Graphite electrodes and nipples (connecting pins) are consumed primarily in electric arc furnace steel production, the steel making technology used by all “mini-mills.” Graphite electrodes are also consumed in the refining of steel in ladle furnaces and in other smelting processes such as production of titanium dioxide.
Electrodes act as conductors of electricity in the furnace, generating sufficient heat to melt scrap metal, iron ore or other raw materials used to produce steel or other metals. The electrodes are consumed in the course of that production.
Electric arc furnaces operate using either alternating electric current (A/C) or direct electric current (D/C). The vast majority of electric arc furnaces use alternating current. Each of these furnaces typically uses nine electrodes (in three columns of three electrodes each) at one time. The other electric arc furnaces, which use direct current, typically use one column of three electrodes. The size of the electrodes varies depending on the size of the furnace, the size of the furnace’s electric transformer and the planned productivity of the furnace. In a typical furnace using alternating current and operating at a typical number of production cycles per day, one of the nine electrodes is fully consumed (requiring the addition of a new electrode), on average, every eight to ten operating hours. The actual rate of consumption and addition of electrodes for a particular furnace depends primarily on the efficiency and productivity of the furnace. Therefore, demand for graphite electrodes is directly related to the amount and efficiency of electric arc furnace steel production.
Electric arc furnace steel production requires significant heat (as high as 5,000 degrees Fahrenheit) to melt the raw materials in the furnace, primarily scrap metal. Heat is generated as electricity (as much as 150,000 amps) passes through the electrodes and creates an electric arc between the electrodes and the raw materials.
Graphite electrodes are currently the only products available that have the high levels of electrical conductivity and the capability of sustaining the high levels of heat generated in an electric arc furnace producing steel. Therefore, graphite electrodes are essential to the production of steel in electric arc furnaces. There is currently no commercially viable substitute for graphite electrodes in electric arc furnace steel making. The cost of graphite electrodes represents about 3% to 4% of the cost of producing steel in a typical electric arc furnace.
