A kind of preparation method of silica sol for acrylonitrile catalyst

Abstract

The invention discloses a preparation method of ludox for an acrylonitrile catalyst. The method comprises: adding sulfuric acid aqueous solution into industrial sodium silicate aqueous solution with a silicon dioxide content of 3-5 wt percent until pH is 9.0-9.5, heating up to 90-95 DEG C, and then keeping warm for 1-2 hours to form ludox base solution; adding water into industrial sodium silicate with a modulus of 3.0-3.3, preparing aqueous solution with a silicon dioxide content of 3-5 wt percent, suspending cation exchange resin by using deionized water, then adding sodium silicate and controlling outlet pH to be 2-3 after ion exchange to obtain silicic acid, adding the silicic acid into the prepared ludox base solution at a speed of 100-200ml / min, keeping pH to be 9-9.5, keeping warm for 1-2 hours under the temperature of 90-95 DEG C, and then cooling to normal temperature; performing ion exchange on a product by using strong-acidity cation exchange resin regenerated by hydrochloric acid, meanwhile keeping pH to be 1-2, and after exchange, adding ammonium hydroxide and adjusting pH to be 9-9.5; finally adding a dispersing agent into the prepared ludox, and performing ultrafiltration and concentration to obtain the ludox. The prepared ludox has the mean grain size of 20-25nm, the sodium ion content less than 0.05 percent, the concentration of 40-50 percent and the viscosity less than 20cps.

Description

technical field [0001] The present invention relates to a preparation method of silica sol, more particularly, to a preparation method of silica sol for acrylonitrile catalyst. Background technique [0002] Silica sol is a stable colloidal solution in which silica nano-colloidal particles are dispersed in water. The average particle size of silica sol is generally 8-100 nm, and its shape is approximately spherical, and the content of silica is generally 20%-30%. . [0003] Acrylonitrile is an important organic chemical raw material, which is produced by ammoxidation of propylene. In order to obtain higher activity, it is generally prepared as a fluidized bed catalyst, and acrylonitrile catalyst usually uses silica sol as a carrier. [0004] The acrylonitrile catalyst is generally composed of a metal salt and a silica sol to form a slurry with a solid content of about 50%, which is prepared into a fluidized bed catalyst by spray drying. At present, the common acrylonitrile ...

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Problems solved by technology

[0005] At present, most domestic silica sol products can only be used as binders in foundry and other industries, with low added value, and cannot be used as acrylonitrile catalyst carriers.