Processing and characterization of Libyan silica sand for welding, electrical, and solar technologies

Abstract

High-purity silica is essential for advanced welding consumables, electrical insulation, and solar applications. This study focuses on improving the characteristics of natural silica sand from Adri Al-Shati, Libya, and assessing its industrial applicability to contribute to the systematic understanding of silica resources in the country. Ultra-fine milling and inorganic acids were used to achieve controlled chemical purification of raw silica to remove metallic impurities. The removal of these impurities enhances the dielectric characteristics of the material, which is an ideal precursor for photovoltaic (PV) technologies, electrical insulation, and welding. Silica sand (RA1), nano-milled silica powder (RA2), and purified (RA3) samples were characterized using X-ray fluorescence (XRF), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), and thermogravimetric analysis (TGA). RA3 was then heated at 1200, 1400, and 1600 °C. Sieve analysis demonstrated a well-defined particle size distribution suitable for the above applications. XRF showed that the SiO₂ purity increased from 91.7% to 99.36%, with a significant decrease in Fe₂O₃ from 0.103% to 0.082% and CaO from 4.12% to 0.478%. XRD and FTIR analyses revealed significant phase transformations from quartz to tridymite and cristobalite above 1200 °C. These high-temperature phase transformations are expected to influence the properties of welding slags, including viscosity and slag detachability. TGA and derivative thermogravimetric (DTG) results demonstrated excellent thermal stability and well-defined thermal decomposition behavior. Overall, this study provides a sustainable approach for the production of high-purity silica from locally available resources, which fulfills stringent technical requirements for advanced industrial applications. The results show the possibility of the use of local raw materials as an economical alternative for the support of industrial self-sufficiency and future use in metallurgical and high-tech areas.