From Local Sand to Functional Silicon: An Integrated Pathway for Producing Photovoltaic-Grade Material from Nigerian Silica Sand

• Tahiru MOHAMMED

  Author

• Muhammad B. MAINA

  Author

• Abba B. MUHAMMAD

  Author

• Muhammad SHUWA

  Author

Nigeria's significant solar energy potential is constrained by a reliance on imported high-purity silicon, despite abundant indigenous silica sand resources. This study presents a complete, integrated experimental pathway to assess the feasibility of producing photovoltaic-grade silicon from River Alau sand in Borno State. The research encompasses: Comprehensive characterization of raw sand using XRF, XRD, and SEM/EDX; Purification via optimized acid leaching (acid was used to remove impurities) and calcination; Carbothermic reduction at a temperature of 1700^◦C was carried out to transform the sample to a metallurgical-grade silicon (MG-Si) and subsequent directional solidification; Evaluation of the electrical and optical properties of the upgraded silicon; and Fabrication and outdoor performance testing of simple solar cells under Maiduguri conditions. The raw sand contained 77.63% SiO₂ with significant impurities (Al₂O₃: 2.10%, K₂O: 6.31%). Purification achieved ≥99.6% SiO₂ purity, reducing key metallic impurities to <0.1%. Carbothermic reduction yielded MG-Si with 78% efficiency, and the upgraded material exhibited suitable properties for PV applications: a resistivity of 4.2 Ω•cm and a band gap of 1.12 eV. Fabricated solar cells generated an open-circuit voltage of 0.48–0.52 V. A preliminary economic analysis suggests a 25–30% potential cost saving in raw material sourcing. This work provides the first proof-of-concept for a viable domestic value chain from Nigerian silica sand to functional photovoltaic silicon, demonstrating technical feasibility and supporting the development of local solar manufacturing capabilities.

• FJET_21_97_97

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