A functioning circular economy is a core topic in the endeavour to achieve greater sustainability. Now, a joint project on the leaching and processing of blast furnace slag from electric arc furnaces marks the official launch of pioneering research to boost the circular economy in the steel industry.
The aim of this publicly funded project, labelled KLASSE (the German acronym for “circular economy – leaching and processing of blast furnace slag from electric arc furnaces”), is to recover valuable metals such as iron, vanadium, manganese and chromium from electric arc furnace slag in an energy-efficient manner, thereby significantly reducing imports of raw materials and cutting environmental pollution. The project is coordinated by Salzgitter Mannesmann Forschung (SZMF). Partners are the Bundesanstalt für Materialforschung und ‑prüfung (BAM), TS Elino, the TU Bergakademie Freiberg and the TU Clausthal.
Every year, steel production generates large quantities of slag, which until now has mainly been used as building materials or disposed of in landfill sites. The strategically important metals it contains, such as vanadium and manganese, are lost in the process. This is exactly where KLASSE comes in: by combining innovative “cold” processing methods with a subsequent direct reduction process, the metals contained are to be specifically separated and reutilised for the first time – with a significantly lower energy input compared to conventional molten metal methods.
Raw materials that are largely imported today can be maintained in the circular economy in the future
Until now, it has been practically impossible to avoid metal losses during the slag phase,” explains Dr Benedikt Ritterbach, Managing Director of Salzgitter Mannesmann Forschung. “For the first time, the approach we are now pursuing opens up the possibility of recovering these metals, which are essential for steel production. This means that raw materials that are largely imported today can be maintained in the circular economy in the future. The enormous potential has already been demonstrated by initial laboratory tests at SZMF. Our intention now, with KLASSE, is to systematically verify and continue to develop this approach.”
In addition to the recovery of metals, the project also envisages upscale utilisation of the remaining mineral fractions, in the building materials industry, for example. KLASSE thus makes a twofold contribution: to conserving natural resources and to strengthening industrial value creation in Germany. Simultaneously, the project supports key objectives in energy and raw materials policy, particularly the lowering of import dependencies for critical and strategic metals.
If the outcome is successful, the plan is to transfer the processes developed during the project to a pilot application and apply them to other types of slag.
Source: Salzgitter AG
