Stabilisation of montmorillonite sols by chemical treatment. Part I. Properties of sodium and calcium montmorillonite sols

Abstract

Abstract According to ultramicroscopical counting and relative viscosity data the micelles of Na and Ca montmorillonite sols are minute flat crystal plates with an average thickness corresponding to that of a packet of about five crystal lattice layers only with an average diameter‐thickness ratio of the order of a few hundred. This is corroborated by electronmicrographs and X‐ray studies. The average thickness of the micelles decreases with decreasing sol concentration, indicating a concentration‐dependent association‐dissociation equilibruim of the crystal lattice layers. Montmorillonite is a peculiar colloid in the sense that the platy micelles may be assumed to bear two basically different double layers, one on the surface of the lattice and a second at the broken lattice edges. The two double layer potentials may even have a different sign.