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Povzetek: As clay deposits become scarce, the brick industry is increasingly seeking additives or substitutes. This study investigates a high- plasticity clay that requires an opening agent, for which was used 10 wt.% of processed steel slag Ekominit S1. Ceramic- technological tests were performed to determine the compressive strength, density and porosity. The addition of Ekominit S1 increased the total porosity by 5% in samples fired at 950 °C, and by 4% in samples fired at 1050 °C, while the compressive strength decreased by 36% in the samples fired at 950 °C and by 38% in those fired at 1050 °C compared to the reference material. Although the mechanical properties were lower than those of the reference, the benefit is reduced shrinkage. The processed steel slag could be incorporated successfully into bricks, which would also reduce the environmental impact of this sector by using secondary products instead of virgin materials.
Ključne besede: clay bricks clay bricks, compressive strength, porosity, opening agent, steel slag
Objavljeno v DiRROS: 15.05.2026; Ogledov: 174; Prenosov: 121
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Povzetek: Steel slag is an abundant by-product of steelmaking and a promising candidate for CO2 sequestration due to its favorable chemical composition and mineralogy. In this study, the CO2 sequestration capacity of the processed steel slag Ekominit was analyzed. Ekominit is a mineral product obtained by processing a mixture of electric arc furnace (EAF) stainless steel slag and ladle slag, currently used only for simple engineering constructions. The study demonstrated a promising sequestration capacity of 127.4 g CO2 per kg of Ekominit, measured using direct semi-dry carbonation under ambient pressure at 40 ± 0.5 °C, 80 ± 3.2% relative humidity, and 20 ± 0.1 vol% CO2 for 5 days, which is within the typical range reported for carbonated steel slags (100–150 gCO2/ kgslag). Although Ekominit did not show sufficient potential as a supplementary cementitious material in mortar, the results confirmed that its incorporation as a filler—with or without carbonation treatment—enhances both the flowability and compressive strength of the mortar. This research emphasizes the dual-function potential of Ekominit: it captures CO2, contributing to the decarbonization of the steel sector, and enables its reuse in construction materials, even improving the performance of mortars when using such carbonated Ekominit as fillers. Through such industrial symbiosis, environmental impact is further reduced by substituting virgin raw materials with secondary products.
Ključne besede: slag, carbonation, sequestration, aggregates
Objavljeno v DiRROS: 06.03.2026; Ogledov: 295; Prenosov: 204
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Ključne besede: ground granulated blast-furnace slag (GGBS), copper tailings (CTs), impermeability, hydration and heat release, cemented backfill
Objavljeno v DiRROS: 22.12.2025; Ogledov: 930; Prenosov: 309
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Povzetek: Technology of alkali activation is an alternative sustainable approach to producing paving paver, where reactive aluminosilicate precursor undergoes a reaction with an alkaline solution to form binded product. The case study presents the functional usability of a technology as part of the Georis project. The construction pavers are composed of over 75% industrial residues, with the majority of the materials sourced from steel slag industry. Laboratory testing of pavers confirmed the promising mechanical properties, demonstrating high compressive and flexural strength, as well as resistance to frost and abrasion. The results support the feasibility of scaling up from lab-scale to pilot manufacturing. The innovative approach in this project was the pilot production process itself, where more than 20 m² of pavers were manufactured and cured in a mobile unit. To assess their real-world performance, a demonstration case was implemented at the SIJ Acroni courtyard, where the pavers were installed to observe their application in a practical setting and to monitor their long-term durability. The valorisation of residues within GEORIS pavers highlights lower CO₂ emissions compared to conventional cement-based pavers and the potential of technology for industrial symbiosis and circular economy initiatives, making it an attractive solution for environmentally conscious industries.
Ključne besede: waste materials, alkali activated material, sustainable approach, slag, pavers
Objavljeno v DiRROS: 07.04.2025; Ogledov: 1119; Prenosov: 730
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Povzetek: Efflorescence, a time-dependent and water-driven phenomenon, is a major concern inalkali-activated materials (AAMs), impacting their practical use and preservation in a time-frozen state for post-characterisation. Although a method for stopping chemical reactions in conventional cements exists, it is time-consuming and not chemical-free. Therefore, this study explored the effects of low-power microwave-induced dehydration on efflorescence, mechanical performance, and structural integrity in AAMs, to create an alternative and more “user-friendly” dehydration method. For this purpose, several mixtures based on secondary raw (slag, fly ash, glass wool, and rock wool) and non-waste (metakaolin) materials were activated with a commercial Na-silicate solution in ratios that promoted or prevented efflorescence. Characterisation techniques, including Fourier-transform infrared spectroscopy and X-ray diffraction, showed that microwave dehydration effectively removed water without altering crystallinity, while mercury intrusion porosimetry and compressive strength tests confirmed increased porosity. In addition to being an efficient, time-saving, and solvent-free manner of stopping the reactions in AAMs, microwave irradiation emerged as an innovative, chemical-free method for evaluating curing finalisation and engineering foams in a stage when all other existing methods fail. However, the artificially provoked efflorescence in aged dehydrated AAMs connected the slipperiness of AAM with the instant extraction of Na, which raised the need for further research into alternative alkali replacements to evaluate the practical use of AAM.
Ključne besede: materials chemistry, alkali-activated materials, geopolymers, slag, fly ash, rock wool, glass wool, metakaolin, microwave irradiation, dehydration, stopping chemical reactions, efflorescence
Objavljeno v DiRROS: 23.12.2024; Ogledov: 1394; Prenosov: 905
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