The many studies performed on the alkaline reaction of bentonite have been directed, obviously, to the montmorillonite alteration.
On the other hand, we have shown that the alkaline reaction of FEBEX bentonite is significantly accelerated with the increase in time and temperature (Ramirez et al., 2002).
Once the nature of the alkaline reaction of bentonite had been studied in detail, the rate of montmorillonite transformation was calculated by using the mineralogical quantification of smectite (calibrated by the decrease of the 4.45 A XRD peak area) in the 75 - 200[degrees]C tests.
The particular nature of FEBEX bentonite alkaline reaction products
The main phases identified in the alkaline reaction of FEBEX bentonite are phillipsite, Mg-clays, analcime, tobermorite and CSH-gels.