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[en] In this paper I present an example of the research that the Mineral Surface Group of the Munster University is conducting in the field of Crystal Growth. Atomic Force Microscopy (Am) in situ observations of different barite (BaSO4) faces growing from aqueous solutions, in combination with computer simulations of the surface attachment of growth units allows us to test crystal growth models. Our results demonstrate the strong structural control that a crystal can exert on its own growth, revealing also the limitation of the classical crystal growth theories (two dimensional nucleation and spiral growth models) in providing a complete explanation for the growth behaviour at a molecular scale. (Author) 6 refs
[en] The Brazilian fertilizers phosphate industry uses a raw material de phosphoric acid, obtained by acid attack to phosphate rock, producing 3 million of tones per year of gypsum as a by-product, named phosphogypsum. The use of this material has been stimulated due to its advantages as building materials and a fertilizer for reducing the environmental impact caused by its disposal product in the neighborhood. Since the phosphate rock have have uranium and thorium associated, during the processing, the natural radionuclides are redistributed through products and by-products. Thus, for a wide utilization of phosphogypsum, a radiological characterization is necessary. This paper present some results of uranium, thorium and radium concentrations in phosphogypsum samples, from representative fertilizers national industries. (author). 8 refs., 2 tabs
[en] In spite of the fact that gypsum is one of the most environmentally friendly binders, utilization of gypsum products is relatively narrow. The main problem of gypsum materials is their low resistance to the wet environment and radical decrease of mechanical properties with increasing moisture. The solution of the problem could be in use of composed gypsum-based binders, usually ternary, comprising gypsum, pozzolan and alkali activator of pozzolan reaction. These materials have a better moisture resistance and often also better mechanical properties. Paper provides literature survey of the possible compositions, properties and ways of utilization of the composed gypsum-based binders with latent hydraulic and pozzolan materials together with some results of present research performed by authors. (paper)
[en] The classification and discrimination of minerals are important in geological research. The distribution of rocks and minerals may be inferred based on their identification, which is helpful for the investigation of some geological and environmental evolution problems, either on the earth or on other planets. LIBS and Raman spectra techniques have shown great advantages in simultaneous multi-component, in-situ, and non-destructive detection and they play an important role in rock composition analysis. In this presentation, six kinds of minerals (Gypsum, Spodumene, Barite, Haematite, Moonstone, and Labradorite) were detected by first using LIBS and Raman systems, and then several other methods (PCA, PLS-DA, ANN, and SVM) were used to evaluate the LIBS, Raman, and the fused LIBS/Raman data, respectively. The results indicate the superiority of the fused LIBS/Raman data in mineral classification, which stems from their complementary analysis abilities when studying element composition and structural features. (paper)
[en] The international Phosphogypsum Working Group (PGWG) has its origins in joint meetings of the Stack Free project and the IAEA (2006). These led to formal joint meetings of the IAEA and FIPR (2006, 2007) and to a number of collaborative activities. Out of these activities came two IAEA sponsored meetings on PG, in 2008 and 2009. Another is planned for 2010. The PGWG has adopted the following vision and mission statements. 1. Vision. PG is a resource not a waste. 2. Mission. Find the point of equilibrium between PG production and consumption based on safe, sustainable use. (author)
[en] In this paper, properties of composite materials containing ternary binders are determined. Except gypsum, ternary binders containing also pozzolans and alkaline component, which serve as an activator of pozzolanic reaction. The main aim of this research was to investigate changes in physical and chemical properties and pore structural characteristics due to additions of ternary binders. Experimental results showed that changes in the properties of the composite depend not only on the amount of the addition, but also on the kind of pozzolan. (paper)
[en] The quality of secondary materials is imperative to promote a circular economy. In order to improve the way in which the quality of recycled gypsum is assessed, European guidelines on recycled gypsum (RG) quality criteria have been outlined in the framework of the Life+ Gypsum to Gypsum (GtoG) project. Such GtoG guidelines, along with the European Standard on gypsum plasterboard EN 520, provided the basis for this study. During the GtoG project, gypsum recycling and plasterboard manufacturing processes were monitored by testing the gypsum feedstock and the plasterboard produced. The aim of this paper is to discuss the results obtained on relevant parameters that characterize gypsum as a secondary raw material, as well as the resulting product. The minimum requirements were fulfilled by 56% of the RG samples and 86% of the plasterboard with increased RG.
[es]La calidad de las materias primas secundarias es fundamental para promover una economía circular. En el marco del proyecto Life+ Gypsum to Gypsum (GtoG), y con el objeto de mejorar el análisis de la calidad del yeso reciclado, se han desarrollado orientaciones en cuanto a los criterios de calidad del material. Estas directrices voluntarias, junto a la norma europea EN 520, son la base del presente trabajo. Los procesos de reciclaje y fabricación se monitorizaron durante el proyecto GtoG, mediante el ensayo de materias primas y placas de yeso laminado. El objetivo del presente artículo es discutir las propiedades del yeso como materia prima secundaria, así como del producto obtenido. Un 56% de las muestras de RG y un 86% de las placas con aumento de contenido de RG cumplieron los requisitos mínimos establecidos.
[en] The microcosmic and macroscopic methods were used to study the compatibility between accelerators and cement. The test results show that the environmental temperature, the water requirement of the normal consistency of the cement, the C3A content, the gypsum compatibility between accelerators and the cement. By testing the compositions and properties of various cements, the relationship between various factors and the compatibility between cement and accelerators is established, which provides theoretical support for the engineering application of accelerators. (paper)
[en] The different systems, and urban subsystems, are not isolated, although today they are managed as such, but integrated into a multidimensional reality where energy flows occur not only within each plane, but between them and in all directions. This integrated reality is an energetic ecosystem, to which we aim to provide balance and sustainability. Once understood this, it is also easy to understand that the mechanisms of rebalancing go through the transfer of the energy resources that are left over in one part of the ecosystem to another part of it where energy is demanded, by the capacity of change of the energy configuration of all the Ecosystem, by the correction of the imbalances and by the symbiotic action between the different systems and subsystems . If we look at the context for opportunities, we see that the two determinants of global development in the coming years are demographic growth and climate change. There is a link between population growth and urbanization in the world in the coming decades, the exponential development of urban areas and the phenomenon of emergence of new megalopolises. The harmonious development of cities is linked to a balance between its density and its complexity . On the other hand, the progressive recovery of urban space for its civic use raises a need to orientate the field of development of the network of infrastructures, services and endowments, towards the underground space. The field of opportunities emerging from integrated management  of underground resources includes the use of subsoil Energy resources for energy capture, exchange and storage. Geothermal exchange allows the inertial use of ground and the built mass buildings and infrastructures, for the accumulation of large quantities of thermal energy with low power and moderate temperature bands, is therefore a Means to accumulate the generated thermal energy and often considered residual, by industrial systems and urban infrastructures and to propitiate its reuse with very low costs, and very long life cycle. The accumulation of thermal energy in the field can also be applied to integrated and distributed systems of solar thermal capture, and solar photovoltaic
[en] 11 gypsum samples of playa deposits from two bore holes in the central Australia have been dated by means of ESR technique. The results obtained indicate that the signal at g=2.0090 is suitable for AD evaluation. The error of AD value, in this case, is about 10-40%. The ability of ESR technique to determine approximate age of gypsum deposits is demonstrated by this study