Preparation method of silicon carbide

Abstract

The invention relates to a preparation method of silicon carbide, which comprises the following steps: (1) mixing tire semicoke with quartz sand to obtain a mixture; (2) carrying out heat treatment synthesis on the mixture obtained in the step (1) under a protective atmosphere to obtain a crude product; and (3) roasting the crude product obtained in the step (2) to obtain the silicon carbide product. The silicon carbide is prepared from the tire semicoke and the quartz sand through a specific preparation method, the purity of the obtained silicon carbide is high, the preparation cost of the silicon carbide is reduced, the problem of high-value utilization of the waste tire semicoke is solved, the raw material cost is low, the yield of the silicon carbide is high, the preparation process is simple, and industrialization is easy to realize.

Description

technical field [0001] The invention relates to the preparation of silicon carbide, in particular to a method for preparing silicon carbide. Background technique [0002] Silicon carbide (SiC), also known as moissanite, has the characteristics of high hardness, high thermal conductivity, small thermal expansion coefficient, and corrosion resistance. Therefore, it has broad application prospects in the production of high-temperature refractory materials. [0003] The current methods of preparing silicon carbide mainly include carbothermal reduction method, chemical vapor deposition method, sol-gel method and arc discharge method. Among them, the carbothermal reduction method is the preferred method for industrial synthesis of silicon carbide. Its main raw materials are carbon-containing materials such as high-quality petroleum coke, coal coke, anthracite and graphite, and silicon-containing materials such as quartz sand or silica gel containing carbon and silicon at the same ...

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Problems solved by technology

[0004] In the existing preparation method, CN110921670A pyrolyzes the raw materials containing organosilicon three-dimensional configuration compound and organosilicon cyclic compound and then reacts to synthesize silicon carbide. The raw material price of this method is too high and the reaction process requires high-pressure conditions. The restrictive conditions High requirements, not conducive to industrial production

[0005] CN109790035A uses spherical silica airgel as silica raw material, and prepares silicon carbide through processes such as dispersion, drying, and heat treatment. This method has high cost of raw materials and requires complex pretreatment of reactants, with many and complicated steps, and The synthesis process of silicon carbide is complex

[0006] CN111484019A uses high-purity graphite powder and high-purity silicon powder as raw materials. The process of preparing silicon carbide involves mixing, sintering, and repeated pressure sintering. The method has high raw material cost, complicated preparation process and long cycle, which is not conducive to large-scale production

The raw material petroleum coke price of this method is relatively high, the preparation process requires high requirements and the cycle is long, which makes the production cost high

[0009] In short, the existing technologies for preparing silicon carbide by carbothermal reduction generally have problems such as high raw material cost, complex synthesis process, long preparation cycle or low silicon carbide yield.

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