Summary of the invention
The present invention is intended to solve the defective of prior art and provides a kind of cast iron product of realizing to hang down the smelting process of the ultra-low sulfur, silicon and titanium grey nodular cast iron by pig iron of silicon, low titanium, super low sulfur and assurance ash mouthization.
The alleged problem of the present invention is solved by following technical scheme:
A kind of smelting process of ultra-low sulfur, silicon and titanium grey nodular cast iron by pig iron, its special feature is: the chemical ingredients of described ultra-low sulfur, silicon and titanium grey nodular cast iron by pig iron is as follows: carbon [C] 4.300-4.600%, silicon [Si] 0.400-0.600%, manganese [Mn] 0.060-0.100%, phosphorus [P]≤0.030%, sulphur [S]≤0.010%, titanium [Ti]≤0.032%, surplus [Fe], described method comprises the steps:
A. blast furnace raw material is selected for use: blast furnace raw material consists of: the high-alkali agglomerate 65-70% of the spheroidal graphite pig iron, and spheroidal graphite pig iron pelletizing 30-35%, the basicity of the high-alkali agglomerate of the described spheroidal graphite pig iron is 1.90-2.00;
B. low silicon smelting: blast-furnace smelting [Si] control 0.15-0.35%, R
2Control 1.15-1.20;
C. stokehole silicon addition: whenever increase the amount that 0.1% [Si] adds the 1.8-2.5kg ferrosilicon powder according to the ton molten iron when tapping a blast furnace, ferrosilicon powder evenly is added on the molten iron stream;
D. stokehole desulfuration treatment: add alkali and fall sulphuring treatment when stokehold sulphur [S]>0.010% adopts, stokehold processing industry alkali add-on is controlled at molten iron 2-4 kilogram per ton, and industrial soda adds with molten iron stream, and the joining day is controlled between the 70-80% of the time of tapping a blast furnace;
E. spray nitrogen in stokehold stirs: increase silicon and add behind the alkali by spray gun nitrogen-blow in the iron ladle molten iron, the winding-up time is 30-60 second, nitrogen gas stream pressure-controlling 500-700Kpa;
F. pig machine inoculation: the stokehold sampling detects, and according to the spoken parts in traditional operas degree, adds the nucleating agent Si-Ba alloy and carry out inoculation in the pig-casting machine trough, and innoculant adding quantity is controlled at≤the 2kg/t molten iron.
The smelting process of above-mentioned ultra-low sulfur, silicon and titanium grey nodular cast iron by pig iron, in the described pig machine inoculation step, nucleating agent is evenly added on the molten iron stream by the nucleating agent adding set, described nucleating agent adding set is separately positioned on the head and the afterbody of pig-casting machine trough side, wherein the nucleating agent of pig-casting machine trough head nucleating agent adding set interpolation is controlled at<the 1kg/t molten iron, after adding nucleating agent, promptly sampling detects, if spoken parts in traditional operas fails to eliminate fully, then start pig-casting machine trough afterbody nucleating agent adding set and add nucleating agent once more.
The smelting process of above-mentioned ultra-low sulfur, silicon and titanium grey nodular cast iron by pig iron, described nucleating agent adding set comprises ladder, outer case, outer case is positioned on the ladder, the defeated material belt that is provided with hopper, frequency modulation motor in the outer case and drives by frequency modulation motor, defeated material belt art end bottom is provided with discharge bucket, the discharge bucket bottom connects discharge port, the terminal corresponding trough of discharge port, and the adjusting plate is established in the discharge bucket bottom.
The low silicon magnesium iron of the direct smelting low-sulfur of the blast furnace of the abandoning tradition of the present invention smelting technology of the pig iron, adopt blast furnace low silicon smelting technology, stokehole silicon addition, the stirring of stokehold spray nitrogen, stokehole desulfuration treatment and pig machine inoculation to produce ultra-low sulfur, silicon and titanium grey mouth nodular pig iron technology, solved the technical barrier of blast furnace stably manufactured ultra-low sulfur, silicon and titanium grey mouth nodular pig iron.Advantage of the present invention is: the product that adopts this method to produce belongs to the ultra-low sulfur, silicon and titanium grey mouth trade mark in the nodular pig iron, this product can be accomplished low [Si], low [Ti], ultralow [S], can realize the ash mouth again, this product is particularly suitable for the production of large-scale as-cast ferrite ductile iron and large-scale high-quality magnesium iron spares such as wind power generation, nuclear fuel storage-transport vessel, has filled up the blank of this series products.The low titanium magnesium iron of the low silicon of present technique and the direct smelting low-sulfur of blast furnace with pig iron technology compare utilization coefficient, magnesium iron than,, aspects such as ash mouth ratio, hot blast temperature are improved, and comprehensive coke ratio obviously descends.
