Mineralogical characterization of Fe driven alteration in smectites The main objective of this research was to enhance the understanding of the interactions of bentonite with iron in the near field of a HLW repository. One target was to investigate natural Fe rich bentonites as a possible analogue. Another topic was to recognize the mineralogical interaction of bentonite with iron powder simulating the contact of bentonite with steel containers (thermodynamic approach). An additional objective was to explore the idea that bentonites have a specific dissolution potential (kinetic approach). In order to take the thermodynamic approach compacted MX80 bentonite and Friedland clay were used as starting materials for clay iron interaction experiments in percolation systems (Clay Iron ratio = 0.1). The natural processes were studied by examining a tropical weathering profile of serpentinized diabase from the Thanh Hoa province of Vietnam. The kinetic approach was taken by investigating a series of well characterized bentonites 9 from API standard series 12 from the BGR collection and 4 others all of them saturated with deionized water (liquid solid ratio = 10 1) and NaCl 1N solution (liquid solid ratio = 4 1) for 30 days followed by exposing the soft gels to mechanical agitation by overhead shaking corresponding to two energy levels (20 rpm and 60 rpm). XRD and TEM EDX measurement were the major analytical techniques applied in this research with FT IR and XRF analyses as additional tools to characterizing the structure and HLW Endlager MX80 bentonit Friedland tons natürliches Analogon Ton Eisen interaktion spezifisches Auflösungspotential HLW repository MX80 bentonite Friedland clay natural analougs clay iron interaction specific dissolution potential