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CN-121974661-A - Anti-erosion low-carbon bottom-coated brick refractory material and preparation method thereof

CN121974661ACN 121974661 ACN121974661 ACN 121974661ACN-121974661-A

Abstract

The invention relates to the technical field of materials, in particular to an erosion-resistant low-carbon bottom-coated brick refractory material and a preparation method thereof, wherein the erosion-resistant low-carbon bottom-coated brick refractory material comprises fused magnesia coarse aggregate, fused magnesia medium aggregate, fused magnesia fine powder, zirconium carbide anchoring modified crystalline flake graphite, boron-doped lignin-based titanium carbide composite micro powder, nano hafnium carbide and phenolic resin bonding agent; according to the invention, through the synergistic protection of three functional components of zirconium carbide anchoring modified crystalline flake graphite, boron doped lignin-based titanium carbide composite micro powder and nano hafnium carbide, the problem that MgO and residual carbon in the brick are subjected to gasification reaction under the VD vacuum degassing working condition of the existing low-carbon magnesia carbon covered bottom brick, and meanwhile, an antioxidation additive promotes the reaction to exacerbate the structural damage of the brick is effectively solved.

Inventors

  • ZHENG SONGMENG
  • CAO YANG
  • LIU ZE
  • Chu Changyu

Assignees

  • 营口黑崎播磨耐火材料有限公司

Dates

Publication Date
20260505
Application Date
20260408

Claims (7)

