By far the largest and most important use of bauxite is for the extraction of aluminum, a metal used mainly in the manufacture of parts for internal-combustion engines and of industrial and household utensils. Bauxite is also used in the manufacture of artificial abrasives, as a source of certain aluminum salts, and in the manufacture of refractory bricks. The first two uses, the manufacture of aluminum and abrasives, are the most essential, though it would be difficult to restrict to any great extent the use in the chemical industry.
The principal bauxite deposits of the world are in the provinces of Var and Herault, southern France; in the former empire of Austria-Hungary; in Arkansas, Georgia, and Alabama; in British and Dutch Guiana; and in northwestern Ireland. Minor deposits are located in Germany, Russia, Venezuela, French Guiana, Brazil, Africa, Australia, and probably China. It is believed that the tropical countries hold immense reserves of bauxite.
Experiments have shown that it is chemically possible to manufacture aluminum from the low-grade (high-silicate) bauxite ores. No commercial process has been perfected, but it seems certain that one or more methods will be developed to the commercial stage in the near future. A reduction in the price of aluminum is not to be expected as a result of this change in practice, however, for the use of low-grade materials will undoubtedly increase the manufacturing costs.
The largest producing bauxite deposits are controlled politically by the United States and France. Great Britain controls a large share of the equatorial regions that probably contain most of the undeveloped deposits. Bauxite may also be found in the colonial possessions of Portugal and Belgium, and in those formerly owned by Germany. The aluminum works of the world are controlled by the United States, Great Britain, France, Germany, Switzerland, Italy and Norway.
Most of the bauxite deposits of the United States are owned by the Aluminum Company of America, which is dominated by the Mellen banking interests, of Pittsburgh, and controls all of the aluminum works of the United States and Canada. Small holdings in the United States are controlled by a subsidiary of the E. I. du Pont de Nemours Co., and by the Norton Co., of Worcester, Mass. The Aluminum Company of America also controls, through subsidiaries, large areas of bauxite land in British and Dutch Guiana. Before the war some of the large French deposits were controlled by German interests. The French industry is largely in the hands of French producers of aluminum, although some of the deposits are said to be controlled by British capital. The main French companies have organized a selling company, L’Aluminium Française.
The British Aluminium Co., controls the deposits in Ireland and is the sole producer of aluminum in England. British capital also controls aluminum works in Norway. The principal bauxite deposits of Italy are probably controlled by the Societa Italiana per la Fabricazione dell’ Alluminio, an Italian-French company. Apparently most of the aluminum industry of the Central Powers is controlled by a German-Swiss company. American interests are reported to have explored bauxite deposits in French Guinea, Africa, but so far as known have produced no bauxite.
CHAPTER XX
EMERY AND CORUNDUM
By Frank J. Katz
USES OF EMERY AND CORUNDUM
Corundum is the natural (mineral) crystalline oxide of aluminum. Emery is a very fine-grained and intimate intergrowth of corundum and other minerals, chiefly magnetite, some varieties containing also important amounts of hematite, spinel, and chlorite. Both emery and corundum are very hard, and break into rough, sharp grains; hence they are used as abrasives for grinding, dressing, and polishing metals—chiefly iron and steel—and glass, and, to a less extent, stone, wood, and other materials. Emery and corundum are used loose in the form of grains, powders, and flours, and also as grains made up into solid wheels, cylinders, blocks, and files of many shapes by means of a great variety of binders. The essential uses are in work on iron and steel and glass. The softer metals and other materials can be worked in many cases to better advantage with other abrasives, such as quartz, tripoli, garnet and pumice.
The essential operations for which emery and corundum are used can be performed with the artificial carbide and alumina abrasives. For some work, however, such substitutions appear not to be advisable, as the abrasive quality and efficiency of both the natural and artificial abrasives depend not only on the hardness of these materials, but also on a number of other factors: among these being the physical qualities of the materials worked; the sharpness of edges and angles of broken particles of the abrasive; the manner in which the abrasive breaks down under use; the manner of, and materials used in, binding the abrasive particles; and the speed and pressure with which they are applied to the work.