Process of Zeolite Formation in the System Na₂O-Al₂O₃-SiO₂-H₂O

Abstract

This paper is aimed at clarification of the change of concentration with time in the liquid phase before crystallization starts. To find optimum conditions for the commercial production of pure zeolites of the types A and faujasite, the reaction of fine-particle amorphous silica with sodium aluminate solution was studied at 20°, 40°, and 75°C. The liquid phase separated by filtration nucleates the zeolite types A, sodalite, phillipsite, and faujasite, depending on stirring time before liquid—solid separation. Quite similar conditions are observed in precipitated sodium aluminosilicate gels and mother liquor.