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- Valorização de recursos minerais : contribuição do projecto MinReMol para uma recuperação sustentável do rénio a partir de resíduos mineirosPublication . Silva, Teresa; Figueiredo, M. Ondina; Santos, Renata; de Oliveira, Daniel Pipa Soares; Veiga, JP; Batista, Maria Joao
- Contribution to the Understanding of the Colour Change in Bluish-Grey LimestonesPublication . Silva, Teresa; De Oliveira, Daniel Pipa Soares; Veiga, JP; Lisboa, Jose; Carvalho, Jorge; Barreiros, M. Alexandra; Coutinho, ML; Salas-Colera, Eduardo; Vigário, RogérioABSTRACT: Bluish-grey limestones have been extensively used as ornamental stones for decoration purposes in buildings, as well as in works of art, and accordingly, have been the target of intense exploration. In Portugal, the Jurassic limestone massif known as the Macico Calcario Estremenho (MCE), has been the source of grey-coloured ornamental stones, namely the Azul Valverde (one of the most well-known bluish-grey limestones) and Atlantic Blue varieties, both of which may undergo colour changes in outdoor environments. In this sense, it is important to understand the sudden colour change from bluish-grey to yellow/beige in the same limestone block in a quarry, or even, what happens to the colour when polished limestone is placed outdoors. This study was undertaken using various techniques, namely XRF (X-ray fluorescence spectrometry), XRD (X-ray diffraction), SEM (scanning electron microscopy), DTA-TG (differential thermal analysis/thermogravimetry) and colourimetry. Synchrotron radiation was also used at the European Synchrotron Radiation Facility (ESRF, Grenoble, France) where XANES (X-ray Absorption Near Edge Structure) spectra at Fe K-edge were collected to ascertain the speciation state of Fe in different coloured zones of the limestone, previously checked by EDXRF (energy dispersive X-ray fluorescence). The presence of Fe2+ and Fe3+ are responsible for the greyish and yellow/brown colour, respectively. On the other hand, the UV radiation from the sun causes a quickened and severe bleaching/fading on the dark blue/grey polished limestone.
- Towards the recovery of by-product metals from mine wastes : an X-Ray absorption spectroscopy study on the binding state of rhenium in debris from a centennial Iberian Pyrite Belt minePublication . Figueiredo, M. Ondina; Silva, Teresa; Veiga, JP; de Oliveira, Daniel Pipa Soares; Batista, Maria JoaoRhenium is a very scarce element, occurring in the Earth's crust mainly carried by molybdenite (MoS2). Due to a very low availability comparative to actual industrial demand, rhenium is nowadays one of the most expensive mineral commodities and an increased interest is focused on exploring residues resulting from a long-term mining, particularly of sulphide ore deposits. It is therefore noteworthy to assign the presence of rhenium (in a concentration up to 3 ppm) in the waste materials from the old sulphur factory at the abandoned mine of São Domingos (Iberian Pyrite Belt, Southeast Portugal), exploited since the Roman occupation of Iberia. Aiming at a potential sustainable recovery of rhenium as a by-product, X-ray near-edge absorption spectroscopy (XANES) was applied to clarify the Re-binding and mode of occurrence by comparing Re L3-edge XANES spectra obtained from mine waste samples (previously fully characterized by X-ray laboratory techniques) with similar spectra collected from Re-rich molybdenites (Mo1-xRexS2) and from Re-O model compounds configuring various valences and coordination environments of rhenium ions. Obtained results are commented, ruling out a possible Re-S binding and rather conforming with the binding of rhenium to oxygen in the analysed mine waste materials.
- Cultural Heritage analysis using Synchrotron Radiation: case studies in Ceramics, Glasses, and Lithologic MaterialsPublication . Veiga, JP; Coutinho, ML; Figueiredo, Elin; Silva, TeresaABSTRACT: Synchrotron radiaton is a powerful tool for non‐destructve analysis of materials in cultural heritage research. It has revolutonized our ability to understand the compositon, structure, and history of cultural heritage objects, leading to significant advances in fields such as archaeology, art conservation, and materials science. Dedicated beamlines for cultural heritage research are available at synchrotron facilites around the world, such as the European Synchrotron Radiation Facility (ESRF), SOLEIL synchrotron, and ALBA synchrotron, providing specialized support and instrumentation for high‐resolution analysis of cultural heritage objects using various techniques, such as X‐ray absorption spectroscopy, X‐ray fluorescence, X‐ray diffraction, and X‐ray imaging.
