1. Manual for use of Al-containing residues in low-carbon mineral bindersSabina Dolenec, Katja Malovrh Rebec, Anja Lešek, Katarina Šter, Lea Žibret, Gorazd Žibret, Klemen Teran, Emil Pučko, Ildikó Merta, Bojan Poletanovic, Elena Yaneva, Peter Kesserű, Ildikó Kovács, Bence Kószó, Alexandra Németh, Richard Laucournet, Mustafa Hadžalić, Emilija Fidanchevski, Biljana Angjusheva, Vojo Jovanov, Miloš Nenadović, Snežana B. Nenadović, Ivana Vukanac, Liljana Kraljević, Mojca Loncnar, Andrej Ipavec, 2020, dictionary, encyclopaedia, lexicon, manual, atlas, map Abstract: Današnje družbe si ni več mogoče predstavljati brez sodobne infrastrukture, ki temelji na uporabi različnih materialov ter zahteva veliko porabo energije. Vzporedno s proizvodnjo materialov, nastajajo ogromne količine različnih industrijskih in rudarskih ostankov (odpadki/stranski proizvodi), ki jih trenutno ne izkoriščamo, sama odlagališča pa so premalo raziskana. Cilj Evropske unije (EU) je povečati učinkovito rabo virov in ponudbo sekundarnih surovin z recikliranjem, popisom odpadkov iz rudarskih in drugih industrijskih dejavnosti ter njihova ponovna uporaba. Veliko industrijskih in rudarskih odpadkov je obogatenih z aluminijem (Al), zato lahko nadomeščajo naravne vire Al v mineralnih veznih, vendar njihova uporaba zahteva obsežno poznavanje njihovih kemijskih, mineraloških, radioloških in fizikalnih lastnosti. Priročnik, ki so ga pripravili partnerji projekta RIS-ALiCE obravnava zakonodajne vidike, ki urejajo uporabo sekundarnih surovin v gradbenih proizvodih, opis najpogostejših industrijskih in rudarskih ostankov, ki vsebujejo Al (nahajališča boksitov, rdeče blato, jeklarske žlindre, pepeli iz različnih industrij, itd.), potencial njihove ponovne uporabe in njihov ekonomski vidik, potencialne zahteve/ovire za uporabo sekundarnih surovin v cementni industriji in opis belitno-sulfoaluminatnih cementov, ki so obetavna rešitev za izvajanje krožnega gospodarstva z uporabo velikih količin odloženih industrijskih in rudarskih odpadkov, bogatih z Al.
Keywords: gradbeni proizvodi, ponovna uporaba, ekonomski vidik, industrija cementa, krožno gospodarstvo, industrijski odpadki, zakonodaja, elektronske knjige
Published in DiRROS: 22.01.2024; Views: 196; Downloads: 78
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2. Effect of the cooling regime on the mineralogy and reactivity of belite-sulfoaluminate clinkersSabina Dolenec, Katarina Šter, Maruša Mrak, Klara Žagar, Andrej Ipavec, Lea Žibret, 2020, original scientific article Abstract: This study investigated the influence of different cooling regimes on the microstructure and consequent reactivity of belite-sulfoaluminate clinkers. The cement clinkers were synthesized by incorporating secondary raw materials, such as titanogypsum and bottom ash, to the natural raw materials. Clinker phases were determined by Rietveld quantitative phase analysis, while the distribution morphology and the incorporation of substitute ions in the phases were characterized by scanning electron microscopy using energy-dispersive X-ray spectroscopy (SEM/EDS). Clinker reactivity was studied using isothermal calorimetry and was additionally investigated through compressive strength, which was determined for the cement prepared from the synthesized clinkers. X-ray diffraction analysis showed that, as well as the three main phases (belite, calcium sulfoaluminate, and ferrite), the clinkers contained additional minor phases (mayenite, gehlenite, arkanite, periclase, and perovskite), the ratios of which varied according to the cooling regime utilized. Microscopic observations indicated that the cooling regime also influenced the crystal size and morphology of the main phases, which consequently affected clinker reactivity. Furthermore, a smaller amount of substitute elements was incorporated in the main phases when cooling was slowed. Results showed that, in comparison to clinkers cooled at slower rates, air quenched clinkers reacted faster and exhibited a higher compressive strength at 7 days.
