Electrophysical Characteristics of the Coal Ash of the Maykuben Basin

Abstract

In this work, the temperature dependences of the electrophysical characteristics (electrical capacitance, electrical resistance, dielectric permittivity) were investigated in the range of 293-483 K for coal ash of the Maikuben basin (Kazakhstan) in its initial form, after electromagnetic (EM) and electrical discharge (ED) treatments. The temperature ranges in which the material exhibits both semiconductor properties and metallic conductivity are established. The band gap width (ΔE) was calculated for the studied samples. The measurement results showed that in comparison with the initial ash and ash after the EM treatment, the ash after the ED treatment has the highest values of electrical capacitance and dielectric permittivity and the lowest electrical resistance. Analysis of the research results showed that coal ash after ED treatment seems promising as a prepared raw material for its further thermochemical processing with the extraction of such valuable components as rare metals, silica, alumina, as well as a capacitive material (capacitor) and semiconductor.