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Influence of alkalis on the phase development of belite-sulfoaluminate clinkers
Barbara Čeplak, Katarina Šter, Maruša Mrak, Luka Škrlep, Mirijam Vrabec, Sabina Dolenec, 2022, izvirni znanstveni članek

Povzetek: This paper presents a study on the influence of different amounts of alkalis (K2O and Na2O) on clinker phase formation, microstructure, phase composition and reactivity of belite-sulfoaluminate cement clinker. Using X-ray powder diffraction and scanning electron microscopy with energy dispersive spectrometry, it was found that the amount of C2S and C4AF increases with the incorporation of alkalis, while the amount of C4A3Ś and CŚ decreases. In addition to the major phases, the samples with alkalis also consist of minor phases such as C3A (tricalcium aluminate), KŚ (arcanite), and KC2Ś3 (Ca-langbeinite). The major ions in the major phases were substituted by alkali cations and some other ions (Ca2+, Al3+, Fe3+, S2-, S6+, Si4+). The alkalis also affect the microstructure of the clinker, e.g., the shape of the grains. Consequently, isothermal calorimetry was used to detect differences in hydration kinetics. The clinker with 2 wt. % K2O content was the most reactive, while the sample with 0.5 wt. % Na content was the least reactive. The latter was primarily influenced by the content of the main and minor phases of the clinker.
Ključne besede: klinker, alkalije, razvoj
Objavljeno v DiRROS: 06.12.2022; Ogledov: 16; Prenosov: 10
.pdf Celotno besedilo (4,45 MB)
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Preliminary chemical and mineralogical characterization of tailings from base metal sulfide deposits in Serbia and North Macedonia
Timotheus Martin Christoph Steiner, Viktor Bertrandsson Erlandsson, Robert Šajn, Frank Melcher, 2022, izvirni znanstveni članek

Povzetek: Tailings of old mines often contain metals, which were not of economic interest or could not be recovered with the existing technology at the time of active mining. This is especially true for metals that often occur as by-products in Cu-Pb-Zn-(Ag-Au) ores as Sb, Mo, Ge, and In. A fundamental characterization of some tailings is presented in terms of their mineralogy and content of valuable metals which could be extracted to finance a possible remediation and improve the supply of the EU with critical metals. Tailings from active and abandoned mines in Serbia (Bor, porphyry Cu/Au; Krivelj, porphyry Cu/Au; Blagodat, hydrothermal Pb-Zn; Lece, epithermal Au; Rudnik, hydrothermal/skarn Pb-Zn) and North Macedonia (Sasa, Pb-Zn; Probištip, Pb-Zn; Bučim, porphyry Cu; Lojane, fault-bound vein-type low-temperature As, Sb, Cr at the contact of rhyolite and serpentinite) were studied. Analysis for major and trace elements used a multi-method approach (lithium borate fusion and ICP-MS/OES analysis, gravimetric analysis, instrumental neutron activation analysis, total digestion ICP-OES, infrared spectroscopy) with mineral identification by scanning electron microscopy. Concentrations of the major commodity elements (Cu, Pb, Zn, Au, Ag) varies within several orders of magnitude depending on mineralogy and ore type. Critical metals (Co, Ga, Ge, Sb) contents are low with some exceptions. Some tailings contain moderate to elevated potentially toxic element levels (As, Cd, Pb, Tl). For the sample from Probištip which yielded the highest valuable metal concentrations (>5000 ppm Pb, 4020 ppm Zn), a heavy mineral concentrate of the sand size fraction (0.06 mm to 0.5 mm) was produced and analyzed by SEM and LA-ICP-MS for additional rare phases and trace elements. In all tailings studied, additional milling would be needed to separate ore from gangue minerals. Increasing metal prices might facilitate feasibility studies for some of the localities in the future, despite the limited quantitative information about the characterized tailings.
Ključne besede: rudniški odpadki, kemija, mineralogija, rudna nahajališča, sulfidi
Objavljeno v DiRROS: 22.11.2022; Ogledov: 139; Prenosov: 16
.pdf Celotno besedilo (4,76 MB)

Solid carriers of potentially toxic elements and their fate in stream sediments in the area affected by iron ore mining and processing
Saša Kos, Nina Zupančič, Mateja Gosar, Miloš Miler, 2022, izvirni znanstveni članek

