TECHNICAL FIELD
[0001] The present disclosure is in the field of metallurgy. More particularly the disclosure
relates to production of a rounded iron powder.
BACKGROUND OF THE DISCLOSURE
[0002] Powdered form of iron, typically in the range of 1-250 microns are iron powders.
Conventional iron powder manufacturing techniques involves Physical (Atomization,
electrolytic) chemical (reduction, decomposition) and mechanical (comminution) ones among
which physical and chemical routes are widely acceptable. Purity, size and shape of iron
powders are specific to their method of synthesis and also influence their end applications.
[0003] Iron powders cater to spectrum of applications including diamond cutting tools, food
fortification, water purification, metal injection moulding, electromagnetic shielding, soft
magnetic composites, break pads, welding electrodes, chemical catalysts, oxygen absorbers,
etc. Among the aforementioned list, certain applications like metal injection molding, soft
magnetic composites and electromagnetic shielding are considered premium due to their
demand for high purity, finer powder size and rounded/spherical morphology. Comparative
study on iron powder properties obtained from various methods of synthesis reveals that iron
powders with spherical morphology, apparent density (AD) of 2.7 to 3.6 and mean particle size
of 4 to 5 microns are synthesized by carbonyl route., iron powders with spherical morphology,
AD > 3 g/cc and mean particle size 60-80 microns are synthesized by gas atomization, iron
powders with irregular morphology, apparent density (AD) of 2.8 to 3 g/cc and mean particle
size of 75 to 105 microns are synthesized by water atomization, iron powders with flaky
morphology, AD of 2 to 2.8 g/cc and mean particle size 40 to 70 microns are synthesized by
electrolytic, and iron powders with irregular morphology, AD of 1.5 to 2.4 g/cc and mean
particle size of 50-75 microns is synthesized by reduction routes.
[0004] Other than carbonyl and gas atomization, rest all method yield irregular iron powders
only. Thus, it is evident that synthesis of iron powders with spherical morphology is important
yet challenging due to high cost of production. However, recent technology advancements in
fields like additive manufacturing (binder jet printing) is shifting widely to accommodate non-

spherical powders. One such alternative that the industry is looking forward to is rounded iron
powder and make the instruments/machine/process in conformity.
[0005] Prior art on synthesis of iron powders of various morphologies from iron oxide exists,
but synthesis of rounded iron powders from irregular iron oxide is less explored. In a patent
US3214262, researchers proposed a method of producing iron powder in which, iron oxide
powder is agglomerated to briquettes and subjected to subsequent heating and reduction to
produce sponge iron, which is further pulverized to produce iron powder. In another work,
US2860044, iron oxide is first mechanically milled to lower sizes and then chemically reduced
to sponge iron cakes, which is further subjected to comminution to get iron powders.
[0006] In a patent US2668105, pulverized iron oxide which is free from silica is mixed with
carbohydrate material which is reduced to get sponge iron which is further ground to iron
powder. In another patent, US2759808, iron powder is produced from iron oxide by the steps
comprising, pulverizing of iron oxide to finely divide form, mixing iron oxide with coke and
binder materials, forming the mixture into briquettes, reducing the formed briquettes in
reduction atmosphere, cooling the treated briquettes and final pulverization of briquettes to
obtained a powdered iron form. In a work, US2927015, researchers proposed synthesis of iron
powder from mill scale iron oxide in which mill scale iron oxide is preliminarily mixed with
ground charcoal and is charged into a retort heating at sufficient temperature and time to get a
reduced product, which is finally pulverized to get pure low-density iron powder.
[0007] In a different work, US3597188, spherical iron shots are made by atomization of molten
stream of iron with a jet of water followed by sintering of obtained spherical shot in presence
of decarburizing agent and subsequent grinding to get high apparent density spherical iron
powders. Other work to obtain spherical iron powder from iron oxide is reports in the patent
US6589667. In this work, synthetically prepared iron containing materials are subject to spray
drying to get spherical dry powders which is further heat treatment for sufficient time and
temperature in a reducing furnace in presence of reducing gases and the product obtained is
optionally sintered to obtain spherical, porous, high strength iron powders. In another
interesting work, US5713982, iron powders of rounded morphology are produced by a method
comprising of steps like heating of sized iron oxide material, reducing the iron oxide material
at suitable temperature and time, cooling the reduced product and finally milling the cooled
product.

