11. Antibacterial properties and cytotoxicity of 100% waste derived alkali activated materials : slags and stone wool-based bindersCaterina Sgarlata, Giovanni Dal Poggetto, Federica Piccolo, Michelina Catauro, Katja Traven, Mark Češnovar, Hoang Nguyen, Juho Yliniemi, Luisa Barbieri, Vilma Ducman, Isabella Lancellotti, Cristina Leonelli, 2021, izvirni znanstveni članek Povzetek: In this study we compare the leaching behavior and the antibacterial and cytotoxic properties of 100% slag or stone wool derived alkali activated materials. The antibacterial activity was measured as the inhibiting capacity against two Gram- negative bacterial strains, Escherichia coli and Pseudomonas aeruginosa and one Gram-positive bacterial strain: Enterococcus faecalis. The cytotoxicity properties were tested on mouse embryonic fibroblast NIH-3T3 cell-line. It was proved that the high quality of the 3D aluminosilicate network of the consolidated materials obtained from powders of CaO or MgO-rich slags or stone wool, opportunely activated with NaO and/or Na-silicate, was capable of stabilizing heavy metal cations. The concentrations of leachate heavy cations were lower than the European law limit when tested in water. The effect of additives in the composites, basal fibers or nanocellulose, did not reduce the chemical stability and slightly influenced the compressive strength. Weight loss in water increased by 20% with basalt fibers addition, while it remained almost constant when nanocellulose was added. All the consolidated materials, cement-like in appearance, exhibited limited antibacterial properties (viability from 50 to 80% depending on the bacterial colony and the amount of sample) and absence of cytotoxicity, envisaging good acceptance from part of the final consumer and zero ecological impact. CaO-rich formulations can replace ordinary Portland cement (showing bacterial viability at 100%) with a certain capability for preventing the reproduction of the E. coli and S. aureus bacteria with health and environmental protection results. Ključne besede: antibacterial properties, cytotoxicity, alkali-activated materials, slag, stone wool, waste utilization, social acceptance Objavljeno v DiRROS: 22.05.2023; Ogledov: 507; Prenosov: 326 Celotno besedilo (2,31 MB) Gradivo ima več datotek! Več... |
12. Alkali activation of metallurgical slags : reactivity, chemical behavior, and environmental assessmentIsabella Lancellotti, Federica Piccolo, Katja Traven, Mark Češnovar, Vilma Ducman, Cristina Leonelli, 2021, izvirni znanstveni članek Povzetek: Alkali-activated materials (AAMs) represent a promising alternative to conventional building materials and ceramics. Being produced in large amounts as aluminosilicate-rich secondary products, such as slags, they can be utilized for the formulation of AAMs. Slags are partially crystalline metallurgical residues produced during the high temperature separation of metallic and non-metallic materials in the steelmaking processes. In the present study, the electric arc furnace carbon or stainless steel slag (EAF) and secondary metallurgical slag such as ladle furnace basic slag (LS) were used as precursors in an alkali-activation process. EAF slag, with its amorphous fraction of about 56%, presented higher contents of soluble Si and Al species with respect to ladle slag R (35%). However, both are suitable to produce AAM. The leaching behavior shows that all the release values are below the regulation limit. All the bivalent ions (Ba, Cd, Cu, Ni, Pb, and Zn) are well immobilized in a geopolymeric matrix, while amphoteric elements, such as As and Cr, show a slight increase of release with respect to the corresponding slag in alkaline and aqueous environments. In particular, for Sb and As of AAM, release still remains below the regulation limits, while Mo presents an increase of leaching values that slightly exceeds the limit for landfill non-dangerous waste. Ključne besede: slag, aluminosilicate materials, chemical reactivity, cold consolidation, alkali activation, leaching test, open access Objavljeno v DiRROS: 22.05.2023; Ogledov: 500; Prenosov: 262 Celotno besedilo (4,49 MB) Gradivo ima več datotek! Več... |
13. Leaching and geochemical modelling of an electric arc furnace (EAF) and ladle slag heapMojca Loncnar, Ana Mladenovič, Vesna Zalar Serjun, Marija Zupančič, Hans A. van der Sloot, 2022, izvirni znanstveni članek Povzetek: Old metallurgical dumps across Europe represent a loss of valuable land and a potential threat to the environment, especially to groundwater (GW). The Javornik electric arc furnace (EAF) and ladle slag heap, situated in Slovenia, was investigated in this study. The environmental impact of the slag heap was evaluated by combining leaching characterization tests of landfill samples and geochemical modelling. It was shown that throughout the landfill the same minerals and sorptive phases control the leaching of elements of potential concern, despite variations in chemical composi- tion. Although carbonation of the disposed steel slags occurred (molar ratio CO3/(Ca+Mg) = 0.53) relative to fresh slag, it had a limited effect on the leaching behaviour of elements of potential concern. The leaching from the slag heaps had also a limited effect on the quality of the GW. A site-specific case, however, was that leachates from the slag heap were strongly diluted, since a rapid flow of GW fed from the nearby Sava River was observed in the landfill area. The sampling and testing approach applied provides a basis for assessing the long-term impact of release and is a good starting point for evaluating future management options, including beneficial uses for this type of slag. Ključne besede: EAF slag, field verification, geochemical modelling, ladle slag, leaching, release prediction, steel slag heap Objavljeno v DiRROS: 28.04.2023; Ogledov: 636; Prenosov: 292 Celotno besedilo (4,37 MB) Gradivo ima več datotek! Več... |
14. Effect of temperature on MgO activity in the CaO-SiO[sub]2-MgO-Al[sub]2O[sub]3 system measured by molten tinYongchun Guo, Fengman Shen, Haiyan Zheng, Shuo Wang, Xin Jiang, Qiangjian Gao, 2022, izvirni znanstveni članek Ključne besede: blast furnace, slag system, activity of MgO, reference-slag, method, enthalpy, solution Objavljeno v DiRROS: 22.06.2022; Ogledov: 633; Prenosov: 196 Povezava na datoteko |