Physicochemical Reactivity in Clay-Rich Materials: Tools for Safety Assessment

摘要: Natural or engineered clay-rich materials are ubiquitous when it comes to achieving sequestration of acid gas, confinement pollutants high level radioactive waste (HLRW), and trapping hydrocarbon oil gas in geological settings. The sequestration, confinement, functions rely on properties such as low permeability, sorption ion exchange capacity, and, some cases, swelling abilities. Clay-rich contain specific clay minerals possessing these due the small size tortuosity pores well very surface area charge (especially smectites). For performance safety purposes, persistence this initial sealing function has be ensured over time, interest foreign anthropogenic (concrete, steel, other situ) will undergo physicochemical interactions may lead irreversible transformations. also subjected perturbations heat release packages case HLRW repository, liquid water vapour transfers. To tackle complexity phenomena, we combine multi-scale multi-technique characterisation (middle far Fourier transform infrared, X-ray diffraction, scanning electron microscopy (SEM) transmission (TEM)) samples coming from laboratory experiments natural analogues, integrate results through reactive transport modelling. As an example, methodology is used establish illitisation claystones a basaltic dyke intrusion. approach compared with classical ones application diagenetic sequences for petroleum exploration discussed. We explore sensitivity smectic (gel phase)/smectite content/composition temperature by investigating between metallic iron smectitic clays. This comprehensive study reveals iron/clay mass ratio threshold above which smectites tend altered into 7 A Fe-rich much lower cation capacity. With description understanding, prediction long-term evolution systems seems at hand. However, modelling overall behaviour remains difficult task because strong, coupling chemical, mechanical potentially mediated gel phase.