Search

CN-120441331-B - Heavy calcium hexaaluminate high-temperature-resistant material and preparation method thereof

CN120441331BCN 120441331 BCN120441331 BCN 120441331BCN-120441331-B

Abstract

The application discloses a heavy calcium hexaaluminate high-temperature-resistant material and a preparation method thereof, and belongs to the technical field of high-temperature-resistant materials. The preparation method of the heavy calcium hexaluminate high-temperature resistant material comprises the steps of mixing aluminum oxide, calcium carbonate and a sintering aid to obtain a mixture, adding a bonding agent into the mixture, performing ball forming treatment to obtain raw balls, drying the raw balls by using pure water as the bonding agent, putting the dried raw balls into an ultra-high temperature shaft kiln for calcination at the calcination temperature of 1760-1810 ℃, and then rapidly cooling to obtain the heavy calcium hexaluminate high-temperature resistant material. The application also provides application of the heavy calcium hexaluminate high-temperature resistant material in hydrogen metallurgy, and the heavy calcium hexaluminate high-temperature resistant material is prepared by adopting the preparation method. The heavy calcium hexaaluminate high-temperature resistant material has high volume density, low apparent porosity and good reducing atmosphere resistance, slag corrosion resistance and creep resistance.

Inventors

  • YE QING
  • SHAO CHANGBO
  • YAN LIN
  • CHEN ZHIQIANG
  • LIU XING
  • LI GUIMEI
  • LI HONGCHAO

Assignees

  • 山东恒嘉高纯铝业科技股份有限公司
  • 邹平恒嘉新材料科技有限公司

Dates

Publication Date
20260505
Application Date
20250409

Claims (8)

  1. 1. The preparation method of the heavy calcium hexaaluminate high-temperature resistant material is characterized by comprising the following steps of: Step S1, mixing aluminum oxide, calcium carbonate and a sintering aid to prepare a mixture, wherein the aluminum oxide is metallurgical-grade aluminum oxide with purity of 99.5% -99.9%, and the aluminum oxide contains amorphous excessive phase aluminum oxide; The sintering aid comprises at least one of a titanium-containing sintering aid and a barium-containing sintering aid, wherein the titanium-containing sintering aid comprises 73-75% of aluminum oxide, 12-13% of calcium oxide and 13-14% of titanium dioxide, and the barium-containing sintering aid comprises 72-74% of aluminum oxide, 12-13% of calcium oxide and 14-15% of barium carbonate; the content of the aluminum oxide is 78-80wt%, the content of the calcium carbonate is 11-13wt%, and the content of the sintering aid is 8-10wt% according to the mass percentage; S2, adding a bonding agent into the mixture, and performing balling treatment to obtain raw balls, wherein the bonding agent is pure water; s3, placing the green pellets in a tower dryer for drying, wherein the highest drying temperature is 300-500 ℃ and the drying time is 5-12 hours; And S4, putting the dried green pellets into an ultra-high temperature shaft kiln for calcination, wherein the calcination temperature is 1760-1810 ℃, the calcination time is 0.5-1.5 h, and then rapidly cooling to 800-1000 ℃ with the cooling rate of 8-10 ℃ per minute, so as to obtain the heavy calcium hexaaluminate high temperature resistant material.
  2. 2. The method according to claim 1, wherein in the step S1, the purity of the calcium carbonate is not less than 98.5%.
  3. 3. The method according to claim 1, wherein in the step S1, the particle size D50 of the mixture is 3.0-5.0 μm.
  4. 4. The preparation method according to claim 1, wherein in the step S2, the content of the binding agent is 17-20wt% based on the mass percentage of the mixture.
  5. 5. The preparation method according to claim 1, wherein in the step S2, the green pellets have a particle size of 18-30 mm.
  6. 6. The method according to claim 1, wherein in the step S4, the calcination temperature is 1770-1800 ℃.
  7. 7. The preparation method of claim 1, wherein the volume density of the heavy calcium hexaaluminate high temperature resistant material is 3.4-3.55 g/cm 3 , the apparent porosity is less than or equal to 8.0%, and the water absorption is less than or equal to 2.0%.
  8. 8. The application of the heavy calcium hexaluminate high temperature resistant material in hydrogen metallurgy is characterized in that the heavy calcium hexaluminate high temperature resistant material is prepared by adopting the preparation method of any one of claims 1-6.

