Method for synthesizing aluminum-rich spinel through low-temperature solid-phase reaction

A technology of aluminum-rich spinel and solid-state reaction, applied in the field of refractory materials, can solve the problem of slag resistance, sintering performance cannot reach the best level, cannot maximize the performance of aluminum-rich spinel, cannot maximize Improve the solid solution content of alumina and other issues to achieve the effect of promoting high-temperature sintering and slag resistance, fine grains, and large solid solution content

Pending Publication Date: 2021-01-26
湖北斯曼新材料股份有限公司
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Problems solved by technology

[0005] When the aluminum-rich spinel is produced by the conventional synthesis process, volume expansion will occur, which is not conducive to its sintering, and its recrystallization ability is very weak. To prepare high-strength, high-performance aluminum-rich spinel products, the synthesis temperature must be more than 1500°C, and the alumina content in the prepared spinel is generally only within 72% to 78%, and it is difficult to reach more than 80%. The corresponding degree of lattice defect is low, and it is impossible to maximize the improvement of alumina solid solution. amount, but also can not maximize the performance of aluminum-rich spinel
And the effect of removing impurities in the synthesis process is poor, and the sodium oxide impurities in the raw materials are easy to form β-alumina, which reduces the formation rate of aluminum-magnesium spinel
When the prepared aluminum-rich spinel is used in corundum spinel castables, its slag resistance and sintering performance cannot reach the best level

Method used

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  • Method for synthesizing aluminum-rich spinel through low-temperature solid-phase reaction
  • Method for synthesizing aluminum-rich spinel through low-temperature solid-phase reaction
  • Method for synthesizing aluminum-rich spinel through low-temperature solid-phase reaction

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preparation example Construction

[0033] The low-temperature synthesis method of aluminum-rich spinel comprises the following steps:

[0034]S1: In parts by weight, mix 80-90 parts of alumina raw materials, 10-20 parts of magnesium oxide raw materials, 0.5-2 parts of magnesium aluminum spinel seed crystals and 0.5-3 parts of additives, and then co-mill to the The particle size of the raw material is in the range of 5-20 μm;

[0035] S2: transfer the co-milled powder in step S1 into a high-temperature kiln, and heat up to 1000-1500°C for calcination;

[0036] S3: keep at the calcination temperature of step S2 for 3-12 hours, and cool naturally or quickly air-cool to normal temperature, and then the aluminum-rich spinel can be prepared.

[0037] The alumina content of the alumina-rich spinel is 80-90%, and the alumina-rich spinel powder can be obtained by grinding the alumina-rich spinel to a particle size of 1-5 μm.

Embodiment 1

[0040] First, in parts by weight, a mixture of 10 parts of magnesium hydroxide and light burnt magnesia, a mixture of 90 parts of industrial alumina powder and calcined α-alumina powder, 3 parts of normal spinel seeds, 2 parts of boric acid and The mixture of magnesium chloride is mixed, and then co-milled until the particle size of the raw materials is in the range of 5-20 μm; the co-milled powder is transferred to a high-temperature kiln, and the temperature is raised to 1000-1100 ° C for calcination; finally, it is kept at the calcination temperature After 8-10 hours, natural cooling or rapid air cooling to room temperature can produce aluminum-rich spinel. The alumina-rich spinel powder can be obtained by grinding the alumina-rich spinel to a particle size of 1.5-3 μm.

[0041] XRD diffraction analysis was carried out on the aluminum-rich spinel powder obtained above, and the synthesized aluminum-rich spinel powder did not contain β-alumina phase, no free magnesium oxide p...

Embodiment 2

[0043] First, in parts by weight, 10 parts of calcined magnesia, 90 parts of calcined α-alumina powder, 0.5 part of normal spinel seed crystals, and 0.5 part of boric anhydride are mixed, and then co-milled until the particle size of the raw materials is Within the range of 5-20μm; transfer the co-milled powder into a high-temperature kiln, heat up to 1400-1500°C for calcination; finally keep at the calcination temperature for 4-6 hours, and cool naturally or quickly air-cooled to room temperature. Alumina-rich spinel. The aluminum-rich spinel powder is obtained by grinding the aluminum-rich spinel to a particle size of 2-5 μm.

[0044] XRD diffraction analysis was carried out on the aluminum-rich spinel powder obtained above, and the synthesized aluminum-rich spinel powder did not contain β-alumina phase, no free magnesium oxide phase, the content of aluminum-rich spinel phase was 48%, and the corundum phase The content is 52%.

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Abstract

The invention belongs to the field of refractory materials, and particularly relates to a method for synthesizing aluminum-rich spinel through a low-temperature solid-phase reaction. The method specifically comprises the following steps: firstly, mixing 80-90 parts by weight of an aluminum oxide raw material, 10-20 parts by weight of a magnesium oxide raw material, 0.5-2 part by weight of magnesium aluminate spinel micro powder and 0.5-3 part by weight of an additive, and co-grinding the materials until the particle size of the raw materials is in a range of 5-20 microns; transferring the co-ground powder into a high-temperature kiln, heating to 1000-1500 DEG C, and calcining; and finally, keeping for 3-12 hours at the calcining temperature, and implementing naturally cooling or quickly air-cooling to room temperature to obtain the aluminum-rich spinel. A low-temperature synthesis process is adopted, the aluminum-rich spinel synthesized through low-temperature calcination is fine in grain and high in lattice defect degree, and meanwhile the prepared aluminum-rich spinel powder is high in activity. The prepared aluminum-rich spinel does not contain beta aluminum oxide or impurity phases such as free magnesium oxide, and the content of aluminum oxide in the aluminum-rich spinel reaches 80-90%. When the prepared aluminum-rich spinel powder is used in a corundum spinel castable, the aluminum-rich spinel powder has the advantages of high sintering strength and strong slag penetration resistance.

Description

technical field [0001] The invention belongs to the field of refractory materials, and in particular relates to a method for synthesizing aluminum-rich spinel by low-temperature solid-phase reaction. Background technique [0002] The magnesium aluminum spinel structure is a cubic crystal system, and the unit cell is composed of 32 cubic closely packed O 2- , 16 Al in octahedral voids 3+ and 8 Mg in the tetrahedral interstitial 2+ composition. each O 2- There are 4 metal coordination ions, 3 of which are in the octahedron and the remaining 1 is in the tetrahedron, and maintain electrical neutrality. Theoretical spinel composition is MgO with a mass fraction of 28.3% and Al with a mass fraction of 71.7% 2 o 3 , MgO and Al at high temperature 2 o 3 It can be dissolved into magnesium-aluminum spinel to form magnesium-rich spinel and aluminum-rich spinel. The positive spinel alumina content is 70-75%, the magnesium-rich spinel alumina content is 60-70%, and the aluminum-...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B35/443C04B35/626C04B35/66
CPCC04B35/443C04B35/62605C04B35/62675C04B35/66C04B2235/5436
Inventor 刘学新熊明继李文
Owner 湖北斯曼新材料股份有限公司
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