cristobalit

摘要

Method for the preparation of cristobalite, by treating sand having an overall iron and titanium content of less than 350 ppm and a titanium content of less than 200 ppm at elevated temperature in the presence of a catalyst and cristobalite obtainable by said method. Such cristobalite is used for the preparation of alkalimetal silicate, suitable for incorporation in detergent compositions comprising a bleach system based on active oxygen. The low metal content of the alkalimetal silicate used has a stabilising effect on the bleach system.