Measurement of the Solid Dielectric Permittivity of Clay Minerals and Granular Samples Using a Time Domain Reflectometry Immersion Method

Abstract

Both porosity and water content of rocks, sediments, and soils can be estimated from measurements of the effective dielectric permittivity. To achieve accurate modeling to obtain either water content or porosity the permittivity of the solid phase must be known. Until recently the most common method of obtaining the permittivity of the solid phase of granular materials relied on packing samples in air and using a mixing model to estimate the permittivity of the solid. This approach preassumes the correctness of the mixing models that we want to test. This work develops a recently proposed immersion methodology suitable for fine‐grained mineral samples and clay minerals. Measured permittivity values were 4.4 for ground quartz, 9.1 for Iceland Spar calcite, 6.0 for biotite mica, 5.8 for phlogopite mica, 5.3 for talc, 5.1 for kaolin, 5.8 for illite, and 5.5 for montmorillonite. The methodology was found to work well other than for the high surface montmorillonite sample where the immersion polar fluid adsorbed to the clay.

Dual Field Calibration of Capacitance and Neutron Soil Water Sensors in a Shrinking–Swelling Clay Soil

“…Many vadose zone hydrologic studies now involve automated measurements of the soil water content. Recent advances in the use of electromagnetic (EM) methods have focused on measurements that respond to changes in soil water content (Topp and Ferré, 2002; Robinson, 2003). These EM methods include remote sensing instruments or in situ devices such as time domain reflectometry (TDR) and capacitance sensors (Hoekstra and Delaney, 1974; Topp and Ferré, 2002).…”

“…Time domain reflectometry is now also increasingly used for volumetric water content measurements (Davis and Chudobiak, 1975; Topp et al, 1980). More details about this method can be found in the literature (e.g., Topp et al, 1980; Evett, 1998; Topp and Ferré 2002; Robinson, 2003).…”

Scrubbing and Inhibiting Coagulation Effect on the Purification of Natural Powder Quartz

“…A 132 is the effective Hamaker constant of substances 1 and 2 interacting in medium 3; it can be calculated by Equation (5), using the Lifshitz approach based on quantum physics [24].ϕ 1 and ϕ 2 are the surface potentials of substance 1 and 2, which are substituted by the measured ζ potential value, κ −1 is the double layer thickness (9.6 nm in 1 mM KCl). ε is the dielectric constant of the aqueous medium (78.4 C 2 · m·J −1 ), ε 0 is the dielectric constant of vacuum (8.854 × 10 −12 C 2 ·m·J −1 ), the dielectric constants of quartz, hematite and orthoclase are 4.3, 6.9 and 81, respectively [25,26].…”

Dielectric relaxation behavior of Callovo‐Oxfordian clay rock: A hydraulic‐mechanical‐electromagnetic coupling approach

“…In the investigated temperature-pressure-frequency range, the permittivity can be considered as frequency independent. Hence, relative effective permittivity of the solid matrix material " r,g can be estimated from mineralogical composition of the solid phases [Robinson, 2004a[Robinson, , 2004b] assuming quasi-isotropy at the sample scale:…”