A successful At-substituted gyrolite has been hydrothermally synthesized at 220°C under saturated steam pressure, and its cation exchange characteristics for K+ and Cs+ ions have been investigated. At-substituted gyrolite took up K + and Cs+ ions of 14 and 20 mequiv/100 g, respectively, and these removal amounts are smaller than those by AI-substituted tobermorites (ca. 80 mequiv/100 8). It was found that Alsubstituted gyrolite exhibited selectivity for univalent cations in the following order: Na' < K + < Cs+ in the lowconcentration regions of K + and Cs+ ions. At-substituted gyrolite did not lose its crystallinity and morphology, and its basal spacing did not change in the cation exchange. These results, therefore, suggest that At-substituted gyrolite may be useful for separation and waste disposal. [Key words: calcium silicate, cation exchange, substitution, aluminum, separation.]

No abstract