Silicon carbide fiber production method using acid soluble dealuminized fly ash and carbide slag

Abstract

The invention provides a silicon carbide fiber production method using acid soluble dealuminized fly ash and carbide slag. The method comprises the steps of (1) incinerating acid soluble dealuminized fly ash to acquire silicious powder, (2) mixing the silicious powder, carbide slag and sodium hydroxide solution uniformly, conducting microwave heating for synthetic reaction, (3) after the completion of the reaction, filtering the mixed slurry to acquire filtered cakes and alkaline filtrate, (4) washing and drying the filtered cakes to acquire silicon carbide fiber, recycling the filtered cake washing waste solution and alkaline filtrate to the sodium hydroxide solution. The invention has the advantages of being low in reaction temperature, short in time, simple in process, and mild in conditions. The acquired silicon carbide fiber has the advantages of being high in purity, singular in material phase without impurities, high in crystallization rate, and big in length-diameter ratio, having the performance full satisfying or surpassing the standard of light calcium sillicate, and at the same time providing a novel solution to the solid waste emission problem involving acid soluble dealuminized fly ash and carbide slag.

Description

technical field [0001] The invention relates to a method for producing xonotlite fiber, in particular to a method for producing xonotlite fiber by using acid-soluble dealuminated fly ash and carbide slag. Background technique [0002] Acid-soluble dealuminated fly ash is the residue left after alumina is extracted from high-alumina fly ash by acid method. The extraction of alumina from high-alumina fly ash originated in the 1950s, and foreign countries were the first to successfully extract alumina from fly ash (alumina content greater than 30%). With the increasingly stringent environmental protection policies in my country and the gradual depletion of high-quality bauxite reserves, the technology of extracting alumina from high-alumina fly ash has been adopted in various places in recent years. Among them, the high-temperature alkaline roasting requires a temperature above 1300°C and consumes a lot of energy. For this reason, CN1927716 discloses a method of utilizing hydr...

AI Technical Summary

Problems solved by technology

In the process of raw material preparation, it is necessary to use a large amount of high-quality silicon ore such as quartz sand and diatomaceous earth to co-melt with soda ash or sodium sulfate in a melting kiln, and then cool, pulverize and dissolve to make it; thus, the selection of silicon raw materials requires mining and Consume a large amount of non-renewable silicon ore resources such as quartz and diatomite; at the same time, calcareous raw materials generally need to use high-quality fuels such as coke or white coal to separately burn lime and refined milk of lime, which consumes a lot of energy and costs, and is harmful to resources and the environment. Great impact

[0007] There are also patent reports using desilication lye to prepare xonotlite, such as CN103539139 and CN103539138. The desilication lye used in these two patents is power plant waste fly ash or coal gangue and milk of lime for dynamic hydrothermal reaction to synthesize xonotlite Some breakthroughs have been made, but this method has problems such as long hydrothermal reaction time, high reaction temperature, long production cycle, high production cost, and low yield, and the prepared xonotlite is a mixed phase with relatively low crystallinity. Poor, low purity, low yield, not suitable for mass production and industrial production

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