Permittivity and AC conductivity measurement of hydrated phyllosilicate minerals

Abstract

In the present study, the relationship between the AC conductivity, permittivity and loss of vermiculite is presented. The way that different materials react when an electromagnetic field is applied depends strongly on the materials' dielectric properties. In industrial processes that employ microwaves, it is important to know in advance the properties of the material to be processed in particular, its dielectric characteristics. Another important factor to be considered is the variation of the AC conductivity, which is strongly influenced by the behavior of the charge carriers with frequency, permittivity and loss tangent. The frequencies used in the study were 1.60 GHz, 1.80 GHz, 2.00 GHz and 2.45 GHz. The technique is based on the measured S-parameters, followed by a numerical determination through a MATLAB® code based on the Nicolson - Ross - Weir noniterative method. The study demonstrated that AC conductivity of vermiculite is dependent on the frequency and loss and that this dependency influences the exfoliation rate of vermiculite when exfoliated by microwave radiation.