EUROPEAN STEEL TECHNOLOGY AND APPLICATION DAYS 2017 - ESTAD 2017

More than 40 Million tons of steel were produced in Germany in 2015. Therefore the total amount of iron and steel slags is about 13 Million tons every year. The black slag from electric steel making (EAF-slag: approx. 2 Million tons every year in Germany) produced during the scrap melting process in the electric arc furnace can be used in the construction of roads and in other high-grade applications. There is a decades-long tradition of utilization of steel slags in general and of EAF-slag in particular in Germany, in Europe and worldwide. The characterization of the properties of EAF-slag depends on different manufacture steps during and after the steel making process. The first step is the selection of different scrap qualities and furnace conditions for scrap melting. Furthermore the addition of slag forming materials is very important for a stable process, but also for the quality of the slag. The quality of EAF-slag is characterized as a metallurgical tool (foamy slag to protect and stabilize the process) and on the other hand as a by-product for high-grade applications (utilization instead of landfilling). Additional treatment of the liquid EAF-slag during the process or during tapping can be advantageous. After the EAF-process the cooling conditions during solidification and follow handling of solidifying slag influence the technical and environmental properties of the EAF-slag, too. The last step is the processing of the EAF-slag, final adjustment of the quality of the EAF-slag can be carried out by metal separation, crushing, sieving, recomposing and treatment of the solidified slag. All these different steps of PRODUCTION of EAF-slag are investigated during a research project by an electric steel work (LSW), a slag processor (MAU) and a research institute (FEhS). The acronym of this research project is PROEOS (PROduction of a high quality Electric arc furnace Slag). After a status-quo investigation of more than 200 different slag samples, first operational tests have been carried out, the results will be described.