Study on thermal insulation zeolite by coal fly ash

Abstract

This paper takes the coal fly ash as the material and makes zeolite with low thermal conductivity under a two-step synthesis for the purpose of thermal insulation. It studies main factors affecting zeolite such as the different concentration of NaOH, the solid-liquid ratio, the silica-alumina ratio, and the crystallization temperature. The optimal conditions were obtained that the NaOH concentration was 3 mol/L, the solid-liquid ratio was 10: 1, the silica-alumina ratio was 2, and the crystallization temperature was 12°C. Zeolites have multiple pores and skeletal structures under SEM observation. The mean particle size was 2.78 um of concentrated distribution. The pore volume was 0.148m 3 /g measured by BET analysis, the specific surface was 118.6 m 2 /g, and the thermal conductivity was 0.153 W/(m·K). Zeolite was proved to be a qualified insulation material which can be used in thermal insulation coating as a new material of energy conservation.