FIELD OF THE INVENTION
The present invention relates to a development of direct reduced iron ore applicable in blast furnace. More particularly, the present invention relates to a development of directly reduced iron/sponge iron suitable for chargeable input in blast furnace for iron making which in turn convertible to steel by further processing.
BACKGROUND OF THE INVENTION
DRI is produced from iron ore in the rotary kiln. In this process iron ore is reduced in the solid state by removing oxygen using coal as the reducing agent. The removal of oxygen leaves a porous structure of iron ore and hence the density of DRI/sponge iron so produced is lower than that of iron ore. Because of its high porosity, DRI has poor thermal conductivity than pig iron or scrap. Therefore, the ideal melting unit for sponge iron should have concentrated high temperature heat source (such as an electric arc furnace) in order to maintain a high temperature differential between the DRI particles and the surrounding area. Therefore Electric Arc Furnaces (EAF) are the first users of DRI. However, with the passage of time, steel makers through blast furnace route also realized the benefits of using DRI.
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A prior art states knowledge, helps steel makers (through blast furnace route) started using DRI to augment hot metal production. When it started using DRI, it used the specification-that is DRI size 3-18mm with 80% (min) Fe Metallic. This was a standard product available in the market development primarily for Electric Arc Furnace.
The inventors during there research found that there are multiple problems with the present specification (3-18 mm) of DRI being used in steel industry as this DRI is primarily meant for EAF. The inventors during their research found that the present DRI has following disadvantages when used in blast furnace:
• Additional Crushing Operation in mines: At Present, Steel makers use 5-18 mm iron ore to produce DRI. In order to produce 5-18 mm iron ore, in mines lump iron ore of size less than 800 mm (<800), called Run-Of Mines (ROM) is crushed using three stage crushers called primary crusher, secondary crusher and tertiary crusher (as shown in figure - 2). At the end of operation, 35% fines of less than 5 mm are produced. The miners would like to maximize 5-18 mm size and minimize less than 5 mm. in other words, the use 5-18 mm iron ore for 3-18 mm sponge iron, produces 35% iron ore fines in mines.

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• Different size range of sponge iron as compared to other raw
material: Most of the raw material used in blast furnace are in
the range of 10-80 mm (Iron Ore: 10-40, Coke: 30-80, Sinter:
5-30) as shown in figure 3. DRI is the only raw material used
in size of 3-18 mm; this has a bearing on operating parameters
of furnace.
• Lower Permeability of Blast Furnace due to proportion of fines
in Sponge Iron: Fines (size less than 5 mm) affect
permeability/air draft and hence blast furnace performance. A
representative graph is shown in figure 4 for the impact of coke
undersize on permeability resistance. It is evident from figure 4
that as proportion of coke undersize increases, the permeability
resistance also increases. The same is can be extrapolated for
sponge Iron undersize as well. The size distribution of the
sponge iron shows that sponge iron of (3-18 mm size) normally
contains fine of approx. 4% of -3 mm sponge fines and 10-
15% of -5 mm sponge fines. In other words, the present
product of DRI brings -14-19% of fines (less than 5 mm)
which has a bearing on blast furnace permeabiiity.
OBJECTS OF THE INVENTION
It is therefore, an object of the present invention to propose a direct reduction of iron ore/sponge iron adoptable to chargeable input of blast furnace which eliminates the disadvantage of prior art.

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Another object of the present invention is to propose a direct reduction of iron ore/sponge iron adoptable to chargeable input of blast furnace which saves energy consumption upto 45%.
A still another object of th present invention is to propose a direct reduction of iron ore/sponge iron adoptable to chargeable input of blast furnace which increases metallic iron content of the burden of blast furnace by 5-7%.
A still further object of the present invention is to propose a direct reduction of iron ore/sponge iron adoptable to chargeable input of blast furnace which utilises low grade coal (high ash coal) for making sponge iron.
A further object of the present invention is to propose a direct reduction of iron ore/sponge iron adoptable to chargeable input of blast furnace which increases production by 6-10% for every 10% metallic irons in the burden.
A still further object of the present invention is to propose a direct reduction of iron ore/sponge iron adoptable to chargeable input of blast furnace which decreases steel making cycle time during subsequent processing.
An yet further object of the present invention is to propose a direct reduction of iron ore/sponge iron adoptable to chargeable input of

