A method for preparing flaky alumina powder

A technology of flake alumina and aluminum hydroxide, which is applied in the direction of alumina/aluminum hydroxide, can solve the problems of small average diameter and thickness of flake powder, insignificant flake characteristics, and expensive raw materials, so as to reduce the calcination temperature , Improve the chemical reaction rate, increase the effect of reactant concentration

Active Publication Date: 2016-07-06
贵州天合国润高新材料科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The traditional preparation method of flaky alumina powder has problems such as expensive raw materials, small average diameter-thickness ratio of flaky powder, insignificant flaky features, complicated process, long preparation cycle and high manufacturing cost.

Method used

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  • A method for preparing flaky alumina powder
  • A method for preparing flaky alumina powder
  • A method for preparing flaky alumina powder

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0023] Example 1: with γ-Al 2 o 3 and TiOSO 4 Preparation of flaky alumina powder as raw material

[0024] γ-Al 2 o 3 Powder is the raw material, add 5wt.% flake α-Al to the raw material powder 2 o 3 Seed (thickness 0.05μm, average aspect ratio 50) and 1.3wt.% morphology inhibitor (TiOSO 4 ), mixed evenly by means of stirring or ball milling, and then dried at 90°C for 2 hours to obtain a mixture. Add 1wt.% dextrin or polyvinyl alcohol to the dried mixture, and shape it under the pressure of 200MPa to obtain a primary green body; the primary green body is calcined at a high temperature at 1000°C for 8 hours. The concentration of hydrogen fluoride in the primary calcination atmosphere is 0.1%, the concentration of ammonia is 0.1%, the concentration of zirconium chloride is 1%, the concentration of hydrogen is 1%, the concentration of nitrogen is 2%, and the balance is air. After the primary calcination, the primary calcined green body is obtained; the primary calcined g...

Embodiment 2

[0025] Example 2: with γ-Al 2 o 3 and ZrOCl 2 Preparation of flaky alumina powder as raw material

[0026] δ-Al 2 o 3 Powder is the raw material, and 15wt.% seed crystal (thickness 0.2μm, average aspect ratio 64) and 4wt.% morphology inhibitor (ZrOCl 2), mixed evenly by means of stirring or ball milling, and then dried at 120° C. for 1 hour to obtain a mixture. Add 0.5wt.% dextrin or polyvinyl alcohol to the dried mixture and shape it under a pressure of 250MPa to obtain a primary green body; the primary green body is calcined at a high temperature at 1150°C for 8 hours . The concentration of hydrogen fluoride in the primary calcination atmosphere is 1.5%, the concentration of ammonia is 1.0%, the concentration of zirconium chloride is 4.0%, the concentration of hydrogen is 2.6%, the concentration of nitrogen is 5%, and the balance is air. After the primary calcination, the primary calcined green body is obtained; the primary calcined green body is broken into powder, a...

Embodiment 3

[0027] Embodiment 3: with η-Al 2 o 3 and ZrCl 4 Preparation of flaky alumina powder as raw material

[0028] η-Al 2 o 3 Powder is used as raw material, 8wt.% seed crystal (thickness 0.1μm, average aspect ratio 53), 1.5wt.% morphology inhibitor (ZrCl 4 ), 2.0wt.% gas source (NH 4 Cl), mixed uniformly by means of stirring or ball milling, and then dried at 100° C. for 1.5 hours to obtain a mixture. Add 1wt.% dextrin to the dried mixture and shape it under the pressure of 550MPa to obtain a primary green body; the primary green body is calcined at a high temperature at 1100°C for 2 hours. The concentration of hydrogen iodide in the primary calcination atmosphere is 1.2%, the concentration of ammonia gas is 0.5%, the concentration of zirconium fluoride is 3.5%, the concentration of hydrogen gas is 1.5%, the concentration of nitrogen gas is 4.5%, and the balance is air. After the primary calcination, the primary calcined green body is obtained; the primary calcined green bod...

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Abstract

The invention provides a method for preparing flaky alumina powder, belonging to the technical field of powder particle size and shape control. The technical process comprises the following steps: by using industrial aluminum hydroxide or transitional-phase alumina powder as a raw material, adding a crystal seed and a crystal grain shape control agent into the raw material powder, uniformly mixing the raw material powder, and pressing into a billet; and carrying out high-temperature calcination on the billet in an atmosphere containing hydrogen halide and shape control component, crushing the calcination billet into powder, carrying out secondary forming, and carrying out low-temperature calcination in an atmosphere containing higher-concentration hydrogen halide, thereby obtaining the flaky alumina powder, of which the thickness is less than 0.2 mu m, the average radius-thickness ratio is greater than 50 and the alpha-Al2O3 content is 100%. The method has the advantages of simple preparation technique and low manufacturing cost.

Description

technical field [0001] The invention belongs to the technical field of powder preparation and powder shape control, and particularly provides a method for preparing flaky alumina powder. Background technique [0002] Flaky alumina is a kind of aluminum oxide with a special structure. Its radial scale is micron scale and its thickness scale is nanoscale or close to nanoscale. It has the dual characteristics of micron powder and nano powder, and has good surface activity and attachment. It is easy to combine with active groups and not easy to agglomerate, and has the characteristics of easy dispersion. In addition to the physical and chemical properties of alumina, flaky alumina powder is also colorless and transparent, and has a strong ability to reflect light and shielding effects. Therefore, flaky alumina powder has great potential in the fields of cosmetics, automotive topcoats, pearlescent pigments, fillers and composite materials. The preparation methods of flake alumi...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01F7/02
CPCC01F7/02
Inventor 章林
Owner 贵州天合国润高新材料科技有限公司
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