Method for producing an ultra fine silica powder
AssigneeDenki Kagaku Kogyo Kabushiki Kaisha
InventorsAkio Yoshida, Hideaki Nagasaka, Akira Kobayashi
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Abstract
A method for producing an ultra fine silica powder, which comprises subjecting a raw material mixture containing a silica powder, a reducing agent comprising a metal silicon powder and/or a carbon powder, and water, to heat treatment at a high temperature in a reducing atmosphere with an oxygen concentration of less than 1 wt % to generate a SiO-containing gas, immediately cooling said gas in an atmosphere containing oxygen, and collecting fine particles.
Claims10
A method for producing an ultra fine silica powder, which comprises subjecting a raw material mixture containing a silica powder, a reducing agent comprising a silicon powder and/or a carbon powder, and water, to heat treatment at a temperature sufficient for a gasification reaction into SiO, in a reducing atmosphere with an oxygen concentration of less than 1 wt % to generate a SiO-containing gas, immediately cooling said gas in an atmosphere containing oxygen, and collecting fine particles, wherein the ultra fine silica powder has a specific surface area of at least 35 m2/g, and has a content of coarse particles having sizes of at least 1 μm of not more than 5 wt %.
A method for producing an ultra fine silica powder, which comprises subjecting a raw material mixture containing a silica powder, a reducing agent comprising a silicon powder and/or a carbon powder, and water, to heat treatment at a temperature sufficient for a gasification reaction into SiO, in a reducing atmosphere with an oxygen concentration of less than 1 wt % to generate a SiO-containing gas, immediately cooling said gas in an atmosphere containing oxygen, and collecting fine particles, wherein the ultra fine silica powder has a specific surface area of at least 35 m2/g, and has a content of coarse particles having sizes of at least 1 μm of not more than 5 wt %, wherein the raw material mixture is an aqueous slurry having a solid content concentration of from 20 to 60 wt %, and the heat treatment is carried out by a flame.
Dependencies are inferred from the claim text.