High Aluminium Dross Ball And Preparation Method
Technical field
The invention belongs to outer processing of molten steel stove and refining, alloying process, be specifically related to a kind of additive that molten steel is carried out the double liquid steel refining of molten steel surface insulation of Alloying Treatment, especially for smelting Clean Steel and ultra-clean steel, and after just producing steel and adding, can make heat preserving agent by very fast covering molten steel surface, after it is transferred to refining furnace with molten steel, has strong desoxydatoin and synthesize well behaved refining agent.
Background technology
As everyone knows, along with the day by day raising of development and national economy to steel grade and specification of quality thereof, the smelting technology of steel develops into two step method steel-making by original single stage method steel-making, and refining and two steps of refining are carried out at the beginning of promptly dividing.By the content of first refining control liquid steel temperature and principal element, make deoxidation removal of impurities Alloying Treatment by refining, to obtain the steel grade of expection kind and quality.
In steel-making, just steel-making water needs at the molten steel surface covering and heat insulating agent before entering refining furnace, to prevent molten steel cooling and surface oxidation, then need carry out deoxidation and Alloying Treatment after entering refining furnace, and the refining slag that causes certain ingredients reaches the purpose of purify hot metal with the detrimental impurity in absorption deoxidation products and the steel.
The insulation measure prior art of molten steel surface roughly has following three kinds: the one, and molten steel band slag is come out of the stove, and utilizes the slag lid of molten steel surface that molten steel is isolated insulation, and this method makes molten steel during refining owing to the reduction of slag is mixed a large amount of the returning of molten steel.The 2nd, molten steel is not with slag to come out of the stove, molten steel surface add heat-insulating property preferably carbonaceous heat preserving agent (as carbonization rice husk) molten steel is isolated insulation, but the carbonaceous heat preserving agent is totally unfavorable to the smelting low carbon steel grade to the recarburization that molten steel causes.The 3rd, adopt low-carbon (LC) protective material, though this protective material has been avoided the undue recarburization of molten steel, the main component Al in the coal dust ash based on the coal dust ash
2O
3And SiO
2, on the one hand during refining owing to reductive action generation molten steel " time silicon " phenomenon, for smelting very unfavorable, a large amount of on the other hand Al of some low-carbon (LC) steel grade (as the deep drawing sheet steel)
2O
3Need to consume a large amount of CaO (lime powder) to form CaAl
2O
4(calcium metaaluminate) slagging come-up, otherwise to reducing the Al in the steel
2O
3It is also very unfavorable to be mingled with.
The deoxidation of molten steel (particularly Clean Steel and ultra-clean steel) finally all will be adopted metallic aluminium, and deoxidation products Al
2O
3Fusing point be 2050 ℃, in molten steel, exist with dendritic or needle-like, cause when the molten steel condensation that dendritic or needle oxide is mingled with in the steel, influenced the quality of steel.In the prior art, adopt composite deoxidant (as AL-Si-Fe alloy, aluminum-manganese-iron alloy) on the one hand, to form Al
2O
3, SiO
2Or MnO, Al
2O
3The low melting point eutectic be convenient to the slagging come-up, but this method use range is limited, because be difficult to form the oxide compound of silicon or manganese under the situation that has a large amount of metallic aluminiums to exist.Al-Ca-Fe alloy and aluminium barium-ferrum alloy at the iron alloy area research replace AL-Si-Fe alloy and aluminum-manganese-iron alloy with this, solve the compound slagging problem of smelting Clean Steel or ultra-clean steel deoxidation products, but have not yet to see the report of success.Be during refining in molten steel, to add calcium oxide on the other hand, to form CaO.Al
2O
3(calcium metaaluminate) low melting point eutectic slagging come-up, but this method be deoxidation preceding, the compound slagging of deoxidation products after, the Al of disperse in steel
2O
3Need considerable time to combine slagging and float, remove Al with CaO
2O
3Dynamic conditions very undesirable.
For making molten steel reach pure, it is assorted that the molten steel degree of depth is taken off, but take off assorted condition and must carry out strong oxygen blast molten steel, make the oxidation of impurities slagging come-up in the molten steel, but the oxygen level in the molten steel can rise simultaneously, must carry out deoxidation treatment to molten steel, the deoxidation material has aluminium, calcium, magnesium, silicon, manganese etc., if adopt the calcium deoxidation then cost is too high, if adopt the magnesium deoxidation then have security hidden danger, silicon, the deoxidation effect of materials such as manganese does not reach re-set target again, original fine aluminium that adopts, ferroaluminium can reach Clean Steel deoxidation target, but can not generate the molten steel surface heat preserving agent, be unfavorable for the absorption of deoxidation products and impurity.
Summary of the invention
In order to overcome the deficiencies in the prior art, the invention provides a kind of be used to smelt pure and ultra-clean steel, the High Aluminium Dross Ball And Preparation Method that detrimental impurity content is extremely low.