Description

Heavy calcium hexaaluminate high-temperature-resistant material and preparation method thereof Technical Field The application belongs to the technical field of high-temperature resistant materials, and particularly relates to a heavy calcium hexaaluminate high-temperature resistant material and a preparation method thereof. Background Hydrogen, a clean and pollution-free reducing agent, is increasingly being used in iron-making processes. Unlike conventional carbon-based reduction, hydrogen reacts with iron oxide or ferrous oxide to produce only water and no greenhouse gases such as carbon dioxide, and is therefore considered to be an ideal alternative to carbon in future steel production. With the development and technical progress of the new energy industry, the cost of hydrogen is expected to decrease, further promoting the economic feasibility of hydrogen as a reducing agent. Currently, iron-making processes using carbon as a reducing agent mainly use brown fused alumina, mullite, alumina, flint clay, silicon carbide products, and the like as refractory materials. The silicon dioxide-containing refractory materials have good performance at the high temperature of the carbon reducer, and can meet the requirements of the traditional iron-making process. However, under the condition of the hydrogen reducing agent, because the hydrogen is gas, the hydrogen can be uniformly distributed and participate in the reaction in the whole blast furnace reaching the corresponding temperature, and a furnace lining made of the refractory material containing silicon dioxide is easily reduced into elemental silicon by the hydrogen at high temperature, so that the structure of the furnace lining is damaged, and the high temperature resistance is reduced or lost. In addition, the materials have higher wettability to molten metal and slag (such as steel and nonferrous metal), accelerate material erosion and shorten the service life. In view of the above challenges, a new refractory material that can accommodate hydrogen reduction processes and has excellent properties is particularly important. In this context, calcium hexaaluminate (CA 6) is an ideal refractory in the hydrogen reductant iron making process due to its excellent chemical stability and low wettability with molten metal and slag. Meanwhile, the thermal expansion coefficient of the composite material is close to that of alumina, and the composite material can be mixed with alumina in any proportion, so that the design flexibility of the composite material is enhanced. The common CA6 products on the current market are a light CA6 heat insulation material with the volume density of less than 0.8g/cm 3 and a heavy CA6 with the volume density of less than 3.1g/cm 3, but the existing CA6 products are not high enough in volume density, large in apparent porosity and low in strength, and cannot provide enough slag corrosion resistance, creep resistance and wear resistance, so that the requirements of the working environment of a ladle or a ladle cannot be met. Therefore, there is a need to develop a heavy calcium hexaaluminate refractory material having good reducing atmosphere resistance, slag corrosion resistance and creep resistance. Disclosure of Invention In view of the above, the application provides a heavy calcium hexaaluminate high temperature resistant material and a preparation method thereof, the heavy calcium hexaaluminate high-temperature resistant material provided by the application has high volume density, low apparent porosity and good reducing atmosphere resistance, slag corrosion resistance and creep resistance. In a first aspect, the application provides a method for preparing a heavy calcium hexaaluminate high temperature resistant material, comprising the following steps: Step S1, mixing aluminum oxide, calcium carbonate and a sintering aid to prepare a mixture; S2, adding a bonding agent into the mixture, and performing balling treatment to obtain raw balls, wherein the bonding agent is pure water; s3, placing the green pellets in a tower dryer for drying, wherein the highest drying temperature is 300-500 ℃ and the drying time is 5-12 hours; And S4, putting the dried green pellets into an ultra-high temperature shaft kiln for calcination, wherein the calcination temperature is 1760-1810 ℃, the calcination time is 0.5-1.5 h, and then rapidly cooling to 800-1000 ℃ with the cooling rate of 8-10 ℃ per minute, so as to obtain the heavy calcium hexaaluminate high temperature resistant material. By adopting the technical scheme, the preparation method disclosed by the application can improve the volume density of the heavy calcium hexaaluminate high-temperature-resistant material, reduce the apparent porosity, and enable the heavy calcium hexaaluminate high-temperature-resistant material to obtain good reducing atmosphere resistance, slag corrosion resistance and creep resistance. The prepared heavy calcium hexaaluminate high-temperature resistant mat