A method for sintering silicon carbide by nitriding reaction of crystalline silicon cutting waste

A technology of sintering silicon carbide and cutting waste, which is applied in the field of comprehensive utilization of secondary resources, can solve problems such as increased manufacturing costs, and achieve the effects of reduced energy consumption, flexible processes, and wide sources

Active Publication Date: 2011-12-14
NORTHEASTERN UNIV LIAONING
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Due to the relatively coarse raw silicon particles in the prior art, the nitriding time is required to be long, and the nitriding temperature is required to be high, resulting in increased manufacturing costs.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0019] According to the fact that free silicon accounts for 10wt% of the total amount of raw materials, use crystalline silicon cutting waste with a free silicon content of 10wt%, and the free silicon content meets the requirements of the preset mixture. The dehydrated alcohol of 5wt% mixes 60min in mixer;

[0020] The uniformly mixed powder is pressed into shape, and the formed green body is dried at a temperature of 100 ± 5° C. to obtain a dried green body;

[0021] Put the dried green body into the nitriding furnace, evacuate to -0.01MPa, open the ventilation valve, pass high-purity nitrogen with a purity of more than 99wt% to +0.01~ +0.02MPa, then open the exhaust valve to continue to pass nitrogen After 30 minutes, heat at a rate of 10°C / min from room temperature to 800°C, and heat at 2°C / min from 800°C to nitriding end point temperature of 1300°C, and finally close the ventilation and exhaust valves, seal and keep warm for 80 minutes, and stop heating , cooling with the...

Embodiment 2

[0023] According to the fact that free silicon accounts for 15wt% of the total amount of raw materials, 75 parts of crystalline silicon cutting waste with a free silicon content of 20wt% and 25 parts of ultrafine silicon carbide micropowder are fully mixed in the mixer for 60 minutes, and the total amount of raw materials is added. 2wt% dextrin, add 5wt% water to dilute, and continue to mix for 60min;

[0024] The uniformly mixed powder is pressed into shape, and the molded green body is dried at a temperature of 100 ± 5° C. to obtain a dried green body;

[0025] Put the dried green body into the nitriding furnace, evacuate to -0.01MPa, open the ventilation valve, pass high-purity nitrogen with a purity of more than 99wt% to +0.01~ +0.02MPa, then open the exhaust valve to continue After 40 minutes of nitrogen gas, heat at a rate of 10°C / min from room temperature to 800°C, and heat at 2°C / min from 800°C to the nitriding end point temperature of 1250°C, and finally close the ven...

Embodiment 3

[0027] According to the fact that free silicon accounts for 25wt% of the total amount of raw materials, 63 parts of crystalline silicon cutting waste with a free silicon content of 40wt% and 37 parts of ultrafine silicon carbide micropowder are fully mixed in the mixer for 60 minutes, and the total amount of raw materials is added. 8wt% glycerol, continue to mix for 60min;

[0028] The uniformly mixed powder is pressed into shape, and the molded green body is dried at a temperature of 100 ± 5° C. to obtain a dried green body;

[0029] Put the dried green body into the nitriding furnace, evacuate to -0.01MPa, open the ventilation valve, pass high-purity nitrogen with a purity of more than 99wt% to +0.01~ +0.02MPa, then open the exhaust valve to continue After nitrogen gas for 35 minutes, heat at a rate of 10°C / min from room temperature to 800°C, and heat at 2°C / min from 800°C to nitriding end point temperature of 1350°C, and finally close the ventilation and exhaust valves,...

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Abstract

The invention belongs to the field of secondary resource integrated utilization, and specially relates to a method for sintering silicon carbide through a crystalline silicon cutting waste material nitridation reaction. The method comprises the following steps of mixing a crystalline silicon cutting waste material and ultrafine silicon carbide micro-powder produced in production of silicon carbide cutting powder, wherein the weight of free silicon is 5 to 25% of the total weight of the mixed material, adding a binder into the mixed material, preparing into a green compact, feeding high purity nitrogen with purity above 99 wt% into a nitriding furnace, and heating the green compact for nitridation treatment to obtain silicon carbide products sintered through a silicon nitride reaction. The method has the advantages that main raw materials adopted by the method are waste materials from industrial production and has a wide source and a low price and thus the waste materials are changed into things of value; the time spent on production processes is short; a production temperature is low; and a production cost is reduced greatly.

Description

technical field [0001] The invention belongs to the technical field of comprehensive utilization of secondary resources, and in particular relates to a method for sintering silicon carbide by nitriding reaction of crystalline silicon cutting waste. Background technique [0002] The world is facing the dual pressure of energy shortage and environmental protection, which promotes the rapid development of solar energy industry. The core component of a solar cell is a crystalline silicon wafer. Currently, the most commonly used silicon wafer manufacturing method is to cut crystalline silicon rods by using multi-wire cutting technology. In the multi-wire cutting process, silicon carbide micropowder is used as abrasive material, and polyethylene glycol is used as a dispersion medium to cut and grind crystalline silicon rods into crystalline silicon wafers. During the cutting process, up to 50% of the crystalline silicon enters the cutting waste slurry in the form of ultrafine sil...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B31/36
Inventor 邢鹏飞王珺庄艳歆任存治涂赣峰
Owner NORTHEASTERN UNIV LIAONING
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