Comparative studies of silicon from rice husk ash and natural quartz

Abstract

Metallothermic process was applied to both rice husk ash and natural quartz as standard ore for production of technical grade polysilicon. Thus the rice husk samples were subjected to thermal treatment at 1000 o C to extract the silica. The silica from rice husk ash and powdered natural quartz were subsequently analysed for the initial impurities and treated with magnesium powder at 1100 o C. The magnesium reduction of these oxides resulted in higher purity silicon from the rice husk ash than the crystalline natural quartz; however the two sources of silica gave silicon purities in the range of 97-98%. This range of purity meets the requirement for steel production and as starting raw material for the semiconductor grade silicon.