Povzetek: The potential environmental impact of historical mining and ore processing on stream sediments and water was studied in a small siderite iron ore deposit with diverse sulfide mineral paragenesis. The main aim was to characterize solid carriers of potentially toxic elements (PTEs) in stream sediments and mine waste, to understand their fate in fluvial systems. General mineralogy (X-ray powder diffraction) and individual solid PTE carriers (scanning electron microscopy/energy dispersive spectroscopy) were correlated with the geochemical composition of stream sediments, mine waste, and stream waters (inductively coupled plasma mass spectrometry). Primary solid PTE carriers were pyrite, chalcopyrite, sphalerite, Hg-bearing sphalerite, galena, and siderite. Slightly alkaline and oxidizing conditions in stream water promoted the transformation of primary phases into secondary PTE carriers. Fe(Mn)-oxide/oxyhydroxides were major sinks for Pb, Zn, and As. Compared to background levels, Co (14.6 ± 2.1 mg/kg), Cu (30 ± 2.9 mg/kg), Ni (32.1 ± 2.9 mg/kg), Pb (64.5 ± 16.4 mg/kg), Zn (175.3 ± 22.5 mg/kg), As (81.1 ± 63.7 mg/kg), and Hg (2 ± 0.8 mg/kg) were elevated in mining area. Mine waste contained similar PTE carriers as stream sediments, but much higher PTE contents. Prevailingly low PTE concentrations in streams, with the exception of As (1.97 ± 2.4 µg/L) and Zn (4.5 ± 5.7 µg/L), indicate the stability of PTE carriers. Environmental effects were not significant, and additional monitoring is recommended.
Ključne besede: environmental mineralogy, environmental geochemistry, potentially toxic elements, stream sediments, solid phases, iron ore deposit, SEM/EDS
Objavljeno v DiRROS: 16.11.2022; Ogledov: 132; Prenosov: 14
.pdf Celotno besedilo (8,07 MB)

The primary and secondary mineral resources of Montenegro and their mapping into the European data model
Slobodan Radusinović, Robert Šajn, Božica Jovanović, Duška Rokavec, Katarina Hribernik, Vasilije Abramović, Matej Draksler, Ivan Danilović, Mia Jovanović, 2022, izvirni znanstveni članek

Povzetek: Primary and secondary mineral resources are of strategic importance to the EU economy. Montenegro, as a country candidate for membership in the EU, is required to follow (and later to implement) European policies, strategies as well as initiatives, including those related to mineral resources and the mining sector. The importance of providing access to mineral raw materials in the future is recognized by the EU, as well as meeting the needs of European industry, maintaining employment and ensuring further development. Considering the overall economic situation in Montenegro, it is important to encourge the mining sector and other industries based on the use of mineral resources in making a greater contribution to the development and sustainability of society as a whole and also increase the share of national GDP. The potential for discovery and utilization of primary and secondary mineral resources in Montenegro is demonstrated. The most important metallic mineral resources are bauxite, lead and zinc, while conventional energy resources include coal (oil and gas potential has yet to be proven). In addition, there are abundant non-metallic mineral raw materials - industrial minerals and construction materials. Secondary mineral resources, especially aluminous red mud (bauxite residue), are also significant and have been the subject of research in recent years. Tailings from flotation processes at operating and abandoned lead and zinc mines might also be of interest for metal recovery. Bottom and flay ash from thermal power plants, slag from steel production, as well as marlstone and limestone from the hanging wall of coal deposits may also have potential. Waste rocks could be used particularly for secondary aggregate production. A database was developed and the most important deposits of primary and secondary mineral resources in Montenegro were mapped during the RESEERVE project. Mineral data were harmonised so as to be INSPIRE compliant. In addition, some novel geochemical exploration results of secondary mineral resources are presented.
Ključne besede: primary and secondary mineral resources, Montenegro, RESEERVE project, European geological data platform (EGDI), INSPIRE
Objavljeno v DiRROS: 16.11.2022; Ogledov: 72; Prenosov: 19
.pdf Celotno besedilo (8,52 MB)

Review of the research and evolution of landslides in the hinterland of Koroška Bela settlement (NW Slovenia)
Tina Peternel, Ela Šegina, Jernej Jež, Mateja Jemec Auflič, Mitja Janža, Janko Logar, Matjaž Mikoš, Miloš Bavec, 2022, izvirni znanstveni članek

Povzetek: This paper gives an overview of landslide research and the activity of landslides located above the Koroška Bela settlement in Northwest Slovenia. There are several landslides in this area and they pose a direct threat to the settlement below. The settlement is very densely populated (about 2,100 inhabitants) and has well-developed industry and infrastructure. It is built on deposits from past debris flows, indicating that large slope mass movements have occurred in the past. In this regard, the hinterland of Koroška Bela has been investigated since 2006, within the framework of various research, technical and European projects. The most extensive geological and geotechnical investigations were carried out after April 2017, when part of the Čikla landslide collapsed and mobilised into a debris flow. All of the investigations which have been carried out over the years revealed that the hinterland of Koroška Bela is characterised by high landslide activity due to geological, hydrogeological and tectonic conditions. In order to protect people and their property, it is essential to implement a holistic mitigation measure which includes remediation works (drainage works, debris flow breaker, etc.) and non-structural measures (monitoring system, early warning system, risk management, etc.). Regular and continuous monitoring of all landslides is also crucial to observe the landslide dynamics and evaluate the effectiveness of structural mitigation measures.
Ključne besede: landslide, debris flow, research, monitoring, landslide evolution, Koroška Bela
Objavljeno v DiRROS: 03.10.2022; Ogledov: 145; Prenosov: 34
.pdf Celotno besedilo (11,09 MB)