[0008] In the above works reported sponge iron powder of lowest density 1.3 to 1.5 g/cc and
mean particle size of 100 microns is produced by use of pulverized mill scale mixed with
charcoal or iron oxide as raw materials (US2927015). No details on the properties of raw
materials used is described. Iron oxide raw materials like pulverized iron oxide and iron ore
are typically used and are being agglomerated in the form of briquettes along with reducing
agents like coke or carbohydrate materials or charcoal which acts as reducing agents.
[0009] Usage of iron oxide without any pre-treatment is not explored. Also, the properties of
iron powders obtained post reduction with respect to their purity, particle size, surface area and
density is not mentioned. Overall, most of the works begun with the iron oxide material to end
up with sponge iron powder synthesis. Synthesis of spherical iron powder is made mostly by
use of molten iron only.
OBJECTS
[0010] An object of the invention is to find a process to produce fine rounded iron powder
from the irregular iron oxide.
[0011] Another object of the invention is to produce a rounded iron powders with lesser carbon
content.
[0012] Another object of the invention is to produce the rounded iron powders with cost
efficient and less complicated process.
STATEMENT OF THE DISCLOSURE
[0013] The present invention provides a method for producing a rounded powders, comprising:
simultaneously heating and reducing an iron oxide in a thermo reduction furnace at 600
0C to 1000 0C under a hydrogen rich gaseous atmosphere to obtain a sponge iron; and
bombarding the sponge iron by means of pressurized gases for 30 to 60 minutes to
obtain the rounded iron powders in an enclosed metallic chamber.
The provision of bombardment of the sponge by means of pressurised gas over the
sponge iron powders with irregular morphology, flowery nature and high surface area for a
prescribed time undergoes inter particle collision as well as collision with pressurized gaseous
jets which leads to intra particle breakage to form finer fractions.

In a preferred embodiment, simultaneously heating and reducing the iron oxide is done for 2
to 6 hrs.
In a preferred embodiment, simultaneously heating and reducing of the iron oxide is done for
2 to 6 hrs.
In a preferred embodiment, the sponge iron is comminuted to produce sponge iron in powder
form when treated at 750 0C to 1000 0C.
In a preferred embodiment, the iron oxide is in the form of powder having chemical
composition of Fe(T) 69.01 to 69.67, ferrous oxide (FeO) 0.26 to 0.77, Silicone dioxide (SiO2)
0.01 to 0.17, calcium oxide (CaO) 0.01 to 0.1, magnesium oxide (MgO) 0.02 to 0.03, manganese
oxide (MnO) 0.18 to 0.27, aluminium oxide (Al2O3) 0.13 to 0.3, sulphur (S) 0.001 to 0.02, carbon
(C) 0.02 to 0.06, along with other incidental trace elements (all in wt%).
In another embodiment, the iron oxide is one or in combination(s) of natural, synthetic,
industrial by-product powder.
In another embodiment, the iron oxide is obtained by spray roasting of pickling solution
obtained during acid recovery process in steel making plant.
In another embodiment, the hydrogen rich gas is one or in combination(s) of cracked ammonia,
hydrogen separated from coke oven gas, pure hydrogen and hydrogen from cracked methane.
In yet another embodiment, the sponge iron comprises irregular morphology with mean particle
size (D50) < 60 microns, purity (Fe(T)%) > 97%, apparent density < 0.7 g/cc, tap density < 1.2
g/cc, hausner ratio >1.7 and BET surface area > 0.7 m2/g when the iron oxide is heated and
reduced at 600 0C to 750 0C.
In yet another embodiment, the sponge iron comprises irregular morphology with mean particle
size <30 microns, purity (Fe(T)%) >97 %, apparent density >0.7 g/cc, tap density >1.2 g/cc,
hausner ratio >1.7 and BET surface area >0.4 m2/g when the iron oxide is heated and reduced
at 750 0C to 1000 0C.
In yet another embodiment, the sponge iron powder is porous with flowery particles.

