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A new state-of-the art synchrotron beamline fully optimized for monochromatic X-ray diffraction at high pressure and high (or low) temperature is presented. In comparison with the old high-pressure beamline ID30, this new beamline exhibits outstanding performance in terms of photon flux and focusing capabilities. The main components of this new instrument will be described in detail and compared with the performance of beamline ID30. In particular, the choices in terms of X-ray source, X-ray optics, sample environment and detectors are discussed. The first results of the beamline commissioning are presented.

Technosols include soils dominated or strongly influenced by human-made materials. Similarly to natural soils, technogenic parent materials submitted to environmental factors undergo weathering and transformation processes. But the pedogenesis of the Technosols remains little known. With this aim in view, a Technosol developing on purely technogenic materials resulting from iron industry was thoroughly characterized in order to discuss pedogenetic evolution of this Technosol using knowledge about pedogenesis of natural soils. Materials and methods:The studied site was a former settling pond, where mainly sludge generated by wet cleaning of blast-furnace fumes was dumped until probably in the mid-20 th century. Thereafter the pond has been colonized by vegetation and is covered by a diversified forest. The soil was composed of contrasted layers. A 20 cm organic layer has developed at the surface. Samples were collected in the first two meters which are under root influence.Elemental composition, agronomic parameters, mineralogy as well as physical and hydraulic properties of the soil materials were characterized.

International audienceLarge surface areas covered with man-made materials are subject to pedogenetic evolution. However, pedogenetic processes in the resulting Technosols are seldom fully assessed. This work was conducted to identify and characterize the processes occurring on deposits of industrial technogenic materials. A former settling pond of the iron and steel industry where a forest has established since termination of the industrial activity approximately 50 years ago was chosen. A 2-m deep pit was opened, and a series of layers of the soil profile were sampled. The macro- and micro-structure were studied, and soil samples were analysed for structural, chemical and mineralogical assessment (chemical analyses, X-ray diffraction, infrared and M¨ossbauer spectroscopies, scanning and transmission electron microscopies coupled with energy dispersion spectrometry). Results showed that the profile was composed of a succession of sub-horizontal layers arranged in two groups according to their structure and composition, linked to the composition of the industrial effluent. Group 1 was composed of iron-, carbonate- and aluminosilicate-rich layers exhibiting a compact structure. Group 2 contained manganese-rich layers with a friable structure. Pedogenetic processes of various intensities were detected at different depths. Besides an accumulation of organic matter at the surface, transformations of minerals were recorded all along the soil profile, with weathering, leaching and precipitation of new phases. Phenomena occurred primarily in specific zones, such as cracks and interfaces between two layers. In conclusion, the soil maintained characteristics of the original industrial material and displayed several stages of pedogenesis, which were controlled chronologically by climatic and biological factors

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The oxidation of a pure pyrite by Thiobacillus ferrooxidans is not really a constant phenomenon; it must be considered to be more like a succession of different steps which need characterization. Electrochemical studies using a combination of a platinum electrode and a specific pyrite electrode (packed-ground-pyrite electrode) revealed four steps in the bioleaching process. Each step can be identified by the electrochemical behavior (redox potentials) of pyrite, which in turn can be related to chemical (leachate content), bacterial (growth), and physical (corrosion patterns) parameters of the leaching process. A comparison of the oxidation rates of iron and sulfur indicated the nonstoichiometric bacterial oxidation of a pure pyrite in which superficial phenomena, aqueous oxidation, and deep crystal dissolution are successively involved.

A multidisciplinary approach has been used to study Au occurrences within pyrite and arsenopyrite in four refractory Au ores from Colombia, France (Le Châtelet and Villeranges) and Portugal (Neves Norte). The Au was characterized by optical and scanning electron microscopy and analysed using electron and ion microprobes to determine Au distribution, with particular attention to spectral interferences in electron and ion microprobes, background measurements in electron probes, and quantitative analysis using external standardization in ion probes. The ionic emission rate is proven to be dependent on the Au status; combined Au has a greater ion emission than metallic Au. Invisible Au occurrences are closely linked to As distribution. Gold bonding in arsenopyrite, examined by transmission electron microscopy, is shown to be dispersed within the FeAsS crystal structure. Typical growth patterns and As-Au diffusion zoning in pyrite and arsenopyrite may account for the very irregular distribution of Au in these minerals.

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