Characterization of atmospheric deposition as the only mineral matter input to ombrotrophic bog
Valentina Pezdir, Martin Gaberšek, Mateja Gosar, 2022, izvirni znanstveni članek

Povzetek: Ombrotrophic peatlands contain a very small percentage of mineral matter that they receive exclusively from atmospheric deposition. Mineral matter deposited on the Šijec bog was characterized using scanning electron microscopy coupled with energy dispersive spectroscopy (SEM/EDS). We collected solid atmospheric deposition from snow, rainwater, and using passive samplers. Samples were collected at average atmospheric conditions and after two dust events. Size, morphology, and chemical composition of individual particles were determined. We distinguished four main particle groups: silicates, carbonates, organic particles, and Fe-oxyhydroxides. Silicate particles are further divided into quartz and aluminosilicates. Proportions of these groups vary between samples and between sample types. In all samples, silicate particles predominate. Samples affected by dust events are richer in solid particles. This is well observed in passive deposition samples. Carbonates and organic particles represent smaller fractions and are probably of local origin. Iron-oxyhydroxides make up a smaller, but significant part of particles and are, according to their shape and chemical composition, of both geogenic and anthropogenic origin. Estimated quantity and percentage of main groups vary throughout the year and are highly dependent on weather conditions. Dust events represent periods of increased deposition and contribute significantly to mineral matter input to peatlands.
Ključne besede: atmospheric deposition, SEM/EDS, mineral matter, peatland
Objavljeno v DiRROS: 08.09.2022; Ogledov: 170; Prenosov: 86
.pdf Celotno besedilo (3,51 MB)
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Biomonitoring and assessment of toxic element contamination in floodplain sediments and soils using fluorescein diacetate (FDA) enzymatic activity measurements: evaluation of possibilities and limitations through the case study of the Drava River floodplain
Péter Szabó, Gyozo Jordan, Tamás Kocsis, Katalin Posta, Levente Kardos, Robert Šajn, Jasminka Alijagić, 2022, izvirni znanstveni članek

Povzetek: The EU Water Framework Directive requires the monitoring and evaluation of surface water sediment quality based on the assessment of risk posed by contamination on the biotic receptors. Floodplain sediments are important receptors of potentially toxic element (PTE) contamination from the upstream catchment areas, and floodplains host climate-sensitive riverine ecosystems and fertile agricultural areas at the same time. This study investigates the effect of PTE contamination on microbial communities in floodplain sediments and soils using the fast, inexpensive and reliable fluorescein diacetate (FDA) method in order to estimate its applicability for sediment quality monitoring and preliminary toxicity-based risk assessment. Sediment and soil samples were collected from the actively flooded alluvial plain and the river terrace areas along a 130-km stretch of the large Drava River floodplain known to be widely contaminated by historical mining, smelting and the associated industry in the upstream Alpine region. Results of detailed data analysis show that the total microbial activity represented by the measured FDA values is related to PTE (As, Cu, Zn, Cd, Pb) concentrations, but this relationship shows significant heterogeneity and depends on the spatial location and on the soil properties such as organic matter content, dissolved salt and nutrient content, and it is specific to the toxic elements. Results show that some microbe species appear to be able to adapt to the elevated PTE concentrations in toxic soil micro-environments, over time. Despite the observed heterogeneity of microbial activity, the results revealed a breakpoint in the FDA dataset around the FDA = 3 FC (fluorescein concentration) value suggesting that microbial activity is controlled by thresholds.
Ključne besede: potentially toxic elements, fluorescein diacetate activity, heavy metals, contamination, biological activity
Objavljeno v DiRROS: 25.08.2022; Ogledov: 212; Prenosov: 52
.pdf Celotno besedilo (6,23 MB)

The Rigelj Formation, a new lithostratigraphic unit of the Lower Permian in the Karavanke Mountains (Slovenia/Austria)
Matevž Novak, Karl Krainer, 2022, izvirni znanstveni članek

