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Preparation method of low-sodium orthohexagonal flaky alpha-alumina micropowder

A technology of alumina micropowder and flaky alumina, applied in chemical instruments and methods, inorganic chemistry, aluminum compounds, etc., can solve the problems of difficult control of particle size and shape, complicated production process, high production cost, etc., and achieve crystal form Well-developed, high-purity, low-cost effects

Inactive Publication Date: 2019-12-13
CHINA JILIANG UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] The invention provides a low-sodium regular hexagonal flaky α-Al 2 o 3 The micropowder preparation method solves the problems of high production cost, complex production process, high sodium content, difficult control of particle size and shape in the prior art

Method used

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  • Preparation method of low-sodium orthohexagonal flaky alpha-alumina micropowder
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  • Preparation method of low-sodium orthohexagonal flaky alpha-alumina micropowder

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preparation example Construction

[0032] A low-sodium regular hexagonal flake α-Al 2 o 3 The preparation method of micropowder, comprises the steps:

[0033] (1) Mix and stir industrial aluminum hydroxide, dispersant and deionized water to form an aluminum hydroxide slurry with a solid content of 10 to 30 wt%, and grind it in a sand mill. The grinding medium is zirconia balls, and the The diameter is 1-5 μm, and the grinding time is 0.5-6 hours to obtain a refined alumina precursor slurry;

[0034] (2) Stir the alumina precursor slurry prepared in step (1) in a water bath at 70-100°C for 10-60 minutes, and add a sodium removing agent to adjust the pH value of the slurry to 4-7 while stirring, and obtain non- Basic alumina precursor slurry;

[0035] (3) The alumina precursor slurry prepared in step (2) is subjected to solid-liquid separation with a high-speed centrifuge to obtain a solid alumina precursor. The centrifugal speed is 2000-10000 rpm, and the centrifugal time is 10-60 minutes;

[0036] (4) The ...

Embodiment 1

[0042] (1) Weigh 6 parts of aluminum hydroxide powder (the initial particle size of the powder is 100 μm, and the content of sodium oxide is 0.35 wt%), 0.1 part of polyacrylamide, and 34 parts of deionized water, and make a hydrogen concentration of 15 wt%. The alumina slurry is then put into a sand mill for grinding to obtain a refined alumina precursor. The grinding medium is zirconia ball, the diameter of the ball is 2μm, and the grinding time is 2h;

[0043] (2) Stir the alumina precursor slurry prepared in step (1) in a water bath at 80°C for 30 minutes, add hydrochloric acid to adjust the pH of the slurry to 4 while stirring, and obtain a non-alkaline alumina precursor slurry material;

[0044] (3) The alumina precursor slurry prepared in step (2) is subjected to solid-liquid separation in a high-speed centrifuge to obtain a solid alumina precursor. The centrifugal speed is 5000 rpm, and the centrifugal time is 30min;

[0045] (4) The solid alumina precursor prepared ...

Embodiment 2

[0052] (1) Weigh 7 parts of aluminum hydroxide powder (the initial particle size of the powder is 80 μm, and the content of sodium oxide is 0.30 wt%), 0.21 parts of triethanolamine, and 33 parts of deionized water, and make a hydrogen concentration of 17.5 wt%. The alumina slurry is then put into a sand mill for grinding to obtain a refined alumina precursor. The grinding medium is zirconia balls, the diameter of the zirconia balls is 1 μm, and the grinding time is 3 hours;

[0053] (2) Stir the alumina precursor slurry prepared in step (1) in a 90°C water bath for 30 minutes, add nitric acid to adjust the pH of the slurry to 5 while stirring, and obtain a non-alkaline alumina precursor slurry material;

[0054] (3) The alumina precursor slurry prepared in step (2) is subjected to solid-liquid separation in a high-speed centrifuge to obtain a solid alumina precursor. The centrifugal speed is 6000 rpm, and the centrifugal time is 30 minutes;

[0055] (4) The solid-state alum...

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Abstract

The invention discloses a preparation method of a low-sodium orthohexagonal flaky alpha-alumina micropowder. The method which takes cheap industrial aluminum hydroxide as a raw material comprises thefollowing steps: mixing the industrial aluminum hydroxide, a dispersant and deionized water to prepare a slurry; carrying out grinding, sodium removal, solid-liquid separation, primary water washing,solid-liquid separation, drying, presintering and secondary water washing to obtain a low-sodium alumina precursor; and then adding a morphology inducer, and performing stirring, mixing and calciningto obtain the low-sodium orthohexagonal flaky alpha-alumina micropowder. The low-sodium regular orthohexagonal flaky alpha-alumina micropowder prepared by the method has a sodium oxide content of below 0.05%, an alpha-Al2O3 content of above 98%, has an orthohexagonal particle morphology, has a side length of below 1.5 [mu]m and a thickness of below 0.5 [mu]m, and can be applied to the fields of semiconductor materials, monocrystalline sapphire, reinforcing agents, protective layers and the like. The preparation method has the characteristics of wide sources of raw materials, simple device andproduction process, low production cost, realization of industrial production, environmental friendliness and the like.

Description

technical field [0001] The invention relates to a method for preparing alumina powder, in particular to a method for preparing low-sodium regular hexagonal flaky α-alumina micropowder. Background technique [0002] Low-sodium flaky α-alumina not only has the high hardness, high melting point, high temperature resistance, corrosion resistance, good thermal conductivity and other excellent properties of conventional α-alumina, but also its special two-dimensional planar structure makes it have good adhesion , significant shielding effect and ability to reflect light and other special properties, it has great application potential in the fields of high-end automotive polishing, gemstone processing and high-precision microelectronics processing, cosmetics, functional coatings and ceramic toughening. [0003] At present, the preparation methods of flake alumina mainly include hydrothermal method, molten salt method, sol-gel method, mechanical method and so on. The flaky alumina ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01F7/44
CPCC01F7/441C01F7/447C01P2002/72C01P2004/03C01P2004/22C01P2006/80
Inventor 李冬云申亚强孙一鸣徐扬葛洪良
Owner CHINA JILIANG UNIV
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