ADVANCED MATERIALS & PROCESSES | NOVEMBER 2026 18 aluminum smelting, was also a pioneer in arc furnace design. In 1907, the first EAF for steel production in the United States was built in Syracuse, New York, using a Héroult design (Fig. 8). At that time, the available maximum diameter of a graphite electrode was 8 in. although larger carbon electrodes were available, albeit with less conductivity. The growth in steel demand during WWI and following years drove EAFs larger and production higher, and in response graphite electrodes were produced in larger quantities and larger sizes to handle more electric current. Electrode diameters went to 12 in., then 14 in., and each decade or so added larger sizes[1]. Today, graphite electrodes of 32-in. diameter are commercially available. THE NUCLEAR AGE: GRAPHITE’S PUREST MOMENT During the Manhattan Project, the milestone of nuclear fission criticality that was reached on December 2, 1942, brought the world into the nuclear age. That top secret experiment, culminating from years of work, principally rested on a suitable neutron moderator material. The neutron moderator material was high purity engineered graphite, most of it from National Carbon Company, machined into bricks and carefully assembled in piles. Chicago Pile 1, where criticality was reached, used almost 400 tons (~45,000 bricks) of engineered graphite (Fig. 9)[4]. Hamilton Young Castner had invented a cheaper way to make sodium hydroxide using electrolysis. He originally used monolithic carbon anodes, which at the time were extruded mixtures of carbon powders (such as gas retort carbon) and a binder that were carbonized. The carbon anodes were chemically attacked in his process. He found that heating the anodes to high temperature through direct resistance heating converted them to a degree of graphitic character, which improved their conductivity and resistance to chemical attack. While he initially ran small batches on his own, he was granted U.S. Patent No. 572,472 in 1896 and collaborated with Acheson to produce monolithic graphite electrodes at production scale in 1897[1]. THE INDUSTRIAL AGE: GRAPHITE GROWS UP With commercial scale engineered graphite available through the efforts of Acheson, Castner, and others, the graphite age effectively began in 1896. The Acheson Graphite Company was formed in 1899, and for production, Niagara Falls became a logical spot for electricity-intensive industries, like those powering electric furnaces. The availability of monolithic graphite electrodes, originally for Castner’s electrolysis process, found use in electric arc furnaces (EAF) for metallurgy. Paul Héroult, who is most associated with DREAMING OF DIAMONDS: DAWN OF GRAPHITE MATERIALS American Edward Goodrich Acheson was the quintessential electrical age inventor. Born in 1856, he had limited formal education but a persistent curiosity in the emerging technologies of electricity. He briefly worked for Thomas Edison, gaining exposure to systems and materials for electricity generation and electric lighting[3]. After leaving Edison’s employment, Acheson began experimenting with electric furnaces heated with arcs from carbon electrodes and powered by dynamo generators. His original ambition was an economical route to artificial diamond, due to its enormous value as a cutting and abrasive medium in a rapidly growing industrial environment. Instead of diamond, his experiments with heating mixtures of coke and clay produced crystals of silicon carbide. Acheson called the material “carborundum,” surmising that it was a compound of carbon and corundum. In 1891, he founded The Carborundum Company to commercialize his discovery and was granted U.S. Patent No. 492,767 on February 28, 1893. Continued experiments where he pushed the temperature higher led to the discovery of highly pure graphite powder in the furnace. He was granted U.S. Patent No. 568,323 in 1896 for the “manufacture of graphite.” In the same time period of Acheson’s work, American chemist Fig. 7 — Columbia dry cell battery (le ). Courtesy of ACS. Schematic of interior construction of dry cell battery (right). Fig. 8 — Design of tilting EAF by Paul Héroult from Dean Stoughton “The Metallurgy of Iron and Steel,” 1908 (le ). Modern EAF with graphite electrodes (right).
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