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Method for preparing beta-silicon nitride toughened particles by recycling waste silicon nitride
The invention provides a method for recycling and preparing beta-silicon nitride from the surface of a waste quartz crucible. The method comprises the following steps: 1, adding diluted acid to silicon nitride raw materials containing impurities such as silicon dioxide, silicon and metal, conducting the first normal-temperature acid pickling, and removing the metal impurities; 2, conducting the secondary hydrofluoric acid pickling, and removing silicon dioxide and part of silicon; 3, adopting pure water for cleaning the mixture till the mixture becomes neutral, and conducting vacuum drying; 4, conducting high-temperature nitrogen treatment at the temperature of 1300-1550 DEG C, and obtaining the beta-silicon nitride; 5, conducting ball-milling, pulverization, screening and grading, and selecting the beta-silicon nitride with the granularity smaller than 10 micrometers. By means of the method, high purity recycling and reuse of a silicon nitride coating on the surface of the waste quartz crucible are achieved, and the obtained beta-silicon nitride can serve as a toughened material in production of silicon nitride ceramics.
Method for preparing beta-silicon nitride toughened particles by recycling waste silicon nitride
The invention provides a method for recycling and preparing beta-silicon nitride from the surface of a waste quartz crucible. The method comprises the following steps: 1, adding diluted acid to silicon nitride raw materials containing impurities such as silicon dioxide, silicon and metal, conducting the first normal-temperature acid pickling, and removing the metal impurities; 2, conducting the secondary hydrofluoric acid pickling, and removing silicon dioxide and part of silicon; 3, adopting pure water for cleaning the mixture till the mixture becomes neutral, and conducting vacuum drying; 4, conducting high-temperature nitrogen treatment at the temperature of 1300-1550 DEG C, and obtaining the beta-silicon nitride; 5, conducting ball-milling, pulverization, screening and grading, and selecting the beta-silicon nitride with the granularity smaller than 10 micrometers. By means of the method, high purity recycling and reuse of a silicon nitride coating on the surface of the waste quartz crucible are achieved, and the obtained beta-silicon nitride can serve as a toughened material in production of silicon nitride ceramics.
Method for preparing beta-silicon nitride toughened particles by recycling waste silicon nitride
ZHENG HAI (author) / TANG MINGLIANG (author) / LIU BAO (author) / YANG XUEGEN (author) / HU ZENGHAN (author) / LI XUE (author)
2016-02-10
Patent
Electronic Resource
English
IPC:
C04B
Kalk
,
LIME
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