used in coarse gangue rejection:
The cell is installed in the grinding circuit and receives the
underflow of the secondary classifiers, and the resultant
tailings are final tailings, and do not require further pro-
cessing (Eriez 2019).
Vollert et al. (2019) report on the installation of
HydroFloat ™ technology at Newcrest’s Cadia Valley opera-
tion: “With the introduction of coarse particle flotation
using the HydroFloat ™ technology, recovery is not only
increased for a given grind size, but also sustained at coarser
grind sizes. In traditional copper concentrators, there is
always a trade-off between recovery and grind size. As pri-
mary grind size is decreased, more power is consumed per
ton of ore resulting in a lower throughput rate for a given
installed power. It has been demonstrated that the applica-
tion of coarse flotation technology such as the HydroFloat ™
has the ability to shift the economic optimum grind size
and increase cash flow.”
WOODGROVE MACHINES
Woodgrove Technologies offers two flotation machines
(Woodgrove 2024). The Staged Flotation Reactor (SFR)
incorporates features of both conventional mechanical cells
and flotation columns. Like the StackCell ®, it provides
separate chambers for different sub-processes, but the SFR
employs three chambers where the StackCell ® has two. The
three SFR chambers are said to enable independent optimi-
zation of the sub-processes in the flotation process: bubble-
particle contact, particle attachment, particle detachment,
and froth recovery.
The Direct Flotation Reactor (DFR), shown in
Figure 13, is considered an improvement to the SFR. It is
designed to prevent formation of a froth and froth-slurry
interface. Independent bubbles are removed from the col-
lection zone in a gas/slurry phase, and recovered at the top
of the vessel. Unattached particles are collected in the lower
half of the vessel. The entire unit is pressurized.
There is little data on the performance of the Woodgrove
machines. The most recent publication described the instal-
lation of an SFR at the New Afton concentrator in Canada,
where it was reported that the SFRs matched the perfor-
mance of the pilot plant and met the design target of 29%
concentrate and 45% recovery within the first few days of
Figure 12. HydroFloat™ Cell, Cutaway and Image (Eriez 2024c)
There are three functional zones in the vessel—the free
settling zone with low solids concentration, the fluidized
bed with a nearly plug-flow mixing regime, and the dewa-
tering zone with higher solids density of about 60%. This
design maximizes particle-bubble collision frequency and
particle residence time and minimizes axial mixing, parti-
cle-bubble detachment rate, turbulence, air consumption,
and froth buoyancy restrictions.
HydroFloat ™ cells are used in scavenging tailings,
where selective recovery of semi-liberated and fully-liber-
ated minerals within the coarse size fraction increases global
recovery. They can also be used in coarse gangue rejection:
The cell is installed in the grinding circuit and receives the
underflow of the secondary classifiers, and the resultant
tailings are final tailings, and do not require further pro-
cessing (Eriez 2019).
Vollert et al. (2019) report on the installation of
HydroFloat ™ technology at Newcrest’s Cadia Valley opera-
tion: “With the introduction of coarse particle flotation
using the HydroFloat ™ technology, recovery is not only
increased for a given grind size, but also sustained at coarser
grind sizes. In traditional copper concentrators, there is
always a trade-off between recovery and grind size. As pri-
mary grind size is decreased, more power is consumed per
ton of ore resulting in a lower throughput rate for a given
installed power. It has been demonstrated that the applica-
tion of coarse flotation technology such as the HydroFloat ™
has the ability to shift the economic optimum grind size
and increase cash flow.”
WOODGROVE MACHINES
Woodgrove Technologies offers two flotation machines
(Woodgrove 2024). The Staged Flotation Reactor (SFR)
incorporates features of both conventional mechanical cells
and flotation columns. Like the StackCell ®, it provides
separate chambers for different sub-processes, but the SFR
employs three chambers where the StackCell ® has two. The
three SFR chambers are said to enable independent optimi-
zation of the sub-processes in the flotation process: bubble-
particle contact, particle attachment, particle detachment,
and froth recovery.
The Direct Flotation Reactor (DFR), shown in
Figure 13, is considered an improvement to the SFR. It is
designed to prevent formation of a froth and froth-slurry
interface. Independent bubbles are removed from the col-
lection zone in a gas/slurry phase, and recovered at the top
of the vessel. Unattached particles are collected in the lower
half of the vessel. The entire unit is pressurized.
There is little data on the performance of the Woodgrove
machines. The most recent publication described the instal-
lation of an SFR at the New Afton concentrator in Canada,
where it was reported that the SFRs matched the perfor-
mance of the pilot plant and met the design target of 29%
concentrate and 45% recovery within the first few days of
Figure 12. HydroFloat™ Cell, Cutaway and Image (Eriez 2024c)