Keywords: clinkers, belite, calcium sulfoaluminate, cooling, microstructure, reactivity
Published in DiRROS: 20.12.2023; Views: 171; Downloads: 71
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3. The Incorporation of steel slag into belite-sulfoaluminate cement clinkersLea Žibret, Katarina Šter, Maruša Mrak, Mojca Loncnar, Sabina Dolenec, 2021, original scientific article Abstract: The potential use of steel slag from treated steel slag in belite-sulfoaluminate cements was investigated in this study. Cement clinkers with two phase compositions were synthesized, allowing the incorporation of different amounts of steel slag. The phase composition and microstructure of cement clinkers at three different sintering temperatures were studied by X-ray powder diffraction and the Rietveld method, as well as scanning electron microscopy with energy dispersive spectrometry. The results showed that the targeted phase composition of clinkers was achieved at a sintering temperature of 1250%C. However, a higher amount of perovskite instead of ferrite was detected in the clinker with a higher content of Ti-bearing bauxite. Apart from the main phases, such asbelite, calcium sulfoaluminate, and ferrite, several minor phases were identified, including mayenite, perovskite, periclase, and alkali sulfates. In both clinker mixtures, a higher content of MgO in the steelslags resulted in the formation of periclase. Furthermore, the hydration kinetics and compressive strength at 7 and 28 days were studied in two cements prepared from clinkers sintered at 1250%C. As evidenced by the results of isothermal calorimetry, the hydration kinetics were also influenced by the minor clinker phases. Cement with a higher content of calcium sulfoaluminate phase developed a higher compressive strength.
Keywords: cements, BCSA, steel slag, secundary row materials, microstructure, clinker phase
Published in DiRROS: 01.08.2023; Views: 252; Downloads: 118
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4. Technical and radiological characterisation of fly ash and bottom ash from thermal power plantEmilija Fidanchevski, Biljana Angjusheva, Vojo Jovanov, Pece Murtanovski, Ljubica Vladiceska, Nikolina Stamatovska Aluloska, Jelena Krneta Nikolić, Andrej Ipavec, Katarina Šter, Maruša Mrak, Sabina Dolenec, 2021, original scientific article Abstract: Huge quantities of fly ash and bottom ash are generated from thermal power plants and it presents great concern for country, mainly due to the environmental effects. In this study, fly ashes and bottom ash were characterized from technical and radiological aspects. Health effect due to the activity of radionuclides 226Ra, 232Th and 40K was estimated via radium equivalent activity (Raeq), external hazards index (Hex), the external absorbed dose rate (D) and annual effective dose rate (EDR). The specific surface area (40.25 m2 g−1), particle density (1.88 g cm−3) and LOI (23.49%) were typical for bottom ash. Siliceous fly ash contained 32% reactive silica. The annual effective dose rate for all ashes is ≤ 0.2 mSv y−1. Both, fly ash and bottom ash present potential secondary raw materials to be used for building purposes as result of their technological and radiological assessment.
Keywords: fly ash, bottom ash, gamma spectrometry, building materials
Published in DiRROS: 22.05.2023; Views: 273; Downloads: 128
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5. Radiological and physico-chemical characterization of red mud as an Al-containing precursor in inorganic binders for the building industryLjiljana Kljajević, Miljana Mirković, Sabina Dolenec, Katarina Šter, Mustafa Hadžalić, Ivana Vukanac, Miloš Nenadović, 2021, original scientific article Abstract: The potential re-use of red mud in the building and construction industry has been the subject of research of many scientists. The presented research is a contribution to the potential solution of this environmental issue through the synthesis of potential construction materials based on red mud. A promising way of recycling these secondary raw materials is the synthesis of alkali-activated binders or alkali activated materials. Alkali-activated materials or inorganic binders based on red mud are a new class of materials obtained by activation of inorganic precursors mainly constituted by silica, alumina and low content of calcium oxide. Since red mud contains radioactive elements like 226Ra and 232Th, this may be a problem for its further utilization. The content of naturally occurring radionuclides in manufactured material products with potential application in the building and construction industry is important from the standpoint of radiation protection. Gamma radiation of the primordial radionuclides, 40K and members of the uranium and thorium series, increases the external gamma dose rate. However, more and more precedence is being given to limiting the radiological dose originating from building materials on the population these days. The aim of this research was to investigate the possible influence of alkali activation-polymerization processes on the natural radioactivity of alkali activated materials synthesized by red mud (BOKSIT a. d. Milići, Zvornik, Bosnia and Herzegovina) and their structural properties. This research confirmed that during the polymerization process the natural radioactivity was reduced, and that the process of alkali activation of raw materials has an influence on natural radioactivity of synthesized materials.
