DISSOLUTION OF AMORPHOUS ALUMINOSILICATE ZEOLITE PRECURSORS IN ALKALINE-SOLUTIONS .1. KINETICS OF THE DISSOLUTION

The kinetics of dissolution of differently prepared amorphous aluminosilicate precursors having various Si : Al molar ratios have been studied by measuring the change in the aluminium and silicon concentrations in the liquid phase as well as the change in the degree of Si polycondensation in the liquid phase during the dissolution in 0.2 mol dm-3 NaOH solution at 80-degrees-C. Applying different kinetic equations for the analysis of the experimental results, it was found that the rate of dissolution of all the solids examined can be described by a modified Nernst's equation. The mechanism of dissolution was also considered.