RAW MATERIAL - Sponge Iron
The major raw material required for production of coal based sponge iron:
- Iron Ore
- Non coking coal
- Dolomite
QUALITY REQUIREMENTS - Iron Ore
The quality of iron ore determines the quality of sponge iron and thus it is essential that right quality of the ore be used in production of sponge iron. Iron ore should be of high grade to ensure that sponge iron produced contains low gangue material and is suitable for use in steel making. The iron content of the ore should preferably be around 65%. Since the gangue (Silica+ Alumina) can not be removed during the process of direct reduction, it should be preferably below 5%. Phosphorous should be preferably be lower than 0.06% and Sulphur below 0.02% Higher phosphorous and sulphur content in the sponge iron would increase the refining time during steel making process and would need more flux.
This will result in higher slag volumes and longer refining time which will make steel making uneconomical due lower productivity and higher power and refractory consumption.
The sized iron ore should possess high strength and good thermal stability during reduction. Friable ores, which deteriorate during the process of reduction, will result in generation of a large amount of fines.
The lump ore used for sponge iron production should be closely calibrated. The top size generally recommended lies within 25mm while the bottom size is 5mm. The ideal size will be determined by the reducibility characteristics and chemical and physical properties of the ore to be used.
Analysis of Iron ore available in Barbil- Joda region of Orissa and NMDC mines indicate the following composition and is considered most suitable for sponge iron manufacturing.
Bailadila Sector
S. N. |
Particulars |
Description |
| Calibrated Lump Ore (DR Grade) |
FE |
67.0% |
67.5% |
Silica |
1.5% Max |
1.25% |
Alumina |
1.5% Max |
1.00% |
SI + AL |
2.6% Max |
2.25% |
Sulphur |
0.01% Max |
0.006% |
Phosphorous |
0.04% Max |
0.030% |
| Size |
| |
+ 40 MM / +31.5 mm |
5% Max |
| |
- 10 MM / -6.3 mm |
10% Max. |
| Calibrated Lump Ore (BF) |
FE |
65.50% |
66.00% |
Silica |
2.00% Max |
1.50% |
Alumina |
2.00% Max |
2.00% |
SI + AL |
4.00% Max |
3.50% |
Sulphur |
0.01% Max |
0.01% |
Phosphorous |
0.05% Max |
0.04% |
| Size |
10-30 MM (31.5mm) |
+ 31.5 MM |
5% Max |
| |
- 6.3MM |
15% Max |
| Or |
|
|
5-15 MM |
+ 15 MM |
6% Max |
|
-5 MM |
5% Max |
Lump |
FE |
65.50% |
66.50% |
Silica |
2.25% Max |
1.50% |
Alumina |
2.25% Max |
2.00% |
SI + AL |
4.00% Max |
3.50% |
Sulphur |
0.01% Max |
0.01% |
Phosphorous |
0.05% Max |
0.04% |
| Size |
10-150 MM |
+ 150 MM |
2.5% Max |
|
- 10 MM |
15% Max. |
Fines (Sinter Feed) |
FE |
65.00% |
66.50% |
Silica |
2.0% Max |
1.50% |
Alumina |
2.5% Max |
2.20% |
SI + AL |
4.5% Max |
3.70% |
Sulphur |
0.02% Max |
0.02% |
Phosphorous |
0.05% Max |
0.05% |
SIZE |
(-10MM+150 MIC) |
+ 10 MM |
5% Max |
|
- 150 MIC |
20% Max. |
The company have tied up with many private mines owners to supply definite grade of iron ore from Barbil- Joda in Orissa and also initiated the process of tying up with NMDC for supply of commodity.
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