Element Bismuth, Bi, Poor Metal
|For the purposes of analysis, bismuth is classed along with the metals of the copper group, because it forms a sulphide which is insoluble in dilute acids as well as in alkali sulphides. According to its chemical affinity, however, it is so closely connected with antimony and arsenic, which belong to the last group, that it must be treated along with these, and is therefore suitably placed at the point of transition from the one group to the other. Of these elements it has the highest combining weight; for this reason, in accordance with the general rule, the basic properties are more strongly marked in it than in the case of its congeners. As the combining weight decreases, the latter rapidly lose their metallic character and the power of forming basic oxides, and finally lead to the non-metallic elements phosphorus and nitrogen, in which the acid-forming properties are completely developed. |
Metallic bismuth is a white, somewhat reddish metal of a well- marked crystalline character; it is brittle, is not ductile, and falls to a powder when struck with a hammer. It melts as low as 270°, and at a bright white heat passes into a vapour, the density of which leads to the molar weight 209, which coincides with the combining weight. It remains unchanged in the air, and is also very resistant to water. It is not attacked by dilute acids; its position in the potential series is between copper and silver, and it therefore inclines towards the noble metals. It therefore occurs in nature in many cases even in the uncombined state; it also occurs combined with sulphur as bismuth glance. Bismuth is readily dissolved by nitric acid with formation of bismuth nitrate and nitrous oxide.
Bismuth readily forms alloys with other metals whereby, in accordance with the general law, the melting point sinks. By the addition of lead, tin, and cadmium, alloys are obtained which liquefy even under 100°; they fuse therefore in boiling water.
The combining weight of bismuth has been determined by weighing the metal and the oxide obtained from it. It is not known with perfect certainty, and we shall take it as Bi = 208.5.
|History of bismuth is complex, because before the middle of 18th century in early times Bismuth was confused with antimony, tin and lead. It has been known in Europe as a peculiar metal as well as in form of salts since 15th century. It was mentioned in many works on 15th - 17th century's authors, especially those of Valentinus and Paracelsus. Its production was first described by Agricola. Edmund von Lippmann in his in "Geschichte des Wismuts zwischen 1460 und 1800" (1930) encountered in the literature from the 15th to the 17th century 21 names for the metal. In 16th and 17th centuries bismuth was widely used in alloys, and its salts applied in medicine and in make-ups. However only in 18th century by the work of Pott and Bergman, bismuth was definitely recognized century as a specific metal. The origine of the name "bismuth" is not clear. Perhaps it came from German Wismuth, presumably weiBe Masse, "white mass".|
Early History Apparently the first mention of bismuth as a true metal was made by Agricola in the sixteenth century; he describes it as a form of lead and outlines a process of extraction by liquation. Bismuth was probably known at a much earlier date, but as it was frequently referred to as marcasite—a name used for many different materials—the early history is confused. Paracelsus in the early sixteenth century regarded bismuth as a semi-metal. It was found associated with ores of tin in Saxony, and during extraction bismuth and tin were melted together, the tin thus becoming brittle and hard. Reference to the discovery of bismuth in Europe was made by a South American priest in a report prepared by him on the metal resources of South America. He wrote - " Bismuth was discovered a few years ago, in the Sudnos Mountains of Bohemia; it is a metal somewhat like a cross between Tin and Lead, without being either of the two."
The metal appears to have been used chiefly in the manufacture of pewter, the addition of bismuth making the metal more sonorous.
The chemistry of bismuth and its compounds was investigated by Lemery, Pott, Geoffroy, Bergmann, Davy, Lagerhjelm, Muir and his collaborators, and others.
The origin of the name is not known with certainty. It has been derived conjecturally from Arabic and from Persian, but it is possibly of German origin, connected with a miners' term wis mat (weisse masse) meaning "white mass."
|Poor Metal Bismuth abundance is 2x10-5 mass % in the Earth's crust, and 2x10-5 mg/l in sea water. It is found in a great number of minerals, the main ones of which are bismuth glance Bi2S3, native bismuth, bismite Bi2O3 and other. In large quantities but small concentrations bismuth is also found as an isomorphic impurity in lead-zinc, copper, molybdenum-cobalt and tin-tungsten ores. Almost 90% of world extraction comes from complex ores processing by-products. |
Although numerous minerals containing bismuth have been described, very few occur in sufficient quantity to be of economic importance. In general they occur in metalliferous veins associated with ores of cobalt, nickel, lead, zinc, tin, silver, etc. The more important ores are those containing native bismuth, bismuthinite or bismuth glance, Bi2S3, tetradymite (sulphide and telluride of bismuth), bismite or bismuth ochre, Bi2O3, and bismutite, Bi2O3.CO2.H2O. Deposits occur in many parts of the world, those of Bolivia being the most productive on account of the bismuth minerals in the mountain of Tazna situated in that country. The deposits in Germany, Czechoslovakia and Hungary are mainly of historical importance. Deposits have also been found in Spain. Bismuth-bearing minerals have so far been found only in small quantities in the British Empire, but attempts have been made to develop those of Australia. Native bismuth and bismuthinite have been found in the wolfram- and cassiterite-bearing veins of Lower Burma. The compositions of some minerals from Vasko (Hungary) are given in the following table
Composition of some Bismuth minerals from Hungary
|Bismuthinite, Bi2S3.||Cosalite, Pb2Bi2S5 or 2PbS.Bi2S3||Rezbanyite, Cu2Pb3Bi10S19 or Cu2S.3PbS.5Bi2S3.|
|Silver||. . .||. . .||0.32||. . .||. . .|
|Silica||. . .||0.43||. . .||. . .||0.12|
An examination of the geological formation of the deposits in South America suggested that as native bismuth was found in the upper oxidised portions of the deposit, it should be regarded as of secondary formation, the primary material being bismuthinite.