A kind of tundish gas permeable brick and preparation method thereof
One, technical field
The invention belongs to Al
2O
3-SiO
2The fire resistant materials technical field.Relate in particular to a kind of Al
2O
3-SiO
2Tundish breathable refractory materials and method thereof.
Two, background technology
Stir by the gas permeable brick Argon in molten steel that is installed in the tundish bottom, make composition and temperature even, can significantly remove non-metallic inclusion in the molten steel, molecule and reduction [O] content, molten steel is played cleaning action.
Select in the material of gas permeable material, generally popular both at home and abroad is magnesia and corundum matter two classes.In use, because of periclasite and wustite formation continuous solid solution, so magnesia gas permeable material has resistivity preferably to the basic slag that contains ferric oxide and calcium oxide, but magnesia thermal expansivity is big, Young's modulus is high, thermal shock resistance is poor, and slag permeates to the periclasite intercrystalline in use, and then causes its structure spalling.By contrast, corundum matter gas permeable brick has characteristics such as good high-temperature performance and anti-thermal shock stability, but pure corundum matter porous plug in use erosion-resisting characteristics is poor, flake-off piece phenomenon is serious.
For further improving corundum matter gas permeable material anti-scour property, adopt more and in matrix, add Cr
2O
3The micro mist measure.The employing fused corundom is main raw material (ZL 95110026.2), adds Cr simultaneously
2O
3The micro mist sintering is made, Cr
2O
3Form the aluminium chromium solid solution with corundum fine powder, then form the glassy phase that contains chromium with other impurity, be the filling of isolated island shape between the chromium corundum crystal, this full-bodied chromium glass that contains stops the infiltration of slag highly beneficial relatively, but too Zhi Mi weave construction makes the thermal shock resistance deterioration, and Cr
2O
3At high temperature volatile, harmful to environment.
Be the anti-erosion of seeking gas permeable material and the overall equilbrium of thermal shock resistance, adopted and in matrix, added spinel (ZL94118264.9), cooperate SiO
2Raw material (spy opens flat 10-251739), adding Al
2O
3ZrO
2Be raw material (spy opens flat 10-280029), add zirconium mullite fine powder (spy opens flat 9-52168), with Al
2O
3ZrO
2Raw material and MgO micro mist add (spy opens flat 9-268051) simultaneously, make spinel, mullite, zirconium mullite constitute the matrix part of porous plug.In corundum matter aggregate, add mullite or original position generation mullite (Nobuyuki Mimure, Hironobu Toritani and Tatsuo Kawakami.GasPermeable Brick for the Refining in Steel Ladles[A] .UNITE ' 89 Congress[C], Vol.1, (1989): 442-452), can improve the thermal shock resistance of material, but because SiO
2Introducing its is reduced in life-span.VladimirV.Primachenko etc. (Vladimir V.Primachenko Valery V.Martynenko and Vladimir A.Ustichenko.TheManufacturing Experience and Application in the Ukraine Mullite-corrundom Purging Plugs for theBlowing of Steel in the Ladles[A] .UNITECR ' 2001 Congress[C], (2001): 490-493) studied the mullite bonded corundum and burnt till gas permeable brick, utilized the mullite characteristics littler to improve spalling than the corundum coefficient of expansion.
Though corundum-mullite matter gas permeable material has permeability preferably, and physical and chemical performance in some aspects also can well adapt to the environment for use at tundish, because the ventilative mode of its diffuse type structure, intensity is lower.
Three, summary of the invention
Task of the present invention provide a kind of have good anti-thermal shock, slag corrosion resistance, scour resistance, environmentally safe, reinforced effects is good, the intensity that can improve fire-resistant ventilative mould material, can improve tundish gas permeable brick of permeability and preparation method thereof simultaneously.
For realizing above-mentioned task, the technical solution adopted in the present invention is: percentage composition mixes the raw material of 76~85% corundum, 5~20% mullites, 2~10% wedding agents, 1~5% silicon powder by weight, adds 0.05~0.20% dispersion agent, 7~9% water, 5~20% dry gel powders, 1~5%AlF
3, stirred 6~8 minutes, casting, through 110 ℃ * 24h drying, 1200~1400 ℃ * 3h burns till.Wherein: described dry gel powder is the prepared gel of sol-gel mullite precursor, dries under 110 ℃ * 24h condition; Dispersion agent is that tripoly phosphate sodium STPP, Sodium hexametaphosphate 99 are mixing in 2: 1 by weight.
