The influence of Al containing component on synthesis of analcime of various crystallographic systems

The influence of the form of the Al-containing component, molar ratio of Na2O:Al2O3:SiO2, and the duration of isothermal curing under saturated steam at 180 st.C have been examined. The results obtained experimentally show that the form of the Al-containing component (Al(OH)3 or GammaAl2O3) significantly affects the formation of crystal system of analcime. Pure analcime of the tetragonal crystallographic system forms under saturated steam at 180 st.C after 7 h of isothermal curing, in the presence of considerable excess of NaOH, only when Al(OH)3 is used in the initial mixture. Pure analcime of the cubic crystallographic system forms when GammaAl2O3 is used in the initial mixture of hydrothermal synthesis.