Interaction of Clay Minerals in Dilute H-Clay Suspension

The effect of H-kaolinite on the pH of a dilute suspension of H-montmorillonite has been studied and the nature of their interaction was examined in relation to their lattice structure and surface property. A small but gradual decrease of pH of the H-montmorillonite suspension was observed up to 18% addition of H-kaolinite beyond which the pH increases rapidly. The titration behaviour is similar to that of HCl-H-clay system. H-kaolinite was found to interact with H-montmorillonite due to the electrostatic attraction between the positive and negative sites of H-kaolinite and H-montmorillonite respectively. The interaction appears to be independent of the structural peculiarity of the clay particles but related to their surface area.