Title: Method of making low-sodium 2-alumina of superfine grains
Application Number: 85102281 Application Date: 1985.04.01
Publication Number: 1003251 Publication Date: 1986.09.17
Approval Pub. Date: Granted Pub. Date:
International Classifi-cation: C01F7/02
Applicant(s) Name: Zhengzhou Light Metal Institute Address:
Inventor(s) Name: Cheng Guangyuang
Attorney & Agent: TIAN JIAXUN
Abstract:
     Modern industry requiries smaller and smaller crytal grains of alumina for makeing ceramic products to be used for precision works, and it is difficult to fulfill these requirements by using the usual method. In the method of this invention, alumina or aluminium hydroxide of industrial grade is used as raw material, by adding 0.03-0.4 percent of fluoride, with or without small amount of boron compound or chloride, and roasting it at 1200-1500 deg.C to transform the raw material to 2-alumina. The grain size of the alumina crystal will be about 1micron. Then, by a simple process of water washing to remove soluble sodium oxide the low-sodium 2-alumina of superfine grains are obtained. This alumina is suitable for making various ceramic products for precision works, and the process for its preparation is simple.
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