Zeolites since their discovery in natural form have promoted a great interest in technological applications as molecular sieves, ion exchangers, catalysts, and especially adsorbents. The synthetic zeolites are usually prepared with saturated aqueous solutions of salts of aluminates, and silicates. But the process of industrial waste processing kaolin has been used to synthesize zeolite A and hydroxysodalite due to equimolar Si/Al ratio. In this work zeolite type hydroxysodalite, Na6[Si6Al6 O4]6.8H2O was synthesized from the fine fraction of two samples from Amazonian soil - rich in kaolinite, [Al2Si2O5(OH)4], which is basically composed of Al and Si, using hydrothermal method. Characterization by FT-IR, TGA/DTA and XRD confirmed that the samples in natura are mainly constituted by kaolinite with 69 and 71% abundance. Rietveld structural refinement showed that the synthesis product consists of a crystalline phase hydroxysodalite of cubic structure (space group , #218) with lattice parameters a = 0.88468 and 0.88594 nm. The fitted data allowed us to estimate the average crystallite size d = 57 nm (both samples), and the surface area, S = 44 and 41 m² g-1 for the samples.
hydrothermal synthesis; Rietveld refinenment; kaolinite; metakaolinite; hydroxysodalite
