Hydrothermal synthesis of the natural, alkaline-earth zeolites via the alte
ration of Y-zeolite is presented. Synthetic versions of the zeolites harmot
ome, heulandite, brewsterite and gmelinite are synthesized from Y-zeolite u
sing alkaline-earth cation containing solutions. The effect of the composit
ion of the starting zeolite, the composition of the solution phase, the pre
sence or absence of seeds and the experimental conditions are discussed. (C
) 1999 Elsevier Science B.V. All rights reserved.