Challenges in coupled on-line-on-mine-real time mineralogical and chemical analyses on drill cores

The SOLSA project aims to develop an innovative on-line-on-mine-real-time expert system, combining sonic drilling, mineralogical and chemical characterization and data treatment. Ideally, this combination, highly demanded by mining and metallurgical companies, will speed up exploration, mining and processing. In order to evaluate the instrumental parameters for the SOLSA expert system, portable and laboratory analyses have been performed on four samples with contrasting lithologies: siliceous breccia, serpentinized harzburgite, sandstone and granite. More precisely, we evaluated the influence of the surface state of the sample on the signals obtained by portable X-Ray Fluorescence (pXRF) for chemistry and portable Infra-Red spectroscopy (pIR) for mineralogy. In addition, laboratory Raman spectroscopy, X-Ray Diffraction (XRD), XRF and ICP-OES laboratory analyses were performed to compare surface bulk mineralogical and chemical analyses. This presentation highlights (1) the importance of coupling chemical and mineralogical analytical technologies to obtain most complete information on samples, (2) the effect of the sample surface state on the XRF and IR signals from portable instruments. The last point is crucial for combined instrumental on-line sensor design and the calibration of the different instruments, especially in the case of pXRF

3D Imaging on heterogeneous surfaces on laterite drill core materials

The SOLSA project aims to construct an analytical expert system for on-line-on-mine-real-time mineralogical and geochemical analyses on sonic drilled cores. A profilometer is indispensable to obtain reliable and quantitative data from RGB and hyperspectral cameras, and to get 3D definition of close-to-surface objects such as rheology (grain shape, grain size, fractures and vein systems), material hardness and porosities. Optical properties of minerals can be analyzed by focusing on the reflectance. Preliminary analyses were performed with the commercial scan control profilometer MI-CRO-EPSILON equipped with a blue 405 nm laser on a conveyor belt (depth resolution: 10 μm; surface resolution: 30x30 μm2 (maximum resolution; 1m drill core/4 min). Drill core parts and rocks with 4 different surface roughness states: (1) sonic drilled, (2) diamond saw-cut, polished at (3) 6 mm and (4) 0.25 μm were measured (see also abstract Duée et al. this volume). The ΜICRO- EPSILON scanning does not detect such small differences of surface roughness states. Profilometer data can also be used to access rough mineralogical identification of some mineral groups like Fe-Mg silicates, quartz and feldspars). Drill core parts from a siliceous mineralized breccia and laterite with high and deep porosity and fractures were analyzed. The determination of holes’ convexity and fractures) is limited by the surface/depth ratio. Depending on end-user’s needs, parameters such as fracture densities and mineral content should be combined, and depth and surface resolutions should be optimized, to speed up “on-line-on-mine-real- time” mineral and chemical analyses in order to reach the target of about 80 m/day of drilled core

Efficient long-term open-access data archiving in mining industries

Efficient data collection, analysis and preservation are needed to accomplish adequate business decision making. Long-lasting and sustainable business operations, such as mining, add extra requirements to this process: data must be reliably preserved over periods that are longer than that of a typical software life-cycle. These concerns are of special importance for the combined on-line-on-mine-real-time expert system SOLSA (http://www.solsa-mining.eu/) that will produce data not only for immediate industrial utilization, but also for the possible scientific reuse. We thus applied the experience of scientific data publishing to provide efficient, reliable, long term archival data storage. Crystallography, a field covering one of the methods used in the SOLSA expert system, has long traditions of archiving and disseminating crystallographic data. To that end, the Crystallographic Interchange Framework (CIF, [1]) was developed and is maintained by the International Union of Crystallography (IUCr). This framework provides rich means for describing crystal structures and crystallographic experiments in an unambiguous, human- and machine- readable way, in a standard that is independent of the underlying data storage technology. The Crystallography Open Database (COD, [2]) has been successfully using the CIF framework to maintain its open-access crystallographic data collection for over a decade [3,4]. Since the CIF framework is extensible it is possible to use it for other branches of knowledge. The SOLSA system will generate data using different methods of material identification: XRF, XRD, Raman, IR and DRIFT spectroscopy. For XRD, the CIF is usable out-of-the-box, since we can rely on extensive data definition dictionaries (ontologies) developed by the IUCr and the crystallographic community. For spectroscopic techniques such dictionaries, to our best knowledge, do not exist; thus, the SOLSA team is developing CIF dictionaries for spectroscopic techniques to be used in the SOLSA expert system. All dictionaries will be published under liberal license and communities are encourage to join the development, reuse and extend the dictionaries where necessary. These dictionaries will enable access to open data generated by SOLSA by all interested parties. The use of the common CIF framework will ensure smooth data exchange among SOLSA partners and seamless data publication from the SOLSA project

