THE SYNTHESIS OF COLLOIDAL ZEOLITE HYDROXYSODALITE SOLS BY HOMOGENEOUS NUCLEATION

Colloidal suspensions of discrete particles of microcrystalline hydroxysodalite have been synthesized from clear homogeneous solutions wherein the average particle size determined by dynamic light scattering is 37 nm with a narrow particle-size distribution. Particle-size analysis performed with various methods yield results that are in agreement. The growth-limiting nutrient has been identified as alumina. As a result, the midsynthesis addition of alumina results in further particle growth to 48 nm with the corresponding increase in zeolite yield. Hence, the fine control of particle size and thereby zeolite yield without the formation of a secondary particle population is shown to be possible. Direct measurements of zeolite yield and particle size allow for a detailed evaluation of the events that occur during crystallization.