Thursday, February 11, 2010

The uses of Lutetium

Although it's virtually unknown, and spectacularly rare (0.00005% by weight of the earth's crust), lutetium is produced in small commercial quantities, and does have its uses.

Lutetium is primarily extracted from the mineral monazite, which contains 0.003% (30 parts per million (ppm)). The chemical process is rather complicated and produces lutetium oxide. Only about 10 tons are produced annually.

The pure metal itself has only recently been extracted and costs about $10,000 (USD) per kilogram, or about 1/3 the price of gold. It's created by reducing a lutetium halide with an alkali or alkali earth metal; for example: 2LuCl3 + 3Ca → 2Lu + 3CaCl2

Most of the uses of lutetium are above my level of understanding, but I'll try to explain them.

  • The radioisotope 176Lu is used to date meteorites
  • The radioisotope 177Lu is sued as a beta emitter for treatment of certain tumors in the neuroendocrine system
  • Cerium-doped lutetium oxyorthosilicate (LSO), which has the chemical formula Lu2SiO5, is the preferred detector material for PET scanners
  • Pure lutetium can also be a catalyst for various organic reactions including petrochemical cracked, polymerization, hydrogenation, and alkyzation

Tomorrow: part 3: Lutetium compounds

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