Research on Obtaining Silica Xerogels from Nepheline and Study of some of their Physical and Chemical Properties

Abstract

The article presents a method to obtain silica xerogels with developed specific surface based on nepheline concentrate acid decomposition in C2H5OH-H2SO4 system. It was found that the use of ethanol instead of water produces stable and steady silica gels. It is proved that the use of ethanol results in almost complete deposition of soda alum and aluminum potassium sulphate out of nepheline decomposition solution without its additional cooling, due to their extremely low solubility in alcohol solution. The morphology, structural and surface properties of synthesized xerogel sample with ~600 m2/g specific surface area (based on the analysis) were investigated; its mixed micro-and mesoporous structure was established. Electron probe microanalysis showed chemical purity of the resulting SiO2.