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CN-121990842-A - Anti-erosion air brick and preparation process thereof

CN121990842ACN 121990842 ACN121990842 ACN 121990842ACN-121990842-A

Abstract

The invention relates to the technical field of air bricks, in particular to an anti-corrosion air brick and a preparation process thereof. According to the invention, a composite coating layer is constructed on the surface of zirconia through modified titanate and modified boric acid, a titanium component is utilized to generate a titanium dioxide compact layer in situ at high temperature to block corrosion of calcium oxide in slag, and meanwhile, a boron component forms a high-melting-point phase to fill grain boundary pores to inhibit slag infiltration and harmful dendrite precipitation, so that the structural stability and slag corrosion resistance of the air brick are improved.

Inventors

  • ZHANG XIAOYUN
  • TONG JING
  • WANG FUJIANG
  • Sun Xingman
  • TANG JIAN
  • SHI JIAN

Assignees

  • 大石桥市冠诚耐火材料有限公司

Dates

Publication Date
20260508
Application Date
20260409

Claims (8)

  1. 1. The anti-erosion air brick is characterized by comprising, by weight, 80-85 parts of fused magnesia particles, 10-12 parts of crystalline flake graphite, 3-5 parts of modified zirconia fine powder, 2-3 parts of metal aluminum fine powder, 1-2 parts of boron carbide fine powder and 3-4 parts of phenolic resin; the particle size of the fused magnesia particles comprises 3-5mm particle size fraction, 1-3mm particle size fraction and 0-1mm particle size fraction, wherein the mass ratio of the 3-5mm particle size fraction fused magnesia particles to the 1-3mm particle size fraction fused magnesia particles to the 0-1mm particle size fraction fused magnesia particles is 3:3:4; The modified zirconia is a compound obtained by coating the surface of the zirconia with modified tetrabutyl titanate and modified boric acid, wherein the modified tetrabutyl titanate is organically chelated and modified tetrabutyl titanate by acetylacetone, and the modified boric acid is organically esterified and modified by N-methyliminodiacetic acid.
  2. 2. The anti-erosion air brick according to claim 1, wherein the preparation method of the modified tetrabutyl titanate comprises the following steps: S11, under the protection of nitrogen, tetrabutyl titanate is dissolved in absolute ethyl alcohol to obtain an ethanol solution of tetrabutyl titanate; s12, dropwise adding an ethanol solution of acetylacetone into an ethanol solution of tetrabutyl titanate under stirring, heating to 60 ℃ for reaction after dropwise adding, obtaining a mixed solution A, and rotationally evaporating the mixed solution A to obtain the modified tetrabutyl titanate.
  3. 3. An erosion resistant air brick according to claim 2, wherein the molar ratio of tetrabutyl titanate to acetylacetone is 1:1.2.
  4. 4. The anti-erosion air brick according to claim 1, wherein the preparation method of the modified boric acid comprises the following steps: S21, sequentially adding boric acid, N-methyliminodiacetic acid, dimethyl sulfoxide, toluene and p-toluenesulfonic acid into a reaction bottle, heating to 110-120 ℃ for reflux water diversion reaction until no water is generated, and obtaining a mixed solution B; s22, cooling the mixed solution B, slowly pouring the cooled mixed solution B into diethyl ether to separate out precipitate, standing, carrying out suction filtration, and washing a filter cake A with diethyl ether at 0-5 ℃ to obtain a crude product; S23, transferring the crude product into a round-bottom flask, adding acetone at 50-60 ℃ for stirring, adding acetone at 50-60 ℃ until the solid is completely dissolved if the solid is not completely dissolved, filtering while the solid is hot, naturally cooling the filtrate to room temperature, then placing the filtrate in 0-5 ℃ for cooling and crystallizing, carrying out suction filtration, washing a filter cake B with acetone at 0-5 ℃, and placing the filter cake B in a vacuum drying oven for drying to obtain the modified boric acid.
