Phase Transformations in an Alkaline Titanosilicate System upon Variation of the Temperature and Time Parameters

Abstract

Using X-ray diffraction study of the solid phases formed in an alkaline titanosilicate system with an invariable concentration of components upon process temperature variation in the 180–210°C range and time variation from 1 to 7 days, structural genesis of the solid phases was established. This allowed predicting the final result, consisting in the formation of an ion exchange material as a powder or granules with a high sorption capacity for Cs⁺ and Sr²⁺ cations. The formation of granules of the titanosilicate sorbent with a colloidal silicon binder induced agglomeration of particles with partial isolation of their pore system, which decreased the sorption capacity for Cs⁺ by a factor of 1.5. Simultaneously, the uptake of Sr²⁺ increased by 10–15% due to the formation of insoluble Sr²⁺ silicate or hydroxide on the surface with pH of 8.5–9.5.