Functionalisation of MgO-C refractories based on recycled raw materails and their impact on steel cleanless
Final Report Abstract
In the present project, the utilization of recyclates from used magnesia-carbon (MgO-C) refractory bricks as secondary raw materials for MgO-C refractories, which are applied, for example, as lining materials for steel casting ladles, was investigated. Two recyclates provided from Horn & Co. Minerals Recovery GmbH & Co. KG, R94A1 and R92A4.5, were selected for the experimental investigations. MgO-C test specimens with different recyclate contents of up to 83 wt% and recyclate-free reference specimens were prepared on a laboratory scale. With increasing recyclate content, an increase in porosity and reduction in strength could not be avoided, whereas the thermal shock resistance improved. The refractoriness under load was similar to that of the reference material when using the recyclate R94A1 up to a recyclate content of 40 wt%. The use of the recyclate R92A4.5 required adapted measures in the preparation of the MgO-C samples, specifically a thermal pretreatment of the recyclate at 380 °C or the replacement of the modified coal tar pitch Carbores® P in the used binder combination by a novolak powder in order to avoid a strong increase in volume of the samples during coking. Overall, on the basis of the results obtained here, the recyclate R94A1 is to be assessed as the more suitable secondary raw material for MgO-C refractories. By adding multi-walled carbon nanotubes (MWCNTs) in combination with nanoscale Al2O3, a MgO-C material with significantly improved thermal shock resistance could be produced at laboratory scale. Here, the mixing order proved to be crucial, making up-scaling to industrial scale difficult. The addition of n-type silicon, which was also investigated, did not reveal any advantage in the case of the MgO-C materials studied. Investigations of R94A1- and of R92A4.5-containing MgO-C samples in contact with 16MnCr5 steel and a slag, both provided by Deutsche Edelstahlwerke Specialty Steel GmbH & Co. KG, in a steel casting simulator did not provide any indication of a negative influence of the recyclates with regard to the number and the size distribution of non-metallic inclusions in the steel. Using two selected recyclate-containing formulations, MgO-C bricks were produced at Refratechnik.
Publications
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Investigations on the influence of recycled materials in magnesia-carbon refractories on the non-metallic inclusions in steel. Vortrag, ICR®2022 – 65th International Scientific Colloquium on Refractories, Aachen, 28.–29. September 2022
Moritz, K.; Dudczig, S.; Veres, D.; Endres, H.G.; Herzog, D.; Schwarz, M.; Schöttler, L.; Schemmel, T. & Aneziris, C. G.
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Magnesia-carbon-refractories from recycled MgO-C materials. Vortrag (virtuell), Unified International Technical Conference on Refractories (UNITECR) 2022, 17th Biennial Worldwide Congress on Refractories, Chicago (Illinois, USA), 15.–18. März 2022
Moritz, K.; Dudczig, S.; Endres, H.G.; Herzog, D.; Schwarz, M.; Schöttler, L.; Veres, D. & Aneziris, C.G.
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Magnesia‐carbon refractories from recycled materials. International Journal of Ceramic Engineering & Science, 4(1), 53-58.
Moritz, Kirsten; Dudczig, Steffen; Endres, Hans Georg; Herzog, Daniel; Schwarz, Matthias; Schöttler, Leandro; Veres, Daniel & Aneziris, Christos G.
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Use of recycled materials for producing magnesia-carbon refractories. Vortrag, REFRA PRAGUE 2022, 21st Conference on modern refractory materials and key achievements in high temperature technologies, Prag, 18.–20. Mai 2022
Moritz, K.; Dudczig, S.; Endres, H.G.; Herzog, D.; Schwarz, M.; Schöttler, L.; Schemmel, T. & Aneziris, C.G.
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Investigation of recyclate-containing magnesia-carbon refractories in a steel casting simulator. Vortrag, KERAMIK 2023 / CERAMICS 2023, 98. DKG-Jahrestagung, Jena / Hermsdorf, 27.–30. März 2023
Moritz, K.; Dudczig, S.; Schwarz, M.; Schemmel, T. & Aneziris, C. G.
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Recyclate-containing magnesia-carbon refractories – Influence on the non-metallic inclusions in steel. Open Ceramics, 16, 100450.
Moritz, Kirsten; Kerber, Florian; Dudczig, Steffen; Schmidt, Gert; Schemmel, Thomas; Schwarz, Matthias; Jansen, Helge & Aneziris, Christos G.
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Recyclate-containing magnesia-carbon refractories – Influence on the non-metallic inclusions in steel. Vortrag, Unified International Technical Conference on Refractories (UNITECR) 2023, 18th Biennial Worldwide Congress on Refractories, Frankfurt am Main, 26.–29. September 2023
Moritz, K.; Kerber, F.; Dudczig, S.; Schmidt, G.; Schwarz, M.; Schemmel, T.; Jansen, H. & Aneziris, C. G.
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Studies on the use of two different magnesia-carbon recyclates as secondary raw material for MgO–C refractories. Open Ceramics, 15, 100426.
Moritz, Kirsten; Brachhold, Nora; Küster, Felix; Dudczig, Steffen; Schemmel, Thomas & Aneziris, Christos G.
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The influence of the MgO-C refractories with different types of magnesia and recyclates on non-metallic inclusions in steel melts. Vortrag, XVIIIth International Conference of the European Ceramic Society (XVIII ECerS), Lyon (France), 02.–06. Juli 2023
Kerber, F.; Moritz, K.; Hubálková, J.; Stadtmüller, T.M.J.; Jansen, H. & Aneziris, C.G.
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Utilization of Recycled Material for Producing Magnesia–Carbon Refractories. Ceramics, 6(1), 30-42.
Moritz, Kirsten; Brachhold, Nora; Hubálková, Jana; Schmidt, Gert & Aneziris, Christos G.
