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CADD generated plan of the primary wet treatment plant designed for
Iscor.
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Heavy minerals treatment plant for Iscor
Bateman Minerals and Industrial Limited has completed the conceptual
and detailed engineering of a 1 200 t/h primary wet treatment plant
for Iscor Heavy Minerals to be built at the Hillendale site near Empangeni,
RSA.
The Primary Wet Treatment Plant (PWP) will separate the gangue material
in the run-of-mine-ore to produce a heavy minerals concentrate (HMC).
The HMC containing ilmenite, rutile and zircon will be transported to
the Minerals Separation Plant (MSP) for further processing.
Details of the process are as follows. The heavy mineral bearing sand
is mined using high pressure water jets. The resulting slurry is pumped
to a rotating trommel screen where the oversized waste material, mainly
vegetation, is removed. The trommel undersize material is collected
in a constant density tank where the slurry is densified and then diluted
to a predetermined density. The slurry is then pumped to the spirals
circuit where it passes through five stages of spiral concentration
to separate the heavy minerals from the lighter gangue. After removal
of the magnetite using a low intensity magnetic separator the HMC is
pumped to a cyclone mounted at the end of the stacker. There it is dewatered
and placed directly on the stockpile from where it is trucked to the
MSP. Sand tailings from the spirals circuit is pumped to the dune rehabilitation
area as backfill. Slimes generated by the PWP are thickened and separated
from the process water using ultra high-rate thickeners.
Several aspects of this project contributed to its complex nature. The
plant comprises a large amount of gravity feed piping which required
careful design. As HDPE (high density polyethylene) will be used extensively
in the spirals circuit to minimise corrosion, the design also required
a considerable amount of supporting steelwork for the HDPE piping.
After three years of operation the plant will have to be moved to a
new site 2 km away. This has been catered for in the modular design
which will enable the major components such as the trommel screen, the
spirals buildings, 12 m diameter thickeners, pipe racks and the stacker
to be moved as separate units with minimal uncoupling of piping and
other gear. About seven years later a more difficult move to a site
39 km distant is envisaged, possibly requiring the plant to be broken
down into even smaller components no larger than 7 to 8 m in height
to comply with road transport restrictions. As a result all tanksare
flanged and the structures have splices to permit dismantling. Some
items such as the flocculant plant, motor control centres (MCCs) and
switch gear assemblies are to be supplied in standard containers for
easy transport. These items will be fully assembled and pre-tested off-site
before delivery.
This phase of the work was awarded as a lump sum contract to BATEMAN
in August 1997 and took about one year to complete. BATEMAN’s responsibilities
included the process engineering and the structural, mechanical, piping,
electrical and instrumentation engineering and design.
Iscor envisages that the next two phases of the project could commence
after mid-1999 which will involve the inspection and expediting of the
equipment, construction management and hot commissioning of the plant.
Should Iscor proceed, BATEMAN will handle phases two and three of the
project.
Please contact Vincent Diesel, Director Special Projects,
on +27-11-899-3213 or
email: industrial.minerals@batemanengineering.com
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