Extraction of silica from natural deposits for the production of silicon in photovoltaic applications

Abstract

The Silica, primarily sourced from silicon dioxide (SiO2) is a common chemical compound abundant in nature, existing in various forms such as quartz, sand, glass, and diverse minerals. It finds extensive use across multiple industries, contributing significantly to glassmaking, ceramics, abrasives, refractory materials, and serving as a crucial component in semiconductor production for electronic chips. This work provides a comprehensive review of the silica elaboration process aimed at obtaining silicon. The initial stage involves the preparation of raw materials, utilizing Algerian sand and diatomite, which undergo meticulous chemical treatment to eliminate unwanted impurities. This method comprises distinct steps, known as the purification process, wherein the sand or diatomite shell is assessed through dissolution in a caustic alkaline solution. This approach indicates the potential to generate high-quality silica from diatomite using an aqueous chemical process. This paper explores the prospect of sand or diatomaceous earth as a novel source of premium-grade silica. It discusses the effects of hydrochloric acid as a solvent for purification. This study contrasts treatment methods before and after acid leaching, focusing on samples with larger particle sizes (ranging from 53 to 300 microns), shorter refining durations (1 to 6 hours), and relatively higher temperatures (30 °C to 70 °C). The findings reveal that the highest purity of silica was attained through HCl treatment (25%).