Structure reorganization in montmorillonite gels during drying

Abstract

The structure evolution of montmorillonite gels, during drying by evaporation, has been studied by scanning electron microscopy (SEM) after hypercritical drying with liquid CO2. Fresh Fe3+1 electrolytes allow clay particles to aggregate to floes with a structure consistent with diffusion-limited aggregation. Compression under the capillary stresses, during evaporation, leads to gelation. During further drying by evaporation, the Fe bonding is strong and prevents the complete collapse of the gel into a parallel stacking of clay plates. On the contrary, such a collapse occurs more easily when fresh Fe electrolyte has not been added.