Bismuth

This metal was named Bismutum by Basile Valentin in 1450 and Wismut by Paracelsus in the 16th century. In his treatise De re metallica, which also dates from the 16th century, Agricola expressed the view that the metal was a variety of lead and called it Plumbum cinerum. Certain alloys used in the 15th century by Gutenberg contained bismuth. The name of the metal is derived from the German weisse masse (white substance). The basic nitrate Bi(OH)2O3 was used by painters in the 16th century and was known as blanc d’Espagne. Industrial production of the metal only began around 1830 in Saxony.

Bi Bismuth

Properties

  • Pinkish metallic lustre and is very brittle.
  • The metallic features are much more clear-cut than is the case for arsenic and antimony.
  • Expands on solidification (+3.3%).
  • Slow solidification causes very characteristic large crystals to form.
  • Unlike most metals, its electrical resistivity in the solid state is greater than in the liquid state.

Applications

  • Bismuth citrate in association with antibiotics is a very efficient agent against the bacteria responsible for stomach ulcers
  • Bismuth metal is added as an alloying element in free cutting steels to improve their machinability.
  • It is used in safety fuses like sprinklers, and occasionally to make moulds in the thermoplastic materials industry.
  • A component of low melting-point solders used in temperature-sensitive electronic assemblies.
  • Some 200–300 tonnes of bismuth a year are used as pigments in paints (e.g. bismuth vanadate BiVO4, which gives a range of bright yellow colours for use in the automotive industry).
  • The oxychloride BiOCl is used in cosmetics to give a pearl-like, shiny lustre to lipsticks, nail varnishes and hair lacquers.
  • In the form of the borosilicate it is used in earthenware enamelling.
  • Bismuth is commonly used as an environmentally-friendly substitute for lead in many applications by virtue of its low toxicity.

Recycling

Bismuth is difficult to recycle because it is used in many dissipative applications, such as pigments and pharmaceuticals. It is recovered from the production processes for lead and copper refining.

PRECIOUS METALS REFINING

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