Austria-based Siemens announced Thursday that they have developed a new electric arc furnace (EAF) specifically developed for direct reduced iron (DRI) melting. Now available in the North American market, the Simetal EAF FAST DRI is designed for a continuous melting process as electrical energy input and DRI are supplied during tapping, which shortens tap-to-tap times and reduces specific energy consumption.
The Simetal EAF FAST DRI electric arc furnace has a tiltable lower vessel with an extensive liquid heel. The resulting continuous flat-bath operation allows electrical energy input and DRI feeding during tapping. Thanks to the patented furnace advanced slag-free tapping system (FAST), charging, tapping and taphole refilling are possible under power-on conditions. Compared with conventional arc furnaces, tap-to-tap times can be reduced by up to 15 percent. Energy consumption is cut by 20 kilowatt-hours per ton and electrode consumption falls by ten percent. The continuous supply of electrical energy during flat-bath operation not only improves productivity, but also avoids line harmonic distortions such as flicker.
The continuous operation of the furnace offers a number of other benefits. Coal and oxygen injection as well as foaming slag control can be implemented even more precisely. Slag- free tapping results in an enhanced alloys yield and better steel desulfurization. Installation of additional burners thus becomes superfluous. Thermal stress on the refractory and structure materials also remains constant, prolonging their useful lives.
The Simetal EAF FAST DRI is designed so that, in combination with the Hot Transport System (HTS) from Siemens, it can also be fed with hot DRI at temperatures of around 600 °C. Thanks to the modular design of the new electric arc furnace, existing furnace installations can also be retrofitted with FAST DRI technology.