Rare Metal Investments – Tellurium

rare metal investments - Bismuth

Tellurium is in the A Basket.

It is a beautiful word, perhaps the best that can be given to an element: Tellurium, derived from the Latin word “earth“.

This metal is as rare as its beautiful name: Only nine other elements are just as rare as the silvery-white metalloid with a metallic lustre. Tellurium is soft on the one hand, and very brittle on the other, and can be processed perfectly to powder. It was discovered in 1782 by the Austrian chemist and mineralogist Franz Joseph Müller von Reichenstein, who at first considered it to be “sulphurised bismuth“. It was only in 1797 that the Berlin chemist Martin Heinrich Klaproth could verify the discovery. Klaproth was a renowned luminary, a man who also discovered uranium, zirconium and cerium and gave the name tellurium to the raw material discovered by Mueller von Reichenstein. He wrote: “To fill this existing gap in the chemical mineralogy, I put forward my experiments and experience with these precious ores, whose main result lies in the discovery and validation of a new peculiar metal, for which I have given the name tellurium, based on our ancient mother earth“.

Four major manufacturing plants for tellurium have been set up to date, which jointly supply two thirds of the market: The United States, Canada, Japan and Peru. Estimated overall world production is about 180 tonnes per year.

But, why is tellurium needed at all? Traditionally, it is important as an alloying element for the cable industry and steel production. It comes in coatings for DVD and Blue-ray discs, as well as in semiconductors; mostly in the field of Photovoltaics, namely in solar systems and the conversion of solar energy into electricity. Even in some fireworks one can admire it when the salts of tellurium render a grass-like green color.

But not only because of the future-proof application methods and the splendid fireworks it is indispensable: Merely because of its beautiful name, the element deserved its discovery in 1782: Tellurium.

Specifications

Element Symbol: Te
Atomic mass: 127.6 amu
Atomic radius: 143.2 pm
Density: 6.24 g/cm³
Color: Silvery White
Melting point: 449.5 °C
Boiling point: 989.8 °C
Heat of evaporation: 48 kJ/mol
Annual production worldwide approx.: 180 t.

Application

  • Semi-conductors
  • Coloration of glass and ceramics
  • Cover for undersea electric cables
  • Solar cells
  • Optical memory (DVD-RW, CD, etc.)
  • Novel material for data storage media, such as “Phase Change Random Access Memory”
  • Alloying constituent for steel, cast iron, lead and copper alloys
  • Photodiode
  • Thin layer solar cells
  • Peltier elements