FIELD OF INVENTION
The present invention generally relates to a method of producing a concentrate
containing very high purity iron oxide with very low alumina and silica from a
poor grade iron ore fines. More particularly, the invention relates to a process for
producing high purity Fe2O3 for value added applications including blast furnace
feed from a poor grade iron ore slime.
BACKGROUND OF INVENTION
Quality of the raw materials for the iron and steel industries plays an important
role in the downstream processes. The fines generated in the iron ore mines and
also in the iron ore washing plants do not satisfy the stringent specifications of
raw materials to be used either for value added application or blast furnace.
Iron ore are beneficiated all over the world for which several techniques are
being used namely spiral, floatex density separators, jigs, multi-gravity
separator, low and high intensity magnetic separator, flotation, selective
dispersion and flocculation and many more with advanced technologies. Iron ore
production entails generation of fines (10-25%) containing high alumina (6-8%),

which is unsuitable for direct use in the blast furnace. Assuming an annual
production of 150 tons of iron ore, the iron values to the tune of 15-25 million
tones is lost every year. The main drawback for use of iron ore ultra fines is
that high level of clay are associated with it. As a consequence, this ultra fines
being rejected and getting wasted including causing environmental hazards. The
particle size of these ultra fines is not suitable to beneficiate it by known
beneficiation processes such as (i) gravity or (ii) magnetic separation.
The known benefication processes separate minerals from the mixture of two
oxides. But, iron ore ultra fines are mixtures of different oxides, which have no
utility . It is mixed with goethite, silica, alumina, alumina silicate,refractory
minerals.
An efficient benefication technology is thus needed which is enabled to
effectively produce two valuable products from the waste which are respectively
suitable for fine magnetic particles for value added application and making
building material, refractory material, nano paint or nano coolant. Large
quantities of ultra fines are

generated during mining and washing of iron ores. If the alumina content of the
slimes can be reduced to below 2%, in the beneficiated product, the following
benefits can be derived immediately:
(1) High mine out put.
(2) Optimum utilization of the natural resources
(3) Reduction at the environmental hazardgenerated due to storage and
disposal of the unsuitable products.
(4) Higher productivity in the blast furnace and the sinter plant
(5) Inerface in production of value added products like application in medical
science, paint formulation, removal of hazardous element from
contaminated water and soil.
Due to ultrafineness of the particles, a process-selection from among the
established techniques has become difficult. Accordingly, it requires a more
dominating property than gravity or magnetic separation of such ultra fines. The
selective flocculation process is known to be adapted to separate iron oxide as
red mud from bauxite. It is expected that such a process could be considered to
beneficiate such ultra fines. Also this process can be deployed to improve the
brightness of selectively separated silica. Thus, a selective flocculation of these
fines could be a viable option for efficient separation of alumina and silica from
the iron bearing minerals.

OBJECTS OF INVENTION
It is therefore an object of the invention to propose a process for producing high
purity Fe2O3 for value added application and blast furnace feed from a poor
grade iron ore slime, which eliminates the prior art disadvantages.
Another object of the invention is to propose a process for producing high purity
Fe2O3 for value added application and blast furnace feed from a poor grade iron
ore slime, which provides a first grade of product containing only very low
amount of alumina and silica adaptable for high-valued product or blast furnace
feed.
A further object of the invention is to propose a process for producing high purity
Fe2O3 for value added application and blast furnace feed from a poor grade iron
ore slime, which provides a second grade of product containing high alumina and
silica suitable for making building or refractory material.

