Purification method of silicon carbide superfine micropowder

Abstract

The invention discloses a purification method of silicon carbide superfine micropowder, which comprises the following steps: mechanically crushing and shaping the selected silicon carbide raw material, washing the shaped raw material with initial water to remove carbon and magnetically separating the washed raw material to remove partial impurities on the surface; airing and drying the raw material washed with initial water, and carrying out crushing by a raymond mill and air flow classification to produce a product the grain diameter of which is between 1 and 15mu m; adding the product into a purification kettle, adding water to produce slurry, adding a flotation agent for floating to remove carbon, wherein the floating agent is kerosene and terpineol; respectively adding hydrochloric acid, sulfuric acid and hydrofluoric acid into the purification kettle; stirring the mixture and then washing with water until the pH value reaches about 7; adding solid sodium hydroxide and solid calcium hydroxide into the purification kettle then washing with water after stirring; and feeding the washed mixture to a classification kettle for classification after the pH value reaches 7. Through the purification treatment by using silicon carbide, the superfine micropowder is easy to separate. The product has the advantages of high purity, small grain diameter distribution, uniform grains, fewer impurities, high quality and wider application range.

Description

technical field [0001] The invention relates to a production technology of silicon carbide, in particular to a method for purifying silicon carbide ultrafine powder. Background technique [0002] Silicon carbide has the characteristics of stable chemical properties, high thermal conductivity, low thermal expansion coefficient, high hardness, wear resistance and strong self-sharpness, and is widely used in processing cemented carbide and optical glass industries. In recent years, with the development of the world's semiconductor industry, silicon carbide has been widely used in multi-wire cutting and grinding of monocrystalline silicon, polycrystalline silicon, and piezoelectric quartz crystals, especially in the rapidly developing photovoltaic industry. Its quality is not only related to its purity, but also related to its particle fineness. The higher the purity, the finer the particle, the higher the application quality and the wider the application range. However, the tr...

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Problems solved by technology

However, the traditional production method can only produce products of about 10 μm, and the particle size distribution is too large, the particles are uneven, and there are many impurities. Because there is no purification treatment, or the method is wrong, the treatment is not thorough, and the iron in the slurry is weakly magnetic. Impurities such as iron compounds, carbon, free silicon, and silicon dioxide of non-magnetic substances cannot be removed, which will cause the ultrafine powder to be difficult to separate