  5. 5. The erosion resistant air brick according to claim 1, wherein said modified zirconia fine powder is prepared by a process comprising the steps of: s1, weighing monoclinic zirconia powder, placing the monoclinic zirconia powder into a three-neck flask, adding absolute ethyl alcohol, and performing ultrasonic dispersion to obtain a suspension; s2, weighing the modified tetrabutyl titanate, dissolving the modified tetrabutyl titanate in absolute ethyl alcohol to obtain a first mixed solution, transferring the first mixed solution into a constant pressure dropping funnel, dropping the first mixed solution into the suspension under stirring, heating to 60 ℃ after the dropping is finished, and stirring at constant temperature for reaction to obtain an active intermediate suspension; s3, weighing modified boric acid, dissolving the modified boric acid in absolute ethyl alcohol to obtain a second mixed solution, adding the second mixed solution into the active intermediate suspension, keeping the temperature at 60 ℃, and continuously stirring and fully mixing to obtain a modified precursor suspension; S4, mixing ammonia water and absolute ethyl alcohol to obtain an ammonia water-alcohol mixed solution, regulating the pH value to 8.0-8.5, transferring the ammonia water-alcohol mixed solution into a constant pressure dropping funnel, and dropping the ammonia water-alcohol mixed solution into the modified precursor suspension at room temperature; S5, centrifugally separating the coated precursor suspension, and removing supernatant to obtain a wet filter cake, washing the wet filter cake with absolute ethyl alcohol, and drying in a vacuum drying oven to obtain precursor powder; s6, filling the precursor powder into a corundum crucible, putting the corundum crucible into a tubular atmosphere furnace, introducing argon, heating to 900 ℃, preserving heat, cooling along with the furnace, and grinding to obtain the modified zirconia.
  6. 6. The anti-erosion air brick according to claim 5, wherein the purity of the monoclinic zirconia powder is not less than 99%, the particle size D50 is 1.0-2.0 μm, and the specific surface area is not less than 10m 2 /g.
  7. 7. The anti-erosion air brick according to claim 5, wherein the addition of the modified tetrabutyl titanate is 5% of the mass of the zirconia powder, and the addition of the modified boric acid is 2% of the mass of the zirconia powder.
  8. 8. A process for preparing an anti-erosion air brick, which is applied to preparing an anti-erosion air brick according to any one of claims 1 to 7, and is characterized by comprising the following steps: Mixing, namely adding fused magnesia particles into an edge mill, dry-mixing, sequentially adding flake graphite, modified zirconia, metal aluminum fine powder and boron carbide fine powder, continuously dry-mixing, and finally adding phenolic resin, wet-mixing until the pugs are uniformly black and are not loose by hand to obtain mixed pugs; Step 2, material trapping, in which the mixed pug is filled into a double-layer plastic bag for sealing, and the material is trapped at 20-30 ℃ to obtain the pug after material trapping; Step M3, molding, namely adding the mud materials subjected to the material trapping into an air brick mold, and carrying out classified compression molding by adopting a hydraulic press to obtain green bricks; M4. drying, namely placing the green bricks into a drying kiln, and drying at 80-120 ℃ until the moisture content is less than 0.5%, thus obtaining dried green bricks; m5. sintering, namely covering the dried brick blank with coke grains, and adopting a carbon-embedded sintering process to obtain the anti-erosion air brick.

