INFLUENCE OF CATIONS ON THE PHYSICOCHEMICAL AND STRUCTURAL-PROPERTIES OF ALUMINOSILICATE GEL PRECURSORS .1. CHEMICAL AND THERMAL-PROPERTIES

The influence of the type of alkali cations on the properties of aluminosilicate gels were studied by chemical and thermal analyses of the solid phases precipitated from the batches of the following molar composition: 4.41 Me2O:Al2O3:3 SiO2:222.2 H2O, where Me+ = Na+, Na+ + K+, Na+ + Li+, and K+. The change in the chemical composition of dry precipitates, influenced by the presence of different cations and their mixtures, is discussed with respect to the interaction of cations with silicate species in the solution and colloid chemistry of gelation processes. Analysis of kinetics of dehydration of gels as well as hydrothermal treatment of the gels confirmed the role of the sodium ion as a "structure-forming" cation and revealed that sodium ions cause the formation of structural subunits inside the gel matrix.