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blast furnace which develops a sponge iron having a size 3-40mm with Fe-Metallic of 80% minimum.
SUMMARY OF THE INVENTION
The development of a new product sponge iron/DRI suitable to address issues in entire value chain from mines to blast furnace. Comprising, the change of sponge iron size for 3 to 18mm to 5-30mm size sponge iron with minimum Fe-metaliic of 80% has been made in order to get the maximum advantage of improved permeability in the blast furnace and minimize generation of iron ore fines in the mines. By increasing the gap of tertiary crusher from 22mm to 34mm, iron ore of size 10-30mm can be produced with negligible effect on the production, resulting in increasing the yield of 10-30 (lumps) from 65% to 67% and reducing generation of iron ore fines by 6%.
Iron ore lumps having size 800 mm are taken from mines. These iron lumps are crushed in a primary crusher to reduce size of 200 mm and there are further crushed in a secondary crusher to reduce sizes 30-40 mm and these crushed particles are still further crushed in a tertiary crusher to reduce size in the order of (10-30)mm.
These 10-30mm size of iron are fed in a rotary kiln along with coke and dolomite for reduction of iron ore and converted to sponge iron. These sponge iron are passed through a cooler and next to a

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vibrating screen to get DRI lumps/sponge iron lump of 5-30 mm size and suitable for blast furnace chargeable Input material along with coke, sinter and iron ore. The use of 5-30 mm size DRI lumps/sponge iron will reduce the addition of DRI/sponge fines from 14-19%to less than 1%.
These reduction of the amount of fines in sponge iron, increases the permeability of the blast furnace resulting increase in production grain of 0.42% at the rate of lOOkg/thm in blast furnace
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING
Fig-1- shows a flow chart of manufacturing process of DRI/Sponge iron in prior art.
Fig-2- shows a flow chart three stage crushing of iron ore in prior art.
Fig-3- shows a line diagram of raw materials of hot metal production through blast furnace in prior art.
Fig-4- shows the effect of coke undersize on blast furnace permeability resistance in prior art.
Fig-5- shows a flow chart of DIR/Sponge iron production and usage in blast furnace (from mines to blast furnace) in prior art.

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Fig-6- shows a line diagram of raw materials of hot metal production through blast furnace
Fig-7- shows a flow chart of DRI/Sponge iron production in blast furnace (from mines to blast furnace) as per present invention.
DETAILS DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION
In the proposed invention as shown in the flow chart of fig 7 wherein the iron ore lumps of less then 800 mm size (1) are taken out from mines (2) and crushed then in a primary crusher (3) to reduce their size to a level of 200mm.
The crushed materials are screened and over size (4) of 200mm are again fed to primary crusher (3) for re-crushing.
The crushed ores of size 200mm (5) are again crushed to a secondary crusher (6) to reduce the size of ores to a level 30-40mm (7). The crushed ores are again screened and the oversize of 30-40mm ores are returned to the secondary crushed (6) for re-crushing. The iron ores of sizes 30-40mm are further crushed in a -tertiary crusher (8) to reduce size in the level of 10-30mm. the crushed material is further screened and the oversized of 10-30min iron ores (9) are returned and send for further crushing in the Tertiary crusher. The undersize of 10-30mm iron ores (10) are
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described and the size remaining to a level of 10-30mm are stored in a receiving system (12) from where the iron ores are fed to a DRI equipment (13) which consist of a (i) rotary kiln where the iron ores of size 10-30mm are fed along with coal and dolomite.
In the rotary kiln iron ores are converted into sponge iron/DRI. After convertion DRI/Sponge iron comes out the rotary kiln. It passes through a cooler (21) and (ii) a vibrating screen and yields as 5-30mm size of 100% DRI/sponge iron (14). These 5-30mm size of sponge iron/DRI (14), 10-40mm size of iron ore (15) (mean particle size-25mm) 30-80mm size of coke (16) (mean particle size-55mm), 5-30mm size of sinter (17) (mean particle size-18mm) are fed as chargeable input material into a blast furnace (18) which inturn produce hot metal (19). This DRI sizes enhances productivity gain of 0.42% @ 100 kg/thm in blast furnace (18) and increase in permeability will enhance the production of blast furnace by 1.1% loading to a saving potential of more Rs 30 Cores/year at the sponge iron consumption level of 4,65,000

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The DRI having size 5-30mm has minimum Fe-metaliic of 80%. The detailed specification of this proposed DRI is mentioned in the table below:
Present Product in use in Blast Furnace (PRIOR ART) Proposed Product of Inventors
Size 3-18 mm (-3 mm: 2% max) 5-30 mm (-5 mm: 1% max)
Fe Metallic 80% min 80% min
Sulphur 0.03% max 0.03% max
Phosphorus 0.05% max 0.05% max
Carbon 0.1 min 0.1 min
SiO2 2.5% max 2.5% max
Al2O3 2.5% max 2.5% max

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WE CLAIM
1. A device of producing sponge iron/DRI suitable for
chargeable input for iron making in blast furnace comprises:-
- a input supply system of iron ore (Run-of-mines).
- a crushing system to reduce the size of ore lumps.
- a converter unit (kiln) to transform iron ore to sponge
iron.
- a cooling system to quench sponge iron to reduce
temperature.
- a vibrating screening system to achieve a desire size of
sponge iron.
2. The device as claimed in claim 1, wherein the run of
mines material of input system in of the size 800 mm.