In still another embodiment, the comminution is facilitated by one or in combination(s) of
impact, shear, attrition, compression, inter particle collision forces by use of one or in
combination(s) of crushers and mills.
In still another embodiment, the pressurized gas used in the bombardment is one or in
combination(s) of inert gases.
In still another embodiment, the pressurized gas streams possess a pressure > 4 bar.
In still another embodiment, enclosed metallic chamber is part of opposed jet mill or fluidized
jet mill or jet mill.
In another embodiment, the present invention provides a rounded iron powder, comprising:
round morphology, with mean particle size (D50) <13 microns, purity (Fe(T)%)
>97 % and C<0.05 (all in wt%).
In a preferred embodiment, wherein the composition of the rounded iron powder is
C- 0.01 to 0.05, Ni- 0.01 to 0.02, Mo- 0.001 to 0.002, Si- 0.03 to 0.05, Al- 0.002 to
0.01, Mg- 0.05 to 0.1, Ti- 0.01 to 0.03, Mn- 0.1 to 0.4, P- 0.01 to 0.03, S- 0.004 to 0.008, Cr-
0.006 to 0.02, W-0.01 to 0.02 Rest Fe and non-traceable impurities (all in wt%).
In an embodiment, the apparent density > 3 g/cc, tap density > 4 g/cc.
In another embodiment, the hausner ratio <1.4.
In yt another embodiment, the BET surface area >0.4 m2/g.
In still another embodiment, the particle size D90 < 30 microns, D50 < 13 microns and D10 < 8
microns.
BRIEF DESCRIPTION OF THE ACCOMPANYING FIGURES
[0014] FIG. 1 depicts a process for producing a rounded iron powder in accordance with an
embodiment of an invention.
[0015] FIGS. 2a- 2b depicts X-ray Diffraction graph and SEM of an iron oxide raw material
for the Process of FIG. 1 as per the experimental analysis.

[0016] FIGS. 3a-3b depicts X-ray Diffraction graph and SEM of a sponge iron powder of the
Process of FIG. 1 as per the experimental analysis.
[0017] FIGS. 4a-4b depicts X-ray Diffraction graph and SEM of the rounded iron powder of
the Process of FIG. 1 as per the experimental analysis.
DETAILED DESCRIPTION OF THE DISCLOSURE
[0018] In accordance with an embodiment of the invention, a method (100) for producing a
rounded iron powder has been described as shown in FIG. 1. At step (104), simultaneously
heating and reducing of an iron oxide in a thermo reduction furnace at 600 0C to 1000 0C under
a hydrogen rich gaseous atmosphere is done to obtain a sponge iron.
[0019] At step (108), bombarding the sponge iron by means of pressurized gases for 30 to 60
minutes is done to obtain the rounded iron powders in an enclosed metallic chamber.
[0020] In an embodiment, simultaneous heating and reduction of the iron oxide is performed
at a temperature at 600 oC, or at 650 oC or at 700 oC or at 750 oC or at 800 oC or at 850 oC.
[0021] At step 104, the irregular shape of the iron oxide reacts with reducing hydrogen rich
gases to undergo reduction from hematite to magnetite to wustite to form the sponge iron with
porous, flowery particles and irregular morphology.
[0022] The iron oxide can be fed into the thermo-reduction furnace or other such furnace. The
thermo-reduction furnace in an embodiment can be but not limiting to tubular type, pusher
type, steel belt type or walking beam type.
[0023] The iron oxide is in the form of powder having chemical composition of Fe(T) 69.01
to 69.67, ferrous oxide (FeO) 0.26 to 0.77, Silicone dioxide (SiO2) 0.01 to 0.17, calcium oxide
(CaO) 0.01 to 0.10, magnesium oxide (MgO) 0.02 to 0.03, manganese oxide (MnO) 0.18 to
0.27, aluminium oxide (Al2O3) 0.13 to 0.30, sulphur (S) 0.001 to 0.020, carbon (C) about 0.02
to 0.06, along with other incidental trace elements (all in wt%). The X-ray diffraction and SEM
of the iron oxide used in one of the embodiment as experimental analysis is shown in FIGS
2a-2b.
[0024] The simultaneous duration for heating and reduction in an embodiment is 2 to 6 hrs.