Embodiment
Blast furnace of the present invention is smelted the combination that is meant blast furnace low silicon smelting, stokehole silicon addition, the stirring of stokehold spray nitrogen, stokehole desulfuration treatment and pig machine inoculation indirectly.Described ultra-low sulfur, silicon and titanium grey nodular cast iron by pig iron chemical ingredients is as follows: carbon [C] 4.300-4.600%, silicon [Si] 0.400-0.600%, manganese [Mn] 0.060-0.100%, phosphorus [P]≤0.030%, sulphur [S]≤0.010%, titanium [Ti]≤0.032%, surplus [Fe].Main technical points of the present invention is embodied in following several aspect:
1, selected blast furnace raw material: blast furnace raw material consists of: the high-alkali agglomerate 65-70% of the spheroidal graphite pig iron, spheroidal graphite pig iron pelletizing 30-35%, wherein the high-alkali sinter basicity of the spheroidal graphite pig iron is controlled at 1.90-2.00.High-alkali agglomerate of described magnesium iron and magnesium iron pelletizing control criterion see attached list 1.
2, low silicon smelting guarantees furnace condition anterograde, reduces the pig iron [Ti] content: [Si] control 0.15-0.35% in the blast furnace ironmaking process, dual alkalinity R
2Be CaO/SiO
2Control 1.15-1.20, (MgO) control 11-13%, with the raising of CaO+MgO content, and CaO (or MgO) and SiO
2Or TiO
2The complex compound quantity that forms increases, and has reduced free SiO in the slag
2Content reduces Si and Ti reducing amount, thereby control [Ti]≤0.032% is realized low [Ti] requirement.
3, stokehole silicon addition is to guarantee that [Si] is at claimed range: before tapping a blast furnace ferrosilicon powder dried to water content less than 0.1%, whenever increasing the consumption that 0.1% [Si] add the 1.8-2.5kg ferrosilicon powder by molten iron per ton when tapping a blast furnace evenly is added to ferrosilicon powder on the molten iron stream, it fully is melted in the molten iron, reaches and increase the silicon purpose.The ferrosilicon powder control criterion sees attached list 2.
4, stokehole desulfuration treatment ultralow to guarantee [S]: for avoiding chilling tendency, do not adopt spray magnesium sulfur removal technology, the stokehold employing adds alkali and falls the sulphur mode.Processing industry alkali when stokehold sulphur [S]>0.010% adds 2-4 kilogram Na according to molten iron per ton
2CO
3Add, the joining day is controlled at 80% of the time of tapping a blast furnace, is beneficial to the abundant contact reacts of industrial soda, guarantees sweetening effectiveness.Industrial soda adds with molten iron stream, when adding industrial soda in molten iron flows, requires as far as possible evenly, stablizes.
5, spray nitrogen in stokehold stirs to guarantee [Si] even: the back of tapping a blast furnace is by spray gun nitrogen-blow in the iron ladle molten iron, by the nitrogen gas stream effect, with the abundant stirring and evenly mixing of molten iron in the iron ladle, reach the purpose of full and uniform composition, solve and to increase the even problem of composition height behind the silicon.Test shows: increase silicon reach 1% promptly 60 tons of iron ladles add under the ferrosilicon 1500Kg situation, stir by stokehold nitrogen, can guarantee that still composition is even, the silicon content composition is poor<0.105%.Winding-up time 30-60 second, nitrogen gas stream pressure-controlling 500-700Kpa.
6, pig machine inoculation is to guarantee eliminating spoken parts in traditional operas: this step is the gordian technique that the present invention eliminates pig iron white structure.Usually adding nucleating agent is to use in the castings production process, the present invention is provided with the nucleating agent adding set at pig-casting machine, in the trough of pig-casting machine, add a certain amount of nucleating agent Si-Ba alloy, the white structure in the pig iron is eliminated, obtain ultra-low sulfur, silicon and titanium grey mouth magnesium iron.
