Impurity optimized silicon is needed for the advancement of terrestrial photovoltaic power generation. In this study an approach to synthesis of solar grade silicon using rice husk ash has been pursued. Metallothermic reduction of the purified rice husk ash (RHA) was investigated within the temperature range of 500-950°C using magnesium in varied amounts. The reduction product was purified by two stage acid leaching sequence. Analysis of the final silicon product by XRD, SEM, and ICP-OES showed crystalline silicon with boron to be less than 3 ppm, corresponding to a reduction by a factor greater than 10 while the phosphorus level was reduced by a factor of over 20 reaching less than 73 ppm. Transition metal impurities and other elements were generally reduced in the processing steps.
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