The technical solution adopted for the present invention to solve the technical problems is: a kind of high alumina slag ball, it contains metallic aluminium (Al), aluminium sesquioxide (Al
2O
3), lime carbonate (CaCO
3), fluorite powder (CaF
2), additive and unavoidable impurities silicon-dioxide (SiO
2), moisture content (H
2O), sulphur (S), phosphorus (P), additive is carbonate compound, alloy element and the oxide compound thereof of alkali metal carbon acid compound or alkaline-earth metal, the main component of additive is titanium dioxide (TiO
2) or boron trioxide (B
2O
3), its component content % by weight is: aluminium 45~75; Aluminium sesquioxide 10~40; Titanium dioxide 3~12 or boron trioxide 1~5; Lime carbonate 2~15; Fluorite powder 1~10; Silicon-dioxide≤7.0; Phosphorus≤0.02; Sulphur≤0.15; Moisture content≤0.5 and other impurity.
In order to adapt to the needs of different steel grades, further, its component content % by weight is: aluminium 45~55; Aluminium sesquioxide 10~15; Titanium dioxide 3~12 or boron trioxide 1~5; Lime carbonate 2~15; Fluorite powder 1~10; Silicon-dioxide≤7.0; Phosphorus≤0.02; Sulphur≤0.15; Moisture content≤0.2; Other material surplus, this component can form liquid slag at molten steel surface.
Further, its component content by weight % be: aluminium 45~55; Aluminium sesquioxide 30~40; Titanium dioxide 3~12 or boron trioxide 1~5; Lime carbonate 2~15; Fluorite powder 1~10; Silicon-dioxide≤7.0; Phosphorus≤0.02; Sulphur≤0.15; Moisture content≤0.2; Other material surplus, this component can form foamy slag at molten steel surface.
The preparation method of above-mentioned high alumina slag ball, has following technical process: the metallic aluminium powder with sampling analysis after qualified, the aluminium ground-slag, the titanium slag powder, the fluorite powder, limestone powder, boric acid powder and bath of glass buying put in place and divide storage to deposit, the starting material weighing and proportioning that chemical examination is qualified, drop into then in the rotary drum mixer and mix, add the bath of glass 9-12% that mother-in-law U.S. degree is 37-42 again, continuously stirring mixes in the twin screws stirrer, immediately material is dropped into roll extrusion balling-up in the pair roller type ball press then, sieve qualified grade and enter in the air cooking equipment air cooking 20-24 hour with 150 ℃-200 ℃, naturally cooling is 10-12 hour behind finished product moisture content≤0.5%, screening, packing, warehouse-in.
Further, the component content of described each raw-material chemical ingredients by weight % be respectively:
Aluminum shot: Al 〉=95%, Cu≤1%, Si≤3%;
Aluminium ground-slag: Al 〉=25%, Al
2O
3≤ 65%, SiO
2≤ 5%;
Titanium slag powder: TiO
2〉=85%;
Fluorite powder: CaF
2〉=98%, SiO
2≤ 1%;
Limestone powder: CaCO
3〉=95%, SiO
2≤ 1%;
Boric acid powder: B
2O
3〉=98%.
When this high alumina slag ball adds in the ladle,, thereby can form tectum at molten steel surface rapidly because spherical material has good flowability after tapping; Because decomposing, the heat effect of molten steel, the lime carbonate in the material produce CO about 1000 ℃
2It is discrete that gas bursts apart spheroid, forms loose meal molten steel surface is played insulation effect.The CO that overflows
2Gas is discharged the molten steel surface air, to prevent the oxidation of molten steel, owing to the insulation effect of pulverulent material, CaCO
3Intensification is decomposed not fierce and is continued for some time, taps to purified time requirement to satisfy.In refining period, in refining period, meal fusion and participate in the deoxygenation of molten steel under agitation condition.
Aforesaid high alumina slag ball, can add alloying agents therein, most typical composition is Al, Ti, Al can aluminum shot form add, other composition can iron alloy the form of pulvis add, add-on can change in sizable scope, reaches as high as weight percent 20%, to adapt to the needs of steel grade alloying.Owing in base-material, there is a large amount of metallic aluminiums protect, thus the alloy element oxidational losses that is added seldom and recovery rate stablize.
Aforesaid high alumina slag ball, can add the carbonate of Ba, Mg, K, Na, Li therein, with part or all of replacement lime carbonate, the carbonate total amount can not cause detrimentally affect to use 15% when following, and the oxide compound of these basic metal or alkaline-earth metal is to CaAl
2O
4(calcium metaaluminate) is that main slag is on good terms and is played modification, rotten and change capillary effect, thereby more helps the pure of molten steel.
Aforesaid high alumina slag ball can add the oxide compound of vanadium, niobium therein, utilizes the reductive action of aluminium to finish to adding the process of alloying constituent in the steel, to reduce the cost of alloying.
