Extraction of Quartz Sand to Derive Nano Silicon by Magnesiothermal Method with Different Ratio of Silica (SiO2) and Magnesium (Mg) Powder

Quartz sand has naturally high silica content, a potential material to be extracted into nano silicon. The applications of nano silicon are widely used in the industrial world. This research extracts nano silicon from quartz sand using the magnesiothermal method. This method is effective and efficient because it uses low temperatures compared to other methods, thus saving energy. XRD patterns of the products obtained show reflections positioned at 28.38◦, 47.24◦, 56.05◦, 69.06◦, 76.31◦ and 87.97◦ 2Θ, which are characteristic for the silicon element, as well as aspherical shape morphology observed from the SEM and TEM images. The SiO₂ and Mg powder mass ratio of 1:1 (sample A) resulted in silicon purity reaching 97.92%, and the mass ratio of 1:1.5 (sample B) obtained a purity of 99.44%. The surface area of sample A is higher (2568 m²g⁻¹ compared to 2146 m²g⁻¹), and the pore size is smaller (1.87 nm compared to 2.01 nm) than sample B's. The crystallite size of sample A (21.23 nm) is similar to sample B's (20.81 nm). Mg binds oxygen from SiO₂, thus splitting the SiO₂ into nano Si and MgO. Purification was done by adding HF and HCl to remove MgO and obtain nano Si. The peaks, shapes, and sizes shown are enough to show that the material extracted from quartz sand by the magnesiothermal method is characteristic of high-purity nano silicon.