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CN-122010582-A - Formula for producing high-temperature wear-resistant acid-alkali-resistant electric smelting zirconium mullite brick

CN122010582ACN 122010582 ACN122010582 ACN 122010582ACN-122010582-A

Abstract

The invention discloses a high-temperature wear-resistant acid-alkali-resistant fused zirconia mullite brick production formula, and belongs to the technical field of high-performance refractory materials. The invention provides a new formula and an ultra-slow cooling process, wherein the formula consists of a matrix forming material, a kyanite/andalusite structure synergistic regulator and a rare earth-alkaline earth metal-boron composite functional auxiliary agent, and the melt property is regulated and controlled through the synergistic effect of a specific proportion. The preparation method comprises the steps of proportioning, smelting, casting and ultra-slow cooling treatment, namely controlling the average cooling rate of the casting from high temperature to 800 ℃ to be less than or equal to 0.5 ℃ per minute. The process guides the inside of the material to form a synergistic structure of a compact matrix and a high-proportion stable stress buffer unit, so that the product has excellent thermal shock resistance and excellent molten salt permeability resistance while maintaining high volume density and high strength, is particularly suitable for extremely harsh environments such as a titanium sponge magnesium electrolytic tank, a tapping tank and the like, and can obviously prolong the service life of equipment.

Inventors

  • MA SONG
  • ZHANG YIFENG

Assignees

  • 郑州安华电熔新材料科技有限公司

Dates

Publication Date
20260512
Application Date
20260225

Claims (9)

  1. 1. The production formula of the high-temperature wear-resistant acid-alkali-resistant fused zirconia-mullite brick is characterized by comprising the following components in percentage by weight: 83-91% of matrix forming material comprising 70-76% of industrial alumina powder, 1-6% of zirconite concentrate powder, 10-14% of high-purity quartz powder and 1-3% of monoclinic zirconia powder; 6-12% of structure synergistic regulator, which comprises 2.5-7.0% of kyanite concentrate powder and 3.5-8.0% of andalusite concentrate powder, wherein the weight ratio of kyanite to andalusite is (0.33-1.67): 1; 3-6% of composite functional auxiliary agent, which comprises 0.6-1.8% of rare earth oxide, 0.4-1.2% of alkaline earth oxide and 0.1-0.6% of boron oxide; The percentages of the components refer to the weight percentage of the formula.
  2. 2. The formula for producing the high-temperature wear-resistant acid-alkali-resistant fused zirconia-mullite brick as set forth in claim 1, wherein the rare earth oxide is yttrium oxide and/or lanthanum oxide, and the alkaline earth oxide is magnesium oxide and/or calcium oxide.
  3. 3. The production formula of the high-temperature wear-resistant acid-alkali-resistant fused zirconia-mullite brick, which is characterized by comprising 3-7% of total ZrO 2 content of zircon concentrate powder and monoclinic zirconia powder.
  4. 4. The formula for producing the high-temperature wear-resistant acid-alkali-resistant fused zirconia-mullite brick, which is disclosed in claim 1, is characterized in that the granularity D90 of kyanite concentrate powder is less than or equal to 0.074mm, and the granularity D90 of andalusite concentrate powder is less than or equal to 0.15mm.
  5. 5. A method for preparing an erosion-resistant and thermal shock-resistant fused zirconia-mullite brick, which adopts the formula for producing the fused zirconia-mullite brick with high temperature wear resistance and acid and alkali resistance as set forth in any one of claims 1 to 4, and is characterized by comprising the following steps: s1, proportioning and homogenizing, namely weighing the raw materials according to a formula, and uniformly mixing; s2, smelting, namely putting the mixture into an electric arc furnace for smelting, and refining for 60-120 minutes at 2050-2200 ℃ after full smelting; S3, casting and initial treatment, namely cooling the melt to 1950-2100 ℃, casting the melt into a die preheated to 100-300 ℃, stirring a riser after casting, and covering the riser with a heat insulation material; S4, performing ultra-slow cooling treatment, namely performing program control slow cooling on the cast, so that the average cooling rate of the whole process of cooling the cast from the casting temperature to 800 ℃ is not more than 0.5 ℃ per minute, and the total slow cooling time is not less than 100 hours; S5, post-treatment, namely demolding the fully cooled casting and processing the casting to a specified size.
  6. 6. The method for producing an erosion-resistant and heat-shock-resistant fused zirconia-mullite brick as set forth in claim 5, wherein in the S4 super-slow cooling treatment step, the cooling rate of the cast at a temperature range of 1200 ℃ to 800 ℃ is controlled to be 0.2 to 0.4 ℃ per minute.
  7. 7. The method for preparing the anti-erosion heat-shock-resistant fused zirconia-mullite brick as set forth in claim 5, wherein the S2 smelting step is classified smelting, and comprises a rapid melting period and a low-temperature refining period.
  8. 8. The method for producing an erosion-resistant and heat-shock-resistant fused zirconia-mullite brick as set forth in claim 5, wherein the duration of stirring the riser in the S3 casting and preliminary treatment steps is 1 to 3 minutes.
  9. 9. The erosion-resistant and heat-shock-resistant fused zirconia-mullite brick prepared by the preparation method of any one of claims 5-8, wherein the performance is that the apparent porosity is less than or equal to 2.5 percent, the volume density is more than or equal to 3.08g/cm 3 , the normal-temperature compressive strength is more than or equal to 268MPa, the water-cooling heat shock cycle time at 1100 ℃ is more than or equal to 25 times, the linear thermal expansion coefficient at 1000 ℃ is less than or equal to 0.62 percent, and the average penetration depth of molten salt statically soaked in 850 ℃ molten anhydrous magnesium chloride for 48 hours is less than or equal to 1.2mm.

