Hydrothermal transformation of magadiite into ferrierite in Al_2O_3-Na_2O-ethylenediamine-H_2O system

摘要

This study investigated the transformation of magadiite into ferrierite in Al_2O_3—Na_2O—ethylenediamine (EDA)—H_2O system. The influence of various parameters such as reaction temperature, time, alkalinity, the reactant Na_2O/SiO_2 ratio and EDA/SiO_2 ratio were examined. Thermal and acid stability of the synthetic ferrierite are presented. Highly crystallized and pure ferrierite could be obtained from dispersion with the molar composition: 0.01 Na_2O: 0.005 Al_2O_3: SiO_2: 30 H_2O: 20 EDA by heating at 433 K for 48 h. The structure of ferrierite was destroyed when the temperature rose above 873 K and the framework of the sample, stirred in 5 mol/L HC1 for 3 h, is consistent with the untreated ferrierite.