NEW CHARGE MATERIAL FOR BLAST FURNACE
NEW CHARGE MATERIAL
FOR BLAST FURNACE
Yogesh Dalmia (speaker)
General Manager of Suraj Products Ltd, India)
Ivan Kurunov (Novolipetsk Steel, Russia),
Richard Steele and Aitber Bizhanov
(J.C. Steele & Sons, Inc, USA)
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NEW CHARGE MATERIAL FOR BLAST FURNACE
CONTENS:
1. Stiff Extrusion as a New Technology for Metallurgical Waist Briquetting
2. Ironmaking plant “Suraj Products Ltd” in Rourkela (India)
3. Components of the charge for briquettes production
4.Technology of briquetting by stiff extrusion
5. Composition and metallurgical properties of Brex
6. Blast Furnaces at the Company “Suraj Products Ltd”
7. Technical-economical parameters of the Blast Furnace operation with Brex in charge
8. Conclusion
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NEW CHARGE MATERIAL FOR BLAST FURNACE
Stiff Extrusion as a New Technology for Metallurgical Wastes Briquetting
In 1993 at
the Bethlehem Steel
Corporation plant (USA) the first industrial
line for production the briquettes from the
metallurgical wastes based on the stiffextrusion technology had started The first
Brex making line had been realized on the
equipment produced “ by J.C.Steele &
Sons” company. The productivity of the
line
was 20 t/hour. The Brex were
produced from the BF sludge and dust.
The Portland cement and the lignin were
used as the binder and plasticizer. The
Brex were used in the Blast Furnace
charge. The line had been in a continuous
operation
till 1996 when the main
production of the Steel plant had been
cancelled.
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NEW CHARGE MATERIAL FOR BLAST FURNACE
Metallurgical plant “Suraj Products Ltd” in Rourkela (India).
Utilization of the new briquetting technology has been renewed only at present time. In April
2011 the industrial line for the production of the Brex from waste has been launched at the
«Suraj Products Ltd» company metallurgical plant in Rourkela (India). The plant produces hot
metal by two small-scale Blast Furnaces and the sponge iron by the kilns. Briquetting line
includes: warehouse of the raw-materials; unit of the charge preparation (dosing, grinding,
stockpiling, hopper feeding); mixing and briquetting unit; line of the transportation of the Brex
to the strengthening area; ready Brex warehouse.
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NEW CHARGE MATERIAL FOR BLAST FURNACE
Components of the charge for briquettes production and technology of
briquetting by stiff extrusion
The components of the Brex are: BOF and BF sludge and dust (66 %), iron ore (28 %),
the Portland cement and plasticizer (6%). The volumetric dosing is being implemented by
the auto loader, which creates the stockpile of the charge mix (without the cement), taking
each component from separate stockpiles. Charge mix is also being fed to the hopper of
the briquetting line by loader where from it goes through the homogenizing mixers to the
extruder. Due to the applied pressure during extrusion and the de-airing of the mix (90%)
in the vacuum chamber the Brex do have a dense structure at the die exit, high initial
strength and a good plasticity. This helps to transport and to stockpile the Brex without
fines generation.
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NEW CHARGE MATERIAL FOR BLAST FURNACE
During the transfers only the defragmentation of the Brex into 2-3 pieces takes place
with the creation of the Brex with the length/diameter ration being 1,3-2,2 while this
value after the die was in the range of 2,5-8,0. Simultaneously a small turning of the
Brex sharp borders takes place. For the strengthening the Brex are being cured in
the stock at the open place.
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NEW CHARGE MATERIAL FOR BLAST FURNACE
Composition and metallurgical properties of brex at “Suraj Products Ltd”
Chemical composition of the Brex after curing:
Fetotal
46-48
CaO
10-11
%; SiO2
7.2-7.7
Al2O3
1.7-1.9
MgO
2.7-2.9
H2Ohyd +C
11-12
СаО/SiO2
1.39-1.42
Mechanical strength measurement of the ready Brex has show very good compressive
strength values (100-130 kgF/cm2). Fine output from Brex during their transit and handling
was not more 5 %.
