Crystallization mechanism of zeolite beta from (TEA)2O, Na2O and K2O containing aluminosilicate gels.

Zeolite BETA is prepared in hydrothermal conditions from tetraethyl orthosilicate, sodium aluminate, tetraethylammonium hydroxide, sodium and potassium hydroxide and water. Detailed chemical analysis of intermediate solid and liquid phases obtained from a large number of gel compositions at different synthesis times as well as SEM and XRD investigations of the solids allow to determine the crystallization mechanism. After nucleation in solution zeolite BETA crystals grow by incorporating TEA-aluminosilicate species from solution. The influence on this process of sodium, potassium, tetraethylammonium, silica, alumina and alkalinity in the gel are discussed.