Keywords: red mud, inorganic binder, DRIFT, natural radioactivity, gamma index, building industry
Published in DiRROS: 12.05.2023; Views: 365; Downloads: 104
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6. Influence of alkalis on the phase development of belite-sulfoaluminate clinkersBarbara Čeplak, Katarina Šter, Maruša Mrak, Luka Škrlep, Mirijam Vrabec, Sabina Dolenec, 2022, original scientific article Abstract: 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.
Keywords: BCSA clinker, microstrcuture, reactivity, alkalis, open access
Published in DiRROS: 06.12.2022; Views: 513; Downloads: 256
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7. Building of the Al-Containing secondary raw materials registry for the production of low CO2 mineral binders in South-Eastern European regionGorazd Žibret, Klemen Teran, Lea Žibret, Katarina Šter, Sabina Dolenec, 2021, original scientific article Abstract: The bottleneck in the process for increasing production of low CO2 mineral binders, based on BCSA (belite sulfoaluminate) clinkers, is the availability of Al-rich raw materials. For that purpose, a new registry of Al-containing secondary mineral residues (industrial and mine waste) has been developed and is presented in this paper. The methodology of creating the registry consists of three main steps: Gathering ideas, consolidation of ideas, and implementation. In order to achieve this, the following methodology was adopted: Analysis of similar registries by potential end-users and seeking potential solutions and tools to be used, and conducting 3 rounds of stakeholder consultations via workshops in order to determine crucial parameters and features the registry needs to contain. The key discussion points were about which data the registry needs to contain, who shall be the potential users, and what are the stakeholderʼs expectations from the registryʼs portal. Potential individual registry variables were identified as being relevant/irrelevant or available/unavailable, and potential solutions for the registrys sustainability were explored. Each Al-rich waste/residue data entry is divided into 10 slots, describing legal status, location, quantities, chemical (REE included), mineralogical, physical and radiological properties, life-cycle assessment, additional data, and data relevancy. The registry will act as a matchmaking tool between producers/holders of Al-rich secondary raw materials and potential producers of cement clinkers.
Keywords: cement, belite sulfoaluminate clinker, waste, by--product, deležniki
Published in DiRROS: 10.06.2022; Views: 525; Downloads: 316
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8. The valorisation of selected quarry and mine waste for sustainable cement production within the concept of circular economyEmilija Fidanchevski, Katarina Šter, Maruša Mrak, Ljiljana Kljajević, Gorazd Žibret, Klemen Teran, Bojan Poletanovic, Monika Fidanchevska, Sabina Dolenec, Ildikó Merta, 2022, original scientific article Abstract: The cement industry could potentially consume large amounts of solid industrial waste in order to improve its sustainability. The suitability of selected quarry and mine waste as secondary raw materials (SRM) was examined for the sustainable production of cement following the concept of a circular economy. The chemical, mineralogical, and radiological characterization of SRM was conducted in this study. Its potential use in low-carbon and low-energy belite-sulfoaluminate cement was investigated by incorporating the examined SRM into cement clinker. Various characterization methods were used to characterize the cement, including X-ray powder diffraction (XRD), thermal analysis (DTA/TG), and isothermal calorimetry. Depending on the chemical composition of the waste, lower or higher amounts were allowed to be incorporated into the raw clinker mixture for a targeted clinker phase composition. Among the samples, differences were observed in the phase composition of synthesized clinkers, which slightly influenced the reactivity of the cement but did not significantly change the compressive strength of the final product.
Keywords: mineralne surovine, rudarski odpadki, rudniki, kamnolomi, cement, klinker, krožno gospodarstvo, BCSA clinker, cement, circular economy, clinker, mine wastes, quarry waste
Published in DiRROS: 10.06.2022; Views: 590; Downloads: 309
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