Extraction of Silicon From Silica Sand by Carbothermic Reduction in Mini DC-EAF

¹ Department of Metallurgical Engineering, Bandung Institue of Technology, Bandung, Indonesia
² Research and Development Department, PT ANTAM Tbk, Indonesia

^* Corresponding author: daletandersen@gmail.com

Abstract

This study explores silicon extraction from silica sand using different carbon sources: graphite powder, coke, and coconut shell charcoal. Experiments were conducted to assess the influence of carbon source variation and briquetting on metallic silicon production. The silica sand sample was characterized using X-ray fluorescence, while proximate analysis was performed on the coke and coconut shell charcoal reductants. Each experiment used 50 grams of silica sand with varying amounts of carbon sources at a C:SiO₂ mole ratio of 1.8:1. The reductants were tested both with and without briquetting using a DC electric arc furnace for 10 minutes. SEM-EDS and X-ray diffraction were employed for result analysis, with comparisons made to other materials. The experiment using coke as a reductant with briquetting yielded the best result with a Si content in the metal of 98.15%. The experiment with a mixture of silica sand and coconut shell charcoal briquette resulted in a SiC product with Si content of 54.46%. The experiment with a mixture of silica sand and graphite briquette resulted in a SiO₂ and SiC product with Si content of 43.17%. The experiment without briquetting using coke as a reductant showed a high SiO₂ content, as seen from the oxygen content of 36.44%. The experiment without briquetting using coconut shell charcoal as a reductant resulted in a SiO₂ and SiC with Si content of 26.64%. The mixture of silica sand and graphite without briquetting produce SiC as a product with Si content of 70.6%.