Zeolitization of Allophane Compacts

Abstract

Zeolite A compacts were directly prepared from allophane compacts through hydrothermal reaction with NaOH solution. The allophane transformed to zeolite A and then the shape of compact has been maintained. The crystallization rate on the surface was faster than that in the internal part. An aging treatment leaded to reduce a difference in crystallization rate between the surface and the internal part. The crystal morphology of zeolite A on the surface exhibits cubic shape consisting of {100} plane. On the other hand, {100} and {110} planes appeared on the crystal formed in the internal part.