Hydrothermal experiments using Fe-bentonite, 2; Identification of change of Fe-bentonite under low oxygen and 150C conditions

Suyama, Tadahiro*; Shibata, Masahiro ; Ueno, Kenichi; Sasamoto, Hiroshi   

A present study was carried out to understand the long-term behavior of Fe-smectite. The starting material (i.e., Fe-bentonite) was prepared by mixing Na-bentonite (Kunipia-F) with FeCl solution in a controlled-atmosphere glove box (O1ppm, N). The experiments were conducted for 1 year and 20 months at 150C. As the results, it was suggested that a dissolution of Fe-smectite and a generation of secondary material which might precipitate on the layer surface of smectite. However the original smectite structure (i.e., 2:1 type octahedral structure) and the initial characteristic of bentonite (e.g., swelling capacity, ion exchange capacity) were maintained. The generation of non-swelling clay mineral which was observed in the similar experiment at 250C was not identified in the present study by XRD analysis.