EUROPEAN STEEL TECHNOLOGY AND APPLICATION DAYS 2017 - ESTAD 2017

In mid of 2015 Acroni, a Slovenian steel producer belonging to the Slovenian Steel Group (SIJ), has awarded Primetals Technologies with an order to supply a new 95 metric ton AOD converter and dedusting system to its steel works in Jesenice. Less than 2 years later, in April 2017 the new process route will be brought into operation resulting in an increase in annual liquid steel production capacity up to 650.000t. Until now, the crude steel has been produced in an electric arc furnace, and decarburized in a VOD converter with a capacity of 90 metric tons. As the duration of treatment is significantly longer than for carbon steels, this plant configuration represents a bottleneck in the stainless steel production that will be eliminated by installing an AOD converter, which will increase both the production capacity and the flexibility of the steel works. Heat processing times for stainless steel can be reduced significantly, e.g. 55min faster tap to tap times at the furnace are possible and more than 2 hours can be saved by replacing treatment at VOD with the new AOD for duplex and ferritic grades. Additional advantages of an AOD converter are the low degree of slagging of alloying elements, such as chromium, and the option of using cheaper ferrochromium grades with an higher carbon content as an alloying addition. Therefore production costs can be reduced for Acroni with results in short payback time of the AOD investment. Latest state of the art technologies have been installed by Primetals Technologies at Acroni’s melt shop like the new material handling system and process automation system specifically designed for AOD converters. This ensures that raw materials are used efficiently, and minimizes treatment times. In addition the converter is equipped with a patented Drive Damper system to reduce the vibrations caused by the injection processes, which results in reduced wear and maintenance costs, while also lengthening the service life of the plant. The dedusting system, which will be installed at the same time as the AOD converter, will not only ensure that emissions are below the current limits, but also increase the energy efficiency and occupational safety in the production environment. In the paper the technical highlights of the project will be summarized as well as project execution and results achieved.