Preparation method of high-temperature ultra-low sodium alumina powder material

A technology of alumina powder and ultra-low sodium, applied in chemical instruments and methods, alumina/aluminum hydroxide, inorganic chemistry, etc. To achieve ultra-low sodium level and other issues, to achieve the effect of superior performance, low manufacturing cost and high added value

Pending Publication Date: 2019-04-12
NORTHEASTERN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

This method removes sodium mainly by adding a mineralizer to react the sodium oxide in the alumina during the high-temperature roasting process, so as to achieve the purpose of removing sodium, but the mineralizer added by this method is mainly fluoride, and the fluoride mineralizer The growth of the crystal grains promoted while removing sodium in the roasting process, the final particle size of alumina is difficult to reach the standard mentioned in the method, as described in Comparative Example 1 below
[0007] Among the above-mentioned methods for preparing high-temperature low-sodium alumina, the content of sodium oxide prepared by the relatively simple process is still high, which cannot reach the ultra-low sodium level, and the particle size is relatively coarse
However, the process of preparing alumina with superior comprehensive performance is too complicated and the cost is high

Method used

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  • Preparation method of high-temperature ultra-low sodium alumina powder material
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  • Preparation method of high-temperature ultra-low sodium alumina powder material

Examples

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Embodiment 1

[0034] A preparation method of high-temperature ultra-low sodium alumina is carried out according to the following steps:

[0035] (1) Spread the industrial aluminum hydroxide flat on a tray, place it in an oven, and dry it at a temperature of 110° C. for 2 to 3 hours to obtain pretreated aluminum hydroxide.

[0036] (2) Mix the pretreated aluminum hydroxide with 0.1% ammonium chloride mineralizer and 0.05% nano-a-alumina seeds uniformly, and place the mixture in a muffle furnace at a temperature of 8°C / min The heating rate is increased to 1400°C, roasted for 30 minutes, and then dropped to room temperature with the furnace to obtain high-temperature alumina.

[0037] (3) The high-temperature alumina obtained above is dilute acid washed with a liquid-solid ratio of 3:1 in a constant temperature magnetic stirrer, the addition amount of dilute hydrochloric acid is 0.012%, the pickling temperature is 50°C, and the magnetic stirring speed is 120r / min. , Stirring time is 20min, washing b...

Embodiment 2

[0040] A preparation method of high-temperature ultra-low sodium alumina is carried out according to the following steps:

[0041] (1) Spread the industrial aluminum hydroxide flat on a tray, place it in an oven, and dry it at a temperature of 110°C for 2 to 3 hours to obtain pretreated aluminum hydroxide with a particle size D (0.5) of about 70 μm.

[0042] (2) Mix the pretreated aluminum hydroxide with 0.1% ammonium chloride mineralizer and 0.05% basic magnesium carbonate seed crystals uniformly, and place the mixture in a muffle furnace at a temperature of 10°C / min The rate was increased to 1400°C, calcined for 20 minutes, and dropped to room temperature with the furnace to obtain high-temperature alumina with w[α-alumina]>96%.

[0043] (3) The high-temperature alumina obtained above is dilute acid washed with a liquid-solid ratio of 4:1 in a constant temperature magnetic stirrer, the addition amount of dilute hydrochloric acid is 0.012%, the pickling temperature is 50°C, and the ...

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Abstract

The invention provides a preparation method of a high-temperature ultra-low sodium alumina powder material. Firstly, industrial aluminum hydroxide is subjected to a drying pretreatment; secondly, an appropriate amount of mineralizer and a seed crystal are added to the pretreated aluminum hydroxide for high-temperature roasting; thirdly, the high-temperature roasting product is subjected to washingwith dilute acid; finally, the washed alumina powder is ball-milled to a certain particle size, and the high-temperature ultra-low sodium alumina powder material is obtained. By adopting the method,the sodium oxide content of industrial alumina can be can effectively reduced, and the thermal shock resistance, electrical insulation, hardness and strength of the alumina powder material can be remarkably enhanced.

Description

Technical field [0001] The invention belongs to the field of powder material preparation. The prepared powder material can be used to prepare medium and high-end ceramic products, such as refractory and wear-resistant ceramics, electric porcelain devices, etc., and specifically relates to a method for preparing high-temperature ultra-low sodium alumina powder material. Background technique [0002] Alumina is a typical amphoteric oxide. It is an odorless, odorless and extremely hard white solid powder. It is usually divided into metallurgical grade alumina and non-metallurgical grade alumina. Non-metallurgical grade alumina is also called chemical alumina. Its main characteristics are low impurity content of sodium oxide, fine particle size, and the presence of multiple crystal phases. These characteristics make chemical alumina possess excellent properties that metallurgical grade alumina does not possess. High-temperature ultra-low sodium alumina is one of them. High temperatur...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01F7/02
CPCC01F7/021C01P2004/61C01P2004/62C01P2006/80
Inventor 罗洪杰吴林丽唐鹏张志刚刘宜汉
Owner NORTHEASTERN UNIV
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