Surface chemistry-rheology inter-relationships in clay suspensions

Abstract

The relationship between electrolyte concentration and thixotropic behaviour in sodium-montmorillonite-based suspensions has been examined with a view to understanding the structural mechanisms that cause the observed thixotropy. Results presented indicate that the changes in the rheological behaviour of sodium-montmorillonite suspensions over the range of added NaCl concentrations can be adequately explained without resorting to the traditional edge-face, heterocoagulation model. The onset of thixotropy at low to moderate NaCl concentrations (0.05-0.1 M) can be explained by a combination of random coagulation and particle orientation effects. At higher NaCl concentrations (≤0.2 M) face-face..