The Al of the corundum of described raw material
2O
3The Al of content 〉=95%, mullite
2O
3The Al of content 〉=65%, wedding agent
2O
3The SiO of content 〉=70%, silicon powder
2Content 〉=88%.The grain composition of raw material is that corundum is that 2~0.15mm, mullite are that 1~0.088mm, wedding agent are that≤10 μ m, silicon powder are≤1 μ m.
Described wedding agent is Alphabond, ρ-Al
2O
3, a kind of in the alumina gel powder, magnalium gel powder or be two kinds or be two or more combinations.
It is main raw material that the present invention adopts corundum and mullite, the selective oxidation Al binding agent, form and the adjustment grain composition by feed proportioning optimization, the corundum-mullite matter gas permeable brick of manufacturing has high durability and good anti-thermal shock, slag corrosion resistance and advantages such as anti-molten steel scouring performance and environmentally safe.The dry gel powder of introducing cooperates certain catalyzer, and the mullite crystal whisker that is generated can further improve intensity, forms little pore and improves permeability.
Four, embodiment
The preparation method of embodiment tundish corundum-mullite matter gas permeable brick is that the weight percentage of its component is with Al
2O
3The plate diamond spar of content 〉=99.8% is 77~83%, Al
2O
3The mullite of content 〉=71% is 10~15%, Al
2O
3ρ-the Al of content 〉=74.5%
2O
3Wedding agent is 3~6%, SiO
2The raw material of the silicon powder 1~3% of content 〉=95% mixes, and adds 7.8% water, 0.1~0.15% dispersion agent, dry gel powder 11%~14%, 3~5% AlF by the raw material of said ratio
3, stir casting after 6~7 minutes, through 110 ℃ * 24h drying, 1200 ℃ * 3h burns till then.Dry gel powder is the prepared gel of sol-gel mullite precursor, dries under 110 ℃ * 24h condition.
The grain composition of each component: corundum: 2~0.15mm, mullite 1~0.088mm, ρ-Al
2O
3Wedding agent is≤10 μ m, silicon powder≤1 μ m.
It surveys physical and chemical index: apparent porosity is 20%, 1200 ℃ * 3h of 110 ℃ * 24h 27%; Volume density is 110 ℃ * 24h 2.5g/cm
3, 1200 ℃ * 3h 2.5g/cm
3Compressive strength is 110 ℃ * 24h 13MPa, 1200 ℃ * 3h 16MPa; Strength at normal temperature is 110 ℃ * 24h 4.8MPa, 1200 ℃ * 3h 4.9MPa; The line velocity of variation is that 1200 ℃ * 3h burns back 0.10%; The normal temperature Gas permeability is 110 ℃ * 24h, 109 milli dyne, 1200 ℃ * 3h, 277 milli dyne, 1500 ℃ * 3h, 318 milli dyne.
Comparative example adopts (with weight percentage): Al
2O
3The plate diamond spar of content 〉=99.8% is 70~76%, Al
2O
3The mullite of content 〉=71% is 16~21%, Al
2O
3ρ-the Al of content 〉=74.5%
2O
3Wedding agent is 3~6%, SiO
2The raw material of the silicon powder 1~3% of content 〉=95% mixes.÷ adds 7% water, 0.1~0.15% dispersion agent, stirs casting after 6~7 minutes, and through 110 ℃ * 24h drying, 〉=1200 ℃ * 3h burns till then.
The grain composition of each component: corundum: 2~0.15mm, mullite 1~0.088mm, wedding agent ρ-Al
2O
3Be≤10 μ m, silicon powder≤1 μ m.
It surveys physical and chemical index: apparent porosity is 28%, 1500 ℃ * 3h of 110 ℃ * 24h 30%; Volume density is 110 ℃ * 24h 2.6g/cm
3, 1500 ℃ * 3h 2.7g/cm
3Compressive strength is 110 ℃ * 24h 14MPa, 1500 ℃ * 3h 21MPa; Strength at normal temperature is 110 ℃ * 24h 2.7MPa, 1500 ℃ * 3h 5.3MPa; The line velocity of variation is that 1500 ℃ * 3h burns back-0.36%: the normal temperature Gas permeability is 110 ℃ * 24h, 91 milli dyne, 1200 ℃ * 3h, 140 milli dyne, 1500 ℃ * 3h, 154 milli dyne.