PROCESSES FOR THE PREPARATION OF SILICA COLLOIDS AND SPHERICAL SILICAS

摘要

1. A process for producing silica colloid by the reaction of a solution of an alkali metal silicate with an acidifying agent by forming a bottoms material containing an aqueous substance by the simultaneous addition of an acidifying agent and the solution of alkali metal silicate characterised by effecting said addition of the reactants at constant volume and continously drawing off the reaction medium and while maintaining a concentration of silica in the reaction medium such as to avoid the agglomeration of colloidal particles.