NON-ISOTHERMAL DEHYDRATION KINETICS OF DIPHASIC MULLITE PRECURSOR GEL

Document Type: Research Article

Authors

1 Department of Chemistry & Environment, Camellia Institute of Technology, Kolkata, India

2 Department of Ceramic Technology, Government College of Engineering & Ceramic Technology, Kolkata, India

Abstract

Aluminosilicate gel precursor having mullite composition was synthesized from inorganic salts of aluminum and silicon by employing sol-gel method. Chemical analysis, surface area and bulk density measurements were performed to characterize the dried gel. The course of the mullitization was examined by FTIR analysis which confirmed the diphasic nature of the gel. SEM and XRD analysis were preformed to study microstructure and phase development. Thermogravimetric (TG) analysis of the dried gel was performed at multiple heating rates and from the results obtained; kinetics of thermal dehydration was studied by applying Friedman differential and Kissinger-Akahira-Sunose integral isoconversional procedures. It was observed that the total dehydration process of the gel was accomplished by two different stages and both the stages followed second order rate kinetics. First stage was assigned to the dehydration of silicon hydroxide gel whereas second stage was associated with aluminum hydroxide gel dehydration.

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