Preparation method of calcium hexaluminate-magnesium aluminate spinel multiphase material with spherical shell-sponge structure

A technology of magnesium aluminum spinel and calcium hexaaluminate, which is applied in the field of preparation of spherical shell-sponge structure calcium hexaaluminate-magnesium aluminum spinel composite materials, can solve the problem that the thermal shock stability is not as good as that of conventional corundum- Mullite, cordierite-mullite, high thermal expansion coefficient, etc., to achieve the effect of improving thermal shock stability

Active Publication Date: 2021-11-12
SINOSTEEL LUOYANG INST OF REFRACTORIES RES
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] Although there are many studies and patents on calcium hexaaluminate, most of them focus on the preparation of lightweight insulation materials, lightweight aggregates, and lightweight products by using in-situ reaction expansion; for calcium hexaaluminate with high thermal shock stability- There are few studies on magnesium-alumina-spinel composite materials. Calcium hexaaluminate and magnesium-aluminum spinel are not as stable as conventional corundum-mullite, cordierite-mullite and other materials due to their high thermal expansion coefficients. However, calcium hexaaluminate has excellent resistance to alkali corrosion from low temperature to high temperature.

Method used

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  • Preparation method of calcium hexaluminate-magnesium aluminate spinel multiphase material with spherical shell-sponge structure
  • Preparation method of calcium hexaluminate-magnesium aluminate spinel multiphase material with spherical shell-sponge structure

Examples

Experimental program
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Effect test

Embodiment 1

[0017] Example 1: The proportion of each component is (mass percentage): 5-0.088mm heavy calcium hexaaluminate particles 70%, calcium hexaaluminate fine powder 26%, alumina micropowder 3%, 0.5-0.1mm electrofusion Magnesium Oxide Granules 1%.

[0018] In Example 1, 2.8% of the pulp solution is first added to the particle part, mixed evenly with a wheel mill, and then the fine powder part mixed with a V-shaped mixer is added to the wheel mill, and the material is discharged after stirring for 5 to 10 minutes. It is molded by vibration and pressure, and dried at 110°C. After heat preservation at 1100°C for 6 hours in a reducing atmosphere, then return to an oxidizing atmosphere, and firing at 1750°C for 8 hours, a calcium hexaaluminate-magnesium aluminum spinel composite material with a spherical shell-sponge structure was obtained. The normal temperature compressive strength is 152MPa. According to the DIN 51068:2008 standard, the number of water-cooled thermal shocks at 1100°...

Embodiment 2

[0021] Example 2: The proportion of each component is (mass percentage): 5-0.088mm heavy calcium hexaaluminate particles 60%, calcium hexaaluminate fine powder 16%, alumina micropowder 18%, 0.2-0.1mm electrofusion Magnesium oxide particles 6%.

[0022] In Example 2, first add 3% water-based resin solution to the granule part, mix evenly with a wheel mill, then add the fine powder part mixed with a V-type mixer to the wheel mill, stir for 5 to 10 minutes, and then discharge , formed by a friction brick press and dried at 110°C. After 1200°C reducing atmosphere for 3 hours, then recovering the oxidizing atmosphere, and 1650°C kiln heat preservation for 8 hours, the calcium hexaaluminate-magnesium aluminum spinel composite material with spherical shell-sponge structure was obtained. The normal temperature compressive strength is 120MPa. According to the DIN51068:2008 standard, the number of water-cooled thermal shocks at 1100°C can reach 25 times.

Embodiment 3

[0025] Example 3: The proportion of each component is (mass percentage): 70% of heavy calcium hexaaluminate particles of 5-0.088mm, 18% of calcium hexaaluminate fine powder, 9% of alumina fine powder, 0.1-0.074mm electrofusion Magnesium oxide fine powder 3%.

[0026] In embodiment three, first add 1% dextrin solution and 1% water-based resin solution to the granule part, mix evenly with a wheel mill, then add the fine powder part mixed with a V-type mixer into the wheel mill, and stir for 5~ After 10 minutes, the material is discharged, formed by vibration and pressure, and dried at 110°C. After heat preservation at 1150°C for 4 hours in a reducing atmosphere, then return to an oxidizing atmosphere, and firing at 1600°C for 8 hours, a calcium hexaaluminate-magnesium aluminum spinel composite material with a spherical shell-sponge structure was obtained. The compressive strength at room temperature is 83MPa. According to the DIN 51068:2008 standard, the number of water-cooled...

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Abstract

The invention belongs to the field of refractory materials, and relates to a preparation method of a spherical shell-sponge structure calcium hexaluminate-magnesium aluminate spinel multiphase material. According to the invention, the method comprises the steps: taking heavy calcium hexaluminate particles, calcium hexaluminate fine powder, aluminum oxide micro powder and fused magnesium oxide as starting materials; adding a binding agent, mixing by an edge runner mill, carrying out mechanical pressing, drying a green body, sintering in a high-temperature kiln or an electric furnace, carrying out solid-phase reaction on the surface of electrically-fused magnesium oxide at the temperature of less than 1,100 DEG C and the alumina micro powder to form a magnesium aluminate spinel shell, carrying out heat preservation in a reducing atmosphere of 1,100-1,200 DEG C for 3-6 hours, and recovering the oxidizing atmosphere, wherein the highest sintering temperature is 1,600-1,750 DEG C.: The thermal shock resistance of the calcium hexaluminate-magnesium aluminate spinel multiphase material is greatly improved, so that the calcium hexaluminate material can be used under the conditions of high alkali erosion and high thermal shock.

Description

technical field [0001] The invention belongs to the field of refractory materials, and in particular relates to a method for preparing a spherical shell-sponge structure calcium hexaaluminate-magnesium aluminum spinel composite phase material. Background technique [0002] Calcium hexaaluminate (CaAl 12 o 19 , abbreviated as CA 6 , mineral name: chertite) is CaO-Al 2 o 3 Department Al 2 o 3 The most abundant calcium aluminate phase has a theoretical density of 3.38 g / cm 3 , the melting point is as high as 1875°C. Calcium hexaaluminate has a series of excellent properties: a wide range of solid solution with iron oxide-containing slag, strong enough resistance to chemical erosion in alkaline environment, highly stable in reducing atmosphere, large main crystallization area, Has low solubility in several multicomponent systems. [0003] The high stability of calcium hexaaluminate in a reducing atmosphere determines that it is suitable for thermal kiln linings with a r...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B35/66C04B35/44C04B35/443C04B35/622
CPCC04B35/66C04B35/44C04B35/443C04B35/622C04B2235/9607C04B2235/3208C04B2235/3217C04B2235/96
Inventor 范沐旭武刚李森寅冯志源王晗侯晓静赵志龙李坤鹏张涛
Owner SINOSTEEL LUOYANG INST OF REFRACTORIES RES
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