Preparation of Silica by Alkaline-Heating and Precipitation Method from Corn Straw Ash

The preparation of silica by an alkaline-heating and precipitation method from corn straw ash (CSA) obtained from a biomass power plant was the focus of this study. Sodium hydroxide was used as the silica extraction reagent, and H2SO4 was the precipitator. The concentration of sodium hydroxide solution was confirmed to have a significant influence on the production of sodium silicate from CSA. The optimum technological parameters for the preparation of sodium silicate and the suitable parameters for the preparation of silica were obtained by experiments and analysis. Fourier transform infrared spectroscopy (FT-IR) was used for confirming that the as-obtained silica has characteristic IR absorption peaks of typical hydrated silicon dioxide. The microstructures of the asobtained silica products were characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Comparison using HG/T3061 (2009) standards, and the characteristics of silica products were used to estimate whether the as-obtained silica products reached market requirements. The results show that the silica products are superior to the standard requirements and have a large market potential.