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 other 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 carbon-free protective material based on the coal dust ash, though this protective material has been avoided the recarburization of molten steel, the main component Al in 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 some has strict control to silicone content very unfavorable, a large amount of on the other hand Al of 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 aluminium killed 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, is not suitable for the use of aluminium killed steel; 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 aluminium killed 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.
Summary of the invention
In order to overcome the deficiencies in the prior art, the invention provides the rudimentary Aluminium Dross Ball And Preparation Method of a kind of detrimental impurity content, be applicable to that aluminium killed steel smelts pure or ultra-clean steel and can very fast generation after just producing steel and adding cover molten steel surface and make heat preserving agent.
The technical solution adopted for the present invention to solve the technical problems is: a kind of aluminium slag ball, contain metallic aluminium (Al), fluorite (CaF
2), lime carbonate (CaCO
3), aluminium sesquioxide (Al
2O
3), silicon-dioxide (SiO
2) and a spot of moisture content (H
2O), phosphorus (P), sulphur (S), copper (Cu) and inevitable other impurity, its component content is (weight %): aluminium 10~45; Aluminium sesquioxide 5~35; Fluorite 10~60; Lime carbonate 5~15; Silicon-dioxide≤5; Moisture content≤0.5; Phosphorus≤0.02; Sulphur≤0.15; Copper≤0.3; Other material surplus.
For adapting to the needs of different steel grades, further, its component content is (weight %): aluminium 20~30; Aluminium sesquioxide 10~15; Fluorite 40~50; Lime carbonate 10~12; Silicon-dioxide≤5; Moisture content≤0.5; Phosphorus≤0.02; Sulphur≤0.15; Copper≤0.3; Other material surplus.
Further, its component content is (weight %): aluminium 10~20; Aluminium sesquioxide 20~30; Fluorite 40~50; Lime carbonate 10~15; Silicon-dioxide≤5; Moisture content≤0.5; Phosphorus≤0.02; Sulphur≤0.15; Copper≤0.3; Other material surplus.
Further, its component content is (weight %): aluminium 23.5~26.5; Aluminium sesquioxide 10~15; Fluorite 43.5~46.5; Lime carbonate 10~12; Silicon-dioxide≤5; Moisture content≤0.5; Phosphorus≤0.02; Sulphur≤0.15; Copper≤0.3; Other material surplus.
Further, its component content is (weight %): aluminium 20~25; Aluminium sesquioxide 30~35; Fluorite 20~35; Lime carbonate 10~15; Silicon-dioxide≤5; Moisture content≤0.5; Phosphorus≤0.02; Sulphur≤0.15; Copper≤0.3; Other material surplus.
A kind of preparation method of aluminium slag ball, have following technical process: the metal aluminum shot with sampling analysis after qualified, aluminium ground-slag, fluorite concentrate, fat lime stone flour, bath of glass buying put in place and divide storage to deposit, the starting material weighing and proportioning that chemical examination is qualified, dropping into mixer then mixes, adding bath of glass again mixes, then material is dropped into roll extrusion balling-up in the pair roller type ball press, drying equipment is drying to obtain finished product.
Further, the component content (weight %) of described each raw-material Chemical Composition is respectively:
Aluminum shot: Al 〉=95%, Cu≤0.5%, Si≤3%;
Aluminium ground-slag: Al 〉=40%, Al
2O
3≤ 55%, SiO
2≤ 5%;
Fluorite powder: CaF
2〉=98%, SiO
2≤ 1%, S≤0.05%, P≤0.03%;
Limestone powder: CaCO
3〉=95%, SiO
2≤ 2%, S≤0.05%, P≤0.01%.