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NEW CHARGE MATERIAL FOR BLAST FURNACE
Hot strength of the sludge Brex ( BF sluge 60 %, BOF sludge 40 %), iron ore-coke Brex
(concentrate -85 %, coke breeze – 15%) and agglomerates have estimated in accordance
with ISO 4696 Standard based on the standard equipment. The following RDI (-3,15) and
RDI (+6,4) values have been received:
Tested materials
RDI (-3,15), %
RDI (+6,4), %
Iron ore-coke Brex
38
62
Sludge Brex
3,5
96,5
Agglomerate (basicity 1,2)
16,9
64
Agglomerate (basicity 1,4)
15,1
60
Agglomerate (basicity 1,6)
8,9
77
On can see that hot strength of Brex is not bad
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NEW CHARGE MATERIAL FOR BLAST FURNACE
Blast Furnaces at the Company “Suraj Products Ltd”
Blast Furnaces at the Company “Suraj Products Ltd” plant (volume 45 m3 and 25 m3) are
equipped by: skip hoist with the volume 0,5m3, double-cone charging device, and hydraulic
equipment for the notch servicing, stoves and dry gas-cleaning system (dust collector + 7
modules of the bag house filters). The furnace has 8 air tuyeres, one hot metal notch and is
being cooled by external watering. Produced hot iron is immediately casted by the casting
machine and the slag is granulated near to the furnace.
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NEW CHARGE MATERIAL FOR BLAST FURNACE
Technical-economical parameters of the Blast Furnace operation
with Brex in charge
The efficiency of the utilization of the Brex can be seen after the comparison of the
operation parameters of the Blast Furnace working on the iron ore and on the charge with
80% of the Brex and 20 % of the iron ore.
Technical-economical parameters of the Blast Furnace operation
Parameters of the Blast Furnace operation
With iron ore
With Brex
Iron ore consumption, kg/t
Brex consumption, kg/t
Lime+ Dolomite consumption, kg/t
Scrap consumption, kg/t
Fe content in fluxed charge *,%
Coke rate, kg/t
Productivity, t/m2 per day
Hot blast temperature, ºС
Tuyere pressure, kg/cm2
Hot metal chemical composition, % : Si
Mn
S
Slag basicity
1500
294
132
57.6
680
1.9
925
0.5
1.4
0.2
0.055
1.09
372
1444
50.4
530
1.62
900
0.36
1.25
0.45
0.044
1.1
Note: * - not accounted for СО2 carbonates.
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NEW CHARGE MATERIAL FOR BLAST FURNACE
One can see that the coke rate after using the charge with Brex (80%) and the iron ore (20
%) decreased by 150 kg/t of hot metal (22%) as a result of the consumption of the carbon
containing Brex as well as due to the removal of the raw fluxes from the charge. Reduction
in the productivity of the Blast Furnace by 15 % with this new charge with Brex is mainly
related with the decrease in Fe content in such charge - 7,2 % compared with the charge
based on iron ore and the raw fluxes. The further growth of the Brex share in the charge
was restricted by the growth of the basicity of the slag due to the high basicity of the Brex
containing the BOF sludge.
680
530
57,6
1,9
50,4
1,62
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NEW CHARGE MATERIAL FOR BLAST FURNACE
Conclusion
The equipment and the technology of the stiff-extrusion make it possible to produce the Brex
having high strength and reducibility. Metallurgical properties of the Brex allow using them
successfully in the Blast Furnace melting. Utilization of the sludge Brex with the basicity 1,4
in the small-scale Blast Furnace at the level of 80% of the charge (1444 kg/t of hot metal)
helped to reject entirely from the introduction of the lime and dolomite and to reduce the
coke rate by 150 kg/t of hot metal.
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