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CN-122010534-A - Low-carbon magnesia carbon refractory material with high thermal shock resistance and slag erosion resistance and preparation method thereof

CN122010534ACN 122010534 ACN122010534 ACN 122010534ACN-122010534-A

Abstract

The invention discloses a low-carbon magnesia carbon refractory material with high thermal shock resistance and slag erosion resistance and a preparation method thereof, and relates to the technical field of magnesia carbon refractory materials. The refractory material comprises, by mass, 40-45 parts of 3-5 mm fused magnesia, 20-25 parts of 1-3 mm fused magnesia, 10-15 parts of less than or equal to 1mm fused magnesia, 8-12 parts of silicon powder, 5-8 parts of a composite additive, 4-6 parts of crystalline flake graphite and 3-5 parts of phenolic resin, wherein the raw materials of the composite additive are alumina powder, lanthanum oxide powder and low-grade andalusite. According to the invention, the alumina powder and the lanthanum oxide powder are utilized to directionally convert the impurity phases in the low-grade andalusite into the spinel, mullite and rare earth lanthanum aluminate with high melting point, so that the problem that the low-grade andalusite is difficult to apply in a metallurgical refractory material is solved, and meanwhile, the ceramic phase structure and distribution of the refractory material are cooperatively regulated and controlled with the andalusite, so that the thermal shock resistance and slag erosion resistance of the refractory material are remarkably improved.

Inventors

  • CHEN YANG
  • YU JI
  • CHEN QIANLIN
  • LI YANHUA
  • WU ZHI
  • LONG SIYI
  • WU YIXIN
  • LIU ZICONG
  • FAN XIAOXUE

Assignees

  • 湖南工学院

Dates

Publication Date
20260512
Application Date
20260303

Claims (10)

  1. 1. The low-carbon magnesia carbon refractory material with high thermal shock resistance and slag erosion resistance is characterized by comprising, by weight, 40-45 parts of 3-5 mm fused magnesia, 20-25 parts of 1-3mm fused magnesia, 10-15 parts of less than or equal to 1mm fused magnesia, 8-12 parts of silicon powder, 5-8 parts of a composite additive, 4-6 parts of crystalline flake graphite and 3-5 parts of phenolic resin, wherein the composite additive is prepared by mixing low-grade andalusite powder, alumina powder and lanthanum oxide powder, and crushing after microwave sintering.
  2. 2. The low-carbon magnesia carbon refractory material with high thermal shock resistance and slag erosion resistance according to claim 1, wherein the mass ratio of the alumina powder to the low-grade andalusite powder is 1 (2-4), and the lanthanum oxide powder accounts for 0.2-0.5wt% of the total mass of the composite additive.
  3. 3. The high thermal shock and slag erosion resistant low carbon magnesia carbon refractory of claim 1, wherein the method of preparing the composite additive comprises the steps of: Adding water into the alumina powder, the low-grade andalusite powder and the lanthanum oxide powder, stirring and mixing to obtain a mixture, wherein the added water amount is 3-5wt%; pressing, forming and drying the mixture under the pressure of 150-180 MPa to obtain a formed blank; Microwave sintering the molded blank for 30-60 min under the condition of 1150-1200 ℃ in the mixed atmosphere of Ar and H 2 to obtain a sintered product; Crushing the sintered product until the grain diameter is less than or equal to 100 mu m, and obtaining the composite additive.
  4. 4. The low-carbon magnesia carbon refractory material with high thermal shock resistance and slag erosion resistance according to claim 1, wherein the alumina powder is alpha-alumina powder with a particle size of 5-6 mu m, the purity is more than or equal to 99wt%, the lanthanum oxide powder with a particle size of 5-6 mu m, the purity is more than or equal to 99wt%, the low-grade andalusite powder with a particle size of less than or equal to 100 mu m, the purity is 70-80 wt%, the SiO 2 content is 13-18 wt%, and the Fe 2 O 3 content is 4-6 wt%.
  5. 5. The low-carbon magnesia carbon refractory material with high thermal shock resistance and slag erosion resistance according to claim 1, wherein the purity of the fused magnesia is not less than 98wt%.
  6. 6. The low-carbon magnesia carbon refractory material with high thermal shock resistance and slag erosion resistance as claimed in claim 1, wherein the grain size of the silica powder is less than or equal to 100 mu m, and the purity is more than or equal to 99wt%.
  7. 7. The low-carbon magnesia carbon refractory material with high thermal shock resistance and slag erosion resistance according to claim 1, wherein the grain size of the crystalline flake graphite is less than or equal to 150 mu m, and the purity is more than or equal to 98wt%.
  8. 8. The low-carbon magnesia carbon refractory material with high thermal shock resistance and slag erosion resistance according to claim 1, wherein the phenolic resin is thermosetting phenolic resin, the viscosity is 1000-2000 mPa.s, the free phenol is less than or equal to 8wt% and the free aldehyde is less than or equal to 5wt%.
  9. 9. The low-carbon magnesia carbon refractory material with high thermal shock resistance and slag erosion resistance according to claim 3, wherein the gas flow rate of the mixed atmosphere is 50-100 mL/min, and the volume ratio of H 2 in the mixed gas is 2-3 vol%.
  10. 10. The method for preparing the low-carbon magnesium-carbon refractory material with high thermal shock resistance and slag erosion resistance according to any one of claims 1 to 9, which is characterized by comprising the following steps: the preparation method comprises the steps of uniformly mixing the raw materials of the components, pressing and forming under the condition of 200MPa, solidifying for 12-18 hours at 110-220 ℃, preserving heat for 3-5 hours under the condition of carbon embedding atmosphere and 1400-1500 ℃, and naturally cooling to obtain the low-carbon magnesia carbon refractory material with high thermal shock resistance and slag erosion resistance.

