Thermochemical transformation of residual materials by synthesizing lightweight granulates

International audienceThe general scope of this concern is to explore the formulation and the production, by thermochemical transformations, of expanded lightweight granulates incorporating residual materials as industrial and sewage sludge, schists, kaolinic waste, wasted glass… Depending on their nature, these materials contain fluxes, calorific power substances and potential pollutants. The possible application fields are light concretes, road engineering, water treatment and hydroponic agriculture. The benefits can be multiple: create new resources from wastes; preserve alluvial resources, humid zones on the river banks and the natural course of rivers; manage hazardous residual materials.Tests on the thermal treatment and the thermochemical expansion were conducted in horizontal experimental set-up including a static electrical furnace. Raw mixtures and treatment products were examined by visible microscopy, scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS), X-ray diffraction (XRD) and infrared spectroscopy (IR). Data analysis of the experimental results showed the possibility of obtaining the expanded granulates at temperatures lower than 1200 °C for a firing time around 10 minutes. The optimal temperature for their synthesis is a function of fluxes content and decreased dramatically with increase of the wasted glass amount. Obtained granulates have a density lower than unity and they have a good mechanical strength fulfilling the conditions for their use as building materials.Sewage sludge, wasted glass as well as incinerator ashes can be used as alternative materials, among other industrial solid wastes, in the formulation of lightweight clay and schist based granulates. Results of this work try to meet the principles of sustainable development preserving both the resources and the environment

An overview study of chlorination reactions applied to the primary extraction and recycling of metals and to the synthesis of new reagents

International audienceEnergy intensive classical metallurgical processes, the depletion of high-grade ores and primary sources push the scientific and technical communities to treat lean and complex ores as well as secondary metal resources for the recovery of valuable metals. Chlorination technique could be a suitable technology for this purpose. This paper Summarizes laboratory experimentation of chlorination processes developed for the extraction of tantalum and niobium from their bearing materials, the upgrading of chromite, the treatment of sulfide concentrates, and the decontamination of jarosite, as well as for the synthesis of potassium ferrate.Each investigation started by a thermodynamic study of different systems (M-O-Cl, M-S-Cl, M = metal) including the calculations of the standard free energy of chlorination reactions and phase stability diagrams of these systems. The kinetics of these chlorination reactions was studied by thermogravimetric analysis. The effects of total gas flow rate, temperature, individual reactant partial pressures, etc., on the chlorination reaction rate were investigated. Besides, experiments were also conducted in tubular furnaces. Several different qualitative and quantitative analyses methods were used to evaluate the selectivity and performance of the chlorination processes.The results reported in this paper show the advantages of the chlorination technology in terms of energy saving. selectivity of the processes,and recovery rate of valuable metals. They also demonstrate the possibility to treat lean raw materials, to improve the decontamination of wastes, to generate environmentally safer residues, to engineer new compounds, etc

Ni-Co sulphide segregation in the Mamb pyroxenite intrusion, Cameroon. Ségrégation de sulfures de Ni-Co dans l'intrusion de pyroxénite de Mamb, Cameroun.

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Column Experiments and Numerical Modelling For In-Situ Leaching of Sandstone Hosted Copper Deposit

International audienceThe BioMOre EU Horizon 2020 project (www.biomore.info) aims at developping “deep-in situ biomining” technology which have recently received an increasing attention from research and industry as a cost effective method for recovering metals from deep burried deposits. It consists in injecting a leach solution into the targeted ore body for dissolving base metal bearing minerals, collecting the pregant solution and in regenerating the leach solution thanks to micro-organisms. This technology is being experimented at reactor scale on a Kupferschiefer copper deposit in Poland as part of the BioMOre project. In this contribution, we present laboratory column experiments investigating the effect of a leaching solution in contact with copper bearing ore crushed at different grain sizes in suitable micro-organism environment conditions. Three stages including (i) water washing, (ii) acid leaching, and (iii) ferric-acid leaching, are successively implemented for progressively dissolving salts, carbonate minerals, and finally copper bearing sulfides. Models have been implemented in PhreeqC in parallel to the column experiments. They consider a one-dimensional double porosity transport model, where dissolution reactions are described by kinetics. We rely on BRGM’s Thermoddem databases [1]. Key parameters such as proportion of advective and diffusive phases, and effective diffusion coefficients were refined by fitting experimental results. The leaching process was then simulated in 3D at a deposit mesh scale by coupling one-dimensional PhreeqC models with a streamline-based fluid flow simulation approach. Such models will be further used within the BioMOre project for optimizing well-design planning and recovery forecasts

Column Experiments and Numerical Modelling For In-Situ Leaching of Sandstone Hosted Copper Deposit

International audienceThe BioMOre EU Horizon 2020 project (www.biomore.info) aims at developping “deep-in situ biomining” technology which have recently received an increasing attention from research and industry as a cost effective method for recovering metals from deep burried deposits. It consists in injecting a leach solution into the targeted ore body for dissolving base metal bearing minerals, collecting the pregant solution and in regenerating the leach solution thanks to micro-organisms. This technology is being experimented at reactor scale on a Kupferschiefer copper deposit in Poland as part of the BioMOre project. In this contribution, we present laboratory column experiments investigating the effect of a leaching solution in contact with copper bearing ore crushed at different grain sizes in suitable micro-organism environment conditions. Three stages including (i) water washing, (ii) acid leaching, and (iii) ferric-acid leaching, are successively implemented for progressively dissolving salts, carbonate minerals, and finally copper bearing sulfides. Models have been implemented in PhreeqC in parallel to the column experiments. They consider a one-dimensional double porosity transport model, where dissolution reactions are described by kinetics. We rely on BRGM’s Thermoddem databases [1]. Key parameters such as proportion of advective and diffusive phases, and effective diffusion coefficients were refined by fitting experimental results. The leaching process was then simulated in 3D at a deposit mesh scale by coupling one-dimensional PhreeqC models with a streamline-based fluid flow simulation approach. Such models will be further used within the BioMOre project for optimizing well-design planning and recovery forecasts

Column Experiments and Numerical Modelling For In-Situ Leaching of Sandstone Hosted Copper Deposit

International audienceThe BioMOre EU Horizon 2020 project (www.biomore.info) aims at developping “deep-in situ biomining” technology which have recently received an increasing attention from research and industry as a cost effective method for recovering metals from deep burried deposits. It consists in injecting a leach solution into the targeted ore body for dissolving base metal bearing minerals, collecting the pregant solution and in regenerating the leach solution thanks to micro-organisms. This technology is being experimented at reactor scale on a Kupferschiefer copper deposit in Poland as part of the BioMOre project. In this contribution, we present laboratory column experiments investigating the effect of a leaching solution in contact with copper bearing ore crushed at different grain sizes in suitable micro-organism environment conditions. Three stages including (i) water washing, (ii) acid leaching, and (iii) ferric-acid leaching, are successively implemented for progressively dissolving salts, carbonate minerals, and finally copper bearing sulfides. Models have been implemented in PhreeqC in parallel to the column experiments. They consider a one-dimensional double porosity transport model, where dissolution reactions are described by kinetics. We rely on BRGM’s Thermoddem databases [1]. Key parameters such as proportion of advective and diffusive phases, and effective diffusion coefficients were refined by fitting experimental results. The leaching process was then simulated in 3D at a deposit mesh scale by coupling one-dimensional PhreeqC models with a streamline-based fluid flow simulation approach. Such models will be further used within the BioMOre project for optimizing well-design planning and recovery forecasts