Flaky alpha alumina and preparation method thereof

An alpha alumina and flake technology, applied in the field of flake alpha alumina and its preparation, can solve the problems of high sintering temperature, long holding time, increased cost, etc., and achieve low calcination temperature, short holding time and low production cost Effect

Pending Publication Date: 2022-07-08
BAISE UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The molten salt method has simple process, uniform composition, good and controllable crystal morphology, and good phase purity. It has become the main method for the preparation of flaky alumina. In the process of preparing flaky alumina by the molten salt method, high temperature sintering is required. The sintering temperature Generally around 1200°C, the holding time is 3-5h, the sintering temperature is high, the holding time is long, and the energy consumption is high, resulting in an increase in cost

Method used

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  • Flaky alpha alumina and preparation method thereof
  • Flaky alpha alumina and preparation method thereof
  • Flaky alpha alumina and preparation method thereof

Examples

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example 1

[0039] A preparation method of flaky alpha alumina, comprising the following steps:

[0040] (1) Weigh 4.5g of sodium chloride and potassium chloride and 2g of aluminum hydroxide, put them into a beaker, add 100mL of deionized water, and ultrasonically disperse them evenly. Cool to obtain mixture A;

[0041] (2) weigh 0.1 g of aluminum fluoride and put it into an alumina mortar together with mixture A described in step (1), and grind evenly to prepare mixture B;

[0042] (3) The mixture B described in the step (2) was transferred to an alumina crucible, then put into a box-type resistance furnace and calcined at a temperature of 750 ° C for 180 min, the heating rate was 9 ° C / min, and the sample was cooled to room temperature, Take out the alumina crucible, and transfer the sample in the alumina crucible to a beaker;

[0043] Add 300-400 mL of water to the beaker, put it into an ultrasonic cleaner, disperse and dissolve by ultrasonic, and after it is completely dissolved, le...

Embodiment 2

[0047] A preparation method of flaky alpha alumina, comprising the following steps:

[0048] (1) Weigh 4.5g each of sodium chloride and potassium chloride, and 2g aluminum hydroxide, put them into a beaker, add 100mL of deionized water, and disperse evenly by ultrasonic, then put the beaker into a blast drying oven and dry at 120°C for 3h, Cool to obtain mixture A;

[0049] (2) weigh 0.1 g of aluminum fluoride and put it into an alumina mortar together with mixture A described in step (1), and grind evenly to prepare mixture B;

[0050] (3) The mixture B described in the step (2) was transferred to an alumina crucible, then put into a box-type resistance furnace for calcination at a temperature of 800 ° C for 60 min, the heating rate was 9 ° C / min, and the sample was cooled to room temperature, Take out the alumina crucible, and transfer the sample in the alumina crucible to a beaker;

[0051] Add 300-400 mL of water to the beaker, put it into an ultrasonic cleaner, disperse...

Embodiment 3

[0055] A preparation method of flaky alpha alumina, comprising the following steps:

[0056] (1) Weigh 4.5g each of sodium chloride and potassium chloride, and 2g aluminum hydroxide, put them into a beaker, add 100mL of deionized water, and disperse evenly by ultrasonic, then put the beaker into a blast drying oven and dry at 120°C for 3h, Cool to obtain mixture A;

[0057] (2) weigh 0.1 g of aluminum fluoride and put it into an alumina mortar together with mixture A described in step (1), and grind evenly to prepare mixture B;

[0058] (3) The mixture B described in the step (2) was transferred to an alumina crucible, then put into a box-type resistance furnace and calcined at a temperature of 900 ° C for 30 min, the heating rate was 9 ° C / min, and the sample was cooled to room temperature, Take out the crucible and transfer the sample in the crucible to the beaker;

[0059] Add 300-400 mL of water to the beaker, put it into an ultrasonic cleaner, disperse and dissolve by u...

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Abstract

The invention provides a preparation method of flaky alpha aluminum oxide, which comprises the following steps: (1) weighing molten salt and an aluminum source, putting the molten salt and the aluminum source into a container, adding deionized water for dissolving, ultrasonically dispersing uniformly, and drying to obtain a mixture; (2) putting the mixture dried in the step (1) into a mortar, adding aluminum fluoride, and uniformly grinding; and (3) putting the powder in the step (2) into a crucible, putting the crucible into a heating furnace, heating to 750-900 DEG C, keeping the temperature for 0.5-5 hours, taking out a solid matter, grinding, and carrying out ultrasonic washing to obtain the flaky alpha aluminum oxide. The preparation method of the flaky alpha alumina is low in preparation temperature and short in reaction time, and the production cost is greatly reduced. The invention also provides the flaky alpha aluminum oxide prepared by the preparation method of the flaky alpha aluminum oxide, the average radial size of the flaky alpha aluminum oxide is 4-5 microns, the thickness is 150-250 nm, and the radius-thickness ratio is 16-25.

Description

technical field [0001] The invention belongs to the technical field of alumina preparation, and in particular relates to a flaky alpha alumina and a preparation method thereof. Background technique [0002] Alumina is a commonly used material for making refractories because of its high hardness and high melting point. Its melting point is 2054°C and its boiling point is as high as 2980°C. As a functional material with excellent performance, flaky alumina inherits all the advantages of ordinary alumina. It has a unique flaky structure, so it has the dual characteristics of micro-powder and nano-powder. Flake alumina is mainly γ-Al in the industry 2 O 3 , β-Al 2 O 3 , α-Al 2 O 3 (commonly known as corundum) these three crystal forms; as the temperature increases, its crystal form will be finally converted from gamma or beta alumina to alpha alumina. Among these three crystal forms, the most stable is alpha alumina, It is the only crystal form that can exist stably at an...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01F7/02C01F7/30B82Y30/00B82Y40/00
CPCC01F7/02C01F7/30B82Y30/00B82Y40/00C01P2002/72C01P2004/03C01P2004/62Y02P20/10
Inventor 周小丽徐敬尧史兵方曹阿林
Owner BAISE UNIV
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