In addition to the manufacture of steel, the application of the electric furnace for producing what are known as ferro-alloys, or alloys of iron, silicon, chromium, manganese, tungsten and vanadium, is now a large and important industry.  Special steels have their uses in different mechanical applications and the advantage of alloying them with the rarer metals has been demonstrated for several important purposes, as for example, the use of chrome steel for armor plate, and steel containing vanadium for parts of motor cars.  These industries for the most part contain electric arc furnaces and have, as their object, the manufacture of ferro-alloys, which are introduced into the steel, it having been found advantageous to use the rare metals in this form rather than in their crude state.

There is one electro-metallurgical process that has made possible the production in commercial form and for ordinary use of a metal that once was little more than a chemical curiosity.  In 1885 there were produced 3.12 tons of aluminum, and its value was roughly estimated at about $12 a pound.  By 1908 America alone produced over 9,000 tons valued at over $500,000,000, while European manufacturers were also large producers.  In 1888 the electrolytic manufacture of aluminum was commenced in America and in the following year it was begun in Switzerland.  Aluminum is formed by the electrolysis of the aluminum oxide in a fused bath of cryolite and fluorspar.  The aluminum may be obtained in the form of bauxite, and is produced in large rectangular iron pots with a thick carbon lining.  The pot itself is the cathode, while large graphite rods suspended in the bath serve as the anodes.  After the arc is formed and the heat of the bath rises to a sufficient degree the material is decomposed and the metal is separated out so that it can be removed by ladling or with a siphon.  The application of heat to obtain this metal previous to the invention of the electric furnace could only be considered a laboratory problem and the expense involved did not permit of commercial application.  Now, however, aluminum is universally available and with the expiration of certain patents, the material has sold as low as 25 cents a pound.

Electrolytic methods serve also for the refining of nickel and for the production of lead, and as in other fields of metallurgy, these processes are attracting the attention of chemists and of engineers.  While tin as yet has not yielded to electrolytic or electro-thermal methods with any success, the removal of tin from tin scraps and cuttings has been carried on with considerable success.  With zinc the electrolytic and electro-thermal processes have not been able yet to compete with the older metallurgical method of distillation, but an important industry is electro-galvanizing, where a solution of zinc sulphate is deposited on iron and gives a protective coating.  Experimental methods with the use of electricity in extracting zinc from its ores are being tested at various European plants, but the matter has not yet reached a commercial scale.