Description

Formula for producing high-temperature wear-resistant acid-alkali-resistant electric smelting zirconium mullite brick Technical Field The invention relates to the technical field of high-performance refractory materials, in particular to a formula for producing high-temperature wear-resistant acid-alkali-resistant fused zirconia mullite bricks. Background In the fields of nonferrous metal metallurgy (such as titanium sponge production), special steel sliding rails, chemical waste liquid incineration and the like, the refractory lining of key high-temperature equipment is subjected to multiple severe stresses for a long time, namely high temperature (usually more than 800 ℃), severe chemical attack of molten salt (such as magnesium chloride) or alkali metal oxide, physical scour and abrasion of materials, and frequent thermal shock caused by process start-stop and power fluctuation. For example, the wear-resistant sliding rail which is influenced by annual stress, deformation impact and friction loss is also required to be a high-temperature-resistant and corrosion-resistant product with ‌ wear resistance and corrosion resistance both ‌ for heavy industrial environments such as special steel factories. The refractory material produced by the electric melting method has the advantages of high purity, high density, stable phase composition and the like, and has excellent corrosion resistance and wear resistance because the refractory material is recrystallized after the raw materials are completely converted into a uniform melt through high temperature. However, the fatal weakness of the conventional fused refractory materials (e.g., fused zirconia-corundum bricks, fused mullite bricks) is their poor thermal shock resistance. The method mainly derives from inherent process characteristics that a melt tends to form a coarse and directly combined crystal structure in the rapid cooling solidification process, the internal elastic modulus of the material is high, the thermal expansion coefficient is large, and meanwhile, pores generated by solidification shrinkage are mostly concentrated shrinkage cavities or irregularly-shaped pores, so that the pores cannot effectively buffer thermal stress, but easily become stress concentration points. Therefore, when subjected to rapid cooling and rapid heating, huge thermal stress is dissipated and released everywhere, and brittle cracking or peeling of materials is extremely easy to occur, so that equipment is stopped unplanned and huge economic loss is caused. Attempts in the industry to improve the thermal shock resistance of electrofusion materials, such as the introduction of small amounts of additives or the simple extension of the holding time, have long been very inefficient, even at the expense of the erosion resistance of their cores. The root cause is that the contradiction between high compactness, high corrosion resistance and high toughness, strong thermal shock resistance cannot be systematically solved from the source of material design, namely the cooperation of the formula design and the process path. The method is characterized in that a stable dispersion strengthening structure capable of effectively dissipating heat stress cannot be actively constructed in the high-density matrix of the electric melting material while the high-density matrix is maintained. Therefore, developing a novel electric melting material capable of synergistically combining the above properties and a preparation method thereof becomes a technical problem to be solved in the art. Disclosure of Invention Object of the invention Aiming at the defects of the prior art, the invention aims to provide a novel fused zirconia mullite brick and a method for preparing the same by electric melting casting. The method aims at actively constructing a synergistic structure consisting of a high-strength compact matrix and a high-proportion stable stress buffer unit in a material through an innovative raw material formula system and a precisely controlled smelting-casting-super slow cooling full-flow process. Therefore, the problem of poor thermal shock resistance of the traditional electric melting material is fundamentally solved, so that the electric melting material can obtain excellent thermal shock fatigue resistance while maintaining excellent molten salt erosion resistance and high strength, and finally the service life under extreme working conditions is obviously prolonged. (II) technical scheme In order to achieve the above purpose, the present invention adopts the following technical scheme: in a first aspect, a raw material formulation for a zirconium mullite brick suitable for electrofusion casting is provided. The formula consists of the following components in percentage by weight, wherein each component is functionally designed based on the role of the component in the formation of a final material structure: Matrix forming material (83-91 wt%) is formed into continuous high-stren