SUMMARY OF THE INVENTION
According to the invention, various grades of rejected ultra fines can be
separated out into two categories, (i) a concentrate for value-added applications
including blast furnace feed by the selective flocculation followed by peptization
process, the concentrate can be further separated into a good concentrate and
a high grade concentrate, the later requiring a two-step selective flocculation
process; and (ii) a tailing (with rich in alumina and silica) containing mostly as
sillimanite and quartz by selective dispersion and selective flocculation process.
Both the alumina and silica levels in the ultra fines are in the range of 2.5 to
14wt%. The alumina and silica levels in the concentrate can be dropped down to
a level of 0.8 whereas both the alumina and silica level in the tailing can be up to
21 wt% with varying level of yield of concentrate. The concentrate is most suited
as the feed material for iron making through the blast furnace route, whereas
the tailing is most suited as the feed material to make building material. The
tailing material may be potentially suited for other applications like feed material
for formulation of

nano paint and nano coolant. Added advantage is that this process is
environmental and eco friendly with zero waste.
Accordingly, the invention provides a process for producing a high purity Fe2O3
for value added application and blast furnace feed from a poor grade iron ore
slime . The process provides a concentrate containing a very high purity iron with
very low alumina and silica from the slime containing high alumina and silica
generated in the iron ore mines and the iron ore washing plants. According to
the process, all the oxide minerals are dispersed and subsequently flocculated
selectively under specific conditions. Two products are produced in this process,
namely a concentrate, and a tailing. The concentrate contains 68.5% Fe with
only around 0.8% alumina and 1.0% silica from the slime containing around
54.5% Fe, 7.61 % alumina and 7.42% silica. This concentrate is suitable for
value added applications like in medical science, paint formulation, removal of
hazardous elements from contaminated water and soil, and also as the blast
furnace feed. The tailing are generated in this process contains 29.8% Fe with
20.5% AI2O3 and 19.68% SiO2 present mainly as the sillimanite and quartz. This
tailing can be utilized as building and refractory material. This process is
environmental friendly with zero waste.

Thus the inventive process can effectively produce two valuable products from
the ultra fines of iron ore. One product is suitable for fine magnetic particle
application or for peptization whereas the other product is suitable for refractory
making, nano paint or nano coolant.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING
Figure 1- schematically illustrates in the form of a flow-chart of the process steps
according to the invention.
DETAILED DESCRIPTION OF THE INVENTION
According to the invention, the difference in surface charge of the iron bearing
minerals and the gangue minerals is utilized first to separate out a first part of
the gangue minerals present in the ultra fines. In the second stage, the materials
from the first stage is subjected to a selective flocculation by adapting modified
starch. By this process, the concentrate gets converted and suitable for use as
the raw material for blast furnace, and the tailing containing high alumina and
silica suitable for use as the building materials.
As shown in figure-1, a non-selective dispersion followed by a selective
flocculation process is proposed to separate out different levels of iron containing

ultra fines into (i) an iron rich concentrate, and (ii) a tailing having high level of
clay and refractory materials. The ultra fines are processed according to the
invention include the ground rejected material of various beneficiation processes
and hydro cyclone over-flow. The processable iron containing ultra fines is the
mixture of Fe, Si and Al oxides with different particle size. The alumina and silica
level of each includes in the range of 2.5 to 14 wt%. The particle size of the ultra
fines is in the range of 100 micron to 100nm, and separated into coarser (more
than 15 micron) and finer (less than 15 micron) categories, by adapting a
hydro-cyclone of different sizes. The coarser particles are caused to undergo wet
grinding under varied concentration to make it finer, finer particles being more
suitable for the process because they offer better liberation and better floc
formation. The dispersant used in the process includes different non-selective
dispersant with different dosages for example, sodium silicate and sodium
hexameta phosphate. The dosages of the dispersant are selected in the range of
20 to 150000 ppm, preferably in the range of 20 to 10000 ppm. The flocculant
includes different starch solutions under varied dosage. The starch includes
potato, wheat and maize. The starch solution comprises plain including caustic
starch solution with varied concentration of caustic for example, in the
concentration range of 0.1 to 10 wt%. The process can be implemented under
varied pH conditions. The range of pH solution includes 2.5 to 11, preferably 8-

10. The concentration of the ultra fines includes in the range of 2 to 25wt%, with
varied settling time for example, between 10 seconds to 20 hours. The process
includes different mixing processes to break agglomerated particles, the mixing
processe comprises magnetic stirring, mechanical stirring or mixing the ultra
fines in solution using ultrasonic treatment. The ultrasonic treatment includes a
treatment time in the range of 1 to 300 minutes under variable ultrasonic power.
The solvent includes double distilled water, distilled water, tap water and
industrial process water. The industrial process water includes different degree
of contamination with different metallic and non-metallic ions and bacteria.

