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Preparation method of alpha-aluminum oxide with narrow original grain size distribution

A technology of alumina and grain size, applied in chemical instruments and methods, alumina/aluminum hydroxide, inorganic chemistry, etc., can solve the problems of wide original grain size distribution, unstable particle size distribution, and poor re-sintering activity. , to achieve the effect of narrow original grain size distribution, perfect grain development and low cost

Active Publication Date: 2021-08-10
中铝山东有限公司
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  • Claims
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Problems solved by technology

[0003] In order to control the original grain size and grain development, realize the narrow distribution of the original grain size, and improve the powder resintering activity and specific surface area, many methods have been proposed, including sol-gel method, hydrothermal synthesis method and aluminum alkoxide method. Hydrolysis, etc., but these methods have limited effects, and the product has problems such as wide primary grain size distribution (D90 / D10>15), unstable particle size distribution, many agglomerations, and poor resintering activity, and the process is complicated and costly. Realizing Large-Scale Industrial Production of Narrowly Distributed Calcined α-Alumina

Method used

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  • Preparation method of alpha-aluminum oxide with narrow original grain size distribution
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  • Preparation method of alpha-aluminum oxide with narrow original grain size distribution

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preparation example Construction

[0030] According to a typical embodiment of the present invention, a method for preparing α-alumina with a narrow primary grain size distribution is provided, the method comprising:

[0031] S1. Mixing the seed crystal and the calcining aid in the raw material aluminum hydroxide to obtain a calcined mixture; the seed crystal is a new crystal phase of α-alumina grown in situ.

[0032] As an optional embodiment, the seed crystal and the calcination aid are mixed in the raw material aluminum hydroxide to obtain the calcined mixture. In terms of weight fraction, the amount of the seed crystal added is 0.1% of the aluminum hydroxide. %-20%.

[0033] The reason for controlling the addition of seed crystals to 0.1%-20% of the aluminum hydroxide is to induce seed crystals, reduce the phase transition temperature of α-alumina, reduce powder agglomeration, control grain size, and enhance powder regeneration. Sintering activity, increase specific surface area, reduce internal defects of...

Embodiment 1

[0047] A method for preparing α-alumina with a narrow primary grain size distribution, the method comprising:

[0048] S1. Using aluminum hydroxide A as raw material, Na 2 O content is 0.35-0.5%;

[0049] S2. Add 0.05% aluminum fluoride (addition accounted for alumina weight %), add in solid form; Add 5% seed crystal α-Al 2 o 3 (the amount added accounts for the weight percent of alumina) S3. uniformly mix the seed crystal with aluminum hydroxide and aluminum fluoride to obtain a mixture, and calcinate it at a temperature of 1450° C. for 30 minutes in a rotary kiln;

[0050] S4. Calcining, cooling and lowering the temperature, and ball milling to a certain particle size, the calcined α-alumina with a narrow particle size distribution of the primary crystal can be obtained.

Embodiment 2

[0052] A method for preparing α-alumina with a narrow primary grain size distribution, the method comprising:

[0053] S1. Using aluminum hydroxide A as raw material, Na 2 O content is 0.35-0.5%;

[0054] S2. Add 0.05% aluminum fluoride (addition accounts for alumina weight %), add in solid form; Add 8% seed crystal α-Al 2 o 3 (addition accounts for alumina weight %)

[0055] S3. uniformly mixing the seed crystal with aluminum hydroxide and aluminum fluoride to obtain a mixture, and calcining at a temperature of 1450° C. for 30 minutes in a rotary kiln;

[0056] S4. Calcining, cooling and lowering the temperature, and ball milling to a certain particle size, the calcined α-alumina with a narrow particle size distribution of the primary crystal can be obtained.

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Abstract

The invention particularly relates to a preparation method of alpha-alumina with narrow original grain size distribution, and belongs to the technical field of inorganic non-metallic materials. The preparation process comprises the following steps: taking aluminum hydroxide (Na2O content is 0.35-0.5%) as a raw material, adding a proper amount of seed crystals and a calcining aid, performing uniform mixing, performing calcining in a rotary kiln at 1,300-1,500 DEG C for 20-60 minutes, performing cooling, and performing ball-milling to a certain grain size, obtaining the original grain size narrow-distribution calcined alpha-alumina (D90 / D10 < = 4), and finally packaging the calcined alpha-alumina into a finished product to be sold. The alpha-aluminum oxide is prepared through seed crystal induction, the phase change temperature of the alpha-aluminum oxide is reduced, powder agglomeration is reduced, the original grain size narrow distribution (D90 / D10 < = 4) of the calcined alpha-aluminum oxide is controlled, and the re-sintering activity and the specific surface area of the alpha-aluminum oxide powder material and the mechanical performance, the compression resistance and the like of downstream products are remarkably improved.

Description

technical field [0001] The invention belongs to the technical field of inorganic non-metallic materials, and in particular relates to a preparation method of alpha-alumina with narrow primary grain size distribution. Background technique [0002] Calcined α-alumina is famous for its excellent properties such as refractory, hardness, heat insulation and electrical insulation, and is widely used in the fields of abrasive materials, refractory materials, special glass, and other structural and functional ceramics. With the continuous improvement of product performance requirements, the requirements for the primary grain size distribution of α-alumina powder in industrial production are also getting higher and higher. [0003] In order to control the original grain size and grain development, realize the narrow distribution of the original grain size, and improve the powder resintering activity and specific surface area, many methods have been proposed, including sol-gel method,...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01F7/44C01F7/02C04B35/10C04B35/66C04B35/626
CPCC01F7/442C01F7/023C04B35/10C04B35/66C04B35/62645C04B35/6261Y02P20/52
Inventor 赵善雷冯晓明贾叶凯秦念勇齐波
Owner 中铝山东有限公司
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