Crystal-guiding and impurity-removal device and method for preparing high-purity alumina polycrystals by virtue of cold crucible

Abstract

The invention relates to a crystal-guiding and impurity-removal device and method for preparing high-purity alumina polycrystals by virtue of a cold crucible. The device comprises the cold crucible, an electromagnetic induction coil, a double-layer water-cooling copper pipe and a lifting system, wherein a high-purity alumina melt is filled into the cold crucible; the double-layer water-cooling copper pipe is connected to the lifting system which is used for controlling the lifting of the double-layer water-cooling copper pipe; the double-layer water-cooling copper pipe can be inserted into thehigh-purity alumina melt in the cold crucible. According to the method, the double-layer water-cooling copper pipe internally carrying circulating cooling water is inserted into the melt, impuritiesin the melt are gradually condensed to the double-layer water-cooling copper pipe in a directional solidification manner and can be extracted before the melt is completely crystallized and solidifiedin the cold crucible, the purity of alumina can be increased from 99.995% to 99.999%, and high-purity alumina polycrystals do not need to be subjected to crushing and impurity removal, so that a largequantity of manpower and material resources are saved, the filling density of the raw materials in a subsequent single crystal furnace is increased to a certain extent, the quality of sapphire singlecrystal is improved, and the energy sources are saved.

Description

technical field [0001] The invention belongs to the technical field of cold crucible preparation of high-purity metal oxides, in particular to a seeding and impurity removal device and method for cold crucible preparation of high-purity alumina polycrystals. Background technique [0002] With the development of high technology, in the field of sapphire single crystal growth technology, the requirements for high-purity alumina polycrystals are very high, and the purity of high-purity alumina polycrystals must reach more than 99.999%. The raw material for the production of high-purity alumina polycrystalline by traditional technology is generally high-purity alumina micropowder with a purity of more than 99.995%, and there are trace impurity elements in the raw material micropowder. [0003] In order to produce high-quality and high-purity high-purity alumina polycrystals, cold crucibles are currently used to prepare high-purity alumina polycrystals, and high-frequency inducti...

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Problems solved by technology

[0004] However, when aluminum oxide polycrystals are crushed to remove impurity areas with sharp tools such as aluminum hammers, other impurities will be brought into the alumina polycrystals, causing pollution to the alumina polycrystals, resulting in a decrease in the purity of the alumina polycrystals, which directly affects subsequent sapphire production. single crystal quality

In addition, a lot of manpower and material resources will be wasted

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