Description

Low-carbon magnesia carbon refractory material with high thermal shock resistance and slag erosion resistance and preparation method thereof Technical Field The invention relates to the technical field of refractory materials, in particular to a low-carbon magnesium-carbon refractory material with high thermal shock resistance and slag erosion resistance and a preparation method thereof. Background Because of excellent thermal shock resistance and slag erosion resistance, the magnesia carbon refractory material becomes an essential basic material in the smelting process including refining process links. In order to meet the use performance, the magnesium-carbon refractory material with the carbon content of 10-20wt% is industrially used, and has the obvious defects that the high carbon content is easy to cause a molten pool carburetion effect in a molten steel decarburization link, the high heat conductivity causes large heat loss, graphite resources are excessively consumed, carbon emission exacerbates environmental load and the like. Low carbonization of the magnesia carbon refractory is imperative. However, the reduction of the carbon content tends to reduce the thermal shock resistance and slag erosion resistance of the magnesia-carbon refractory material, and cannot meet the urgent demands of the advancement of the high-quality clean steel smelting technology. The introduction of the high-efficiency additive is one of effective methods for improving the high-temperature service performance of the low-carbon magnesium-carbon refractory material, but at present, some problems still exist: For example, the technology of the patent of 'a preparation method of high corrosion resistance low carbon magnesia carbon refractory material' (CN 202510738149.8) is used for preparing the low carbon magnesia carbon refractory material by using Ti 3SiC2 powder additive, but the Ti 3SiC2 raw material has the problems of high cost and adverse industrialized application. In another technical scheme disclosed in the patent 'a low-carbon magnesia carbon refractory material for clean steel smelting and a preparation method thereof' (CN 202411554021.8), high-grade andalusite/mullite is adopted as a composite additive, and a small amount of silicon dioxide low-melting phase generated by high-temperature decomposition of the high-grade andalusite can be converted into a high-melting phase through high-temperature structural reconstruction, so that the performance of the refractory material is improved. The high-grade andalusite and mullite raw materials used in the scheme have higher cost, are unfavorable for low-cost popularization and application, and the low-grade andalusite with large reserves and low price can not be directly used because of excessive internal liquid phase of the refractory material at high temperature due to high impurity content and inherent low-melting phase content and superposition of silicon dioxide low-melting phase generated by high-temperature decomposition of the low-grade andalusite. In order to meet the development strategy of clean steel smelting technology innovation, energy conservation, emission reduction and efficient resource utilization in metallurgical industry, the patent aims to prepare the refractory additive with excellent service performance and low cost advantages by taking low-grade andalusite as a raw material, and realize high-value utilization of low-grade low-cost resources while improving the service performance and the service life of the magnesia carbon refractory material. Disclosure of Invention The invention aims to provide a low-carbon magnesia carbon refractory material with high thermal shock resistance and slag erosion resistance. The low-carbon magnesia carbon refractory material with high thermal shock resistance and erosion resistance is prepared from, by weight, 40-45 parts of 3-5 mm fused magnesia, 20-25 parts of 1-3 mm fused magnesia, 10-15 parts of less than or equal to 1mm fused magnesia, 8-12 parts of silicon powder, 5-8 parts of a composite additive, 4-6 parts of crystalline flake graphite and 3-5 parts of phenolic resin, wherein the composite additive is prepared by mixing low-grade andalusite powder, alumina powder and lanthanum oxide powder, and crushing after microwave sintering. Further, the mass ratio of the alumina powder to the low-grade andalusite powder is 1 (2-4), and the lanthanum oxide powder accounts for 0.2-0.5wt% of the total mass of the composite additive. Further, the preparation method of the composite additive comprises the following steps: Adding water into the alumina powder, the low-grade andalusite powder and the lanthanum oxide powder, stirring and mixing to obtain a mixture, wherein the added water amount is 3-5wt%; pressing, forming and drying the mixture under the pressure of 150-180 MPa to obtain a formed blank; Carrying out microwave sintering on the molded blank for 30-60 min under the condition of 1150-1200 ℃ in a mixed atmo