Rate of Thermal Dehydration of Kaolinite in Vacuum

Abstract

The dehydration of kaolinite was carried out in a vacuum to evaluate the kinetics without the marked effect of water vapor. Samples of carefully fractionated particles were used and the effect of surface area was determined. At pressures in the order of 1μ of Hg the reaction was found to be diffusion‐controlled, with an activation energy of 43.5 kcal. The rate of dehydration was found to decrease linearly with increasing water vapor at moderate pressures. A change from parabolic to first‐order kinetics was observed with increasing pressures.