LETTER TO THE EDITOR

Particle dehydration and interparticle binding have been advocated to explain the coagulation of silica sols by alkaline salts. Those approaches are reexamined in the light of experimental data that have recently been published. It is proposed that coagulation of silica by alkaline cations, when it occurs, is caused by interparticle hydroxo bridging. Copyright 1997 Academic Press. Copyright 1997Academic Press