Rare earths, aka lanthanides

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Astronuc

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Rare earths are of considerable interest in modern technology.

China has substantial deposits of light and heavy rare earths. Australia and the US have deposits as well.

Recently, Japan has identified substantial deposits in its exclusive economic zone.
http://www.asahi.com/ajw/articles/AJ201804170045.html

The deposits, estimated at 16 million tons, lie at a depth of 5,700 meters about 250 km south of Minami-Torishima island in the Pacific Ocean.
It was estimated that the deposits contain enough dysprosium, which is used in the production of hybrid auto motors, to last for 730 years, and 420 years’ worth of terbium, which is used in magneto-optical discs, among other things.
 

Astronuc

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Crustal Abundance (parts per million) of lanthanides, and scandium and yttrium. Elements listed with Z and element symbol.
Code:
Nickel (28Ni)        90
Zinc (30Zn)          79
Copper (29Cu)        68
Cerium (58Ce)        60.0
Lanthanum (57La)     30.0
Cobalt (27Co)        30
Neodymium (60Nd)     27.0
Yttrium (39Y)        24.0
Scandium (21Sc)      16.0
Lead (82Pb)          10
Praseodymium (59Pr)  6.7
Thorium (90Th)       6
Samarium (62Sm)      5.3
Gadolinium (64Gd)    4.0
Dysprosium (66Dy)    3.8
Tin (50Tn)           2.2
Erbium (68Er)        2.1
Ytterbium (70Yb)     2.0
Europium (63Eu)      1.3
Holmium (67Ho)       0.8
Terbium (65Tb)       0.7
Lutetium (71Lu)      0.4
Thulium (69Tm)       0.3
Silver (47Ag)        0.08
Gold (79Au)          0.0031
Promethium (61Pm)    1E-18

Promethium is naturally radioactive
Reference: EPA, Rare Earth Elements: A Review of Production, Processing, Recycling, and Associated Environmental Issues (2012)

The REEs are sometimes classified as light RE: lanthanum, cerium, praseodymium, neodymium, samarium, europium, and heavy RE gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium. Scandium and yttrium are lighter than the lanthanides.
 
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Might be slightly off topic, but how can someplace (like Japan) have an abundance of rare elements?
Plate tectonics? ancient meteor strike?
 

Astronuc

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anorlunda

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Might be slightly off topic, but how can someplace (like Japan) have an abundance of rare elements?
Plate tectonics? ancient meteor strike?
I was going to move this thread to the Earth forum so that you could get an answer to that. But I forgot to reckon with @Astronuc , his knowledge is encyclopedic. :wink:
 

Astronuc

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