The invention has the beneficial effects as follows one, detrimental impurity content such as silicon, sulphur, phosphorus is extremely low, is specially adapted to smelt Clean Steel and ultra-clean steel; The control of moisture content has avoided material to enter the phenomenon of raising a dust in the molten steel.Two, can in sizable scope, change the component content of deoxidation and alloy element, adapt to the needs that many steel grades change.Three, in the scope of certain content, can select basic metal or alkaline earth metal oxide (form with carbonate cpds adds) to finish modification to refined synthetic slag, particular requirement such as rotten arbitrarily.Four, raw material common, be easy to get, balling technique is simple, reliable, does not have the component segregation fluctuation, it is simple to add technology, molten steel surface is sprawled excellent thermal insulation performance.Five, deoxidation and refining are carried out synchronously, and oxide inclusion significantly reduces in the molten steel.
Embodiment
Raw-material preparation:
By the component content of each raw-material Chemical Composition by weight % be respectively:
Aluminium powder: Al 〉=95%, Cu≤0.5%, Si≤0.5%;
Aluminium ground-slag: Al 〉=25%, Al
2O
3≤ 65%, SiO
2≤ 5%;
Titanium slag powder: TiO
2〉=85%;
Fluorite powder: CaF
2〉=98%, SiO
2≤ 1%;
Limestone powder: CaCO
3〉=95%, SiO
2≤ 1%;
Boric acid powder: B
2O
3〉=98%.Requirement, with metallic aluminium powder, aluminium ground-slag, titanium slag powder, fluorite concentrate, limestone powder, boric acid powder, bath of glass purchase respectively put in place and divide the storage deposit, to the starting material sampling analysis, each raw-material chemical composition is respectively:
Aluminium powder: Al 98.5%, Cu 0.3%, Si 0.42%;
Aluminium ground-slag: Al 25.3%, Al
2O
364.5%, SiO
23.1%;
Titanium slag powder: TiO
286.2%;
Fluorite powder: CaF
298.26%, SiO
20.68%;
Limestone powder: CaCO
396.3%, SiO
20.52%;
Boric acid powder: B
2O
398.32%.
The preparation of aluminium slag ball, embodiment one
The qualified raw material of chemical examination is weighed: aluminium powder 385Kg, aluminium ground-slag 500Kg, titanium slag powder 35Kg, fluorite powder 25Kg, limestone powder 40Kg, to mix (15 minutes) in the above-mentioned raw material input rotary drum mixer of weighing, input mother-in-law U.S. degree is 37 bath of glass 50Kg and uniform mixing in the twin screws stirrer in the material that mixes, the material of uniform mixing is rolled into the spherical particle of 10~20mm in the pair roller type ball press, with the spherical particle input is in the drying plant of fuel with the coke, hot blast with 200 ℃ of left and right sides temperature, through oven dry in 20~24 hours, treat that moisture content of finished products is less than after 0.2%, naturally cooling 10-12 hour, screen once more, packing, warehouse-in.
The component content of the chemical ingredients of above embodiment finished product % by weight is:
Al:50.57;
Al
2O
3:32.25;
TiO
2:3.02;
CaF
2:2.45;
CaCO
3:3.85;
SiO
2:3.27;
H
2O:0.16;
P:0.008;
S:0.079。
Embodiment two
The qualified raw material of chemical examination is weighed: aluminium powder 460Kg, aluminium ground-slag 200Kg, titanium slag powder 135Kg, fluorite powder 75Kg, limestone powder 115Kg, to mix (15 minutes) in the above-mentioned raw material input rotary drum mixer of weighing, input mother-in-law U.S. degree is 37 bath of glass 50Kg and uniform mixing in the twin screws stirrer in the material that mixes, the material of uniform mixing is rolled into the spherical particle of 10~20mm in the pair roller type ball press, with the spherical particle input is in the drying plant of fuel with the coke, hot blast with 150-200 ℃ of left and right sides temperature, through oven dry in 20~24 hours, treat that moisture content of finished products is less than after 0.2%, naturally cooling 10-12 hour, screen once more, packing, warehouse-in.
The chemical ingredients of above embodiment finished product % by weight is:
Al:50.37;
Al
2O
3:12.90;
TiO
2:11.63;
CaF
2:7.36;
CaCO
3:11.07;
SiO
2:3.30;
H
2O:0.16;
P:0.008;
S:0.079。
The test application examples: the high alumina slag ball of the inventive method preparation, carried out using in batches in Shanghai Baosteel company, its result shows: the present invention has good application art, accomplish " one expects the end, the omnidistance processing ", easy and simple to handle, particularly it is in molten steel surface explosion slagging, because TiO
2With B
2O
3An amount of existence, absorb Al easily
2O
3The slagging come-up, and sprawl covering well, have the tight insulation and the effect of air-isolation.In refining furnace, add stirring, show very ideal washery slag ability, the slagging-off effect is remarkable.When the needs Alloying Treatment, the present invention who adds the alloy element preparation that contains needs makes alloying and handles, and the alloy element recovery rate improves greatly, and effect is very remarkable.