The effect of reaction temperature and time on the zeolitisation of natural kaolinite

Abstract

A locally avaliable kaolinite has been decomposed by the hydrothermal technique. Kaolinite activated at 600 degrees C was subjected to hydrothermal treatment with NaOH solution in aqueous media for different reaction times at various temperatures. Both kaolinite and the final experimental products after the treatment were characterized by XRD and FT-IR spectra. It has been concluded that calcination at 600 degrees C was the key step for the process and, metakaolinite, the calcined product from kaolinite, is a convenient starting material for the hydrothermal treatment. The influence of time and temperature on the reaction products were evaluated in terms of composition of the final products formed in the metakaolinite-alkaline system. Hydrothermal treatment of metakaolinite proved that the reaction products were found to be zeolite NaA and hydroxy sodalite.