Microstructure and properties of the sintered composites from zeolite 4A and magnesium oxide

The composites obtained from synthetic zeolites and varied metals have big potential as new materials for use in many industrial processes. This paper presents composites prepared from zeolite 4A (Z4A) and magnesium oxide (MgO/Z4A). The manufacturing of these composites had the aim of obtaining a new material by combining the zeolite properties with the physical and chemical properties of the incorporated metal oxide. Commercial zeolite produced by the soda plant Govora from Romania is in natrium form. The exchange of magnesium into the zeolite 4A can be accomplished directly from this precursor using nitrate or acetate solution under well-specified conditions until the volume concentration is reached. The microstructure, thermal and mechanical properties of the prepared composites through texture studies, X-ray diffraction, transmission electron microscopy (TEM) were investigated and then the properties were compared with zeolite 4A properties without magnesium addition. The attaining of a uniform distribution of magnesium into zeolite mass, good wetting between substances in immersion process and porosity of the material are presented and discussed. The addition of magnesium oxide into zeolite mass increases mechanical and thermal resistance of the composites and these can be used as refractory material. The reduction of magnesium oxide until magnesium, changed the chemical properties and the composites were used in the processes by mass transfer, such as adsorption and catalysis. (C) 2001 Elsevier Science B.V. All rights reserved.