BISMUTH ORES
Economic Features
Bismuth metal is used in alloys, to which it gives low fusibility combined with hardness and sharp definition. Bismuth alloys are employed in automatic fire sprinklers, in safety plugs for boilers, in electric fuses, in solders and dental amalgams, and in some type and bearing metals. Bismuth salts find a considerable application for pharmaceutical purposes, especially in connection with intestinal disorders, and the best grades of bismuth materials are used for this purpose. The salts are also used in porcelain painting and enameling and in staining glass.
Bolivia is the most important producer of bismuth ore. The output is controlled entirely by British smelting interests. An important deposit exists in Peru, the output of which is limited by the same British syndicate. Considerable bismuth is produced in Australia, Tasmania, and New Zealand, all of which likewise goes to England. Germany before the war had three smelters which produced bismuth from native ores in Saxony; bismuth was one of the few metals of which Germany had an adequate domestic supply. Recently southern China is reported to be mining increasing amounts of bismuth.
The United States produces the larger part of its bismuth requirements, chiefly from plants installed at two lead refineries. A further installation would make this country entirely independent of foreign supplies if occasion required. Imports, from England and South America, have been steadily declining, but during the war were somewhat increased. The United States does not export bismuth so far as known.
Geologic Features
The principal minerals of bismuth are bismuthinite (bismuth sulphide), bismutite (hydrated carbonate), bismite or bismuth ocher (hydrated oxide), and native bismuth.
The native metal and the sulphide are believed to be formed mainly as primary minerals of igneous origin. In the deposits of New South Wales they are found associated with molybdenite in quartz gangue, in pipe-like deposits in granite. The oxide and the carbonate are probably products of surface weathering. The Bolivian deposits contain the native metal, the oxide, and the carbonate, associated with gold, silver, and tin minerals, in one locality in slates and in another locality in porphyry. The origin is not well known.
In the United States, the sulphide, bismuthinite, is found in the siliceous ores of Goldfield, Nevada (p. 230), and in minor amounts in a great number of the sulphide ores of the Cordilleran region. The ores of the Leadville and Tintic districts (pp. 219 and 235) yield the larger part of the United States production, the bismuth being recovered as by-product from the electrolytic refining of the lead bullion. Large amounts of bismuth pass out of the stacks of smelters treating other western ores, and while it would not be cheap nor easy to save the bismuth thus lost, it could probably be done in case of necessity.