Authors:
Dr. Kirsten Moritz | Technische Universität Bergakademie Freiberg, Institute of Ceramics, Refractories and Composite Materials | Germany
Florian Kerber | Technische Universität Bergakademie Freiberg, Institute of Ceramics, Refractories and Composite Materials | Germany
Dr.-Ing. Steffen Dudczig | Technische Universität Bergakademie Freiberg, Institute of Ceramics, Refractories and Composite Materials | Germany
Dr. Gert Schmidt | Technische Universität Bergakademie Freiberg, Institute of Ceramics, Refractories and Composite Materials | Germany
Prof. Dr.-Ing. habil. Christos G. Aneziris | Technische Universität Bergakademie Freiberg, Institute of Ceramics, Refractories and Composite Materials | Germany
Dr.-Ing. Thomas Schemmel | Refratechnik Steel GmbH | Germany
Prof. Dr.-Ing. habil. Helge Jansen | Refratechnik Steel GmbH | Germany
Dr. Matthias Schwarz | Deutsche Edelstahlwerke Specialty Steel GmbH & Co. KG | Germany
Against the background of the need for sustainable and economical use of raw material and energy resources, the recycling of refractories for reuse as raw materials in the refractories production is becoming increasingly important. Magnesia-carbon (MgO-C) materials are among the most widely used refractories for applications in the steel industry.
This presentation deals with the influence of different percentages of a MgO-C recyclate on the physical, mechanical, and thermomechanical properties of MgO-C refractory specimens. In addition to test bars, bricks with dimensions of 160 mm x 114 mm x 100 mm were produced and examined. Another focus was on investigating the influence of the recyclate on the population of non-metallic inclusions in the steel. For this purpose, MgO-C specimens were tested in a steel casting simulator in contact with molten steel and slag. Subsequently, the solidified steel was investigated by an automatic feature analysis in a PSEM ASPEX.
Increasing recyclate contents generally led to an increase in porosity and an associated decrease in strength, on the other hand to an improved thermal shock resistance. However, it was possible to produce MgO-C bricks of a composition with a recycled content of approx. 65 wt%, the cold modulus of rupture of which was only slightly lower than that of the reference material made exclusively from virgin raw materials. Accordingly, the thermal shock resistance was also similar to that of the reference material.
No negative influence of the recyclate on the steel cleanliness in terms of critical non-metallic inclusions was observed.