Crystal growing and reaction kinetic of large NaX zeolite crystals

Large crystals zeolite NaX with a uniform size of 50 μm were grown by a continuous crystallization method from seed crystals (10 μm) formed in a mother solution with the 3.5Na2O:Al2O3:2.1SiO2:1000H2O composition. In order to grow zeolite NaX crystals to an appropriate size by the continuous method, the mother solution was fed into an autoclave a solution with various seed contents (3–20 wt.%); the autoclave has at 90 °C and the solution was added after 7, 12, 16, 19 and 24 days or at 100 °C after 7 and 9 days. The morphology of NaX zeolite crystals when viewed from the top shows an octahedron that is formed from eight equilateral triangles. These triangular faces intersect all three crystallographic axes at the same distance having an average lattice constant a = 24.9911 Å and a SiO2/Al2O3 molar ratio of 2.1–2.4. The activation energy for growth of NaX zeolite crystals was found to be 43.2 kJ/mol.