Graphite electrodes are an essential component of Electric Arc Furnaces (EAFs), powerful melting pots that turn scrap steel into molten metal. Graphite electrodes also are used to refine steel in ladle furnaces.
In EAF applications, the furnace, or "pot" is filled (or "charged") with selected scrap metals and then sealed with a top, or lid. Graphite electrodes — three are deployed in most EAFs — are inserted into the pot through the lid. The electrodes can be as small as three inches in diameter or as large as 30 inches in diameter and weigh more than two tons. They’re designed to conduct electricity (at 80,000 amps or more) and to withstand incredibly high temperatures.
The electricity flows through water-cooled cables into the electrodes to the tip of the electrode, where it jumps, or arcs, to the nearest piece of scrap metal in the pot. The intense heat at the tip of the electrode — 3,000 degrees Celsius (about 5,000 degrees Fahrenheit) — melts the metal.
Graphite is used because it’s the only material that can withstand such temperatures.