[0025] In an exemplary embodiment, simultaneous heating and reduction of iron oxide is
performed for 2 hrs, or at 3 hrs, or 4 hrs, 5 hrs, or at 6 hrs.
[0026] The iron oxide when heated and reduced at temperature between 600-750 deg. C, the
sponge iron obtained is either in the form powder or loose cake and that can be powdered easily
which does not require any kind of comminution.
[0027] When the iron oxide is heated at 750-1000 deg. C, the sponge iron obtained is in the
form of cake which is comminuted to produce in the form of powder.
[0028] In an embodiment, comminution is facilitated by one or in combination(s) of impact,
compression, shear and attrition forces by use or in combination(s) of crushers and mills not
limited to jaw crusher, hammer mill, centrifugal mill or vibratory disk mill.
[0029] In an embodiment, comminution is applied for a time period in the range of 5 minutes
to 30 minutes. In an exemplary embodiment, comminution is applied for a time-period of 10
minutes, or 20 minutes.
[0030] In an embodiment, the iron oxide is one or in combination(s) of natural, synthetic,
industrial by-product powder. The iron oxide synthetic powder is produced by spray roasting
of pickling solution obtained during an acid recovery process in steel making plant.
[0031] In an embodiment, when the iron oxide is heated and reduced at 600 0C to 750 0C, the
sponge iron comprises irregular morphology with mean particle size (D50) < 60 microns, purity
(Fe(T)%) > 97%, apparent density < 0.7 g/cc, tap density < 1.2 g/cc, hausner ratio >1.7 and
BET surface area > 0.7 m2/g.
[0032] Similarly, when the iron oxide is heated and reduced at 750 0C to 1000 0C, the sponge
iron obtained comprises irregular morphology with mean particle size <30 microns, purity
(Fe(T)%) >97 %, apparent density >0.7 g/cc, tap density >1.2 g/cc, hausner ratio >1.7 and BET
surface area >0.4 m2/g. The diffraction and SEM of the sponge iron in one of the embodiment
as experimental analysis is shown in FIGS 3a-3b.
[0033] Furthermore, the iron oxide is not limited to synthetic hematite but may also include a
synthetic hematite from other sources and/or magnetite and/or iron-oxyhydroxide that has a
high iron content. The process may also be extended to the other type of iron oxide ore as well.

[0034] The hydrogen rich gas is one or combination(s) of cracked ammonia, hydrogen
separated from coke oven gas, pure hydrogen and hydrogen from cracked methane. Other
sources for Hydrogen rich gas may also work.
[0035] At step 108, the sponge iron is subjected to bombardment by means of pressurized gas
jets at a prescribed pressure in the enclosed metallic chamber which is part of opposed jet mill
or fluidized jet mill or jet mill for a prescribed time.
[0036] At this step, the sponge iron powders with irregular morphology, flowery nature and
high surface area when subjected to bombardment by means of pressurized nitrogen gas jets at
a prescribed pressure in an enclosed metallic chamber of opposed jet mill or fluidized jet mill
or jet mill without classification for a prescribed time undergoes inter particle collision as well
as collision with pressurized gaseous jets which leads to intra particle breakage to form finer
fractions.
[0037] Simultaneously these finer fractions get into rounded morphology due to the inherent
spongy nature of synthesized sponge iron powders.
[0038] In an embodiment, bombardment is performed by means of pressurized inert gases like
nitrogen or argon or combination(s).
In an embodiment, the inert gases pressures >4 bar.
[0039] The rounded iron powder comprises of rounded morphology, with mean particle size
(D50) <13 microns, purity (Fe(T)%) >97 %, C<0.05, apparent density > 3 g/cc, tap density >
4 g/cc, hausner ratio <1.4 and BET surface area >0.4 m2/g.
[0040] The rounded iron powders comprises of particle size D90< 30 microns, D50<13
microns and D10< 8 microns. The diffraction and SEM of the rounded iron powder in one of the
embodiment as experimental analysis is shown in FIGS 4a-4b.
[0041] Rounded morphology of the powders can be explained as the morphology between
irregular ones and true spherical ones, mostly nearby spherical morphology. Though they do
not feature the sphericity and flowability as with the spherical powders, they stand far superior
to irregular ones.
[0042] Comparison between the SEMs of the iron oxide, the sponge iron and the rounded iron
powder distinctly depicts the rounded morphology for rounded iron powder.

