Glass-ceramics with a zeolite phase

Abstract

Zeolites are hydrated alumino-silicates. They crystallize in framework structures. Zeolites are used in the catalysis, adsorption, drying and separation technologies. Glass-ceramics are polycrystalline solid materials. They also have interesting properties. A new field of application can be opened by combination of the properties of zeolites and glass-ceramics. For example, material surfaces can be functionalized (membranes, foams) or special geometries for catalysis can be stabilized. The goal of the work was to design glassceramics with zeolite(s) as crystal phase(s). The glasses with zeolite compositions were melted from raw materials with partial substitution of NaF for Na2CO3. Samples of the glasses were crystallized at various temperatures. The zeolitic phase Na6[AlSiO4]6 was precipitated in K 1 1/2 samples at all temperatures. Na6[AlSiO4]6 is a zeolite of the sodalite type. The obtained zeolite does not correspond to the synthesis compositions of the glasses. It is remarkable that the zeolite itself is OH- and/or F- -free, although the presence of these anions is necessary for the zeolite formation.