After ore is pried from the ground and unwanted minerals are sifted away to make a concentrate of minerals, complex acid and chemical treatments are required to separate individual rare earths into quantities that are useful. Many of the 17 rare earths share such similar physical properties that separating individual elements can require several months and 1,000 chemical treatments.

Grr. No, many of them share such similar chemical properties that we have to use physical differences to separate them.

5 thoughts on “Grrr”

  1. I think they may be right on this one. I’m not a mining engineer, but I work in the oil & gas business. CO2 has very similar “physical” properties (density, boiling point, etc..) to the other gases in the natural gas mixture that you need to use chemical reactions to remove the CO2.

    Tim adds: And I do work with rare earths. And they are chemically almost exactly the same (chemistry is about electrons in the outer ring, they all have the same number of them) therefore you cannot use chemical processes to separate them. You end up having to use their different physical properties to do it.

  2. “they all have the same number of them”. Not really true. Lanthanum, cerium, gadolinium and lutetium have a single valence electron in the d shell, and the others have partially filled f shells. In their +3 oxidation state (very common) they are as near as dammit identical, particularly in terms of ionic radius (which varies only by 20% from one end of the series to the other). This means very similar lattice energies which makes separation hard.

  3. Why not turn ’em into gases and pop ’em through gas centrifuges? There may be some going spare in Iran.

  4. As dearime alludes to, the ultimate expression of this is concentration of U235, which relies entirely on slight physical differences.

  5. “Why not turn ‘em into gases and pop ‘em through gas centrifuges? There may be some going spare in Iran.” probably effective, might not be efficient.

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