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Povzetek: The Geological Survey of Slovenia (GeoZS), with the assistance of the ENALOS Research and Development (ENALOS), the Slovenian National Building and Civil Engineering Institute (ZAG) and the Katholieke Universiteit Leuven (KUL), has compiled a report documenting the demonstration and application phase of the project. This report contains a technical analysis on the materials produced as well as an economic analysis, and thus more accurately calculates the financial benefits of the technology.
Ključne besede: odpadni materiali, waste materials, alkalijsko aktivirani materiali, alkali activated material, trajnostni pristop, sustainable approach, jeklarska žlindra, steel slag, rdeče blato, red mud
Objavljeno v DiRROS: 15.01.2026; Ogledov: 178; Prenosov: 0
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Povzetek: Mineral CO2 sequestration is a promising carbon capture and storage approach based on the chemical reaction of CO2 with alkaline materials containing Ca- and Mg-rich (hydr)oxides and silicates. This results in the formation of relatively insoluble and storable carbonates. This study investigates six ashes of different origins and chemical compositions to assess their CO2 sequestration potential and leaching behavior, offering insights into their environmental impact and potential risks. The carbonation experiments were conducted under controlled laboratory conditions and the CO2 sequestration capacity was quantified using a pressure calcimeter, supported by thermogravimetric analysis. Wood ashes and ash from the co-combustion of biomass from a paper mill showed the highest carbonation potential, with CO2 sequestration capacities between 344.8 and 432.3 g CO2 per kg of ash and carbonation efficiencies between 82.4 % and 94.4 %. In addition to the high sequestration capacity of the ashes, carbonation was found to affect the leaching behavior of the ash in the environment by changing its mineralogical composition. The process consistently reduced pH and generally decreased the leaching of certain trace elements, except for Mo, and Cr. Nevertheless, the reduction in the leachability of several elements suggests a partial environmental benefit of carbonation. The findings highlight the dual functionality of the carbonation: it provides a viable route for the permanent binding of CO2 and can enhance the stabilization of industrial residues. However, the persistence of metal leaching indicates that its overall effectiveness in mitigating environmental risks associated with residue disposal or reuse remains material-dependent.
Ključne besede: enforced carbonation, maximum sequestration capacity, leaching, heavy metals, mineralogy, bio-based ash
Objavljeno v DiRROS: 13.01.2026; Ogledov: 132; Prenosov: 103
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Povzetek: Clay-based materials typically require high-temperature processing (>900 ◦C), resulting in high energy consumption. This study explores cold sintering of metakaolin (MK) powders to achieve high mechanical strength at significantly lower processing temperatures. By applying uniaxial pressure of 400 MPa and heating to only 240 ◦ C in the presence of 15 mol/L NaOH solution, successful densification of structurally sound and dense samples with an average density of 2.16 g/cm³ and a biaxial flexural strength of ~35 MPa was achieved. This strength surpasses that of conventionally sintered MK (1470 ◦C) by ~30 %. Densification was found to be governed by synergistic mechanisms involving MK exfoliation, conformal sintering around aggregates, and the precipitation of an amorphous sodium aluminosilicate hydrate phase. Crack formation was avoided through process optimization and verified using X-ray micro-computed tomography. These findings offer new insights into the chemo- mechanical mechanisms of cold sintering and demonstrate its potential as an efficient route for producing structural materials.
Ključne besede: cold sintering, metakaolin, geopolymer, delaminations, exfoliation
Objavljeno v DiRROS: 15.10.2025; Ogledov: 334; Prenosov: 147
Celotno besedilo (7,70 MB)
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Povzetek: In this study the microstructural characteristics of the materials selected from two cultural-heritage sites (the Dornava Manor, Slovenia, and the Bač Fortress, Serbia) and of the model samples - the control and aged ones - were investigated. The samples were characterized by means of mercury intrusion porosimetry (MIP) and total-specific-area analysis (BET). A good agreement was achieved between the samples of the brick and mortar from the Bač Fortress,or the samples of the natural stone and render from the Dornava Manor, and the corresponding model samples.
Ključne besede: materials, microstructure, brick, natural stone, mortar, frost resistance
Objavljeno v DiRROS: 26.09.2025; Ogledov: 350; Prenosov: 158
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Povzetek: This study deals with the mechanical and microstructural characterization of geopolymers synthesized from locally available fly ash. A low calcium fly ash was activated using a sodium silicate solution. Samples were characterized by means of flexural and compressive tests, Fourier Transform Infrared (FTIR) spectroscopy, X-ray powder diffraction (XRD), and scanning electron microscopy(SEM). Porosity and pore size distributions were identified using mercury intrusion porosimetry and gas sorption. The compressive strength of the produced geopolymers, which is in the range of 1.6 to 53.3 N/mm2, is strongly related to the water content as well as SiO2/Na2O mass ratio of an alkali activator. The compressive strength significantly increased with decreases in the water content and increased silicon concentration used for the synthesis of geopolymers.
Ključne besede: geopolymers, fly ash, microstructure, mechanical properties
Objavljeno v DiRROS: 05.09.2025; Ogledov: 496; Prenosov: 237
Celotno besedilo (1,29 MB)
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