Ambient‐Dried Silica Aerogel Powders Derived from Coal Gangue by Using One‐Pot Method

Abstract

In this paper, we report a new and convenient method for the synthesis of insulating aer-ogel by recycling solid waste coal gangue, which can reduce the industrial production cost of silica aerogels and realize high value‐added utilization of solid waste. Sodium silicate was prepared from a cheap industrial waste coal gangue as the precursor for silica aerogels, which was used for silica wet gel preparation by a one pot method; this method of solvent exchange/surface modification was carried out quickly by mechanical stirring process, and the wet gels derived from coal gangue were dried under ambient pressure condition. A high surface area (~748 m2/g) nanostructured aerogel with a 3D open porous microstructure was synthesized, which exhibits a low density (~0.18 g/cm3) and a superior thermal insulation performance (~0.033 W∙m−1∙K−1). More significantly, the synthetic yield of silica aerogel powder by recycling coal gangue can reach 92%.