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A cluster of five cyclones, 600mm in diameter, operating in closed circuit on the two primary milling stages |
Multotec Ensures Improved Process Efficiencies At Nickel Upgrade Project In Zimbabwe
It is significant that Multotec
classification cyclones have been selected for a
nickel upgrade project where the primary objective
is to increase process efficiencies and ensure a
better yield.
Multotec received an order for the design,
manufacture and supply of various classification
cyclone clusters for installation in the nickel
recovery plant at a mine in southern Africa.
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“The existing plant is being upgraded
to increase capacity and we believe that the successful
performance and reliability of the Multotec cyclones
installed in the plant more than seven years ago played a
significant part in securing this order,” says Pieter
Neveling, contracts engineer at Multotec Process Equipment.
It was forecast that the underground ore body’s
grade was to increase substantially and the
processes being used are being upgraded to include
new technologies. While the extraction process
itself remains the same, the process control around
the new equipment has received greater emphasis with
the focus on achieving stable optimised feed
conditions.
“The Multotec cyclones make up one of the components of the whole circuit and
will certainly contribute to optimising this section of the circuit,” Neveling
explains.
Multotec was approached by the mine to assist in providing a more efficient
process solution. Multotec analysed the data based on the current operating
conditions and did test work analysis on the current ore body to optimise
equipment selection for the process.
Cyclones are being used for four process functions:
Primary milling cyclones
A cluster of five Multotec HC heavy duty cyclones were selected for this
particular application. The cyclones have steel shells and are rubber lined.
They have nominal diameters of 600 mm with cone angles of 30 degrees and include
barrel sections. The cyclones are housed in a five-way distributor, D5-60/5,
which includes the overflow and underflow launders, while knife gate valves are
used as isolation valves.
Regrind milling cyclones
A cyclone cluster of five Multotec polyurethane cyclones with diameters of 350
mm were selected for the regrind milling application. These Type
VV350-15-1/A-A70 cyclones are fitted with 15 degree cones. These cyclones are
fitted in a D5-35/5 5-way distributor.
MgO removal cyclones
If not removed from the circuit, magnesium oxide will have a detrimental affect
on the flotation efficiency, making this a critical component within the process
plant. A cyclone cluster of five Multotec polyurethane cyclones with diameters
of 350 mm were chosen for the removal of the magnesium oxide. These
VV350-15-1/A-b/40 cyclones are fitted with 15 degree cones. Overflow and
underflow launders are included. Knife gate valves are used as isolation valves
and the cluster was fitted in a D5-35 five-way distributor.
Dewatering cyclones
Multotec technology which improves the efficiency of the grinding process
through the use of dewatering cyclones was proven in the existing flow sheet and
this process was expanded in the new plant. In order to achieve a very fine cut,
a 100 mm diameter Multotec polyurethane cyclone was chosen for this application.
These Multotec cyclones were fitted with 8 degree cones and a barrel.
Due to the space constraints in the plant, a unique design was used; a 60-way
cyclone cluster housing sixty 100 mm diameter polyurethane cyclones. Overflow
and underflow launders are included while manual Saunders valves are used as
isolation valves.
“This design was a first for Multotec. Use of 3D modeling software made it
possible to design a complicated cyclone cluster with cyclones placed on two
pitch circles, thus enabling a scattered arrangement of two rows of cyclones on
the circumference of the distributor,” Neveling explains. |
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