Grained Binder-Free Zeolites: Synthesis and Properties

Data on the synthesis and main quality characteristics (crystallinity, adsorption capacity with respect to H2O, RSH, H2S, CO2, and C6H6, and mechanical strength) of binder-free zeolites A and X with grains representing monolithic intergrowths of crystals are generalized for the last 15-20 years. Variants of their synthesis are considered. The characteristics of these crystalline aluminosilicate micro-, meso-, and macroporous materials and zeolite-containing adsorbents with binders are compared. Grained binder-free zeolites A and X, widely used in adsorption processes, are shown to be superior to their analogues with binders in adsorption capacity and mechanical strength. Most of the methods developed for preparing these zeolite materials have passed pilot-scale tests, and some of them have already been put in operation at OOO Salavat Catalyst Plant (synthetic zeolites NaA-BS, STO (Branch Standard) 05766575-109-2008, and KA-BS, TU (Technical Specifications) 2161-126-05766575-2005); OOO Ishimbai Specialized Chemical Catalyst Plant (CaA-U (5A), TU (Technical Specifications) 2163-004-05766557-97, KA-U (improved) (3A), TU (Technical Specifications) 2163-006-05766557-98, and NaA-U (improved) (4A), TU (Technical Specifications) 2163-003-05766557-97); and at OOO RealSorb Molecular Sieves Plant (NaA, TU (Technical Specifications) 2163-005-21742510-2004, KA-NPG, TU (Technical Specifications) 2163-009-21742510-2005, and CaA-NPG, TU (Technical Specifications) 2163-006-21742510-2004). Main trends of studies in the given field are formulated for the near term.