Kinetics and Mechanism of Zeolite "m" Crystallization

The numerous structurally possible hypothetic zeolite frameworks were suggested recently. One of the forecasting structurally-possible and practically realized zeolite is the zeolite "m". This zeolite was realized by hydrothermal crystallization in Na2O-Al2O3-SiO2-H2O system at 150ºC in the NaOH solution of various concentrations from the mixture of meta-kaolin and obsidian. Initial reaction masses have the following compositions: Na2O/Al2O3 = 5.5-6.5; SiO2/ Al2O3 = 21-27; H2O/Al2O3 = 60-120. Its hypothetic structure with cubic symmetry and parameters of elementary cell a = 19.5±0.5Å has the chemical formula : Na16Al16Si112O256·64H2O. Phase and chemical composition of crystallization products have been determined by the methods of Xray phase (DRON-2.5; CuKα-radiation; Ni-filter), thermo graphic (Derivatograph Q-1500D) and X-ray spectral (SRM-18).The kinetics of zeolite "m" crystallization has been studied and crystallization mechanism is given.

کلیدواژه ها:

Zeolite m ، meta-kaolin ، hydrothermal crystallization