Method of preparing good dispersion and high-purity ultra-fine alpha-Al2O3

Abstract

The invention discloses a preparing method of excellent dispersing high-pure ultra-fine alpha-Al2O3, which comprises the following steps: adopting analytic pure aluminium-alcohol salt hydrating reaction; balling; drying; sintering; adding one carboxyl acid or surface activator in the dehydrating course; adding alpha-Al2O3 seed and additive ammonium salt in the balling course.

Description

technical field [0001] What the present invention relates to is a kind of α-Al 2 o 3 preparation method, especially a kind of good dispersibility, high-purity ultra-fine α-Al 2 o 3 method of preparation. Background technique [0002] Due to its high purity and small particle size, high-purity ultra-fine alumina powder shows optical, electrical, magnetic, thermal and mechanical properties that conventional materials do not have, so it is widely used as a new functional material in optics, chemical industry and Special ceramics and many other fields. However, the alumina powder usually prepared by the liquid phase method needs to be converted into α-Al at high temperature. 2 o 3 , and the precursor is prone to agglomeration after high-temperature calcination, the specific surface area decreases sharply, and the average particle size increases sharply. It is difficult to obtain high-quality ultrafine powder with good dispersibility. Therefore, how ...

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Problems solved by technology

The methods disclosed in these two patents are relatively convenient to implement and can produce high-purity products. However, during the production process of this method, alkoxide hydrolysis is easy to form hydrogen bonds, resulting in hard agglomeration, and the alumina precursor produced needs to be processed at high temperature. It can be transformed into α-Al only after burning 2 o 3 , hard agglomeration is also very easy to occur during the burning process, and it is difficult to produce high-quality ultrafine α-Al with good dispersion 2 o 3 powder

In this regard, there are many studies to control the agglomeration of powder by improving the hydrolysis process of aluminum alkoxide. The Chinese patent "High-purity ultra-fine dispersed spherical Al 2 o 3 Preparation method of powder", application number: 95111112.4, using water vapor to improve the kinetic conditions of aluminum alkoxide hydrolysis, so that the hydrolysis rate is relatively low, so as to prepare dispersed aluminum hydroxide powder, Japanese patent "preparation of aluminum hydroxide by continuous method ", application number: 93119973.5, by shortening the hydrolysis reaction time of aluminum alkoxide, and adding a certain amount of additives in the hydrolysis process to improve the hydrolysis conditions of aluminum alkoxide, so as to obtain uniform and dispersed aluminum hydroxide, but the improvement of these processes All are just improvements to the hydrolysis process of aluminum alkoxide, ignoring that aluminum hydroxide will also undergo hard agglomeration during the burning process, and the process is relatively complicated

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