EFFECT OF THERMAL TREATMENT ON THE BENTONITE PROPERTIES.

The main objective of this study is to investigate the changes in structure, surface area and porosity of monomineral fraction of the local bentonite upon heating at 300, 500 and 650 °C. IR spectroscopy, DTA, XRD and N 2 adsorption method were employed for the analyses. The non-heated montmorillonite was characterized by a basal spacing of 1.50 nm, after thermal treatment of 0.98 nm. This decrease was attributed to the loss of interlamellar water, finally a phase transformation occured. Changes of the crystal structure related with the decrease of the value of specific surface area and total pore volume. [ABSTRACT FROM AUTHOR]