What are graphite electrodes and needle coke?
Graphite electrodes are the main heating element used in an electric arc furnace, a steelmaking process where scrap from old cars or appliances is melted to produce new steel. Electric arc furnaces are cheaper to build than traditional blast furnaces, which make steel from iron ore and are fuelled by coking coal. But the cost of steelmaking is higher since they use steel scrap and powered by electricity. The electrodes are part of the furnace lid and are assembled into columns. Electricity then passes through the electrodes, forming an arc of intense heat that melts the scrap steel. Electrodes vary widely in size but can be up to 0.75 metres (2 and a half feet) in diameter and as much as 2.8 meters (9 feet) long. The largest weigh more than two metric tons. It takes up to 3 kg (6.6 lb) of graphite electrodes to produce one tonne of steel. The tip of the electrode will reach 3,000 degrees Celsius, half the temperature of the sun’s surface. Electrodes are made of graphit