When this aluminium 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, meal fusion and participate in the deoxygenation of molten steel under agitation condition,
Calcium Fluoride (Fluorspan) in deoxidation products aluminum oxide and the fluorite powder produces reaction,
The aluminum trifluoride that generates becomes gas evolution, and the calcium oxide of generation continues and deoxidation products aluminium sesquioxide chemical combination,
More than reaction is carried out simultaneously with the chemical combination process, and the dynamic conditions of deoxidation products chemical combination slagging is highly beneficial, finally generates with CaAl
2O
4(calcium metaaluminate) is main slag phase, the theoretical fusing point of this slag is 1575 ℃, when the Calcium Fluoride (Fluorspan) more than 10% and a small amount of silicon-dioxide exist, its fusing point can be reduced to about 1400 ℃, has bigger alternate tension force with molten steel, can float slagging well and can not form in steel is mingled with, thereby more helps the pure of molten steel.
When adopting part aluminium ground-slag to replace metallic aluminium powder, when the part calcium carbonate powder replaced the fluorite powder, the main component of this aluminium slag ball was metallic aluminium, Calcium Fluoride (Fluorspan), lime carbonate, aluminium sesquioxide, silicon-dioxide, and its deoxidation and purifying reaction can be expressed with following formula:
Oxygen in the reactant on the following formula left side is from molten steel, and all the other materials are the agent for refining and heat-insulating composition, and the above composition material of per kilogram can be in conjunction with the oxygen about 0.25 kilogram, CO
2Gas generates effusion, AlF between soak
3Gas generates during deoxygenation refining and removes.
Aforesaid aluminium 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 20 (weight %), 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 aluminium slag ball can add the carbonate of Ba, Mg, K, Na, Li therein, and with part or all of replacement lime carbonate, the carbonate total amount can not cause detrimentally affect to use 15% when following.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 aluminium slag ball, available Ti partly or entirely replaces Al, to satisfy steel grade with Ti deoxidation and alloying (as stainless steel etc.).
Aforesaid aluminium 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, foreign matter contents such as carbon, silicon, sulphur, phosphorus are very low, are specially adapted to low-carbon (LC), low silicon Clean Steel and other ultra-clean steels; Defective heat preserving agents such as flyash, carbonization rice husk have been replaced; 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 the lime carbonate compound 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
The preparation of aluminium slag ball:
By (the component content (weight %) of each raw-material Chemical Composition is respectively:
Aluminum shot: Al 〉=95%, Cu≤0.5%, Si≤3%;
The aluminium ground-slag; Al 〉=40%, Al
2O
3≤ 55%, SiO
2≤ 5%;
Fluorite powder: CaF
2〉=98%, SiO
2≤ 1%, S≤0.05%, P≤0.03%;
Limestone powder: CaCO
3〉=95%, SiO
2≤ 2%, S≤0.05%, P≤0.01%.)
Requirement, with metal aluminum shot, aluminium ground-slag, fluorite concentrate, fat lime stone flour, 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:
Aluminum shot: Al 95.8%, Cu 0.32%, Si 2.37%;
Aluminium ground-slag: Al 40.29%, Al
2O
351.36%, SiO
23.48%;
Fluorite powder: CaF
298.26%, SiO
20.67%, S 0.03%, P 0.023%;
Limestone powder: CaCO
396.3%, SiO
20.52%, S 0.032%, P 0.015%.
The qualified raw material of chemical examination is weighed: aluminum shot 160Kg, aluminium ground-slag 250Kg, fluorite powder 450Kg, limestone powder 125Kg, to mix (15 minutes) in the above-mentioned raw material input rotary drum mixer of weighing, input 50Kg modulus is 3.5~3.7 bath of glass and uniform mixing in 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, it is in the drying plant of fuel with the coke that spherical particle is dropped into collecting bin, temperature with about 200 ℃, through oven dry in 20~24 hours, treat that moisture content of finished products less than after 0.5%, screens once more, puts in storage.
The chemical ingredients of above embodiment finished product is (weight %):
Al: 24.9;
Al
2O
3:12.5;
CaF
2:44.12;
CaCO
3:11.78;
SiO
2:3.26;
H
2O:0.16;
P:0.008;
S:0.079;
Cu:0.144。
Test application examples: the aluminium 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, it is good to sprawl covering, has 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, has obtained stokehold technician and operative employee's appreciation for this reason.