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Sponge Iron is a
metallic product
formed by the
reduction of iron
ore at temperature
just below the
fusion point of
iron. This product
has derived the name
"Sponge Iron" due to
its porous nature.
It is also called as
Direct Reduced Iron
(DRI).
Properties
Sponge Iron is a
substitute of steel
scrap for steel
making through the
secondary route i.e.
DR/EF route. This
also replaces
ferrous scrap as a
coolant in LD
converter. The value
of DRI is measured
by comparing its
cost and properties
with those of scrap.
It's non pyrophoric.
It's free from tramp
elements viz Copper,
Zinc, Tin, Chromium,
Tungsten and
Molybdenum etc that
are usually present
in scrap. It has low
Sulphur content. It
has the ability to
use low grade fuels
and fuels that are
unacceptable for
conventional iron
making. It is more
suited for some
special
metallurgical
processes than
conventional iron &
steel products e.g.
Precipitation of
copper from leaching
solution during
copper extraction.
Production of metal
objects by powder
compaction. |
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Specifications
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PARTICULARS
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SPONGE
IRON LUMPS
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SPONGE
IRON FINES
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TOTAL
IRON
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91.5%
Min
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92%
Min
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METALLIC IRON
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80% Min
|
82% Min
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DEGREE OF METALLIZATION
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88% Min
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90% Min |
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CARBON |
0.2% Min |
<0.25% Min |
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SULPHUR |
LESS THAN 0.04% Min |
LESS THAN 0.04% Min |
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PHOSPHOROUS |
LESS
THAN 0.45% |
LESS
THAN 0.45% |
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GANGUE |
LESS
THAN 5% |
LESS
THAN 5% |
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NON MAGNETIC |
LESS
THAN 0.5% |
LESS
THAN 1.5% |
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SIZE |
3
to 20 mm |
0
to 5 mm |
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For better melting
results, the
criteria for
selection of sponge
iron are
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- High total iron content
- High degree of metallization
- Low gangue, sulphur and phosphorus contents
- Suitable size, range and
shape
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Advantages
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Advantages of using Sponge Iron in Electric Arc / Induction Furnaces in the charge mix are:
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DRI
permits automatic continuous or batch charging.
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It helps create a foamy slag - provides lower electricity consumption, faster melting time. decreased electrode consumption, longer refractory life and enhanced steel quality .
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The chemical composition of DRI is known exactly and is uniform
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It contains very low levels of undesirable metallic impurities.
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Use of DRI permits dilution with low cost (more available) scrap.
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Less noise occurs during melt down with DRI than scrap.
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It does not require de-sulphurising and de-phosphorising process in Electric Arc / induction
furnaces.
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