744 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
is an especially important point, to avoid excessive capital
and operating costs the geotechnical engineer, where pos-
sible, must perform his tests with representative filter cake
so that the target moisture content specified is not unneces-
sarily low.
It is critical that detailed test work be carried out on
representative tailings slurry samples. Comprehensive labo-
ratory test work should trial different chamber configura-
tions (fixed-volume as well as variable-volume) so that the
most economic plate pack is selected for the full-scale fil-
ters (Kaswalder et al., 2014 Kaswalder et al., 2018) .This
work is normally carried out in a filtration laboratory using
a sophisticated bench-scale test unit as shown in Figure 3)
Membrane squeezing and cake blowing may be
included in the dewatering process. Feed pressure, squeez-
ing pressure and compressed air consumption must be
optimized to suit the cake moisture target. It is strongly
recommended that these tests be carried out on representa-
tive slurry samples (Kaswalder et al., 2014)
Once the plate pack configuration and the process has
been optimized, larger-scale pilot filters, shown in Figure 4,
can be used to produce the volumes of filter cake that geo-
technical engineers require so they can conduct their tests
on the material and use the results to design the full-scale
dry stack.
FILTRATE QUALITY MANAGEMENT
Filter Cloth Washing System
Many filter presses have a cloth rinsing system that needs
a water delivery of approximately 1,000 m3/h at relatively
low pressure. A standard centrifugal pump is used for this
duty. Recycled water or filtrate is usually used rather than
process water. The cloth rinsing stage of each filter cycle
normally lasts a few seconds (long enough for any cake resi-
due to be removed from the filter cloths). Storage tanks for
this cloth rinsing water need to be included in the overall
plant design. The cloth rinsing water needs to be collected
from each filter drip tray and it is usually returned to the
feed slurry upstream of the thickener.
More sophisticated filter presses can also be fitted with
a high-pressure cloth washing system that usually operates
once per day. This is a very thorough cloth washing pro-
cess that uses spray bars moved up and down between the
plates by a robot. The water pressure required for this is at
least 50 bars. A multistage centrifugal or a piston pump
is used for this duty. Process water is usually used because
the total water volume required for a full cloth wash is
relatively small. Recycled water (filtrate) could possibly be
used instead of process water but there may be the need for
removing solid particles (polishing) so it’s compatible with
pump and the spray nozzles remain clean. Chloride content
Figure 2. cake moisture vs dewatering process for different copper tailings
is an especially important point, to avoid excessive capital
and operating costs the geotechnical engineer, where pos-
sible, must perform his tests with representative filter cake
so that the target moisture content specified is not unneces-
sarily low.
It is critical that detailed test work be carried out on
representative tailings slurry samples. Comprehensive labo-
ratory test work should trial different chamber configura-
tions (fixed-volume as well as variable-volume) so that the
most economic plate pack is selected for the full-scale fil-
ters (Kaswalder et al., 2014 Kaswalder et al., 2018) .This
work is normally carried out in a filtration laboratory using
a sophisticated bench-scale test unit as shown in Figure 3)
Membrane squeezing and cake blowing may be
included in the dewatering process. Feed pressure, squeez-
ing pressure and compressed air consumption must be
optimized to suit the cake moisture target. It is strongly
recommended that these tests be carried out on representa-
tive slurry samples (Kaswalder et al., 2014)
Once the plate pack configuration and the process has
been optimized, larger-scale pilot filters, shown in Figure 4,
can be used to produce the volumes of filter cake that geo-
technical engineers require so they can conduct their tests
on the material and use the results to design the full-scale
dry stack.
FILTRATE QUALITY MANAGEMENT
Filter Cloth Washing System
Many filter presses have a cloth rinsing system that needs
a water delivery of approximately 1,000 m3/h at relatively
low pressure. A standard centrifugal pump is used for this
duty. Recycled water or filtrate is usually used rather than
process water. The cloth rinsing stage of each filter cycle
normally lasts a few seconds (long enough for any cake resi-
due to be removed from the filter cloths). Storage tanks for
this cloth rinsing water need to be included in the overall
plant design. The cloth rinsing water needs to be collected
from each filter drip tray and it is usually returned to the
feed slurry upstream of the thickener.
More sophisticated filter presses can also be fitted with
a high-pressure cloth washing system that usually operates
once per day. This is a very thorough cloth washing pro-
cess that uses spray bars moved up and down between the
plates by a robot. The water pressure required for this is at
least 50 bars. A multistage centrifugal or a piston pump
is used for this duty. Process water is usually used because
the total water volume required for a full cloth wash is
relatively small. Recycled water (filtrate) could possibly be
used instead of process water but there may be the need for
removing solid particles (polishing) so it’s compatible with
pump and the spray nozzles remain clean. Chloride content
Figure 2. cake moisture vs dewatering process for different copper tailings