  1. 1. The corrosion-resistant low-carbon bottom-coated brick refractory material is characterized by comprising, by weight, 45-52 parts of fused magnesia coarse aggregate, 15-20 parts of fused magnesia aggregate, 15-22 parts of fused magnesia fine powder, 3-4 parts of zirconium carbide anchoring modified crystalline flake graphite, 1-1.5 parts of boron-doped lignin-based titanium carbide composite micro powder, 1-3 parts of nano hafnium carbide and 3-5 parts of phenolic resin binder; the grain diameter D50 of the nano hafnium carbide is 100-200 nm, and the purity is more than or equal to 99%; The mass fraction of carbon in the refractory material is 4-8wt%, and the formula does not contain metal aluminum powder, metal silicon powder and boron carbide.
  2. 2. The corrosion-resistant low-carbon bottom-coated brick refractory material according to claim 1 is characterized in that the grain size of the fused magnesia coarse aggregate is 3-5mm, the MgO content is more than or equal to 97wt%, the grain size of the fused magnesia aggregate is 1-3 mm, the MgO content is more than or equal to 97wt%, and the grain size of the fused magnesia fine powder is less than 0.088mm, and the MgO content is more than or equal to 97wt%.
  3. 3. The erosion-resistant low-carbon bottom-coated brick refractory according to claim 1, wherein the preparation method of the zirconium carbide anchoring modified crystalline flake graphite comprises the following steps: S11, dissolving bis (cyclopentadienyl) zirconium dichloride in anhydrous tetrahydrofuran, stirring at room temperature until the bis (cyclopentadienyl) zirconium dichloride is completely dissolved, then adding furfuryl alcohol, and continuously stirring to obtain a precursor solution A; S12, placing flake graphite in a sealed infiltration tank, vacuumizing to-0.09 MPa, maintaining, then slowly injecting the precursor solution A, standing and infiltration under-0.09 MPa, recovering normal pressure, filtering, and placing the infiltration product in vacuum for drying to obtain a dried product; s13, placing the dried product in a tube furnace, introducing high-purity argon, and heating according to the following two procedures, wherein the first section is heated to 600 ℃ at 2 ℃ per minute and is kept at the temperature for 2 hours, the second section is heated to 1550 ℃ at 5 ℃ per minute and is kept at the temperature for 3 hours, and then the temperature is reduced to room temperature at 5 ℃ per minute, so that the zirconium carbide anchoring modified crystalline flake graphite is obtained.
  4. 4. The erosion-resistant low-carbon bottom-coated brick refractory material according to claim 3, wherein the grain size D50 of the crystalline flake graphite is 50 μm, the grain size of the zirconium carbide nano particles in the zirconium carbide anchoring modified crystalline flake graphite is 5-20 nm, and the zirconium carbide loading amount is 9.0-9.8wt%.
  5. 5. The corrosion-resistant low-carbon bottom-coated brick refractory material according to claim 1, wherein the preparation method of the boron-doped lignin-based titanium carbide composite micro powder comprises the following steps: S21, under the protection of nitrogen, dissolving an organic solvent lignin in absolute ethyl alcohol, adding trimethyl borate, stirring for 1.5-2.5 hours at 45-55 ℃, then carrying out reduced pressure distillation at 35-45 ℃ and 3-7 kPa, slowly dropwise adding an absolute ethyl alcohol solution of titanium acetylacetonate, and continuously stirring for 1.5-2.5 hours at 45-55 ℃ to obtain a precursor solution B; S22, preparing spherical micro powder from the precursor solution B through spray drying, controlling the particle size D50 to be 10-20 mu m, and then heating the spray dried product to 250 ℃ in an air atmosphere at 1 ℃ per minute for 1h to obtain a preoxidation stabilization treatment product; S23, placing the preoxidation stabilization treatment product in a tube furnace, introducing high-purity argon, and performing temperature programming according to the following two steps, wherein the first step is to heat up to 1000 ℃ at 2 ℃ per min for 2h, the second step is to heat up to 1450 ℃ at 5 ℃ per min for 3h, and then cooling to room temperature at 5 ℃ per min, and performing ball milling to obtain the boron-doped lignin-based titanium carbide composite micro powder.
  6. 6. The corrosion-resistant low-carbon bottom-coated brick refractory material according to claim 5, wherein the particle size D50 of the boron-doped lignin-based titanium carbide composite micro powder is 8-15 mu m, the TiC loading amount is 8-12 wt%, the boron doping amount is 1:10 in terms of B/C molar ratio, and the product does not contain crystalline TiB 2 .
  7. 7. The method for preparing the corrosion-resistant low-carbon bottom-coated brick refractory material according to any one of claims 1 to 6, which is characterized by comprising the following steps: S1, mixing, namely placing zirconium carbide anchoring modified crystalline flake graphite, boron doped lignin-based titanium carbide composite micro powder and nano hafnium carbide into a mixer for premixing, adding coarse fused magnesia aggregate, aggregate in fused magnesia and fused magnesia fine powder, dry mixing, adding phenolic resin binder, and continuously mixing until the materials are uniform to obtain a mixture; S2, molding and curing, namely filling the mixture into a steel mold, pressing and molding on a hydraulic press, demolding and drying to obtain a dried blank; S3, sintering, namely placing the dried blank body in a high-temperature furnace, and sintering under the protection of argon gas according to the following procedures of heating to 600 ℃ at 3 ℃ per minute, preserving heat for 1h at 5 ℃ per minute, heating to 1000 ℃ at1 ℃ per minute, preserving heat for 1h at1 ℃ per minute, heating to 1200 ℃ at 5 ℃ per minute, preserving heat for 3h at 1550 ℃ at 5 ℃ per minute, cooling to 1000 ℃ at 5 ℃ per minute after the heat preservation is finished, and cooling to room temperature along with the furnace, so as to obtain the corrosion-resistant low-carbon bottom-covering brick refractory material.

