La mineralització kàrstica (Ba, Cu, Pb, Zn, Sb) de Rocabruna i de can Pubill, Pirineu Oriental: geologia, morfologia i gènesi

La mineralització consisteix en el rebliment de cavitats metriques de morfologia karstica, encaixades en dolomies Cambro Ordovicianes. Les cavitats son plenes de baritina amb una aureola centi a millimétrica de quars i sulfurs (tetraedrita-tennantita, calcopirita, galena, esfalerita). La mineralització és situada a prop i per sota d'una paleosuperficie sobre la qual es depositaren els red-beds, amb disseminacions de baritina, de facies garumniana (Cretaci superior-Paleoce). Les condicions de deposició son coherents amb una precipitació a partir de solucions, inicialment acides, que omplien cavitats preexistents

Solid and Aqueous Speciation of Yttrium in Passive Remediation Systems of Acid Mine Drainage

International audienceYttrium belongs to the rare earth elements (REEs) together with lanthanides and scandium. REEs are commonly used in modern technologies, and their limited supply has made it necessary to look for new alternative resources. Acid mine drainage (AMD) is a potential resource since it is moderately enriched in REEs. In fact, in passive remediation systems, which are implemented to minimize the environmental impacts of AMD, REEs are mainly retained in basaluminite, an aluminum hydroxysulfate precipitate. In this study, the solid and liquid speciation and the local structure of yttrium are studied in high-sulfate aqueous solutions, basaluminite standards, and samples from remediation columns using synchrotron-based techniques and molecular modeling. Pair distribution function (PDF) analyses and ab initio molecular dynamics density functional theory models of the yttrium sulfate solution show that the YSO4+ ion pair forms a monodentate inner-sphere complex. Extended X-ray absorption fine structure (EXAFS) and PDF analyses show that Y is retained by basaluminite, forming a monodentate inner-sphere surface complex on the aluminum hydroxide surface. EXAFS of the column samples shows that more than 72% of their signal is represented by the signal of basaluminite with which YSO4+ forms an inner-sphere complex. The atomic view of the REE configuration in AMD environments could facilitate a deeper research of REE recovery from waste generated in AMD remediation systems

Synthesis of high ion exchange zeolites from coal fly ash

This study focuses on the synthesis at a pilot plant scale of zeolitic material obtained from the coal fly ashes of the Teruel and Narcea power plants in Spain. After the optimisation of the synthesis parameters at laboratory scale, the Teruel and Narcea fly ashes were selected as low and high glass fly ashes. The pilot plant scale experiments were carried out in a 10 m3 reactor of Clariant SA (Barcelona, Spain). The results allowed obtaining 1.1 and 2.2 tonnes of zeolitic material with 40 and 55% of NaP1 content, in two single batch experiments of 24 and 8 hours, for Teruel and Narcea fly ashes, respectively. The cation exchange capacities (CEC) of the final product reached 2.0 and 2.7 meq g-1 for Teruel and Narcea zeolitic material, respectively, which are very close to the usual values reached by the high quality natural zeolitic products. Finally, with the aim of testing possible applications of the commercial NaP1-IQE and pilot plant NaP1-Narcea zeolitic products in water decontamination, efficiency for metal uptake from waste waters from electroplating baths was investigate

Customization, extension and reuse of outdated hydrogeological software

Each scientist is specialized in his or her field of research and in the tools that he or she uses during the research in a specified site. Thus, he or she is the most suitable person for improving the tools by overcoming their limitations to realize faster and higher quality analysis. However, most scientists are not software developers. Hence, it is necessary to provide them with an easy approach that enables non-software developers to improve and customize their tools. This paper presents an approach for easily improving and customizing any hydrogeological software. It is the result of experiences with updating several interdisciplinary case studies. The main insights of this approachhave been demonstrated using four examples: MIX (FORTRAN-based), BrineMIX (C++-based), EasyQuim and EasyBal (both spreadsheet-based). The improved software has been proven to be a better tool for enhanced analysis by substantially reducing the computation time and the tedious processing of the input and output data files

Denitrification in a hypersaline lake–aquifer system (Pétrola Basin, Central Spain): The role of recent organic matter and Cretaceous organic rich sediments