[0043] The composition of the rounded iron powder is C- 0.01 to 0.05, Ni- 0.01 to 0.02, Mo-
0.001to 0.002, Si- 0.03 to 0.05, Al- 0.002 to 0.01, Mg- 0.05 to 0.1, Ti- 0.01 to 0.03, Mn- 0.1 to
0.4, P- 0.01 to 0.03, S- 0.004 to 0.008, Cr- 0.006 to 0.02, W-0.01 to 0.02 Rest Fe and non-
traceable impurities (all in wt%).
Examples:
[0044] Rounded iron powders are synthesized by the method as stated in Process (100) where
the iron oxide is a spray roasted by-product of steel making plant. Chemistry/composition of
the iron oxide powder is provided in Table 1. The X-ray diffraction analysis and SEM of the
iron oxide raw material is shown in the FIG. 2a-2b respectively.
Table 1

Composition
(wt %) Fe(total)
[Fe(t)] FeO
0.39 CaO
0.01 SiO2
0.08 S MgO MnO Al2O3
0.02 0.027 0.26 0.16 C
Spray Roasted
Iron Oxide 69.15



0.041
Table 2 (Example 1)

Process Attributes Values for Sponge Iron
Powder Values for Rounded Iron
Powder
Thermo-reduction furnace Pusher type Not Applicable
Hydrogen rich gas Source Cracked ammonia Not Applicable
Temperature 700 deg C Not Applicable
Time duration 240 minutes (4 hrs) Not Applicable
Fe (T) % 97.8 97.3
Apparent Density (g/cc) 0.67 3.34
Tap Density (g/cc) 1.15 4.42
Hausner ratio 1.72 1.32
Particle size D90 /D50 /D10
(microns) 57.4 (D50) 18.8/8.3/4.3
BET surface area (m2/g) 0.71 0.47
Bombardment Time Not Applicable 60 minutes (1 hr.)

Morphology Irregular Rounded
Comminution facilitated Not required Not required
Gas Pressure Not Applicable 6 bar
Pressurized Gas Not Applicable Nitrogen
Table 3 (Example 2)

Process Attributes Values for Sponge Iron
Powder Values for Rounded Iron
Powder
Thermo-reduction furnace Pusher type Not Applicable
Hydrogen rich gas Source cracked ammonia gas Not Applicable
Temperature 650 deg C Not Applicable
Time duration 300 minutes (5 hrs) Not Applicable
Fe (T) % 98.1 97.4
Apparent Density (g/cc) 0.6 3.29
Tap Density (g/cc) 1.1 4.4
Hausner ratio 1.83 1.34
Particle size D90 /D50 /D10
(microns) 37.4 microns (D50) 21.5/10.8/6.31
BET surface area (m2/g) 0.8 0.43
Bombardment Time Not Applicable 60 minutes (1 hr.)
Morphology Irregular Rounded
Comminution facilitated Not required Not required
Gas Pressure Not Applicable 5 bar
Pressurized Gas Not Applicable Nitrogen

Table 4 (Example 3)

Process Attributes Values for Sponge Iron
Powder Values for Rounded Iron
Powder
Thermo-reduction furnace Pusher type Not Applicable
Hydrogen rich gas Source Pure hydrogen gas Not Applicable
Temperature 650 Not Applicable
Time duration 240 minutes ( 4 hrs) Not Applicable
Fe (T) % 97.5 97.2
Apparent Density (g/cc) 0.65 3.16
Tap Density (g/cc) 1.2 4.36
Hausner ratio 1.85 1.38
Particle size D90 /D50 /D10
(microns) 45.9 (D50) 24.9/10.2/5.52
BET surface area (m2/g) 0.79 0.50
Bombardment Time Not Applicable 60 minutes (1 hr.)
Morphology Irregular Rounded
Comminution facilitated Not required Not Applicable
Gas Pressure Not Applicable 5 bar
Pressurized Gas Not Applicable Nitrogen
Table 5 (Example 4)

Process Attributes Values for Sponge Iron
Powder Values for Rounded Iron
Powder
Thermo-reduction furnace Pusher type Not Applicable
Hydrogen rich gas Source Cracked ammonia Not Applicable
Temperature 750 deg C Not Applicable
Time duration 240 minutes (4 hrs) Not Applicable
Fe (T) % 97.8 97.3
Apparent Density (g/cc) 0.73 3.15
Tap Density (g/cc) 1.25 4.34

Hausner ratio 1.71 1.38
Particle size D90 /D50 /D10 30.0 (D50)
(microns) 28.5/11.2/6.19
BET surface area (m2/g) 0.56 0.49
Bombardment Time Not Applicable 30 minutes
Morphology Irregular Round to spherical shaped
Comminution facilitated hammer mill for 10 minutes Not Applicable
Gas Pressure Not Applicable 6 bar
Pressurized Gas Not Applicable Nitrogen
Table 6 (Example 5)

