The uses of aluminum are myriad, chief among them are in the manufacture of parts of internal-combustion engines, and the fabrication of industrial and household utensils.
CHANGES IN PRACTICE OF ALUMINUM MANUFACTURE
Heretofore bauxites low in silica (2 to 5 per cent. SiO2) have been used for the preparation of alumina for the manufacture of aluminum. Many experimenters have endeavored to utilize low-grade (high-silica) bauxites, or aluminum silicates for the recovery of alumina. These experiments show that it is chemically possible to produce low-silica alumina from many aluminous materials, but not on a commercially profitable basis. It seems reasonably certain that one or more of the methods of handling low-grade bauxite or even aluminous silicates will be developed to the commercial stage, even under ordinary conditions, in the near future. That event should tend to revolutionize the aluminum industry, as clays and shales carrying from 25 to 35 per cent. Al2O3 are of widespread occurrence. Whether it would materially lower the price of aluminum is more doubtful, for the costs of manufacture would be raised by the increased cost of treating the low-grade crude material.
GEOLOGICAL DISTRIBUTION
The European bauxite deposits are in folded sedimentary rocks, mainly of Cretaceous age. In the United States bauxite deposits are surficial and have resulted from the alteration of either sedimentary kaolin (aluminum silicate) or kaolin derived from the weathering of syenite or of dolomitic limestones. In the tropical fields, which have as yet been little exploited and are in fact little known, the bauxites seemingly are surficial deposits derived from the alteration of feldspathic rocks.
GEOGRAPHICAL DISTRIBUTION
The chief bauxite deposits of Europe are in the provinces of Var and Herault, in southern France, though other deposits are known in Bouches du Rhone and several other southern provinces. In central Italy bauxite has been mined for some years. In Germany low-grade bauxite has been mined in the Vogelsberg Mountains, Hesse, near Königswinter, in the lower Rhine country, and is known in Hanover. In the former Empire of Austria-Hungary there are extensive bauxite deposits in the Bihar Mountains and in the provinces of Istria, Croatia, and Dalmatia. Bauxite is also known in northwestern Russia, about 200 miles southeast of Petrograd. Bauxite has been mined for a number of years from beds in northwestern Ireland.
In the United States, bauxite has been mined for years in central Arkansas, northwestern Georgia, northeastern Alabama, and southeastern Tennessee, and more recently from the central Georgia field, which is being extended into west-central Georgia.
In South America, extensive deposits of good bauxite have been found in British and Dutch Guiana, and it is reported that there are evidences of bauxite in eastern Venezuela, western French Guiana, and northeastern Brazil.
In Africa, bauxite of good quality is reported to have been developed near the coast of French Guinea and to have been found in a number of inland localities in that colony. Vague rumors are current of large areas of bauxitic laterite[146] at many places in equatorial Africa.