A Candy-Mold Technique in An Argon-Free Atmosphere Magnesiothermic Process for Producing Silicon

Abstract

Silicon is a material that plays a significant role in the electronics industry as a semiconductor material. Silica, which is commonly known as silicon dioxide, is present in nature. The separation of silicon from its oxide is achieved through the magnesiothermic reduction. In the current research, we report our success using the magnesiothermic method to reduce the silica (SiO₂) at temperatures below the melting point of magnesium. Both powders with molar ratio of Mg:SiO₂ = 1:2 are mechanically ground and then sealed in the stainless-steel tube. The silica reduction process was analyzed using an X-ray diffractometer at various heating temperatures (400, 500, 600, and 700 °C) in an argon-free atmosphere. When heated at temperature of 500 °C, we found that silicon began to separate at around 19 wt.%, according to the results of quantitative analysis. After eliminating magnesium oxide from selected samples using a leaching process, 90 wt.% of crystalline silicon was obtained. Further evidence of silicon reduction from the reaction of magnesium and SiO₂ is provided by a shift in the Raman spectroscopy peak from 462 cm⁻¹ to 517 cm⁻¹ for samples heated at 400 °C and 500 °C. Consequently, it can be stated that this method of reducing silica at low temperatures can be applied without requiring the use of argon gas during the heating process.