Description

Anti-erosion low-carbon bottom-coated brick refractory material and preparation method thereof Technical Field The invention relates to the technical field of materials, in particular to an erosion-resistant low-carbon bottom-coated brick refractory material and a preparation method thereof. Background The ladle bottom bricks bear the static pressure, thermal shock and slag erosion of high-temperature molten steel for a long time, and magnesia carbon bricks are widely adopted due to the excellent slag resistance and high-temperature strength. With the improvement of the control requirement of the clean steel smelting on the carburetion of molten steel, the carbon content of the bottom-coated brick is reduced, however, the oxidation resistance is reduced due to the reduction of the carbon content, and the prior art generally introduces antioxidant additives such as metal aluminum powder, metal silicon powder or boron carbide to compensate, so that the scheme is widely verified in normal pressure and high temperature environments. However, the Vacuum Degassing (VD) furnace is operated by placing the whole ladle in a sealed vacuum tank, the ladle bottom brick is directly exposed to the composite extreme environment of high temperature and vacuum, and the prior art scheme has the fundamental defects that firstly, mgO matrix is converted into an effective oxidant under the high temperature vacuum condition, and gasification reaction is carried out between MgO(s) +C(s) - →Mg (g)/(CO (g)) and residual carbon in the brick. The vacuum condition greatly reduces the partial pressure of the gaseous products, so that the reaction balance moves to the positive direction, the initial temperature is obviously reduced to be within the refining working temperature range, the reaction rate is greatly improved, a large amount of gaseous products escape to form communicated pores in the brick body, the compact structure is damaged, and the erosion resistance and the scouring resistance are sharply reduced. Secondly, the existing antioxidant additives (aluminum powder, silicon powder and boron carbide) are specially designed for normal pressure oxidation atmosphere, cannot form a compact oxide protection layer under vacuum conditions, exist in a reduced state, further participate in MgO-C gasification reaction, exacerbate the degradation of brick body tissues, and enable an additive system introduced for the purpose of antioxidation to become a cause of acceleration failure under vacuum working conditions. Disclosure of Invention (1) Technical problem to be solved The invention aims to provide an anti-corrosion low-carbon bottom-coated brick refractory material and a preparation method thereof, so as to solve the problem that the existing low-carbon magnesium-carbon bottom-coated brick has gasification reaction between MgO and residual carbon in the brick under the VD vacuum degassing working condition, and meanwhile, an anti-oxidation additive promotes the reaction to aggravate the structural damage of the brick. (2) Technical proposal In order to achieve the aim, on the one hand, the invention provides an erosion-resistant low-carbon bottom-coated brick refractory material, which comprises, by weight, 45-52 parts of fused magnesia coarse aggregate, 15-20 parts of aggregate in fused magnesia, 15-22 parts of fused magnesia fine powder, 3-4 parts of zirconium carbide anchoring modified crystalline flake graphite, 1-1.5 parts of boron-doped lignin-based titanium carbide composite micro powder, 1-3 parts of nano hafnium carbide and 3-5 parts of phenolic resin binder; the grain diameter D50 of the nano hafnium carbide is 100-200 nm, and the purity is more than or equal to 99%; The mass fraction of carbon in the refractory material is 4-8wt%, and the formula does not contain metal aluminum powder, metal silicon powder and boron carbide. Further, the grain size of the coarse aggregate of the fused magnesia is 3-5 mm, the MgO content is more than or equal to 97wt%, the grain size of the aggregate in the fused magnesia is 1-3 mm, the MgO content is more than or equal to 97wt%, the grain size of the fine powder of the fused magnesia is less than 0.088mm, and the MgO content is more than or equal to 97wt%. Further, the preparation method of the zirconium carbide anchoring modified crystalline flake graphite comprises the following steps: S11, dissolving bis (cyclopentadienyl) zirconium dichloride in anhydrous tetrahydrofuran, stirring at room temperature until the bis (cyclopentadienyl) zirconium dichloride is completely dissolved, then adding furfuryl alcohol, and continuously stirring to obtain a precursor solution A; S12, placing flake graphite in a sealed infiltration tank, vacuumizing to-0.09 MPa, maintaining, then slowly injecting the precursor solution A, standing and infiltration under-0.09 MPa, recovering normal pressure, filtering, and placing the infiltration product in vacuum for drying to obtain a dried product; s13, placing