We Claim:
1. A process for producing high purity Fe2O3 for value-added applications
including blast furnace feed from a poor-grade iron ore slime, comprising
the steps of:
-separating through a non-selective dispersion of iron-containing ultra fines
having different particle sizes ranging between 100 micron to 100 nm, into
coarser and finer categories in a plurality of hydrocyclones of different sizes,
wet-grinding the coarser category with a particle size of more than 15
microns under varied concentration to convert into finer category with a
particle size of less than 15 microns; and allowing the produced fines in a
single benefication step to undergo a selective flocculation by adapting a
modified starch which generates a first concentrate containing around 68.5%
Fe, 0.8% alumina, and 1% silica, and a first tailing containing around 29.8%
Fe, 20.5% alumina, and 19.67% quartz;

- allowing the first concentrate to undergo a further dispersion
followed by a further selective flocculation to produce high grade
concentrate and a second tailing, the high grade concentrate being
suitable for value-added applications; and
- allowing the first tailing to undergo a selective flocculation to
produce a second concentrate and a second tailing, the second
tailing being suitable as material for refractory and building
construction, wherein the second concentrate suitable for
peptization.

2. The process as claimed in claim 1, wherein the ultra fines constitutes the
mixture of Fe, Si, and Al-Oxides, and wherein the aluminium and silica
comprises 2.5 to 14 wt%.
3. The process as claimed in claim 1, wherein the dispersant comprises non-
selective dispersant applied with different dosages.
4. The process as claimed in claim 1 or 3, wherein the dispersant comprises
sodium silicate and sodium hexameta phosphate.

5. The process as claimed in claim 1 or 4, wherein the dosages of the
dispersant is selected in the range of 20 to 15000 ppm, preferably in the
range of 20 to 10000 ppm.
6. The process as claimed in claim 1, wherein the starch includes potato,
wheat, maze, and wherein the starch solution comprises a plain including
a caustic starch solution with varied concentration of caustic starch for
example, in the concentration range of 0.1 to 10.0 wt%.
7. The process as claimed in claim 1, wherein the process is enabled to be
implemented under varied pH-concentration for example, in the range of
2.5 to 11, preferably in the range of 8-10.
8. The process as claimed in claim 1, wherein the concentration of the
ultrafines is in the range of 2 to 25 wt% with varied settling time for
example, between 10 seconds to 20 hours.

9. The process as claimed in claim 1, wherein the ultrasonic treatment
comprises a treatment time in the range of 1 to 100 minutes under
variable ultrasonic power, and wherein the solvent comprises one of a
double-distilled water, tap water, and industrial process water.
10. A process for producing high purity Fe2O3 for value-added applications
including blast furnace feed from a poor-grade iron ore slime, as substantially
described and illustrated herein with reference to the accompanying drawings.

The invention relates to a process for producing high purity Fe2O3 for valueadded
applications including blast furnace feed from a poor-grade iron ore slime,
comprising the steps of separating through a non-selective dispersion of ironcontaining
ultra fines having different particle sizes ranging between 100 micron
to 100 nm, into coarser and finer categories in a plurality of hydrocyclones of
different sizes, wet-grinding the coarser category with a particle size of more
than 15 microns under varied concentration to convert into finer category with a
particle size of less than 15 microns; and allowing the produced fines in a single
benefication step to undergo a selective flocculation by adapting a modified
starch which generates a first concentrate containing around 68.5% Fe, 0.8%
alumina, and 1% silica, and a first tailing containing around 29.8% Fe, 20.5%
alumina, and 19.67% quartz; allowing the first concentrate to undergo a further
dispersion followed by a further selective flocculation to produce high grade
concentrate and a second tailing, the high grade concentrate being suitable for
value-added applications; and allowing the first tailing to undergo a selective
flocculation to produce a second concentrate and a second tailing, the second
tailing being suitable as material for refractory and building construction, wherein
the second concentrate suitable for pelletization.