Description

Anti-erosion air brick and preparation process thereof Technical Field The invention belongs to the technical field of air bricks, and particularly relates to an anti-corrosion air brick and a preparation process thereof. Background The air brick is a key element for blowing argon gas from the bottom in ladle refining, and a zirconium oxide material is often adopted for a working surface to enhance the heat shock resistance and the scouring resistance. However, zirconia suffers from severe chemical attack when high alkalinity refining slag is used. At high temperature, the high calcium oxide slag permeates into the reaction layer to cause the stabilizer in the zirconia grains to be desolventized in the slag, so that the zirconia is instable and is converted from tetragonal phase to monoclinic phase, and meanwhile, calcium oxide, silicon dioxide and the like in the slag react with the zirconia to generate low-melting-point calcium zirconium silicate, so that the zirconia particles are dissolved to damage the compact structure of the reaction layer. Zr 4+、Ca2+、Si4+ plasma generated by the reaction of zirconia and slag enters a slag phase, migrates to the outer side of the reaction layer under the drive of temperature or concentration gradient, and precipitates a branched crystalline zirconium-containing silicate phase when the reaction layer is partially supersaturated. These re-precipitates have weak binding force with the matrix and induce local stress, which results in loosening of the structure outside the reaction layer and generation of microcracks. The loose layer is easy to peel off under the flushing of molten steel, and a fresh interface is exposed to accelerate the corrosion loss. The negative feedback cycle finally leads to the falling of crystal grains and loose structure of the working surface, and the service life is greatly shortened. Disclosure of Invention (1) The technical problems to be solved are as follows: The invention aims to provide an anti-corrosion air brick and a preparation process thereof, which are used for solving the problems that the high-alkalinity slag chemically erodes zirconia and secondary dendrites are separated out again, so that the compactness and continuity of a reaction layer are damaged. (2) The technical scheme is as follows: in order to achieve the aim, in one aspect, the invention provides an anti-erosion air brick, which comprises the following components, by weight, 80-85 parts of fused magnesia particles, 10-12 parts of crystalline flake graphite, 3-5 parts of modified zirconia fine powder, 2-3 parts of metal aluminum fine powder, 1-2 parts of boron carbide fine powder and 3-4 parts of phenolic resin; the particle size of the fused magnesia particles comprises 3-5mm particle size fraction, 1-3mm particle size fraction and 0-1mm particle size fraction, wherein the mass ratio of the 3-5mm particle size fraction fused magnesia particles to the 1-3mm particle size fraction fused magnesia particles to the 0-1mm particle size fraction fused magnesia particles is 3:3:4; The modified zirconia is a compound obtained by coating the surface of the zirconia with modified tetrabutyl titanate and modified boric acid, wherein the modified tetrabutyl titanate is organically chelated and modified tetrabutyl titanate by acetylacetone, and the modified boric acid is organically esterified and modified by N-methyliminodiacetic acid. Further, the preparation method of the modified tetrabutyl titanate comprises the following steps: S11, under the protection of nitrogen, tetrabutyl titanate is dissolved in absolute ethyl alcohol to obtain an ethanol solution of tetrabutyl titanate; S12, dropwise adding an ethanol solution of acetylacetone into an ethanol solution of tetrabutyl titanate under stirring, heating to 60 ℃ for reaction after dropwise adding to obtain a mixed solution A, and performing rotary evaporation on the mixed solution A to remove a solvent to obtain modified tetrabutyl titanate, and sealing and preserving. Further, the molar ratio of tetrabutyl titanate to acetylacetone is 1:1.2. Further, the preparation method of the modified boric acid comprises the following steps: S21, sequentially adding boric acid, N-methyliminodiacetic acid, dimethyl sulfoxide, toluene and p-toluenesulfonic acid into a reaction bottle, heating to 110-120 ℃ for reflux water diversion reaction until no water is generated, and obtaining a mixed solution B; S22, cooling the mixed solution B, slowly pouring the cooled mixed solution B into diethyl ether to separate out precipitate, standing to enable the precipitate to be complete, filtering, and washing a filter cake A by using diethyl ether at 0-5 ℃ to obtain a crude product; S23, transferring the crude product into a round-bottom flask, adding 50-60 ℃ of acetone, stirring, adding 50-60 ℃ of acetone if the solid is not completely dissolved until the solid is completely dissolved, filtering while the solid is hot (a funnel needs to be preheat