Referring to Fig. 1, for realizing that pig-casting machine adds nucleating agent, the present invention is provided with nucleating agent adding set 3,4 at the trough side of pig-casting machine, and nucleating agent adding set 4 is arranged on the head of pig-casting machine trough 2 sides, and nucleating agent adding set 3 is arranged on the afterbody of pig-casting machine trough side.According to molten iron whitening degree, can add nucleating agent once or twice.Wherein the nucleating agent of pig-casting machine trough head nucleating agent adding set 4 interpolations is controlled at<the 1kg/t molten iron, after adding nucleating agent, make the best use of time to take a sample and detect to organize whether form the ash mouth, in particular cases fail to eliminate fully as if white structure, then start pig-casting machine trough afterbody nucleating agent adding set 3 according to the whitening degree and add nucleating agent once more, twice nucleating agent adds total amount and is no more than the 2kg/t molten iron.
Referring to Fig. 2, nucleating agent adding set 3 of the present invention is identical with 4 structure, its formation comprises ladder 6, outer case 7, outer case is positioned on the ladder, the defeated material belt 11 that is provided with hopper 9, frequency modulation motor 8 in the outer case and drives by frequency modulation motor, defeated material belt bottom is provided with discharge bucket 12, and the discharge bucket bottom connects discharge port 14, the terminal corresponding trough of discharge port, discharge bucket bottom are provided with regulates plate 13.In nucleating agent adding set when work,, hopper 9 is according to the iron water amount nucleating agent of packing into, and under the effect of material feeder 10, nucleating agent drops to defeated material belt 11, and nucleating agent is transported to discharge bucket by defeated material belt, falls uniformly on the molten iron stream through discharge port 14.Adjust the rotating speed of frequency modulation motor 8 and can adjust defeated material amount.Adjust the aperture position of regulating plate 13, can control nucleating agent and add speed.
Subordinate list 1 blast furnace raw material control criterion
The name of an article |
TFe % |
SiO
2 %
|
Al
2O
3 %
|
P % |
S % |
TiO
2 %
|
R
2 |
Mn |
|
Screening % |
Rotary drum % |
Agglomerate (high-alkali) |
|
≤5.3 |
≤1.8 |
≤0.015 |
≤0.03 |
≤0.080 |
±0.06 |
≤0.10 |
|
|
|
Pelletizing |
≥62 |
≤8.0 |
≤2.0 |
≤0.015 |
≤0.10 |
≤0.050 |
≤0.4 |
≤0.10 |
|
≤5% (≤6.3mm) |
≥88 |
Subordinate list 2 ferrosilicon powder control criterions
The present invention be 600m in useful volume
3The level blast furnace is directly smelted the low silicon magnesium iron of super low sulfur and is compared at utilization coefficient, magnesium iron with the pig iron and be improved than aspects such as, ash mouthful ratio, hot blast temperatures, and comprehensive coke ratio obviously descends, and its correlation data sees attached list 3.
Subordinate list 3 parameter comparison
Sequence number |
Index |
Unit |
600m
3The level blast furnace is directly smelted
|
600m
3The level blast furnace is smelted indirectly
|
1 |
Utilization coefficient |
t/m
3.d
|
3.43 |
4.01 |
2 |
Comprehensive coke ratio |
Kg/t |
453 |
431 |
3 |
Magnesium iron ratio up to standard |
% |
16.95 |
71.85 |
4 |
Ash mouthful ratio |
% |
58.9 |
100 |
5 |
Hot blast temperature |
℃ |
1155 |
1185 |
The ultra-low sulfur, silicon and titanium grey nodular cast iron by pig iron and the prior art that adopt the technology of the present invention to produce see attached list 4 at the magnesium iron of blast furnace direct production with the contrast of pig iron chemical ingredients.
Subordinate list 4 magnesium irons contrast with pig iron chemical ingredients
Composition (%) |
[C] |
[Si] |
[Mn] |
[P] |
[S] |
[Ti] |
Blast furnace is directly smelted |
4.20-4.50 |
0.40-0.60 |
0.06-0.10 |
0.025-0.030 |
≤0.020 |
≤0.040 |
The technology of the present invention |
4.30-4.60 |
0.40-0.60 |
0.06-0.10 |
0.025-0.030 |
≤0.010 |
≤0.032 |
Can find out that by subordinate list 4 it is higher relatively and can't all reach mouthful requirement of section ash with pig iron sulphur content directly to smelt magnesium iron at blast furnace, and the present invention adopts indirect smelting technology at blast furnace, but the magnesium iron pig iron of the ultralow sulphur content of stably manufactured, section ash mouthful.
