Process Microstructural analysis after sintering at 1500°C Mechanical properties • Cold Crushing Strength determination (CCS): • Resonant Frequency Damping Analysis (RFDA): Beneficiaries Use of Metallurgical Residues as potential Raw materials for High Performance Refractory Castables Mathilda Derensy1, Thorsten Tonnesen1, Jong-Won Shin2, Jesus Gonzalez-Julian1 1. Institute of Mineral Engineering, RWTH Aachen University, Forckenbeckestraße 33, 52074 Aachen, Germany 2. Calderys Deutschland GmbH, In der Sohl 122, 56564 Neuwied, Germany CESAREF PhD 04 : Industrial and Academic supervisors: Acknowledgements: Mathilda DERENSY MSCA Doctoral candidate mail: derensy@ghi.rwth-aachen.de This project has received funding from the European Union's Horizon Europe research and innovation program under grant agreement no.101072625 Goals: Results and Discussion: Development of mineral processing route of aggregates and study of the behavior in refractory castables. Further thermo-mechanical tests with castables containing vanadium slag as the bonding phase. Different trials to extract the vanadium in a sustainable way Contact different slag suppliers for further comparison with current slag composition Ongoing work: • Strength decreases significantly when adding slag to the formulation but the reference is based on high alumina castables, rarely employed in industries • E and G modulus data do not display considerable deviation with the different amounts of slag • Vanadium reacts preferably with Mg, Al and Ca towards a stable phase after sintering and does not attack the alumina grains. Conclusion: Context: The steelmaking industry generates several by-products during the different stages of steel production. As a by-product, vanadium slag account for more than 60% of the world’s overall production. However, it is tough to find vanadium in its pure state as it occurs in combination with various minerals. Using secondary resources for refractory castables solves the issue of natural raw materials, reduces costs related to their extraction and processing, and is friendly to the environment. Figure 1. Towards a new steel production route. Figure 2. Microstructure analysis of a castable with 0% slag; 2.5 wt.% slag and 2.5 wt.% cement and 5 wt.% slag after sintering at 1500°C for 6h and corresponding EDS scans of the different points on the graph. 1 2 3 4 5 6 7 O 56.28 57.09 57.56 55.28 57.02 56.68 57.55 Na 0.06 0.15 0.30 1.84 Mg 0.59 0.20 0.82 1.48 Al 39.54 39.40 42.44 41.16 42.98 38.88 37.55 Cl 0.19 Ca 3.25 3.16 3.07 3.27 1.37 V 0.28 0.35 0.21 Figure 3. Cold crushing strength experiment (Top) and resonant frequency damping analysis (Bottom) on castables after sintering at 1500°C/6h. 2.5 wt.% slag ; 2.5 wt.% cement 1 2 3 20 µm 5 wt.% slag 5 wt.% slag 6 7 100 µm 20 µm 0% slag (5 wt.% cement) 0% slag (5 wt.% cement) 4 5 20 µm 100 µm Advanced metal extraction of vanadium 2 min Dry mixing 5 min mixing Wet chamber 24h Demolding 1500°C 6h Dryer 24h Coarse Aggregate Fine Aggregate Porosity Matrix (ultra-fine) As coarse aggregates As bonding phase Castable Microstructure Raw Materials H2O + Deflocculant Mold Use Vanadium slag in castables composition Good properties to withstand harsh conditions Reducing emissions and costs related to extraction Reducing waste by recycling