On the campus of the Freiberg University of Mining and Technology, Germany, research has been conducted since 1765 on the extraction, processing, refining and reuse of raw materials and substances. The sustainable use of resources is also the driving force for innovative research projects at the Chair of Ceramics under the leadership of Professor Aneziris - a topic of great relevance, both today and in the founding days.
Carbon-bonded alumina filters after application in industrial steel casting
Aneziris
The silver city Freiberg is home to the oldest still existing University of Mining and Metallurgy in the world: The Freiberg University of Mining and Technology. This connection still determines the scientific focus of the research institution with about 4000 students, which carries the byname "resource university". The Chair of Ceramics at the Institute of Ceramic, Glass and Construction Materials, which has been led by Professor Christos G. Aneziris since 2001, also conducts research with a view towards sustainability. The chair builds a bridge between mechanical engineering and process engineering and works along the entire ceramic functional chain: from powder, through ceramic technology to the component, to component integration. The professorship is involved in both basic research projects and application-oriented work together with industrial partners.
Small inclusion - enormous effect
Only recently, for example, the Collaborative Research Centre 920 (SFB 920) entered the third phase. Under the heading "Multifunctional filters for molten metal filtration - a contribution to Zero Defect Materials", scientists at the Freiberg University of Mining and Technology are developing novel intelligent filter materials and filter systems as well as model-supported filter designs for purer molten metals. The SFB 920 thus makes an important contribution to the development of highly durable, functional and adaptive mechanical components for safety and lightweight constructions.
During the production process of metallic casting materials, many different impurities are present in the melt. One way to remove these inclusions from the molten metal is to use ceramic filter systems. The inclusions are retained on the filter surface or are deposited inside the filter. A new hybrid filter system has been developed in order to increase filtration efficiency and to remove inclusions with different chemical compositions from molten metal in the future. The patented process consists of at least two ceramic filter materials with different coatings. This reduces reject rates for users and further processing. In the steel casting simulator, this filter combination has already been able to remove over 95 % of inclusions.
But the endurance test, an application in a real production environment, still had to be mastered. "We used the filters in the tundish at Thyssenkrupp Steel Europe in Duisburg, Germany, for the first time. There, the filter can be easily changed and blockages can be avoided," says Aneziris. The first application was successful: "In continuous casting, the filter lasted 45 minutes. In this time, about 400 tons of steel have been casted.”
Plans for the future
In the third project period, which is funded by the German Research Foundation until 2023, the influence of a combined cleaning process on the mechanical properties of the end product and thus the reliability of the component will be investigated. The main focus will be on the further transfer of the research results into practical application. The vision: "The filters will be researched for different metal melts and thus make a significant contribution to the recycling of scrap, among other things," says Professor Aneziris.