Process Attributes Values for Sponge Iron
Powder Values for Rounded Iron
Powder
Thermo-reduction furnace Pusher type Not Applicable
Hydrogen rich gas Source Pure hydrogen Not Applicable
Temperature 700 deg. C Not Applicable
Time duration 180 minutes (3 hr) Not Applicable
Fe (T) % 98.2 97.6
Apparent Density (g/cc) 0.65 3.53
Tap Density (g/cc) 1.15 4.47
Hausner ratio 1.77 1.27
Particle size D90 /D50 /D10
(microns) 47.9 (D 50) 22.9/9.8/5.4
BET surface area (m2/g) 0.8 0.44
Bombardment Time Not Applicable 60 minutes (1 hr.)
Morphology Irregular Rounded
Comminution facilitated Not required Not Applicable
Gas Pressure Not Applicable 5 bar
Pressurized Gas Not Applicable Nitrogen

Table 7 (Example 6)

Process Attributes Values for Sponge Iron
Powder Values for Rounded Iron
Powder
Thermo-reduction furnace Pusher type furnace Not Applicable
Hydrogen rich gas Source Pure hydrogen Not Applicable
Temperature 800 Deg. C Not Applicable
Time duration 120 minutes (2 hr) Not Applicable
Fe (T) % 97.9 97.5
Apparent Density (g/cc) 0.74 3.04
Tap Density (g/cc) 1.26 4.08
Hausner ratio 1.7 1.34
Particle size D90 /D50 /D10
(microns) 23.8 (D 50) 29.8/12.1/7.24
BET surface area (m2/g) 0.45 0.51
Bombardment Time Not Applicable 60 minutes (1 hr)
Morphology Irregular rounded
Comminution facilitated hammer mill for 10 minutes Not Applicable
Gas Pressure Not Applicable 4.5 bar
Pressurized Gas Not Applicable Nitrogen
Table 8 (Example 7)

Process Attributes Values for Sponge Iron
Powder Values for Rounded Iron
Powder
Thermo-reduction furnace Pusher type Not Applicable
Hydrogen rich gas Source Cracked ammonia gaseous Not Applicable
Temperature 850 deg. C Not Applicable
Time duration 240 minutes (4 hrs) Not Applicable
Fe (T) % 98.1 97.8
Apparent Density (g/cc) 0.9 3.1
Tap Density (g/cc) 1.58 4.18
Hausner ratio 1.76 1.34

Particle size D90/D50 /D10
(microns) 27.5 (D 50) 28.6/12.7/5.66
BET surface area (m2/g) 0.41 0.48
Bombardment Time Not Applicable 60 minutes (1 hr)
Morphology Irregular morphology rounded
Comminution facilitated hammer mill for 10 min Not Applicable
Gas Pressure Not Applicable 6 bar
Pressurized Gas Not Applicable Nitrogen
[0045] FIGS. 3a-3b depicts X-ray Diffraction graph and SEM of the sponge iron as per
example 7.
[0046] FIGS. 4a-4b depicts X-ray Diffraction graph and SEM of the rounded iron powder of
the example 7.
Advantage:
[0047] The current disclosure proposes a novel way of synthesizing rounded iron powders
from irregular iron oxide using simple 2-stage process in which iron oxide is thermo-
chemically reduced to obtain special sponge iron powder which in the second stage is subjected
to rapid bombardment without classification using pressurized gaseous jets to obtain iron
powder with rounded morphology along with high density, finer size and high purity.
[0048] The disclosure opens a scope of using iron powders produced from chemical reduction
route to enter into premium applications segments like metal injection molding and additive
manufacturing which is otherwise only possible by carbonyl and atomization synthesis routes.
[0049] The present disclosure provides a simple, cost-effective, non-toxic and efficient method
of producing rounded iron powders with high purity, fine size and high density. Said rounded
iron powder with high purity is immensely useful and can be employed in different industries,
including powder metallurgy, additive manufacturing, diamond tools, welding and chemical
industry. Highly pure iron powder especially finds applications in porous electrodes, metal
injection molding (MIM), water treatment, food agriculture, catalyst, electromagnetic and
metal fuel applications.

