Abstract
The effects of thermal treatment on the structural, electrical, and dielectric properties of scoria collected from Harrat Rahat in Saudi Arabia have been investigated. The raw scoria was thermally treated at two different temperatures (800 and 1000 degrees C). The crystalline phase, morphology, and chemical group functions of natural and treated scoria samples were studied using XRD, SEM, FTIR/Raman spectroscopies, respectively. The XRD results showed no apparent differences between the raw sample and treated at the temperature of 800 degrees C. While it showed a decrease in the intensities of the XRD pattern and Raman spectra of the scoria treated at the temperature of 1000 degrees C, this could be attributed to the formation of a hematite-ilmenite solid solution. The tested raw scoria showed excellent thermal stability up to the temperature of 800 degrees C. At higher temperatures, however, its mineral and chemical compositions can be slightly affected. Electrical and dielectric properties were explored in detail at different temperatures and frequencies. The results did not show any considerable changes between raw and treated scoria samples. Likewise, conductivities and dielectric constants revealed stable values up to 700 K. This type of scoria, therefore, can be a promising material for use as high-voltage power insulators.