The Dielectric Properties of Clay Suspensions in the Frequency Range from 50 Hz to 20 Khz

摘要

The dielectric properties of Na- and K-montmorillonite suspensions with concentrations varying from 2.5% to 0.10% by weight were measured at 25C in the frequency range of 50 Hz to 20 kHz. Effects of electrode polarization were minimized by using the same stainless steel electrodes at different interelectrode distances and a correction was applied to compensate for stray fields. This investigation establishes the fact that the high dielectric constants of clay suspensions at audiofrequencies are real and not the result of electrode polarization. The polarization that determines the dispersion is an interfacial phenomenon between the ionic atmosphere and the negatively charged clay particle. The results of this study show that clay suspensions have the same dispersion as soil samples, indicating the probability that the dispersion of wet soils in the frequency range from 50 Hz to 20 kHz is similar for most soils. The actual value of the dielectric constant however, cannot yet be predicted.