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3. The device as claimed in claim 1, wherein the device
system consists of three stages of crushers marked primary
crusher, secondary crusher and tertiary crusher.
4. The device as claimed in claim 3, wherein the Run-of-
Mines materials are supplied into primary crusher and are
crushed producing particles of size 200 mm at the out put of
the crusher.
5. The device claimed in claim 4, wherein the out put
material of size 200 mm at the primary crusher are fed to the
operation of the secondary crusher producing material of size
greater than 30 mm and less than 40 mm at the out put of the
secondary crusher.
6. The device as claimed in claim 5, wherein the out put
materials of size (30 to 40) mm are put to the input of the
tertiary crusher for further operation to produce the material
size (5 to 30)mm and less than 5 mm at the output of tertiary
crushing operation.

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7. The device as claimed in claim 6, wherein the particles
produced at the output of the tertiary operation are 67% of the
size of (5-30) mm and 33% of the size less than 5 mm.
8. The device as claimed in claim 7, wherein the particles of
size (5-30) mm are separated and collected in a receiving
system for further processing in a converter kiln.
9. The device as claimed in claim 8, the selected size of iron
ore particles are fed in a converter kiln along with coal and
dolomite to convert iron ore into sponge iron after reduction.
10. The device as claimed in claim 9, wherein the sponge iron
so produced are quenched in a cooler
11. The device as claimed in claim 10, wherein the cooled
sponge iron are separated from fines in a vibrating screen to
collect the desire size 100% is the range 5mm to 30mm.
12. A process for producing sponge iron/DRI suitable for the
chargeable input for iron making in blast furnace comprising
the following steps:-

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supplying the input material of Run-of-Mines of the size 800mm into a primary crusher to produce the particle size 200mm.
feeding the out put of primary crusher into a secondary crusher to produce the particle size of 30-40mm.
charging the out put of secondary crusher into at least one tertiary crusher to produce the particle size of 5 mm-30mm.
reducing the iron ore in a kiln with coal and dolomite to covert the iron ore into sponge iron.
quenching the sponge iron in cooer to reduce the heat
sorting the sponge iron by passing it in a vibrating screen to collect the desire size sponge iron (5-30mm) of size for use in blast furnace for higher permeability and higher productivity gain.

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13. The process as claimed in claim 12, wherein the particle
of size (5-30) mm are produced 67% and particles of size less
than 5mm are produced 33% of the total amount of total
amount of input material, resulting less amount of fine.
14. A device for producing sponge iron/DRI suitable for the
chargeable input for ion making in blast furnace as substantially
illustrated and described herein with reference to
accompanying drawings.
15. A process for producing sponge/DRI suitable for the
chargeable input for iron making in blast furnace a substantially
described and illustrated herein with reference to
accompanying drawings.
16. A blast furnace used the sponge iron/DRI of the site (5-
30) mm produced by the device as claimed in 1 to 11 and by
the process as claimed in 12, 13 and has higher permeability
and higher productivity by gain for the production of iron.

The development of a new product sponge iron/DRI suitable to address issues in entire value chain from mines to blast furnace. Comprising, the change of sponge iron size for 3 to 18mm to 5-30mm size sponge iron with minimum Fe-metaliic of 80% has been made in order to get the maximum advantage of improved permeability in the blast furnace and minimize generation of iron ore fines in the mines. By increasing the gap of tertiary crusher from 22mm to 34mm, iron ore of size 10-30mm can be produced with negligible effect on the production, resulting in increasing the yield of 10-30 (lumps) from 65% to 67% and reducing generation of iron ore fines by 6%.
Iron ore lumps having size 800 mm are taken from mines. These iron lumps are crushed in a primary crusher to reduce size of 200 mm and there are further crushed in a secondary crusher to reduce sizes 30-40 mm and these crushed particles are still further crushed in a tertiary crusher to reduce size in the order of (10-3G)mm.
These 10-30mm size of iron are fed in a rotary kiln along with coke and dolomite for reduction of iron ore and converted to sponge iron. These sponge iron are passed through a cooler and next to a vibrating screen to get DRI lumps/sponge iron lump of 5-30 mm size and suitable for blast furnace chargeable Input material along with coke, sinter and iron ore. The use of 5-30 mm size DRI lumps/sponge iron will reduce the addition of DRI/sponge fines from 14-19%to less than 1%.
These reduction of the amount of fines in sponge iron, increases the permeability of the blast furnace resulting increase in production grain of 0.42% at the rate of 100kg/thm in blast furnace