Extraction and Processing of Crystalline Metallurgical-Grade Silicon Prepared from Rice Husk Byproduct

  • C. Iyen
  • B. O. AyomanorEmail author
  • V. Mbah
Conference paper
Part of the The Minerals, Metals & Materials Series book series (MMMS)


Rice husk, an agricultural waste product, could yield valuable silica under controlled temperature and time, and possesses one of the natural polymorphs of silica. Its low production cost makes it most viable for preparing metallurgical-grade silicon of high purity needed for solar cell technology. In this work, high purity metallurgical-grade silicon (MG-Si) ~98.6% has been prepared from rice husk ash (RHA) by solid-liquid extraction (acid leaching). The RHA silica was leached using HNO3 and HCl solutions. The acid-leached rice husk was filtered, washed, dried, and calcined at 1000 °C for 5 h. Further purification was achieved by pulverizing and thoroughly mixing the silica with magnesium powder at a ratio of 1.0 g SiO2 to 0.8 g Mg and annealing at 1100 °C to form magnesium silicide. The material produced was characterized by X-ray fluorescence spectroscopy (XRF), X-ray diffraction (XRD), Transmission electron Microscopy, Thermogravimetry, and Raman. Elemental analysis using XRF showed the percentage of silicon in the produced material to be 98%, major impurities found are Mg (0.96%), Ca (0.08%), Fe (0.2%), K (0.26%), and Al (0.39%). XRD analysis detected only crystalline Si. Further analysis using Raman spectroscopy showed a clear polycrystalline Si line at 516.6 cm−1.


Rice husk ash Anneal Metallothermal Leaching 


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© The Minerals, Metals & Materials Society 2020

Authors and Affiliations

  1. 1.Department of Pure and Applied PhysicsFederal University WukariWukariNigeria
  2. 2.Department of Science Laboratory TechnologyFederal Polytechnic NasarawaNasarawaNigeria

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