BATEMAN jig for iron-ore processing
Tests conducted at the Sishen Iron Ore Mine in the Northern Cape
Province, South Africa, have proved that the incorporation of the
enhanced technology of a new fines gate has overcome the problem experienced
worldwide in the separation of fine ferrous ores. The new jig gate
minimises the back mixing of fine concentrate with reject before discharge.
BATEMAN can therefore offer a leading-edge solution to the processing
and upgrading of ferrous ores using jigs.
In addition, the PLC based JigScan controller offered with APIC jigs
for beneficiation of ferrous ores provides improved control over product
quality, consistency and higher yields of "on-specification"
product.
The upgrading of ferrous ores by jigging has been a definite trend
in recent years in South Africa, as well as internationally in countries
such as Australia, India and South America. In cases where the cut
density exceeds 4,0 g/ml or where test work has shown that jigs offer
sufficient performance, jigs are now the preferred route, as opposed
to other density-separation techniques, due to their simplicity and
low running costs.
An ongoing development programme by BATEMAN, in association with
Mintek and the Julius Kruttschnitt Mineral Research Centre (JKMRC)
in Australia, has seen major improvements in the technological components
of these air-pulsed gravity separators, and has ensured that the BATEMAN
jigs offer superior separating performance for a wide range of materials
with specific gravities from above 1 (coal) to as high as, but not
limited to, 7 (ferroalloys).
The new BATEMAN fines gate system, designed by the BATEMAN jigging-group
engineers from the first test-work phase with the client, enables
the APIC jig to beneficiate fine ore fractions to required product
specifications. Tests, using a long-profile, half industrial-scale
APIC jig at Sishen, had shown that beneficiation of lumpy ore (-25
mm +8 mm) was achieved easily. However, typical of conventional fines
jigs around the world, beneficiation of finer fractions to product
specification could not be achieved with an absolute consistency because
of sometimes misplaced material at the gate discharge. Chemical analysis
of the layers of ores in the jig showed that, while the jig had stratified
the coarse sinter material very well, up-currents before the gate
of the pilot jig were too strong, resulting in some fine particles
remixing during the releasing cycle.
However, further tests at Sishen using the new gate, reported on
in a paper by Kumba Resources, showed that after only a few trial
runs the coarse sinter specification was not only exceeded, but was
achieved with absolute consistency. The percentage iron in the product
varied between 65 and 66% with an iron recovery above 85%.
For lumpy ore, the product specification was reached consistently
throughout, with the percentage iron in the product easily reaching
66%, with an iron recovery above 90%.
The JigScan control system is the result of an initial 10 years of
development by JKMRC, and has been used very successfully in industry,
with one JigScan user crediting the system with an 8 % improvement
in yield of on-specification fine iron ore. With this fully-integrated
automatic system, much of the operator attention needed for efficient
operation of a jig is reduced or eliminated and the operator can focus
on other tasks. The system maintains a stable stratification, automatically
rectifies abnormal behaviour due to feed or fluid dynamics and sequences
start-ups and shut-downs to optimise production. JigScan is now fitted
with high-speed programmable logic controllers (PLC) offering well
known advantages over computer based systems.
Bucket elevators for the extraction and dewatering of sinks material
after separation are standard equipment on pneumatic jigs despite
heavier maintenance costs. However, screen discharge systems installed
under the jig hutches are now used by BATEMAN in all APIC jigging
plants to reduce operating costs and plant price.
For more information, please contact:
Vincent Dieudonné, Manager, Jigging, on +27-11-899-2343, or
email jigging@batemanengineering.com;
or
Grant Loveday, Process Engineer (Australia) at +61-7-3320-3327,
or email grant.loveday@batepro.com.au.
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Copyright BATEMAN 2004
BATEMAN
APIC JIG
