Influence of Alkalinity on the Synthesis of Zeolite A and Hydroxisodalite from Metakaolin

Reference	Presenter	Authors (Institution)	Abstract
06-031	Raphael Cons Andrades	Andrades, R.C.(Universidade de São Paulo); Valenzuela-Diaz, F.R.(Universidade de São Paulo); Neves, R.F.(Universidade Federal do Pará); Bastos Andrade, C.G.(Polytechnic School of the University of São Paulo); Munhoz Jr, A.H.(Universidade Presbiteriana Mackenzie);	Zeolite A and hydroxisodalite were synthesized from kaolin waste of processing industries for paper coating. Kaolin was calcined at 700 $°$C for 3 hours to dehydroxilate kaolinite and obtain metakaolin, an amorphous material with Si/Al ratio equal to 1, being suitable for production of zeolite A. Zeolites were synthesized under static hydrothermal conditions by reacting metakaolin with NaOH solutions of different concentrations, namely: 1, 1.8, 3, 5, and 9 M. All the syntheses were performed at 110 $°$C for 24 hours. The zeolitic products were characterized by means of XRD, Fourier Transform Infrared Spectroscopy (FTIR), Thermal Methods (DTA and TG), and nitrogen adsorption isotherm for measuring BET surface area. The main results showed that the higher the NaOH concentration in the reaction medium, the higher the proportion of hydroxisodalite in the zeolitic samples.
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