Method for preparing anhydrous boron oxide

Abstract

The invention discloses a method for preparing anhydrous boron oxide. The method comprises the following steps: (1) carrying out vacuum dehydration treatment of boric acid to obtain boron oxide; (2) placing boron oxide in a crucible, heating to 400-500 DEG C, and then keeping for 30 min; (3) carrying out microwave heating dehydration treatment of boron oxide with the dehydration time of 10-40 min; and (4) under a normal temperature and normal pressure condition with the water content of less than 1 ppm, cooling to the room temperature to obtain anhydrous boron oxide. The method has the advantages of simple production process and low production cost, and the obtained product has the water content of below 150 ppm and the purity of up to 99.999%.

Description

technical field [0001] The invention relates to the field of boron oxide, in particular to a method for preparing anhydrous high-purity boron oxide. Background technique [0002] Boron oxide generally exists in the form of colorless glassy crystals or powders. It is the main oxide of boron and is widely used as a cosolvent in the decomposition of silicate, a dopant in the preparation of semiconductor materials, and an acidic compound in organic synthesis. Catalysts, refractory additives in the paint preparation process, boron elements and the preparation of various borides, etc. However, the use of such additives has high requirements for the water content and impurity content of boron oxide, such as in In the crystal preparation process of III-V compound semiconductors such as gallium arsenide, indium phosphide, gallium nitride, etc., it is necessary to use anhydrous high-purity boron oxide as a liquid sealant, and the purity of boron oxide is required to be ≥99.999%, and t...

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Problems solved by technology

[0003] Usually people use normal pressure method or reduced pressure method to prepare boron oxide, but the water content of boron oxide prepared by this method is relatively high, and there are many impurities, and its water content and impurities are not up to the requirements.

At present, there is also a preparation method of anhydrous boron oxide, such as the Chinese patent whose patent number is 200810155689.X, and the patent name is a preparation method of high-temperature covering agent grade boron oxide. The principle of this invention patent is to first heat boron oxide in the air, Then put the boron oxide into a platinum crucible, place it in a medium-frequency induction heating vacuum furnace at 1500°C, and use a two-stage dehydration process for dehydration to obtain boron oxide with a water content below 200ppm. High temperature requires a lot of energy consumption. Due to the high temperature and high requirements for appliances, platinum crucibles are required to hold boron oxide, so the manufacturing cost is high, which is not conducive to large-scale production of enterprises.