Alkali hydrothermal synthesis of zeolite a using oxide by-products

Abstract

The alkali hydrothermal synthesis of zeolite A using oxide by-products such as blast furnace (BF) slag and aluminum dross was investigated. Na-P1 (Na 6Al6Si6O32.12H2O) was synthesized directly in NaOH aqueous solution for 86.4 ks at 373 K using BF slag, Al2O3, and SiO2. On the other hand, zeolite A was successfully synthesized by a two-step method including an elution treatment of Al2O3. Under optimal conditions, the formation ratio of zeolite A in various compounds contained in the product was 56%. The utilization of dross residue squeezed out from the aluminum dross as a raw material to synthesis of zeolite A let this ratio increase to 60%. The heat of water adsorption of the product synthesized by the two-step method using BF slag, SiO2, and aluminum dross residue was measured, and it was 184 J/g, being higher than that of commercial zeolite A. © 2011 ISIJ.