Hydrothermal synthesis of zeolite Tin aqueous alkaline solutions without using templates was investigated. Zeolite T crystals were prepared via hydrothermal synthesis using milk-like aluminosilicate gel with a composition of aSiO(2):bAl(2)O(3):cNa(2)O:dK(2)O:xH(2)O. The effects of molar compositions including silicon module (n(RM) = a/b) and relative alkalinity (alpha = OH/SiO2), and crystallization conditions including crystallization temperature (T) and time (t) on the yield of T-type crystals were investigated. This research work examines changes in the yield of crystalline zeolite phases by varying the gel composition parameters (n(RM) = 20-25, and alpha = 0.71-0.82) and crystallization process temperature and time (T = 100 degrees-140 degrees C, t = 120-216 h), while keeping constant the parameters [OH] = 2.77 m, U-RM(Na/Na + K) = 0.75, stirring time = 24 h, stirring temperature = 30 degrees C, and drying temperature = 100 degrees C. The crystal species of zeolite T were characterized by XRD (X-ray diffraction) and SEM (Scanning Electron Microscope). (C) 2010 Elsevier B.V. All rights reserved.