Method for preparing flake alpha-Al2O3 granular powder

A granular powder and sheet-like technology, which is applied in the field of preparation of inorganic materials, can solve problems such as polluting the furnace body, polluting the environment, and high energy consumption, and achieves the effects of low cost, simple processing process, and low energy consumption

Inactive Publication Date: 2009-12-09
LANZHOU UNIVERSITY
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  • Summary
  • Abstract
  • Description
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Problems solved by technology

The raw materials used in these methods generate toxic gases, such as Al 2 (SO) 3 Decomposition produces SO 3 gas, pollution
Some molten salts are also toxic, such as fluoride, and their volatiles may also corrode or contaminate the furnace
Moreover, these methods require high-temperature calcination (above 1000 ° C), so energy consumption is large in industrial production

Method used

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  • Method for preparing flake alpha-Al2O3 granular powder
  • Method for preparing flake alpha-Al2O3 granular powder
  • Method for preparing flake alpha-Al2O3 granular powder

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preparation example Construction

[0022] The preferred preparation method of the present invention is to prepare the soluble inorganic salt solution of aluminum into an aqueous solution, and then add an appropriate amount of alkali to make the pH value of the system greater than 6, filter out aluminum hydroxide, dry it after washing, and grind it into fine powder, and then add the fine powder after grinding into the potassium sulfate aqueous solution with a concentration of 0.001-0.5mol / L, wherein the molar ratio of potassium sulfate to aluminum hydroxide is 5-15, and the The mixed powder of aluminum hydroxide and potassium sulfate is obtained by drying under the conditions, and the mixed powder is calcined at 850-1050° C. for 2-5 hours, and the calcined product is washed with water to remove the potassium sulfate, and then dried.

[0023] The alkali that the present invention adds is preferably ammoniacal liquor.

Embodiment 1

[0026] First, distilled water and Al(NO 3 ) 3 9H 2O configure the solution with aluminum ion concentration of 0.1mol / L, then slowly add 3mol / L ammonia water dropwise into the prepared solution until the pH value of the solution is 9. The obtained aluminum hydroxide was filtered and washed well 8 times with distilled water and then 2 times with alcohol. The aluminum hydroxide wet gel was placed in an oven and dried at 80° C. to obtain the aluminum hydroxide xerogel. Grind aluminum hydroxide dry gel into fine powder, and add the fine powder to potassium sulfate aqueous solution to obtain a suspension, wherein the molar ratio of potassium sulfate to aluminum hydroxide is 6, stir the suspension thoroughly, and dry it in a water bath at 80°C A mixed powder of aluminum hydroxide and potassium sulfate was obtained. Place the mixed powder in Al 2 o 3 In a crucible, calcined at 900°C for 2 hours, the reaction product was washed with water several times to remove potassium sulfate...

Embodiment 2

[0028] First, distilled water and Al(NO 3 ) 3 9H 2 O Prepare a solution with an aluminum ion concentration of 0.1 mol / L, and then add α-Al with a particle size of about 50 nm to the solution 2 o 3 Seed. The amount added is that the prepared aluminum hydroxide is completely decomposed into Al 2 o 3 5 wt% of the theoretical total. will be added with α-Al 2 o 3 The aluminum nitrate solution of the seed crystal was placed in an ultrasonic cleaner for 10 minutes so that the α-Al 2 o 3 The seeds are well dispersed into the solution. Subsequently, 3 mol / L ammonia water was added dropwise to the solution to prepare aluminum hydroxide. Subsequent technical process is completely identical with embodiment 1. The prepared flaky α-Al 2 o 3 The X-ray diffraction spectrum of the granular powder and figure 1 same. image 3 For the prepared flake α-Al 2 o 3 Scanning electron micrographs of the particles. Flake α-Al 2 o 3 The particles have an average diameter of 400 nm and...

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Abstract

The invention discloses a method for preparing flake alpha-Al2O3 granular powder. The method comprises the following steps: preparing water solution by inorganic salt solution of aluminum, then adding proper amount of alkali into the water solution to make the pH value of a system more than 6, filtering, washing and drying the aluminum hydroxide, grinding the aluminum hydroxide into fine powder, adding potassium sulphate into the ground fine powder, or adding the fine powder into potassium sulphate water solution according to a molar ratio of the potassium sulphate to the aluminum hydroxide of 5 to 15, calcining the mixed powder for 2 to 5 hours at the temperature of between 850 and 1,050 DEG C, washing a calcined product by water to remove the potassium sulphate, and drying the product.

Description

technical field [0001] The present invention relates to a kind of preparation method of inorganic material, exactly the present invention is a kind of preparation flaky α-Al 2 o 3 Granular powder method. Background technique [0002] α-Al 2 o 3 (commonly known as corundum) is the most stable phase of all alumina, belonging to A 2 B 3 The compound, trigonal crystal system, has the characteristics of high melting point (2053°C), high hardness (Mohs hardness 9), anti-oxidation, high temperature resistance, corrosion resistance, high thermal conductivity, and high resistivity. As a special alumina and an important powder material, flaky alumina particles not only have the excellent properties of ordinary alumina, but also have a special two-dimensional sheet structure, moderate surface activity, good adhesion, reflective The ability of light and the significant shielding effect have attracted the attention of inorganic material researchers. [0003] The thermal conductivi...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01F7/02
Inventor 李建功苏兴华李建卫寇昕莉黄娟娟沈利亚
Owner LANZHOU UNIVERSITY
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