Note: Descriptions are shown in the official language in which they were submitted.
'Y~i
This invention desc~ibes a process for beneficiation
of titanium ores, which basically consists of the removal of
impurities from titanium ore through a series of mechanical
operations, rising the titanium dioxide content to levels
consistent with those required either for direct commercialization
or for the production of a raw material for more sophisticated
concentration processes, aiming at obtaining products with higher
titanium dioxide (TiO2) contents.
The world scarcity of high grade titanium ores has
caused intenslve research in order to obtain richer concentrates
from the poor ores.
The use of poor ores by a number of consumers has
led to the production of highly polluting effluents that go
against the low which is increasingly more strict against
pollution. This fact gives rise to the consumers increasing
need to search high grade concentrates which would reduce the
referred inconvenience to a minimum.
The various existing patents related to the bene-
ficiation of titanium ores generally use ilmenite, an abundant
ore with a TiO2 grade varying between 45 and 58~. The processes
for concentration of ilmenites, on the other hand, produce
polluting effluent substances, which simply transferred the
pollution problem from the consumer to the producer.
The present invention provides a process forbene-
ficiation of titanium ores, in which titanium appears as an
oxide, comprising the following stages: scrubbing and desliming
of the ore, followed by magnetic separation to remove magnetite;
grinding of the non-magnetic fraction and separation of fines to
obtain a ground concentrate which is subjected to flotatlon,
to remove phosphates; calcination and reduction of dry concentrate
obtained after flotation which then undergoes low intensity
magnetic separation to obtain a reduced non-magnetlc fraction;
the reduced non-magnetic fraction then undergoes electrostatic
separation to obtain a titanium oxide concentrate.
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In accordance with the p~esent iPxention scrubbing
and desliming may be pe~foxme~ until a f~actio~ ~et~een 18
and 0.105 millimeters is ohtained~
In accordance with the invention magnetic separation
may be carried out in a magnetic field of between 300 and
3000 Gauss.
In accordance with the invention the grinding of the
non-magnetic fraction may be carried out in closed circuit to
a size of 0.841 millimeters and the size calibration may be
carried out in a plain inclined and fixed screen.
In accordance with the present invention the flotation
may be carried out under conditions which make it possible to
obtain a concentrate with less then 3~ of P2O5.
In accordance with the present invention the calcination
may be carried out at a temperature equal to or less than
900C .
In accordance with the present invention the reduction
may be carried out at temperatures of between 400 and 600C
in a reducing atmosphere in which the gas for reduction contains
at least 10% of reducing gas.
In accordance with the present invention the electro-
static separation of the reduced non-magnetic fraction may be
carried out in an electric field of between 5 KV and 50 K~.
The importance of the new invention process for
beneficiation of titanium ore to obtain concentrates with high
TiO2 content is based on the use of ores in which titanium
is found as an oxide (TiO2) and not as a titanate which requires
chemical processes for its concentration. In this new invention
process, mechanicai operations are required and the production
of effluent substances is practically eliminated.
The invention now presented satisfies the co~sumer's
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needs to obtain a product with high TiO2 content which,
moreover, does not go against the increasingly rigid anti-
pollution laws during this operation.
According to this invention, the raw material used
in the new process are ores in which titanium appears mainly,
but not exclusively, as impure oxides, by the presence of
silica and compounds of iron, calcium, magnesium, pho9phorus,
aluminium, sodium and potassium.
The ore initially undergoes a disaggregation step
through scrubbing, followed by desliming when the fraction
above O.lOSmillimeters is recovered.
The fraction is recovered, with a maximum size of
18 milimeters, undergoes a low intensity magnetic separation
during which the magnetite is removed. The non magnetic
fraction is ground in closed circuit to attain 0.841millimeter~,
The fines are separated in a plain, inclined and fixed screen,
or in an equivalent equipment, which closes the circuit.
The uniformely ground material is then conditioned
with flotation anionic reagents and i~ sent to the rougher
flotation cell , producing a concentrate which undergoes at
least one operation in a cleaning flotation cell providing
a concentrate from which most of the impurities constituted
by phosphates have been removed.
The concentrate, after its drying, i~ sent to
calcining in rotating furnace at the maximum temperature of
900C. The calcined concentrate undergoes reduction at a
temperature between 400 and 600C with a reducing gaseous
mixture and while still hot, is submitted to a low intensity
magnetic separation.
The hot non-magnetic fraction is then sent to the
electrostatic separation ~ystem, constituted by at least two
stages. The first system produces a tailing from which
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silica and a pre-concentrate are removed as the main impurities.
In the second stage a final concentrate and a medium concentrate,
which is recircled, are obtained.
EXAMPLE
1000 kg of ore with 20,66% TiO2 content were fed to
a scrubber and were then sent to a classifier in which the
fraction with grain size above approximately 0.105millimeters
wa~ separated. This fraction, representing 56.9% of the
feeding, has undergone magnetic separation in 900 gauss field.
The non magnetic fraction, which represents 28.6%
of the feeding, fed a closed grinding circuit, reducing its
grain size to 0.841 milimeters. At this stage the fraction
has already presented a content of 41.09% of TiO2.
The pulp obtained was conditioned and floated for
the removal of phospates.
After drying and calcining at 700C, the flotation
concentrate was cooled down to 500C and reduced in a reducing
atmosphere containing 24% of C0.
The reduced material, still hot, was submitted to
a magnetic separation in 900 gauss field, providing a non-
magnetic concentrate with 55.25% of TiO2.
While still hot, the fraction was sent to the
first electrostatic separation in a 15 KV field, resulting
in the ~eparation of a ~iliceous tailing.
In a second electrostatic separation in a 25 KV field,
a final product with 84.70% of TiO2 and a tailing-which was
recycled in the first stage of the electrostatic separation
was obtained.
The results obtained are shown in the table below.
.
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Product o~ Weiqht % TiO2% Recovery
1. Calculated feeding100,00 20.66 100.00
2. Slime and fines 0,105mm 43.10 10.03 20.92
3. Magnetics 28.30 16.21 22.20
4. Phosphate concentrate 6.15 0.60 0.18
5. Magnetic 7.45 46.00 16~59
6. Siliceous tailing 7.83 28.28 10.72
7. Titanium concentrate7.17 84.70 29.39
The example above is presented for better clarifica-
tion to the experts in the technique, however it i~ not
limitative to the invention.
