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Alpha-alumina micro-powder, preparation method and application thereof

A technology of alumina micropowder and alumina, applied in chemical instruments and methods, alumina/aluminum hydroxide, inorganic chemistry, etc., can solve the problems of high impurity content, low sphericity, wide particle size distribution, etc., and achieve low impurity content , high sphericity and narrow particle size distribution

Inactive Publication Date: 2020-06-19
LUOYANG ZHONGCHAO NEW MATERIAL SHARES CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The purpose of the present invention is to overcome the uncontrollable particle size, wide particle size distribution, low sphericity and high impurity content of α-alumina micropowder in the prior art, and propose α-alumina micropowder and its preparation method and application

Method used

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  • Alpha-alumina micro-powder, preparation method and application thereof
  • Alpha-alumina micro-powder, preparation method and application thereof
  • Alpha-alumina micro-powder, preparation method and application thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0074] (1) Mix 1kg of industrial alumina (purity>99%), 4g of polyvinyl alcohol and 4L of deionized water to form a uniform slurry, and use nitric acid (1mol / L) to adjust the pH of the slurry to 5;

[0075] (2) The slurry obtained in step (1) is ball milled in a ball mill to obtain a liquid slurry containing intermediate particles (wherein, the D of the intermediate particles 50 = 1 μm, and (D 90 -D 10 ) / D 50 = 3.3; D of target alumina powder 50 -0=1.5 μm), the ball milling condition is: the mass ratio of grinding ball (alumina with a purity of 97%) to industrial alumina=15:1; the first grinding ball (diameter is 1mm) and the second grinding ball ( 3mm in diameter) mass ratio = 4:1;

[0076] (3) The slurry after ball milling is pressed into a filter cake in a filter press, evaporated to dryness quickly by flash evaporation, and crushed to obtain the first alumina powder;

[0077] (4) 3 g of boric acid and 3 g of aluminum fluoride were added to the first alumina powder, mix...

Embodiment 2

[0079] (1) Mix 1 kg of industrial alumina (same as Example 1), 2 g of polyacrylamide and 2.5 L of deionized water to form a uniform slurry, and use nitric acid (5 mol / L) to adjust the pH of the slurry to 6;

[0080] (2) The slurry obtained in step (1) is ball milled in a ball mill to obtain a liquid slurry containing intermediate particles (wherein, the D of the intermediate particles 50 = 1.8μm, and (D 90 -D 10 ) / D 50 = 3.7; D of the target alumina powder 50 -0=3μm), the ball milling conditions are: the mass ratio of grinding balls (alumina with a purity of 97%) to industrial alumina=10:1; the first grinding ball (2mm in diameter) and the second grinding ball (diameter 5mm) mass ratio = 2:1;

[0081] (3) The slurry after ball milling is pressed into a filter cake in a filter press, evaporated to dryness quickly by flash evaporation, and crushed to obtain the first alumina powder;

[0082] (4) 2.5 g of boric acid and 7.5 g of ammonium chloride were added to the first alum...

Embodiment 3

[0084] (1) 1 kg of industrial alumina (same as Example 1) was mixed with 2.5 L of deionized water to form a uniform slurry, and the pH of the slurry was adjusted to 3 using sulfuric acid (5 mol / L);

[0085] (2) The slurry obtained in step (1) is ball milled in a ball mill to obtain a liquid slurry containing intermediate particles (wherein, the D of the intermediate particles 50 = 0.8μm, and (D 90 - / D 10 ) / D 50 = 3; D of the target alumina powder 50 -0=3.5μm), the ball milling conditions are: the mass ratio of grinding balls (aluminum oxide with a purity of 97%) to aluminum oxide=20:1; the first grinding ball (diameter is 1mm) and the second grinding ball (diameter 2.5mm) mass ratio = 3:1;

[0086] (3) The slurry after ball milling is pressed into a filter cake in a filter press, evaporated to dryness quickly by flash evaporation, and crushed to obtain the first alumina powder;

[0087] (4) 5.8 g of boric acid and 4 g of ammonium fluoride were added to the first alumina p...

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Abstract

The invention relates to alpha-aluminum oxide micro-powder, a preparation method and application thereof, wherein the sphericity of the alpha-alumina micro-powder is 0.5-1, and the particle size D50-0of the alpha-alumina micro-powder is 0.5-8 [mu]m. The method comprises the following steps: (1) pulping: mixing an aluminum oxide raw material and a solvent to prepare slurry, and adjusting the pH value of the slurry to 3-6 by using an acid; (2) ball milling: carrying out ball milling on the slurry obtained in the step (1), and controlling the granularity of intermediate particles in the slurry according to the target granularity of an end product; (3) removing of the solvent in the ball-milled slurry obtained in the step (2) to obtain first aluminum oxide powder; and (4) calcining: mixing the first aluminum oxide powder with a mineralizing agent, and calcining to obtain the alpha-aluminum oxide micro-powder with the target particle size. The alpha-alumina micro-powder provided by the invention is high in sphericity and narrow in particle size distribution, particularly the target particle size of a final product can be modulated according to requirements, the modulation range is 0.5-8 [mu]m, the impurity content is low, and the alpha-alumina micro-powder is particularly suitable for the fields of heat conduction, insulating fillers and the like.

Description

technical field [0001] The invention relates to the field of preparation of α-alumina micropowder, in particular to α-alumina micropowder and its preparation method and application. Background technique [0002] α-alumina has the advantages of heat conduction and insulation, and is often used as heat conduction filler and insulation filler to prepare heat conduction silica gel, insulating parts cast by epoxy resin, and polymer material cast parts such as filling glue. With the improvement of the automation of the pouring production line, the viscosity and usable time range of the pouring mixed system are required to be narrowed. The shape, grain size, particle size composition and fluidity of α-alumina powder have a great influence on the performance of the casting process. The existing domestic α-alumina micropowder has problems such as wide particle size distribution, unstable powder particle size distribution, low sphericity, needle-like crystals, poor fluidity, and high...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01F7/02
CPCC01F7/023C01F7/021C01P2002/72C01P2004/03C01P2004/62C01P2004/61C01P2006/80
Inventor 李敏吴建华裴广斌
Owner LUOYANG ZHONGCHAO NEW MATERIAL SHARES CO LTD
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