- An approach to the binding state of indium in natural chalcogenides through the analysis of In L3 edge XANES spectraPublication . Silva, Teresa; de Oliveira, Daniel Pipa Soares; Veiga, JP; Rosa, Diogo; Figueiredo, M. OndinaA study using synchrotron radiation X-ray absorption spectroscopy at In L3-edge is presented, as a contribution to interpret the binding state of indium in natural chalcogenides considering the increase of applications of this scarce metal.
- Ancient glazed ceramic tiles : a long-term, study from the remediation of environmental impacts to the non-destructive characterization of materialsPublication . Figueiredo, M. Ondina; Silva, Teresa; Veiga, JPSince the involvement in a national research project in 1995-1997 with the partnership of the National Tile Museum in Lisbon, until a recent European project with partners from Mediterranean countries which cultural patrimony entails glazed ceramic tiles, the authors have been active in the non-destructive characterization of ceramic and vitreous materials used to manufacture ancient decorated tiles (16th-19th century) through the access to the European Synchroton Research Facility (ESRF, Grenoble/France). As an input to the preservation of this important cultural patrimony through the improvement of restoration techniques, a synopsis is presented of the work so far developed.
- Co and Cu K-edge XANES study of the glazed tiles from the Fronteira Palace (Lisbon, Portugal) [Poster]Publication . Coutinho, ML; Silva, Teresa; Figueiredo, Elin; Rolim, M.; Salas-Colera, Eduardo; Veiga, JPABSTRACT: The Fronteira Palace located in Lisbon was built during the second half of the seventeenth century. The Palace is known for its unique azulejos (Portuguese glazed tiles) dated from the 17th and 18th century which were profusely used both in the interior of the palace and on its magnificent formal gardens. The gardens have a unique cladding of high relief lustre tiles combined with blue-and-white tiles adorning the Gallery of the Kings (Figure 1). Samples of azulejos from Gallery of the Kings, were characterized in a previous work by PIXE. They display a silica alkali-lead glass or silica alkali glass and chromophores based on Co for the blue colouring and Cu for the red-lustre effect . In fact, the analyses showed that the colourless glaze has a lead-alkali silicate composition and a copper-rich lustre overlay, in agreement with the Manise lustreware production (Spain) after the XVII century. To achieve a comparison between manufacturing techniques and pigments used samples were characterized using X-Ray Absorption Spectroscopy. XANES techniques can provide information on the structural behaviour of transition metals in the vitreous matrix - namely, their bonding state and coordination environment, providing relevant information regarding the Co and Cu as chromophores.
- A XANES approach to the blue pigments in ceramic heritage [Resumo]Publication . Coutinho, ML; Veiga, JP; Ruivo, Andreia; Silva, Teresa; Salas-Colera, Eduardo; Bottura Scardina, Silvia; Lima, Augusta; Figueiredo, Elin; Cotte, Marine; Lima, M.M.R.A.
- Opportunities for recovering critical raw materials from mine wastes : the type-case of rhenium in residues from the exploitation of old portuguese minesPublication . Figueiredo, M. Ondina; Silva, Teresa; Batista, Maria Joao; Veiga, JP; de Oliveira, Daniel Pipa Soares
- The case study of the medieval town walls of Gubbio in Italy : first results on the characterization of mortars and bindersPublication . Carvalho, Fernanda; Lopes, Andreia; Curulli, Antonella; Silva, Teresa; Lima, M.M.R.A.; Padeletti, Giuseppina; Ronca, Sara; Padeletti, Giuseppina; Veiga, JPABSTRACT: Good conservation and restoration practices of cultural heritage assets rely on the knowledge of original materials. In the framework of the HERACLES Project (HERACLES—HEritage Resilience Against CLimate Events on Site, H2020 Grant Agreement 700395), dealing with the effects of climatic actions and natural hazards on built heritage, a set of important heritage sites are currently under study to improve their resilience against climate events. Among these are the medieval Gubbio Town Walls in Italy. The present work focuses on the mortars and binders of this monument and collected samples related to different parts of the Walls, corresponding to various historical periods of construction and interventions. They were characterized to determine their minerochemical composition, thermal behavior, and morphology. For that purpose, ex-situ laboratory techniques, such as X-ray diffraction (XRD), wavelength dispersive X-ray fluorescence (WDXRF), optical microscopy (OM), polarized light microscopy (PLM), scanning electron microscopy (SEM), and simultaneous differential thermal analysis and thermogravimetry (TG-DTA) were used to discern trends in different sampling areas due to construction/reconstruction periods and building techniques.