Browsing by Author "Salpagarov, Eldar"

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    DFG 465144480: Boron-free self-glazing Al₂O₃-C refractories
    (Technische Universität Bergakademie Freiberg, 2026-04-01) Roungos, Vasileios; Gehre, Patrick; Salpagarov, Eldar; Aneziris, Christos G.
    Al₂O₃-C refractories are extensively used as functional components in the continuous casting of steel. These high-duty products such as submerged entry nozzles, ladle shrouds, and monoblock stoppers contain up to 30 wt.-% carbon and present excellent mechanical, thermal and chemical properties, enabling the cost- and quality-effective implementation of the continuous casting process. Ceramic glazes are externally applied on Al₂O₃-C flow control refractory products to protect carbon from oxidation. These glazes typically contain boron. However, the increasing requirements for clean steel technology along with environmental- and health issues associated with boron compounds will make the utilization of boron-free glazes a necessity in the upcoming years. New boron-free self-glazing Al₂O₃-C formulations with sodium carbonate, wollastonite and magnesia additives were developed with the assistance of the FactSage software tool. These compositions presented a softening point in the range of 1000-1100 °C for self-glaze formation, which is the typical preheating temperature range for Al₂O₃-C functional refractory products. In addition, the influence of particle packing on their oxidation resistance was investigated, based on established particle size distribution models.
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    GRK2802: Non-metallic Inclusion Evolution in Interaction of Al-killed Mn-B Steel with Desulfurization Slag and MgO-C Refractories Containing Environmentally Friendly Binders and Recyclates
    (Technische Universität Bergakademie Freiberg, 2026-05-20) Bellé, Matheus Roberto; Neubert, Lukas; Yehorov, Anton; Kerber, Florian; Gunasekar, Dinesh Kumar; Salpagarov, Eldar; Aneziris, Christos G.; Volkova, Olena
    The high-temperature interaction between Al-killed Mn-B steel, desulfurization slag, and carbon-bonded magnesia refractories containing conventional, environmentally friendly binders and recyclate systems was systematically investigated using finger immersion testing at 1600 °C for 30 minutes. Chemical analysis of steel and slag, combined with SEM/EDX characterization of refractory/steel/slag interfaces and non-metallic inclusions (NMIs), was performed to interpret reaction mechanisms and the evolution of inclusions. Significant slag modification occurred during testing, characterized by MgO enrichment, CaO and Al2O3 depletion, and the formation of Fe- and Mn-bearing oxides. In the steel, pronounced decarburization, sulfur increase, boron depletion, and enhanced oxygen and nitrogen contents were observed, indicating reoxidation and interfacial reactions. Independent of refractory condition, MgAl2O4 spinel and Ca2SiO4 phases were detected in the infiltrated refractory zone. Refractories containing recyclates and alternative binders chemically modified the inclusion population and significantly increased NMI number density, particularly Mn-Si-Ti-based inclusions. The results demonstrate that refractory composition strongly influences slag chemistry, inclusion characteristics, and steel cleanliness. These findings provide a new understanding of refractory-slag-steel interactions during secondary metallurgy and highlight the need for optimized slag/refractory formulations to ensure inclusion control and steel quality under increasingly sustainable material strategies.