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A kind of preparation method of synthesizing α-alumina by hydrothermal method

A technology of alumina and hydrothermal method, applied in chemical instruments and methods, inorganic chemistry, aluminum compounds, etc., can solve the problems of increased impurities, decreased product purity, complex and cumbersome preparation process, etc., and achieves high particle dispersion, particle size The effect of narrow diameter distribution

Active Publication Date: 2018-01-30
SHENZHEN SENIOR TECH MATERIAL
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The preparation of alumina by chemical precipitation method, such as Chinese Patent Publication No. CN 104229846 A, uses activated fly ash as a raw material to obtain alumina through precipitation. The advantage is that Al is extracted from activated fly ash and alumina is prepared. However, the prepared The alumina purity is not high-purity, and the calcination temperature is as high as 1200 degrees, the energy consumption is serious, and the obtained alumina is seriously agglomerated
Chinese Patent Publication No. CN 102826579 A uses aluminum flakes and isopropanol as raw materials to prepare ultra-high-purity, ultra-fine alumina powder, but the preparation process is complex and cumbersome, and the cost is high
Due to multiple calcinations and different calcination atmospheres, it will increase energy consumption and the steps are cumbersome; and adding carbon black during calcination will make the obtained α-Al 2 o 3 The purity of the product decreases and the impurities increase

Method used

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  • A kind of preparation method of synthesizing α-alumina by hydrothermal method
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  • A kind of preparation method of synthesizing α-alumina by hydrothermal method

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Effect test

Embodiment 1

[0036] (1) Accurately weigh Al(NO 3 ) 3 9H 2 O, put it into a rapidly stirring vessel filled with pure water, and make Al(NO 3 ) 3 9H 2 O is soluble in pure water.

[0037] (2) Al 3+ Drop the salt solution into the rapidly stirred high-purity ammonia solution for hydrolysis, and the molar concentration of ammonia water is 4.8mol L -1 , ammonia and Al 3+ The molar ratio is about 3.8:1; water cooling during hydrolysis and the temperature of the solution in the container is controlled to be less than 50°C; the pH value of the solution after hydrolysis is controlled at about 9.2; dropwise adding Al 3+ The saline solution was added dropwise within 5 minutes.

[0038] (3) After the reaction, press filter to remove most of the water in the aluminum hydroxide sol, and add α-Al to the aluminum precursor 2 o 3 Seed crystals, ultrasonic dispersion treatment was carried out before the seed crystals were added to ensure that the seed crystal particles were monodisperse particles;...

Embodiment 2

[0046] (1) Accurately weigh Al(NO 3 ) 3 9H 2 O, put it into a rapidly stirring vessel filled with pure water, and make Al(NO 3 ) 3 9H 2 O is soluble in pure water.

[0047] (2) Al 3+ Drop the salt solution into the rapidly stirred high-purity ammonia solution for hydrolysis, and the molar concentration of ammonia water is 4.0mol L -1 , ammonia and Al 3+ The molar ratio is about 4.5:1; water cooling during hydrolysis and the temperature of the solution in the container is controlled to be less than 50°C; the pH value of the solution after hydrolysis is controlled at about 9.5; dropwise adding Al 3+ The salt solution was added dropwise within 6 minutes.

[0048] (3) After the reaction, press filter to remove most of the water in the aluminum hydroxide sol, and add α-Al to the aluminum precursor 2 o 3 Seed crystals, ball milling and dispersion treatment before adding seeds to ensure that the seed crystal particles are monodisperse particles; the average particle size ra...

Embodiment 3

[0056] (1) Accurately weigh Al(NO 3 ) 3 9H 2 O, put it into a rapidly stirring vessel filled with pure water, and make Al(NO 3 ) 3 9H 2 O is soluble in pure water.

[0057] (2) Al 3+ Drop the salt solution into the rapidly stirred high-purity ammonia solution for hydrolysis, and the molar concentration of ammonia water is 5.3mol L -1 , ammonia and Al 3+ The molar ratio is about 3.8:1; water cooling during hydrolysis and the temperature of the solution in the container is controlled to be less than 50°C; the pH value of the solution after hydrolysis is controlled at about 9.7; dropwise adding Al 3+ The salt solution was added dropwise within 5.5 minutes.

[0058] (3) After the reaction, press filter to remove most of the water in the aluminum hydroxide sol, and add α-Al to the aluminum precursor 2 o 3 Seed crystals, ball milling and dispersion treatment before adding seeds to ensure that the seed crystal particles are monodisperse particles; the average particle size ...

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Abstract

The invention relates to a synthesis method of alpha-alumina by a hydrothermal method. The method employs the hydrothermal method, a seed crystal alpha-Al2O3 is added in a resultant aluminium hydroxide sol. According to the invention, a hydrothermal reaction is used for obtaining gamma-AlOOH powder having small particle size, narrow particle size distribution and high sintering activity under high temperature and high pressure environment of a reaction vessel, and the alpha-Al2O3 is finally synthesized at a calcining temperature (800-1150 DEG C) which is lower than phase transition temperature of the alpha-Al2O3 by 1200 DEG C. The synthesized alpha-Al2O3 has the advantages of high particles dispersibility and narrow particle size distribution, specific surface is 1-20 m<2> / g, average particle size is 350-500 nm, purity can reach as high as 99.99%, the alpha-alumina can be used for lithium battery diaphragm coating ceramic materials, laser matrix materials, semiconductor matrix materials, high-voltage components, and optical elements and various precious machinery parts. The method is used for preparing the alpha-Al2O3 with uniform particles dispersibility, small particle size and high purity. The method can solve the insufficiency in current industrial production technology, reduces energy consumption, simplifies the technology, and increases production efficiency; and the prepared alpha-Al2O3 has the advantages of high purity, small particle size, high dispersibility and narrow particle size distribution.

Description

technical field [0001] The invention relates to the technical field of inorganic non-metallic materials, in particular to a preparation method for synthesizing α-alumina by a hydrothermal method. Background technique [0002] α-Al 2 o 3 It is a corundum structure and belongs to the trigonal crystal system. α-Al 2 o 3 Material An important inorganic non-metallic material with stable chemical properties, corrosion resistance, and excellent electrical insulation. It has the characteristics of high melting point (2050°C), high hardness (Mohs hardness 9), compact structure, high strength, and good wear resistance, so it is widely used in lithium battery diaphragm coating ceramic materials, ceramic materials, semiconductor materials, surface Protective materials, biological materials, optical materials, refractory materials, substrates of integrated circuit boards and other fields. [0003] With the rapid development of electronic communication and other industries in recent...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01F7/44
CPCC01F7/448C01P2004/03C01P2004/51C01P2004/62C01P2006/12C01P2006/80
Inventor 廖培龙曹江廖柳辉杨雪梅陈良
Owner SHENZHEN SENIOR TECH MATERIAL