Several embodiment below are provided:
Embodiment 1: at 600m
3The level blast-furnace smelting magnesium iron pig iron is chosen the blast furnace raw material according to subordinate list 1 standard, the wherein high-alkali agglomerate 66.61% of the spheroidal graphite pig iron, spheroidal graphite pig iron pelletizing 33.39%, and the high-alkali sinter basicity of the spheroidal graphite pig iron is controlled at 1.98; Blast-furnace smelting [Si] control 0.15-0.35%, R
2Control 1.15-1.20, control [Ti]≤0.032%; Molten iron detects that [Si] is 0.15%, [S] is 0.014%; Take by weighing ferrosilicon powder 270kg according to subordinate list 2 standards, when tapping a blast furnace ferrosilicon powder evenly is added on the molten iron stream; Processing industry alkali Na subsequently
2CO
3200kg, the back of tapping a blast furnace is by spray gun nitrogen-blow in the iron ladle molten iron, nitrogen gas stream pressure-controlling 600Kpa, 40 seconds winding-up time; Utilize pig-casting machine nucleating agent adding set 4 to add the nucleating agent Si-Ba alloy according to the 0.8kg/t molten iron, white structure all disappears after testing.Chemical ingredients is as follows after testing for this stove product (50 tons): carbon [C] 4.360%, silicon [Si] 0.450%, manganese [Mn] 0.062%, phosphorus [P] 0.024%, sulphur [S] 0.009%, titanium [Ti] 0.028%, surplus [Fe].
Embodiment 2: at 600m
3The level blast-furnace smelting magnesium iron pig iron is chosen the blast furnace raw material according to subordinate list 1 standard, the wherein high-alkali agglomerate 70% of the spheroidal graphite pig iron, spheroidal graphite pig iron pelletizing 30%, and the high-alkali sinter basicity of the spheroidal graphite pig iron is controlled at 1.95; Blast-furnace smelting [Si] control 0.15-0.35%, R
2Control 1.15-1.20, control [Ti]≤0.032%; Molten iron detects that [Si] is 0.35%, [S] is 0.011%; Take by weighing ferrosilicon powder 110kg according to subordinate list 2 standards, when tapping a blast furnace ferrosilicon powder evenly is added on the molten iron stream; Processing industry alkali Na subsequently
2CO
380kg, the back of tapping a blast furnace is by spray gun nitrogen-blow in the iron ladle molten iron, nitrogen gas stream pressure-controlling 700Kpa, 30 seconds winding-up time; Utilize pig-casting machine nucleating agent adding set 4 to add the nucleating agent Si-Ba alloy according to the 0.9kg/t molten iron, white structure all disappears after testing.Chemical ingredients is as follows after testing for this stove product (40 tons): carbon [C] 4.460%, silicon [Si] 0.460%, manganese [Mn] 0.065%, phosphorus [P] 0.025%, sulphur [S] 0.010%, titanium [Ti] 0.030%, surplus [Fe].
Embodiment 3: at 600m
3The level blast-furnace smelting magnesium iron pig iron is chosen the blast furnace raw material according to subordinate list 1 standard, the wherein high-alkali agglomerate 65% of the spheroidal graphite pig iron, spheroidal graphite pig iron pelletizing 35%, and the high-alkali sinter basicity of the spheroidal graphite pig iron is controlled at 2.00; Blast-furnace smelting [Si] control 0.15-0.35%, R
2Control 1.15-1.20, control [Ti]≤0.032%; Molten iron detects that [Si] is 0.30%, [S] is 0.015%; Take by weighing ferrosilicon powder 230kg according to subordinate list 2 standards, when tapping a blast furnace ferrosilicon powder evenly is added on the molten iron stream; Processing industry alkali Na subsequently
2CO
3_ 120kg, the back of tapping a blast furnace is by spray gun nitrogen-blow in the iron ladle molten iron, nitrogen gas stream pressure-controlling 500Kpa, 60 seconds winding-up time; Utilize pig-casting machine nucleating agent adding set 4 to add the nucleating agent Si-Ba alloy according to the 0.6kg/t molten iron, white structure fails all to disappear after testing, starts nucleating agent adding set 3 and adds the nucleating agent Si-Ba alloy once more according to the 0.7kg/t molten iron.This stove product (40 tons) chemical ingredients is as follows after testing: carbon [C] 4.580%, silicon [Si] 0.590%, manganese [Mn] 0.061%, phosphorus [P] 0.023%, sulphur [S] 0.008%, titanium [Ti] 0.032%, surplus [Fe] all is an ash mouthful tissue.