Colloidal silicon oxide

Abstract

The present invention provides colloidal silica containing silica particles with excellent density and excellent maintenance of surface irregularity under alkaline conditions, and a method for manufacturing the colloidal silica. The present invention provides a colloidal silicon oxide, which is a colloidal silicon oxide containing silicon oxide particles, characterized in that: (1) the content of metallic impurities in the aforementioned colloidal silicon oxide, as measured by an atomic absorption spectrometer, is less than 1 ppm, and the metallic impurities are sodium, potassium, iron, aluminum, calcium, magnesium, titanium, nickel, chromium, copper, zinc, lead, silver, manganese, or cobalt; (2) the surface roughness (B1 / S1) of the silicon oxide particles is 1.1 or more, which is calculated by dividing the BET specific surface area (B1) measured by the following BET specific surface area measurement method by the specific surface area (S1) calculated by the following SEM minor axis; (3) the reduction rate of the specific surface area of ​​the aforementioned silicon oxide particles during heat treatment under alkaline conditions is less than 15.0%.

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