Elaboration de nouvelles compositions de bioverres destinés à la chirurgie réparatrice

Bioglasses are materials used as bone filling and able to form a bond with the host environment by developing a hydroxyapatite layer (HCA) at their surface. The glass bioactivity is defined by its layer formation time in the body fluid. The aim of this work is to link some bioglass essential properties with their compositions by the mean of mathematical formulas. These properties are called responses, and are studied by mixtures designs. There are seven of them: powder mixtures melting temperature, glass transition and crystallization temperatures, the working range, the density, the bioactivity and the thickness of the hydroxyapatite layer. These whole characteristics have an important role for the choice of a bioglass. For example, melting temperature informs on the synthesis ease, characteristic temperatures indicate the preparation possibilities (glass bulk, porous, granules…). Bioactivity and HCA thickness study permits to point out the most efficient glasses for repairing surgery utilization. Mixtures designs have been applied on SiO2-CaO-Na2O system, P2O5 and CaF2-doped. Obtained formulas point out different response areas for all properties, which inform on the existence of a bioglass with defined properties and indicate its or their compositions.Les bioverres sont des matériaux utilisés comme comblement osseux ayant la particularité de former une liaison intime avec le milieu hôte grâce au développement d’une couche d’hydroxyapatite carbonatée cristallisée (HAC) à leur surface. La bioactivité d’un verre est définie par le temps de formation de cette couche dans le milieu physiologique. Le but de la thèse est de déterminer des formules mathématiques permettant de relier différentes propriétés essentielles de bioverres à leur composition. Celles-ci, appelées réponses, sont étudiées par plans de mélanges. Elles sont au nombre de sept : la température de fusion des mélanges de poudre, les températures de transition vitreuse et de cristallisation, la plage de travail des verres, la densité, la bioactivité et enfin l’épaisseur de la couche d’hydroxyapatite carbonatée. Ces caractéristiques jouent toutes un rôle important quant au choix d’un bioverre pour une utilisation donnée. Par exemple, la température de fusion des mélanges renseigne sur sa facilité de synthèse, les températures caractéristiques indiquent les possibilités de mise en forme (verres massifs, poreux, granules…). L’étude de la bioactivité et de l’épaisseur de la couche d’HAC permet de connaître la composition des verres les plus performants pour l’utilisation en chirurgie réparatrice. Les plans de mélanges ont permis d’étudier de manière systématique le système simple SiO2-CaO-Na2O, puis dopé par P2O5 et enfin par du fluor. Les formules obtenues mettent en évidence des lignes d’isoréponses pour toutes les propriétés recherchées, ce qui renseigne sur l’existence ou non d’un verre de propriétés définies et dans le cas échéant indique sa ou ses compositions

Phase transformations in BOF slag: crystallography, microstructure and thermodynamic modelling

International audienc

Detection and Identification of Asbestos in Aerosols by LIBS in a Low Temperature Plasma

International audienc

Bio-precipitation of arsenic and antimony in a sulfate-reducing bioreactor treating real acid mine drainage water

