ZEOLITE

Zeolites. Crystalline aluminosilicates, composed of silica (SiO2) and alumina (Al2O3), in various proportions plus metallic oxides. Produced by hydrothermal treatment of a solid aluminosilicate or of a gel obtained by the reaction of sodium hydroxide, alumina hydrate and sodium silicate. The initially obtained product, or a naturally occurring analog, may be partially ion-exchanged to introduce other cations. Specific zeolites are identified by notations indicating crystal structure and predominant cation, e.g., KA, CaX, NaY