SOME ASPECTS OF THE SYNTHESIS OF MODERN ZEOLITE ADSORBENTS - DEHYDRATOR OF THE TYPE ‘A’ (4A)

Abstract

The current tendency in the production of adsorbents is the development of zeolites with a complex of adsorption properties and high mechanical strength. The main raw materials for the synthesis of zeolites LTA (NaA and its exchangeable forms), FAU (NaX, NaY and their exchangeable forms) are traditionally sodium aluminate and sodium silicate gels, as well as kaolin clays. This piece of work reviews the impacts of the raw mixture’ components on the properties of the type ‘A’ zeolite adsorbents obtained by the recrystallization of kaolinite method. The aim of the research is an attempt to develop a technology for the synthesis of zeolite adsorbents, the main crystalline phase of which is zeolite A, using raw materials containing signifi cant amounts of impurity minerals (quartz, illite). Characteristics of the samples of the zeolite adsorbents synthesized using Angren kaolin and the spent alumina adsorbents, which are the waste products from the Bukhara refinery, are presented. In general, the work is focused on the use of the kaolin raw materials somewhat depleted in aluminum and kaolinite in production of zeolite adsorbents - dehydrator of hydrocarbon and other gases used for technological purposes. Interesting results were achieved when a sodium aluminate solution based on the spent alumina adsorbents had been used in the crystallizable reaction mixture, preformed in the form of granules. The obtained samples were composite and featured the property of surface adsorption of benzene, the desorption of which occurs at a high rate. The developed technology enables obtaining zeolite-containing adsorbents with a wide range of adsorption-desorption properties.