Arsenic (As) and antimony (Sb) from mining sites can seep into aquatic ecosystems by acid mine drainage (AMD). Here, the possibility of concomitantly removing As and Sb from acidic waters by precipitation of sulfides induced by sulfate-reducing bacteria (SRB) was investigated in a fixed-bed column bioreactor. The real AMD water used to feed the bioreactor contained nearly 1 mM As, while the Sb concentrations were increased (0.008 ± 0.006 to 1.01 ± 0.07 mM) to obtain an Sb/As molar ratio = 1. Results showed that the addition of Sb did not affect the efficiency of As bio-precipitation. Sb was removed efficiently (up to 97.9% removal) between the inlet and outlet of the bioreactor, together with As (up to 99.3% removal) in all conditions. Sb was generally removed as it entered the bioreactor. Appreciable sulfate reduction occurred in the bioreactor, which could have been linked to the stable presence of a major SRB operational taxonomic unit affiliated with the Desulfosporosinus genus. The bacterial community included polymer degraders, fermenters, and acetate degraders. Results suggested that sulfate reduction could be a suitable bioremediation process for the simultaneous removal of Sb and As from AMD

LIBS in a low temperature plasma for the detection of airborne asbestos

International audienceForbidden in french constructions since 1997, asbestos remains present in most of the buildings constructed before this date. Thus, during work or in case of degradation, asbestos fibres can be emitted in air. The smaller the asbestos particles, the longer they stay in suspension in air, increasing the hazard of inhaling them. The current determination of airborne asbestos presence in France follows a long and cumbersome normative protocol (NF X 43-050), with an analysis carried out on a Transmission Electron Microscope at laboratory after air filtration on-site. Such a protocol induces wasting time between the sampling and the results delayed not less than 48 hours and therefore prevents for the intervention on-site-on-time. Thus, the demand of a real-time measurement increases, even if it is only an alert technique. The PLASMIANTE project aims to develop an apparatus able, on-site and in near-real-time, to analyse the particles present in an air sample and to identify the presence of asbestos. The device will sample air and send the particles in a reactor in which they will be trapped in a low-temperature argon plasma. Among several diagnostics that will be applied directly on the particles in suspension in the plasma, Laser Induced Breakdown Spectroscopy will be used to identify the presence of asbestos in the samples. In this study, we present the first results of LIBS applied to particles of asbestos, building materials and mixtures in suspension in a low temperature plasma

Hydrogenation behavior of the solid solutions RE₄NiMg_1−<i>x</i>Al<i>_x</i> and RE_4−<i>y</i>NiMg_1+<i>y</i> with RE = Gd and Y

The solid solutions RE4NiMg1−xAlx (0 x 4−yNiMg1+y (0 y 4RhIn type structure, space group F-43m. The solubility is much lower in the case of Y than for Gd which is linked with steric effects. The hydrogen sorption is irreversible and the large exothermicity of the reaction can lead to the decomposition of the compounds into rare earth hydrides and metallic Ni and Mg. Nevertheless, it is shown that the Y based compounds can absorb almost 3 wt.% of hydrogen at room temperature and under moderate pressure. Furthermore, the solid solutions do not allow destabilization of the hydrides

PLASMIANTE: A plasma filter for the detection of airborne asbestos.

International audienceEven if forbidden in french constructions since 1997, asbestos remains present in most of the buildings constructed before this date. Thus, in the case of degradations, asbestos fibers can be emitted in air. The smaller the asbestos particles, the longer they stay in suspension in air, increasing the risk of inhalation. The current determination of asbestos presence in air in France follows a long and cumbersome normative protocol (NF X 43-050), with an analysis carried out on a Transmission Electron Microscope at laboratory after air filtration on-site. Such a protocol is therefore accompanied by numerous error factors. PLASMIANTE aims to develop a direct and global on-line analysis method to detect, identify and characterise in real time asbestos fibers potentially present in the air. To this end, particles will be trapped in a low pressure plasma and analyzed with several metrological methods such as multi angle laser light scattering, the effect of the particles on the electrical characteristics of the plasma and the discharge, Infra-Red spectroscopy and Laser Induced Breakdown Spectroscopy (LIBS). This contribution presents the aim of the project along with the first results and the challenges we will face