PUMPS_proof 23/08/2016 15:19 Page 3
PUMPS
The newly upgraded HVF Pump is available for
purchase from GIW — and its list of applications
is still growing. It has been tested extensively in
the company’s advanced hydraulics lab, and it is
currently slated to undergo an even more
specialised and rigorous testing process that
places the new urethane suction liner and insert
in the most tenacious, aggressive applications
“What usually happens with froth pump
applications is that the air builds up at the
suction eye and causes the pump to quit
pumping,” he says. “Depending on the size of
the plant, it can be very disruptive. You have to
shut down pumps, let the system settle, and then
restart the pumps. In some plants, this has been
accepted as part of the process, so to account for
this, duplicate pumping systems have been
installed so while one is operating, the other can
be shut down in order to reprime.”
The HVF Pump helps overcome this costly and
time-consuming obstacle by having venting holes
in the froth impeller and a de-aeration chamber
that removes and redirects the air to the top of
the sump.
“We found a way to remove the air,” Inglett
says. “It seemed so obvious once we designed it,
but it was something completely new for slurry
pumps.”
The product has been an excellent addition to
GIW’s line of slurry pumps. However, Inglett and
his team realised that the design could be
improved upon even further.
While froth typically isn’t abrasive, some
applications float silica or separate other
aggressive, ultrafine materials that result in
more wear. GIW engineers decided to
upgrade the materials and design to make
the pump more marketable and useful in
both regular situations and these higherwear applications.
The HVF Pump is now designed with a
urethane suction liner and insert for the deaeration chamber, and for applications that rely
on elevated temperatures, it can also take a highchrome metal suction liner or insert. The new
HVF Pump parts are more compact to minimise
interference, and they feature standard-sized,
threaded connections that simplify installation.
Additionally, the high-chrome grade of the
impeller has been upgraded across the entire line
of pumps, which can triple wear life.
“If the customer has more aggressive froth
services, this pump will cover it,” Inglett says.
“When it comes to design and materials, GIW
strives to put our best foot forward to develop a
pump suited for the application.”
Tough slurry pumping
FLSmidth is delivering a Counter Current
Decantation (CCD) thickener circuit at Swakop
Uranium’s Husab project in Namibia. The scope of
the order for the Husab CCD circuit comprises
eight 40 m diameter thickeners, one of which is a
high density pre-leach feed thickener and the
other seven being high rate CCD thickeners.
FLSmidth is also supplying a 25 m diameter ADU
(ammonium diuranate) high rate thickener for
installation further down the process. In addition
to this, 38 Krebs® centrifugal pumps will also be
installed in all slurry pumping applications on the
project.
The CCD thickener circuit is used to recover
soluble metal as pregnant liquor solution from
ore leach residue. The basis of CCD operation is
to concentrate the leached solids, thereby
minimising liquor content in the underflow slurry
that flows in one direction. The underflow slurry
is then diluted with wash liquor that flows in the
opposite direction, while the leached solids are
concentrated repeatedly. The amount of liquor in
the thickener underflow contributes to
determining the number of CCD stages required
to recover the desired amount of soluble metal.
SEPTEMBER 2016 | International Mining 111