Agricultural regions in semi-arid to arid climates with associated saline wetlands are one of the most vulnerable environments to nitrate pollution. The Pétrola Basin was declared vulnerable to NO3 − pollution by the Regional Government in 1998, and the hypersaline lake was classified as a heavily modified body of water. The study assessed groundwater NO3 − through the use of multi-isotopic tracers (δ15N, δ34S, δ13C, δ18O) coupled to hydrochemistry in the aquifer connected to the eutrophic lake. Hydrogeologically, the basin shows two main flow components: regional groundwater flow from recharge areas (Zone 1) to the lake (Zone 2), and a density-driven flow from surface water to the underlying aquifer (Zone 3). In Zones 1 and 2, δ15NNO3 and δ18ONO3 suggest that NO3 − from slightly volatilized ammonium synthetic fertilizers is only partially denitrified. The natural attenuation of NO3 − can occur by heterotrophic reactions. However, autotrophic reactions cannot be ruled out. In Zone 3, the freshwater–saltwater interface (down to 12–16 m below the ground surface) is a reactive zone for NO3 − attenuation. Tritium data suggest that the absence of NO3 − in the deepest zones of the aquifer under the lake can be attributed to a regional groundwater flow with long residence time. In hypersaline lakes the geometry of the density-driven flow can play an important role in the transport of chemical species that can be related to denitrification processes.Depto. de Geodinámica, Estratigrafía y PaleontologíaFac. de Ciencias GeológicasTRUECastilla–La Mancha GovernmentSpanish GovernmentCatalan Governmentpu

Tratamiento pasivo de aguas ácidas de mina con alta concentración de metales

La Faja Pirítica Ibérica contiene alrededor de un centenar de focos de generación de drenaje ácido de mina (AMD). Los sistemas tradicionales de tratamiento pasivo son ineficientes para este tipo de AMD, ya que debido a su alta acidez y concentración de metales, tiene lugar una abundante precipitación de sólidos. Como consecuencia se produce una colmatación de la porosidad y/o un recubrimiento muy rápido de los granos de reactivo. Para resolver este problema se ha desarrollado un material reactivo nuevo consistente en una mezcla de arena de caliza y virutas de madera. El pequeño tamaño de los granos produce la disolución rápida antes de su recubrimiento. La alta porosidad de la viruta retrasa la colmatación de los poros. La disolución de calcita eleva el pH hasta valores de 6.5 y los hidróxidos de los metales trivalentes (Al, Fe(III)) precipitan, pero no consigue una remoción completa de los metales divalentes. La magnesia cáustica (MgO) mantiene el pH entre 8.5 y 10, permitiendo la eliminación completa de metales divalentes.The Iberian Pyrite Belt (IPB) contains about one hundred abandoned sources of acid mine drainage (A MD). Traditional remediation systems are inefficient to treat the IPB mine waters. Due to their high acidity and metal loads, large amount of solids precipitate and clogging of porosity or passivation (coating) of the reactive grains quickly occurs. A mixture of fine-grained limestone sand and wood shavings was developed to overcome these problems. The small grains provide a large reactive surface and dissolve almost completely before they get coated. The high porosity retards clogging. Calcite dissolution only raises pH to values around 6.5, at which the hydroxides of trivalent metals (Al, Fe) precipitate, but it is not high enough to remove divalent metals. Caustic magnesia (MgO) buffers the solution pH between 8.5 and 10, and is very efficient to remove divalent metals from the water previously treated with calcite.Universidad Nacional de La Plat

An experimental evaluation of the understanding of safety compliance needs with models

Proceedings of: 36th International Conference on Conceptual Modeling, ER 2017, Valencia, Spain, November 6–9, 2017Context: Most safety-critical systems have to fulfil compliance needs specified in safety standards. These needs can be difficult to understand from the text of the standards, and the use of conceptual models has been proposed as a solution. Goal: We aim to evaluate the understanding of safety compliance needs with models. Method: We have conducted an experiment to study the effectiveness, efficiency, and perceived benefits in understanding these needs, with text of safety standards and with UML object diagrams. Results: Sixteen Bachelor students participated in the experiment. Their average effectiveness in understanding compliance needs and their average efficiency were higher with models (17% and 15%, respectively). However, the difference is not statistically significant. The students found benefits in using models, but on average they are undecided about their ease of understanding. Conclusions: Although the results are not conclusive enough, they suggest that the use of models could improve the understanding of safety compliance needs.The research leading to this paper has received funding from the AMASS project (H2020-ECSEL grant agreement no 692474; Spain’s MINECO ref. PCIN-2015-262) and the AMoDDI project (Ref. 11130583). We also thank the subjects that participated in the experiment