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Resumo Produtos zeolíticos foram sintetizados a partir de um resíduo industrial do processo de beneficiamento de caulim. O material de partida foi submetido a tratamento térmico a 700 °C durante 2 h. As sínteses foram realizadas com a reação do resíduo com NaOH e uma fonte adicional de sílica, em condições hidrotermais, para relações molares de SiO2/Al2O3 de 2 a 4, tempos de cristalização de 24 a 72 h e temperaturas de 90 a 120 °C. A matéria-prima inicial foi caracterizada por FRX, DRX, MEV e TG/DSC, e os produtos sintetizados por meio de DRX, MEV, TG/DSC, FTIR, área específica BET e distribuição de diâmetro de poros. O ensaio realizado a 90 °C, com 48 h de cristalização e relação SiO2/Al2O3 igual a 3 revelou melhor resultado com a formação de sodalita como única fase cristalina. A partir das técnicas de caracterização, foi possível confirmar a formação da sodalita, observando-se os principais aspectos referentes a essa zeólita.

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QUANTIFICATION OF MULLITE FROM KAOLIN WASTES FROM THE AMAZON REGION: USE OF THE RIETVELD METHOD. Mullite is used to obtain a refractory material, there are several factors that influence the synthesis process of mullite: the preparation of the mixture, the precipitation and the reaction of SiO2 and Al2O3. For the synthesis of mullite, samples of kaolin processing residues were used as precursor material, because it presents SiO2 and Al2O3 in its composition. This work aimed to identify, by X-ray diffraction, and quantify the mineral phases present in samples of kaolin processing residues from the Amazon region calcined at 1300, 1400 and 1500 ºC, using the Rietveld method. The method allowed the refinement of the complex crystalline structures and was applied to the data supply for quantitative analyses with satisfactory results of good accuracy. The results of the quantification of crystalline and non-crystalline phases (with internal standard) in the samples calcined at 1500 ºC presented approximate values of mullite (62%), cristobalite (32%) and non-crystalline phases (6%), for both samples, indicating that the refinement model applied is optimal. These results obtained from the quantification of the phases by the method of Rietveld are presenting coherent and satisfactory values, in comparison with the theoretical ones by the phase diagram Al2O3 and SiO2

High-purity SAPO-34 was synthesized using industrial kaolin waste produced in the Amazon region as the main source of silicon and aluminium. The hydrothermal method was applied to investigate the effect of the Si/Al ratio and crystallization time on the phase formation and purity. The materials were characterized by X-ray fluorescence, X-ray diffraction, thermogravimetric analysis, and scanning electron microscopy, which demonstrated that SAPO-34 with greater purity was obtained only for the composition whose Si/Al ratio was approximately 1, which was obtained by inserting Al 2 O 3 into the synthesis gel.