A kind of preparation method of high-purity large particle size silica sol

Abstract

The invention discloses a preparation method of high-purity large-particle-size silica sol, which belongs to the technical field of silica sol preparation. The specific preparation method comprises the following steps of mixing an acidic silica sol solution with a pH value of 2-3 with polyethylene glycol 2000-10000, adjusting the pH value to 8-9.5, and heating and boiling to obtain sol crystal grains, adding acid activated resin, washing the resin until the pH value is 3.0-4.5, adding an aluminum salt modifier and water glass, and carrying out ion exchange reaction on the water glass to obtainaluminum modified silicic acid, and adding aluminum modified silicic acid into the sol crystal grains, adding an alkaline solution to adjust the pH value to 9.5-10.5, synthesizing while performing ultrafiltration, and heating to synthesize the high-purity large-particle-size silica sol. The acidic silica sol is subjected to hydroxylation reaction, so that the gel is aggregated to form a large-particle silica sol matrix, the water glass is used as a raw material, the aluminum-modified active silicic acid is prepared by adopting an ion exchange method, ultrafiltration and synthesis are carriedout simultaneously, the particle size is increased quickly, the energy consumption is low, the synthesis period is short, the production efficiency is improved, and the polishing requirements of noveldevices in electronic industry can be met.

Description

technical field [0001] The invention belongs to the technical field of silica sol preparation, and in particular relates to a preparation method of high-purity and large-diameter silica sol. Background technique [0002] Silica sol is a colloidal solution in which amorphous silica particles are dispersed in water. It is a very important inorganic material and is widely used in petroleum catalysis, precision casting, textiles, papermaking, refractory materials, coatings and electronics. According to the pH range of the solution, it can be divided into acidic silica sol and alkaline silica sol, and alkaline silica sol is a stable system. According to colloid theory, the size of silica sol particles is divided into 5-100nm. However, due to the development and progress of silica sol technology, silica sol has broken through the traditional 100nm dividing line, tending to a larger particle size and stable silica sol system. [0003] At present, the preparation methods of silica...

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Problems solved by technology

[0007] Aiming at the problems in the prior art that the silica sol has small particle size, difficult particle size control, large dispersion and poor stability, the present invention provides a preparation method of high-purity large-particle-size silica sol, which can synthesize silica sol with a smaller particle size Silica sol with large size, higher concentration and more uniform particle size distribution can meet the polishing requirements of new devices in the electronics industry

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