Arc Furnaces: Ancient Electric Arc Furnace History and Photographs
Arc furnaces may be ancient history—ever since the ancient Egyptian, Babylonian, Indian, Hebrew, Parthian, Greek, Roman, and other civilizations employed electric carbon arc technology to light up their temples, tombs, and lighthouses. In The Electric Mirror on the Pharos Lighthouse and Other Ancient Lighting, Larry Brian Radka has presented adequate ancient physical and literary electric lighting evidence to firmly establish that fact.
However, in the ancient nineteenth century, Sir Humphrey Davy and other researchers redeveloped the electric carbon arc technology of the distant past for that purpose as well as for melting materials at extremely high temperatures. By hooking up two wood-charcoal sticks to batteries, touching them together, and holding the two electrified carbons close to each other, he generated an electric arc that may have reached nearly 4000 degrees centigrade. In one of his early lecture-experiments, recorded in one of two large volumes of his notes between 1805 and 1812, in the library of the Royal Society, he said the light of its “spark” or arc “was so intense as to resemble that of the sun.”
Later, John Tyndall wrote: “The arc of flame between the carbon terminals was four inches long, and by its heat quartz, sapphire, magnesia, and lime were melted like wax in a candle-flame; while fragments of diamond and plumbago rapidly disappeared, as if reduced to vapor.” The professor also claimed that Davy “fused iridium, the alloy of iridium and osmium, and other refractory substances” as well.*
Since Davy’s early experiments, the practical development of electric carbon arc furnaces had to wait for powerful electric generators to replace the expensive electric battery technology used to fire most of the primitive ovens of the first half of the nineteenth century. According to a 1914 publication by the U. S. Department of Interior,* many chemists and metallurgists had conducted small experiments with electric carbon arc furnaces at the time, but it was probably not until 1882, when Siemens conducted its experiments, that electric arc furnaces reached a level of technology that satisfied commercial interests.
“Then,” according to the above publication, “came the furnace of E. H. and A. H. Cowles, who in 1885 invented an arc furnace for the production of aluminum alloys and for a variety of other purposes. A year later, Paul Héroult and C. M. Hall patented processes for the production of aluminum. In 1893, Wilson, aided by data gathered by Moissan in his classical experiments, developed the calcium-carbide furnace, which was followed in 1896 by Acheson’s carborundum furnace. Two years later, Captain Stassano of Italy patented an electric furnace for smelting iron ores, and the following year demonstrated the working of his process. In 1900, the production of ferro-alloys in the electric furnace was begun, and at the present time practically all ferro-alloys are made in electrically heated furnaces.
“As a result of the work of Stassano and of the successful making of ferro-alloys in the electric furnace, steel was next made in France by Héroult and in Sweden by Kjellin, under patents taken out in 1900. In 1906, experiments on the reduction of iron ores in the electric furnace were conducted by the Canadian Government and by Grönwall, Lindblad, and Stalhane in Sweden. The production of pig iron in the electric furnace in Sweden at the present time is a direct result of the work of the three men mentioned.”
“In the development of the electric furnace, its uses have been extended, and today it is used not only in metallurgy but in many branches of applied chemistry as well.”
This publication, by the Bureau of Mines, went on to explain the types of arc furnaces by relating that
“Arc furnaces may be classified, according to the method used in forming the arc, in two general types: (1) Furnaces in which the arc plays between two or more electrodes in the neighborhood of the material to be treated, and (2) furnaces in which the arc is maintained between one carbon electrode and the charge, the latter acting as a second electrode.
“The Stassano furnace [above] is a good illustration of the first type. An arc is maintained between the ends of the two electrodes, and in this way the metal and slag are heated by the heat radiated from the arc.
“The Siemens vertical-arc heating furnace, shown below, is a furnace of the second type. In this furnace, the charge d, which is in contact with the lower electrode c, is heated by maintaining an arc between the end of the upper electrode b and the charge d.”
A circa 1915 publication, Modern Inventions and Great Discoveries, included in its pages the illustration below of the “Stassano Electric Arc Furnace at Turin, Italy,” and generally described “The Electric Furnace” and its merits as follows:
“The invention of the electric furnace, which generates a heat of greater intensity than any other human device, has rendered possible the manufacture of some materials, like artificial diamonds and other gems, that were formerly produced only by the mysterious process of Nature. Many new commercial products also owe their origin to the electric furnace. It is the only means for commercially producing carborundum, the hardest of all manufactured products; calcium carbide, and artificial graphite, though the latter is produced by other means. It has made a useful commercial metal of aluminum, reducing its price from $12.00 a pound to less than 25 cents. It is also used in all methods of fixing nitrogen and the manufacture of artificial nitrates, which are all very important to agriculture.
“The electric furnace has also revolutionized the steel industry. By its means, steel of crucible quality is produced almost as cheaply as by the open-hearth process; while steel rails and heavy-duty steel of crucible texture and toughness are produced at only a slight increase of cost over the comparatively impure and unreliable products of the past.”
Notes:
*See The Electric Mirror on the Pharos Lighthouse and Other Ancient Lighting and the Philosophical Magazine, volume xxxv, page 463.
**Read the 1914 Bureau of Mines publication titled The Electric Furnace in Metallurgical Work, by Dorsey A. Lyon, Robert M. Keeney, and Joseph F. Cullen.
This page was last modified on Wednesday, August 18, 2010