GeochemistryLab experiments

GeoResources has a x-ray tomograph Nanotom Phoenix (GE). This tool is used to explore the architecture of solid samples with a resolution that may be less than the micrometer. The principle is to illuminate the sample with a beam of X rays and record, by using a detector of photon X, absorbed beam having crossed the solid to be analyzed. Repeat the acquisition of images at different angles of rotation and the obtained cuts are then reconstructed using algorithms appropriate to form a three-dimensional image of the sample. This technique provides a nondestructive study which reveals the characteristics of the internal structure of the sample: size, shape, and spatial distribution of the elements, heterogeneities and defects (pores, inclusions, mineral phases...). The reconstructed object can then be manipulated in all directions of space and virtual cuts can be performed in any part of the sample with a high quality 3D imaging. The size of the scans objects can vary from less than 1 mm to maximum ten centimetres. The spatial resolution may reach 0.5 μm for the smallest samples.

The study of the reactivity and stability of phases in fluid/mineral-solution/gas/organic-matter systems requires the application of experimentation. Therefore, GeoRessources is equipped with a set of autoclaves with hot and cold joints, in-situ sampling capabilities, thermal gradients, gas pressure control and oxydo-reduction state monitoring. Experiments are conducted in batch-type reactors of various sizes: welded gold capsules, stainless steel and titanium chambers with or without sapphire windows, and in situ Raman and pH measurements. Experiments may be conducted using hazardous gases (SOx, NOx, H2, H2S, CO) within a secured laboratory. Specific autoclaves (IMAGES, MIRAGES, COTAGES) have been designed for gas-injection applications with flow and thermal-gradient controls. Miniaturisation has enabled us to develop microchemistry capillary techniques to monitor volumes, pressures and temperatures for the measurement of chemical solubilities, kinetics and reactivities at the micrometric scale.

Associate professor in GeosciencesGeochemistry, thermodynamic, GISGeological sequestration of CO2Mechanisms of glass alterationStudy of water/gas/materials systems

Geological storage of High level nuclear wastes

Thèse de Doctorat. Étude de l'altération des vitraux médiévaux. Contribution au comportement à long terme des verres de confinement Financement ADEME et SITA