There are numerous processes that enable melting or heating processes by means of electrical energy. Direct heating processes include induction heating, which is frequently used for thin sheets and the specific heating of small areas. In addition, there are also dielectric and conductive processes.
There are many indirect heating solutions. The most classic ones are resistance heating conductors. Temperatures of up to 1,200 degrees Celsius can be achieved by using nichrome resistors. Graphite conductors are able to reach temperatures of up to 2,000 degrees Celsius. These temperatures are already sufficient for many furnaces.
Electric arc furnaces reach maximum temperatures of up to 10,000 degrees Celsius. As a result of their high active power, they can melt down, in large plants with an output of more than 100 megawatts, more than one million tonnes of raw steel a year. The furnaces, otherwise known as EAFs (Electric Arc Furnace), now account for more than a quarter of the steel produced, partly because almost no other melting technology can compete in terms of recycling. Reprocessing from steels that are no longer needed will continue to be of increasing importance in the future, because significantly less energy is required than in the extraction of raw ores.
An electric arc furnace not only requires electrical energy, but also gases that in principle damage the climate balance. Additional burners, for example, add natural gas and oxygen to the process in order to heat more cleanly. Nevertheless, the CO2 balance is better than that of a normal furnace, and the total energy requirement per tonne of produced steel is also lower.