I/We Claim:
1. A method for producing a rounded powders, comprising:
simultaneously heating and reducing an iron oxide in a thermo reduction furnace at
600 0C to 1000 0C under a hydrogen rich gaseous atmosphere to obtain a sponge
iron; and
bombarding the sponge iron by means of pressurized gases for 30 to 60 minutes to
obtain the rounded iron powders in an enclosed metallic chamber.
2. The method as claimed in claim 1, wherein simultaneously heating and reducing the
iron oxide for 2 to 6 hrs.
3. The method as claimed in claim 1, wherein the sponge iron is comminuted to produce
sponge iron in powder form when treated at 750 0C to 1000 0C.
4. The method as claimed in claim 1, wherein the iron oxide is in the form of powder
having chemical composition of Fe(T) 69.01 to 69.67, ferrous oxide (FeO) 0.26 to 0.77,
Silicone dioxide (SiO2) 0.01 to 0.17, calcium oxide (CaO) 0.01 to 0.1, magnesium
oxide (MgO) 0.02 to 0.03, manganese oxide (MnO) 0.18 to 0.27, aluminium oxide
(Al2O3) 0.13 to 0.3, sulphur (S) 0.001 to 0.02, carbon (C) 0.02 to 0.06, with other
incidental trace elements (all in wt%).
5. The method as claimed in claim 1, wherein the iron oxide is one or in combination(s)
of natural, synthetic, industrial by-product powder.
6. The method as claimed in claim 1, wherein the iron oxide is obtained by spray roasting
of pickling solution obtained during acid recovery process in steel making plant.
7. A method as claimed in the claim 1, where in the hydrogen rich gas is one or in
combination(s) of cracked ammonia, hydrogen separated from coke oven gas, pure
hydrogen and hydrogen from cracked methane.
8. A method as claimed in the claim 1, where in the sponge iron comprises irregular
morphology with mean particle size (D50) < 60 microns, purity (Fe(T)%) > 97%,
apparent density < 0.7 g/cc, tap density < 1.2 g/cc, hausner ratio >1.7 and BET surface
area > 0.7 m2/g when the iron oxide is heated and reduced at 600 0C to 750 0C.

9. A method as claimed in the claim 1, where in the sponge iron comprises irregular
morphology with mean particle size <30 microns, purity (Fe(T)%) >97 %, apparent
density >0.7 g/cc, tap density >1.2 g/cc, hausner ratio >1.7 and BET surface area >0.4
m2/g when the iron oxide is heated and reduced at 750 0C to 1000 0C.
10. A method as claimed in the claim 1, where in the sponge iron powder is porous with
flowery particles.
11. A method as claimed in the claim 1, where in the comminution is facilitated by one or
in combination(s) of impact, shear, attrition, compression, inter particle collision forces
by use of one or in combination(s) of crushers and mills.
12. A method as claimed in the claim 1, where in the pressurized gas used in the
bombardment is one or in combination(s) of inert gases.
13. A method as claimed in the claim 1, where in the pressurized gas streams possess a
pressure > 4 bar.
14. A method as claimed in the claim 1, wherein the enclosed metallic chamber is part of
opposed jet mill or fluidized jet mill or jet mill.
15. A rounded iron powder, comprising:
round morphology, with mean particle size (D50) <13 microns, purity (Fe(T)%)
>97 % and C<0.05 (all in wt%).
16. The rounded iron powder as claimed in claim 15, wherein the composition of the
rounded iron powder is
C- 0.01 to 0.05, Ni- 0.01 to 0.02, Mo- 0.001to 0.002, Si- 0.03 to 0.05, Al- 0.002 to 0.01,
Mg- 0.05 to 0.1, Ti- 0.01 to 0.03, Mn- 0.1 to 0.4, P- 0.01 to 0.03, S- 0.004 to 0.008, Cr-
0.006 to 0.02, W-0.01 to 0.02 Rest Fe and non-traceable impurities (all in wt%).
17. The rounded iron powder as claimed in claim 15, wherein the apparent density > 3 g/cc,
tap density > 4 g/cc.
18. The rounded iron powder as claimed in claim 15, wherein the hausner ratio <1.4.

19. The rounded iron powder as claimed in claim 15, wherein the BET surface area >0.4
m2/g.
20. The rounded iron powder as claimed in claim 15, where in the particle size D90 < 30
microns, D50 < 13 microns and D10 < 8 microns.