Optimizing the Sonication Method to Extract Silica and Synthesize Silicon from Coal Fly Ash for Lithium-Ion Battery Anode Material

Ridho Rizki Ananda (Study Program D-IV Industrial Chemical Technology, Department of Chemical Engineering, Politeknik Negeri Sriwijaya, Palembang, South Sumatera, Indonesia.)
Rusdianasari Rusdianasari (Department of Chemical Engineering, Politeknik Negeri Sriwijaya, Jalan Srijaya Negara, Palembang, Indonesia)
Akbar Ismi Aziz Pramito (1Study Program D-IV Industrial Chemical Technology, Department of Chemical Engineering, Politeknik Negeri Sriwijaya, Palembang, South Sumatera, Indonesia.)

AJARCDE (Asian Journal of Applied Research for Community Development and Empowerment)
Vol. 10 No. 3 (2026)

Fly ash is a solid waste generated from coal combustion in power plants. This study presents an optimized method for extracting high-purity silica from coal fly ash using Sequential Acid-Alkaline Leaching (SAAL) with HCl concentration variations (1–3 M), followed by magnesiothermic reduction and ultrasonic bath sonication (90–150 minutes) to produce nanosilicon. X-ray fluorescence (XRF) analysis showed that 1 M HCl produced the highest silica purity (97.86%). Scanning Electron Microscopy (SEM) characterization revealed that 150 minutes of sonication significantly reduced average silicon particle size to 6.26 nm through acoustic cavitation mechanisms. Electrical testing showed a resistance value of 3.93 M?. These findings demonstrate an effective approach for converting coal waste into high-value nanosilicon, supporting sustainable industrial practices and circular economy principles. Contribution to Sustainable Development Goals (SDGs):SDG 7: Affordable and Clean EnergySDG 9: Industry, Innovation and InfrastructureSDG 12: Responsible Consumption and Production