Competent solutions for new challenges in steelmaking (English)

Increased demand for steelmaking raw materials has exerted great pressure on the available resources. Steelmaking producers all over the world are looking for ways to compensate the resulting high costs in order to gain a competitive edge over their rivals. Fuel or gas burners integrated into the water cooled side panels of the EAF, which were introduced several years ago reduced the energy costs of electric arc furnaces while at the same time increasing productivity. The next EAF development step concentrated on oxygen injection. SIS, a new oxygen injection system based on novel shrouding technology, offers lower energy consumption, higher reliability and easier handling along with reduced tap-to-tap time. The erection of scrap preheating shafts on top of electric arc furnaces proved problematic because of sub-optimum energy usage and reported maintenance problems. As a consequence the concept of a primary energy melter (PrEMelt) was investigated, which combines energy savings with reduced CO2 emissions. PrEMelt as a continuous melting process opens up the perspective of continuous steelmaking. Coke supply is reaching critical limits. With the growing importance of hot metal with its low content of tramp elements, the general interest shifts towards coal based smelting processes. Efficient energy use requires the subsequent use of the rich off-gas from these processes, for example by direct reduction. The result is a mix of hot metal and DRI to which neither the BOF nor the EAF are particularly suited. The CONARC process was developed not only to fill this technological gap but also to permit a flexible response to the constantly changing raw material markets.