Sedimentation Rate of Sodium Montmorillonite Suspension under High Ionic Strength

Abstract

The settling rate of the interface between sodium montmorillonite sediment and supernatant liquid was measured under a condition of high ionic strength as a function of solid volume fraction. The results were analyzed using the method of Michaels and Bolger to elucidate the physical indexes of flocculated sediment such as the settling velocity (Q_f), the representative diameter (d_f), and the increase ratio of effective volume fraction (α) of floc. The applicability of this method to sodium montmorillonite was confirmed bycomparing the Qf and df values obtained from this method with those from the direct measurement previously reported. The floc of sodium montmorillonite retains more water compared with that of kaolinite and other materials.