Thermal decomposition kinetics of aluminum sulfate hydrate

Abstract

The kinetics of individual stages of thermal decomposition of Al 2 (SO 4 ) 3 •18H 2 O were studied by TG method. It is found that Al 2 (SO 4 ) 3 • 18H 2 O decomposes to Al 2 O 3 in four major stages, all of endothermic. Some of these major stages are formed by sub-stages. The first three major stages are dehydration reactions in which two, ten and six moles water are lost, respectively. The last major stage is sulfate decomposition. In this study the kinetic parameter values of these major and sub-stages were calculated by integral and differential methods. The alterations of activation energies with respect to the decomposition ratio and to the method were investigated. © 2009 Akadémiai Kiadó, Budapest, Hungary.