Process for ordinary pressure continuous synthesizing silicon nitride powder by fluidized bed tech.

A technology of silicon nitride powder and silicon nitride, applied in chemical instruments and methods, nitrogen compounds, inorganic chemistry, etc., can solve the problems of high equipment cost and poor safety, reduce production cost, improve production efficiency, and improve production safety effect

Active Publication Date: 2006-06-28
UNIV OF SCI & TECH BEIJING
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  • Abstract
  • Description
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  • Application Information

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Problems solved by technology

[0007] The purpose of the present invention is to provide a method for continuously synthesizing silicon nitride powder at atmospheric pressure using fluidized bed technology, which solves the problems of high equipment cost and poor safety in high-pressure combustion synthesis

Method used

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  • Process for ordinary pressure continuous synthesizing silicon nitride powder by fluidized bed tech.
  • Process for ordinary pressure continuous synthesizing silicon nitride powder by fluidized bed tech.
  • Process for ordinary pressure continuous synthesizing silicon nitride powder by fluidized bed tech.

Examples

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Embodiment 1

[0031]Example 1: Put 60g of Si powder with an average particle size of 10 μm in an oven, dry at 90°C for 8 hours under the protection of nitrogen, and stir once every 1 hour to speed up the drying speed, and then put the dried silicon powder in Sieve in a 400-mesh sieve, collect the sifted silicon powder and put it into a vibrating fluidized feeder. The inner diameter of the vibrating feeder is 40mm, and the height is 200mm. The particles are hollow alumina balls with a diameter of 100 μm, and high-purity nitrogen gas is introduced from the bottom, and the nitrogen flow rate is 0.3m 3 / h. After the silicon powder is rapidly fluidized by nitrogen, under the vibration force of the vibration motor, the stirring of the stirring motor and the impact of the fluidized particles, the agglomerated ultrafine powder is broken and entrained to form a gas-solid two-phase flow. It is preheated to 900°C by an electric heating tube preheater. The inner diameter of the inner tube of the prehe...

Embodiment 2

[0032] Example 2: Mix Si powder with an average particle size of 20 μm and silicon nitride powder as a nucleating agent at a mass ratio of 1:1, take 120 g of the powder, put it in an oven, and store it at 90 ° C under nitrogen protection. Dry for 8 hours, and stir once every 1 hour to speed up the drying speed. Then put the dried material into a 400-mesh screen and sieve it. Collect the sieved material and put it into the storage bin. The inner diameter of the storage bin is 80mm , with a height of 100mm. Turn on the vibrating screening motor, and some materials will fall into the vibrating fluidized feeder. When the height of the material reaches 60mm, turn off the vibrating screening motor. The inner diameter of the vibrating feeding device is 40mm, the height is 200mm, 2 vibration motors, 1 stirring motor, the fluidized particles are hollow alumina balls with a diameter of 100μm, and high-purity nitrogen gas is introduced from the bottom, and the flow rate of nitrogen gas i...

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Abstract

A process for continuously synthesizing silicon nitride powder under ordinary pressure by fluidized bed includes such steps as using N2 to carry the Si powder or the mixture of Si powder and silicon nitride in high-speed fluidized bed, fluidizing, fast leaving from the high-speed fluidized bed, coming in high-temp nitrifying furnace, combustion for synthetic reaction, cooling by heat exchanger, and collecting the product by bag capture.

Description

technical field [0001] The invention relates to a method for continuously synthesizing silicon nitride powder at atmospheric pressure by utilizing a fluidized bed technology, and belongs to the technical field of preparation of ultrafine silicon nitride powder. Background technique [0002] Si 3 N 4 Ceramics have the characteristics of light specific gravity, small thermal expansion coefficient, high hardness, high elastic modulus, thermal shock resistance, corrosion resistance, wear resistance, good high temperature mechanical properties, etc., and are widely used in metallurgy, aerospace, aviation, petroleum, chemical industry, machinery, etc. , electronics and other industries. However, compared with metal-based materials, the high cost of silicon nitride ceramics limits its large-scale application. In general, the preparation of high-quality Si 3 N 4 Ceramic products, need high-quality Si 3 N 4 powder. Therefore, the preparation of high-quality, low-cost silicon ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B21/068C04B35/584C04B35/626
Inventor 王立尹少武董继昌吴平童莉葛
Owner UNIV OF SCI & TECH BEIJING
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