EUROPEAN STEEL TECHNOLOGY AND APPLICATION DAYS 2017 - ESTAD 2017

Considerable amounts of slag and dust are produced in integrated – iron ore based – steelmaking as well as in EAF – scrap based – steelmaking. These by-products still contain considerable amounts of metals in metallic and oxide form and are nowadays only partly processed and recycled, the rest has to be landfilled. Typical solutions are internal recycling via the sinter plant and the blast furnace, briquetting and charging to the BF, BOF or EAF as well as mechanical processing and low value external applications like road construction or filler materials. Primetals technologies developed an innovative process that allows reduction of all metal oxides in the slag or dust, collect the metal phase and bring all metals back into the main process. The remaining mineral fraction can be modified if necessary with respect to its basicity to allow its usage as a high value material in the cement and binder industry. For example slags from converter steelmaking processed this way can be directly used as a high value cement clinker substitute, while the metal recovered is dephosphorized and used as hot metal or scrap substitute in the converter. The process itself takes place in a modified electric arc furnace with coal injection and quasi-continuous liquid slag charging. In the paper the process principles including different ways of utilization of the mineral fraction are shown together with business cases – for an integrated steel plant for carbon steel production and for and EAF processing mainly DRI.