System for synthesizing silicon nitride by fluidized bed reactor

Abstract

The invention relates to a system for synthesizing silicon nitride by a fluidized bed reactor. The system comprises the fluidized bed reactor, a nitrogen supply unit and a silicon powder supply unit, the fluidized bed reactor comprises a shell, a lower cavity of the shell is used for performing nitridation reaction for nitrogen and silicon powder under the fluidization condition, an air supply opening and a material supply opening are formed in the shell wall of the bottom of the shell, the nitrogen supply unit comprises a heating device for heating the nitrogen, an air outlet of the heating device is connected with the air supply opening, the silicon powder supply unit comprises a feeding barrel and a Venturi charging device, the feeding barrel is used for containing the silicon powder, a discharging port of the feeding barrel is connected with a powder inlet of the Venturi charging device, a discharging port of the Venturi charging device is connected with the material supply opening, and a discharging port in the top of the shell is connected with a cyclone separator for recovering synthesized silicon nitride. According to the system, the silicon powder and the nitrogen react under the fluidization condition, the synthesized Si3N4 cannot aggregate and cake, and continuous production of the Si3N4 can be achieved.

Description

technical field [0001] The invention relates to the field of silicon nitride synthesis, in particular to a system for synthesizing silicon nitride using a fluidized bed reactor. Background technique [0002] Silicon nitride (Si 3 N 4 ) Ceramic is an advanced engineering ceramic material, which has the characteristics of high strength, high hardness, corrosion resistance, wear resistance and good thermal shock and mechanical shock resistance at room temperature and high temperature. People have used it to develop Manufactured bearings, steam turbine blades, mechanical seals and other mechanical components, and have been widely used in metallurgy, aviation, petrochemical, machinery, electronics and other industries. Nearly 20 to 30 years Si 3 N 4 Very popular and valued. Therefore, the fabrication of high-quality, low-cost Si 3 N 4 Powder has become a common concern in the industry. [0003] There are many ways to prepare silicon nitride powder, which are silicon powde...

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Problems solved by technology

[0004] Preparation of Si by Direct Nitriding of Silicon Powder 3 N 4 is currently prepared Si 3 N 4 The main method of powder, but the main disadvantage of this method is the synthesis of Si 3 N 4 It is easy to agglomerate and agglomerate, therefore, the Si generated after the reaction 3 N 4 Grinding and homogenization are required; another disadvantage of this method is that the production process is intermittent and discontinuous

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