Emanation thermal analysis (ETA) supplemented by thermogravimetry (TG and D
TG) and evolved gas analysis (water) were used for the characterization of
the thermal behavior of montmorillonite samples saturated with lithium, sod
ium, magnesium and aluminum cations. The ETA revealed microstructure change
s that occur during the gradual heating of the clay. These changes are asso
ciated with the dehydration, dehydroxylation and formation of an amorphous
meta-montmorillonite phase, and its subsequent annealing and recrystallizat
ion. On the basis of the ETA results it was demonstrated that exchangeable
metallic cations have a great effect on the thermal behavior of montmorillo
nite.