Kinetic studies on leucite precursors

Abstract

Kinetic studies were performed on two types of leucite precursors. These precursors were prepared using a hydrothermal method at 150°C; the reaction time was 1.5 hours. In order to obtain precursors having different amounts of seed the molarity of KOH was changed. These intermediate products were subsequently calcinated from 5 minutes to 72 hours at temperatures of 850°C, 900°C, 950°C, 1000°C and 1050°C. The crystallinities of the powders were calculated by X-ray diffraction analysis. The crystallization curves for the synthesis of leucite exhibited a typical sigmoidal characteristic. Using different kinetic equations it was found that the Avrami-Eroféev model is the most appropriate to describe the experimental data. Using the Avrami-Eroféev model n reaches an average value of 2.9 which is connected with the three-dimensional growth of nuclei. The calculated activation energy of crystallization of leucite was 385 kJ mol -1 for non-seeded precursors and 246 kJ mol -1 for seeded precursors, respectively.© Versita Warsaw and Springer-Verlag Berlin Heidelberg.

Synthesis and Characterization of Leucite Using a Diatomite Precursor

“…Synthesis of leucite has been achieved in the past by various methods, including the solid state method 7–11 , the sol-gel method 12–14 , the molten salt technique; 8,15 the coprecipitation method 16 , the hydrothermal cation exchange from analcime 17,18 and the technique from a hydrothermally-derived precursor 3,17,19,20 .…”