Povzetek: The Rigelj Formation is a new lithostratigraphic unit of the Lower Permian Rattendorf Group in the Karavanke Mountains. The Formation is up to 105 m thick and mainly composed of siliciclastic and fossiliferous carbonate sediments that are entirely of shallow-marine setting. Conglomerates are interpreted as shoreface deposits, sandstones as deposits of the upper to lower shoreface, and fossiliferous siltstones as offshore deposits. Fossiliferous limestones were deposited in a shallow, open-marine shelf environment of moderate to low energy (wackestone, floatstone) and strong water turbulence (packstone, rudstone). The siliciclastic and carbonate lithotypes form some well-developed backstepping cycles starting with conglomerates, overlain by sandstones, siltstones and fossiliferous limestones that formed in an open shelf environment without siliciclastic influx. Similar sedimentary cycles are developed in the Grenzland Formation of the Carnic Alps. The fusulinid fauna indicates that the Rigelj Formation ranges in age from the late Asselian to the middle Sakmarian. In the western Karavanke Mountains and near Trögern, the Lower Permian lithostratigraphic succession is very similar to the succession in the Carnic Alps with Tarvis Breccia resting on the Trogkofel Limestone and the Goggau Limestone. Unlike this, in the central part of the Karavanke Mountains (Dovžanova Soteska–Mt. Pleschiwetz/Plešivec area) the Rigelj Formation is erosively overlain by the Tarvis Breccia. The stronger diversification of the sedimentary environments within the Karavanke-Carnic Alps in the Lower Permian after the uniform sedimentation in the Upper Carboniferous can be attributed to block-faulting.
Ključne besede: Lower Permian, Southern Alps, Dovžanova soteska, Mt. Pleschiwetz / Plešivec, Clastic Trogkofel Beds, fusulinid biostratigraphy
Objavljeno v DiRROS: 25.08.2022; Ogledov: 169; Prenosov: 49
.pdf Celotno besedilo (3,45 MB)

Evaluation of thermal conductivity estimation models with laboratory-measured thermal conductivities of sediments
Simona Adrinek, Rao Martand Singh, Mitja Janža, Mateusz Żeruń, Grzegorz Ryżyński, 2022, izvirni znanstveni članek

Povzetek: Thermal conductivity is one of the key parameters for estimating low-temperature geothermal potential. In addition to field techniques, it can be determined based on physical parameters of the sediment measured in the laboratory. Following the methodology for cohesive and non-cohesive sample preparation, laboratory measurements were carried out on 30 samples of sediments. Density, porosity and water content of samples were measured and used in thermal conductivity estimation models (TCEM). The bulk thermal conductivity (λb) calculated with six TCEMs was compared with the measured λb to evaluate the predictive capacity of the analytical methods used. The results show that the empirical TCEMs are suitable to predict the λb of the analysed sediment types, with the standard deviation of the residuals (RMSE) ranging from 0.11 to 0.35 Wm−1 K−1. To improve the fit, this study provides a new modified parameterisation of two empirical TCEMs (Kersten and Côté&Konrad model) and, therefore, suggests the most suitable TCEMs for specific sample conditions. The RMSE ranges from 0.11 to 0.29 Wm−1 K−1. Mixing TCEM showed an RMSE of up to 2.00 Wm−1 K−1, meaning they are not suitable for predicting sediment λb. The study provides an insight into the analytical determination of thermal conductivity based on the physical properties of sediments. The results can help to estimate the low-temperature geothermal potential more quickly and easily and promote the sustainable use of this renewable energy source, which has applications in environmental and engineering science.
Ključne besede: thermal conductivity, non-cohesive sediment, cohesive sediment, estimation model
Objavljeno v DiRROS: 25.08.2022; Ogledov: 159; Prenosov: 84
.pdf Celotno besedilo (2,61 MB)
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Mid-Cretaceous calcarenite in stone products from the Roman colony of Emona, Regio X (modern Ljubljana, Slovenia)
Rok Brajkovič, Bojan Djurić, David Gerčar, Blanka Cvetko Tešović, Boštjan Rožič, Luka Gale, 2022, izvirni znanstveni članek

Povzetek: Over the course of studying stone products from theRoman colony of Emona (Regio X), stratigraphicallyundefined calcarenite that was used to make simplesepulchral and architectural stone products wasdetected. The calcarenite used is late Aptian to earlyCenomanian in age. The corresponding facies werefound in the Lower Flyschoid Formation outcroppingnear the town of Medvode, within the local radius ofEmona. The Roman quarry was likely located in thisarea near the Sava River. According to the collecteddata, the quarry was in operation mainly in the 1stcentury.
Ključne besede: Cretaceous, microfacies, quarry production, Regio X, Roman time, stone products
Objavljeno v DiRROS: 17.08.2022; Ogledov: 235; Prenosov: 93
.pdf Celotno besedilo (12,01 MB)
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