Chemical reduction of silica into silicon from extracted quartz sand using sodium hydroxide and hydrochloric acid solutions

Abstract

Quartz sand as the natural source of silica was sampled from Tanjung Tiram District, Asahan Regency, North Sumatra in which the extracted silica were utilized and chemically reduced into silicon. Extraction of silica from quartz sand was conducted by adding 10 N NaOH solution and 6 N HCl in three different phases. The yield of extracted silica were 29.6, 21.9, and 10.8 g from each extraction phase. The extracted silica was characterized using FT-IR and XRD. Amorphous silica from each phase was reduced with magnesium to obtain silicon. Purification of silicon followed three steps through the first reaction with 2 N HCl, the second phase with 2 N HCl and 25% CH3COOH, and the third phase with 25% CH3COOH and 4.8% HF solutions. The yield of purified silicon were 1.1345, 1.2727, and 3.4551 g from each phase and were characterized further using BET, SEM, and XRD.