STRUCTURAL MODIFICATIONS IN PHILLIPSITE-RICH TUFF INDUCED BY THERMAL-TREATMENT

A phillipsite-tuff from the South of Tenerife (Canary Islands) has been treated at several temperatures between 150 and 600-degrees-C, and the induced structural changes have been studied by different techniques: FTi.r., XRD, d.g.t.-d.s.c., and porosimetry. Results show an aluminum migration toward the surface, creating amorphous zones and new -OH groups. The pore size and the zeolite framework undergo a reduction, and the beta-angle of the unit cell rotates as a consequence of the heating.