German plantmaker Siemens has announced that it has succesfully developed the Simetal EAF Quantum electric arc furnace, combining tried-and-tested elements of preheating furnace technology with a number of new developments.
These include a new scrap charging process, an efficient preheating system, a new tilting concept for the lower shell, and an optimized tapping system. A reference furnace with a tapping weight of 100 tons achieves an output of 1.35 million tons of crude steel per year with a tap-to-tap time of 33 minutes. The electrical energy consumption, at just 280 kilowatt-hours per ton, is considerably lower than that of a conventional electric arc furnace. Coupled with a lower consumption of electrodes and oxygen, this results in a total specific conversion cost advantage of around 20 percent.
The Simetal EAF Quantum is designed as a shaft furnace. Unlike a conventional electric arc furnace, it is not necessary to raise the roof and retract the electrodes in order to charge the furnace. The other benefit of charging via a shaft is that the scrap is preheated by the offgas of the melting process, which significantly reduces energy requirements.
In conjunction with a patented, slag-free tapping system, charging, tapping and taphole refilling can all be done under power on. This leads to extremely short tap-to-tap times and high productivity.