http://www.asyura2.com/11/hasan72/msg/326.html
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夢はあるが、中国みたいに、ちょっと掘れば出てくるというものではない
遥かに高い採掘コストを考えれば、実用化は大分先の話だな
http://headlines.yahoo.co.jp/hl?a=20110703-00000828-yom-sci.view-000
太平洋にレアアース鉱床…陸上埋蔵量の８００倍
読売新聞 7月4日(月)2時2分配信
ハイブリッド車のモーターやＬＥＤ照明などに不可欠なレアアースを豊富に含む鉱床が、太平洋の深さ３５００〜６０００メートルの海底に大量に存在することを、東京大工学系研究科の加藤泰浩准教授らの研究グループが発見した。
資源量は、陸上埋蔵量（約１億１０００万トン）の８００倍に及ぶと見積もられ、中国依存の供給事情や将来の枯渇などの懸念を抱えるレアアースの安定確保につながる成果として注目される。
成果は、４日の英科学誌ネイチャー・ジオサイエンス電子版に発表される。
グループでは、日本や米国が参加した国際深海掘削計画などで太平洋の広範囲で採取され、参加各国の研究機関に保管されている２０００を超える海底堆積物の試料の組成を分析した。
最終更新:7月4日(月)2時2分
読売新聞
Yahoo!ニュース関連記事
東大、太平洋にレアアース資源を発見写真（レスポンス） 19時20分
東大など、太平洋の海底に陸上埋蔵量の約1000倍となるレアアース鉱床を発見写真（マイコミジャーナル） 19時10分
情報ＢＯＸ：世界各地のレアアース埋蔵量（ロイター） 18時59分
太平洋海底に巨大レアアース鉱床、陸上埋蔵の1000倍か（ロイター） 15時5分
太平洋海底に大量のレアアース〜東大チーム映像（日本テレビ系（NNN）） 13時45分
この記事に関連するニュース一覧を見る（13件）
http://www.nature.com/ngeo/journal/vaop/ncurrent/carousel/ngeo1185-f1.jpg
Deep-sea mud in the Pacific Ocean as a potential resource for rare-earth elements
Yasuhiro Kato,
Koichiro Fujinaga,
Kentaro Nakamura,
Yutaro Takaya,
Kenichi Kitamura,
Junichiro Ohta,
Ryuichi Toda,
Takuya Nakashima
& Hikaru Iwamori
World demand for rare-earth elements and the metal yttrium―which are crucial for novel electronic equipment and green-energy technologies―is increasing rapidly1, 2, 3. Several types of seafloor sediment harbour high concentrations of these elements4, 5, 6, 7. However, seafloor sediments have not been regarded as a rare-earth element and yttrium resource, because data on the spatial distribution of these deposits are insufficient. Here, we report measurements of the elemental composition of over 2,000 seafloor sediments, sampled at depth intervals of around one metre, at 78 sites that cover a large part of the Pacific Ocean. We show that deep-sea mud contains high concentrations of rare-earth elements and yttrium at numerous sites throughout the eastern South and central North Pacific. We estimate that an area of just one square kilometre, surrounding one of the sampling sites, could provide one-fifth of the current annual world consumption of these elements. Uptake of rare-earth elements and yttrium by mineral phases such as hydrothermal iron-oxyhydroxides and phillipsite seems to be responsible for their high concentration. We show that rare-earth elements and yttrium are readily recovered from the mud by simple acid leaching, and suggest that deep-sea mud constitutes a highly promising huge resource for these elements.
At present, 97% of the world's production of rare-earth elements
and yttrium (REY) is accounted for by China, although China
has only one-third of global reserves and the Commonwealth of
Independent States, the United States, and Australia together have
another one-third of reserves1. China's dominance pertains to
heavy rare-earth elements (HREE; conventionally Gd to Lu, but
Eu is included here), which are especially important materials for
high-technology products including electric automobiles and flatscreen
televisions8. HREE reserves are almost all in ion-absorptiontype
ore deposits in southern China, whereas light REE (LREE)
can be obtained from carbonatite/alkaline igneous complexes in
other countries13. We report here the great potential of deep-sea
REY-rich mud in the Pacific Ocean as a new mineral resource for
REY, especially HREE, because the mud commonly has a higher
HREE/LREE ratio than the southern China ion-absorption-type
deposits, as described below.
We studied drill core samples from 51 sites obtained by the Deep
Sea Drilling Project/Ocean Drilling Program (DSDP/ODP) and
piston core samples from 27 sites obtained by the Ocean Research
Institute, the University of Tokyo (Supplementary Table S1), which
cover a major portion of the Pacific Ocean (Fig. 1). Many of the
DSDP/ODP holes penetrated a depth greater than 50m below
seafloor (mbsf), whereas most of the University of Tokyo piston
cores are 10m long and some are less than 3m long (Fig. 2
and Supplementary Fig. S1). We measured chemical compositions
of 2,037 bulk-sediment samples to evaluate the potential of
seafloor sediment as a REY resource (Supplementary Data S1 and
also see Methods).
REY-rich mud (generally metalliferous sediment, zeolitic clay,
and pelagic red clay in lithology) is mainly distributed in two
regions: the eastern South Pacific and central North Pacific (Fig. 1).
In the eastern South Pacific (520 S, 90150 W), the REY-rich
mud has high REY contents, 1,0002,230 ppm total REY (6REY)
and 200430 ppm total HREE (6HREE). REY contents of the mud
are comparable to or greater than those of the southern China
ion-absorption-type deposits (6REYD5002,000 ppmI6HREED
50200 ppm; refs 9,10); notably, the HREE are nearly twice as
abundant as in the Chinese deposits. The core profiles reveal that
the REY-rich mud has accumulated to thicknesses of 10m at
Sites 76 and 319 (Figs 2b, 3 and Supplementary Fig. S1). The
REY-rich mud lies at the surface and is less than 3m thick at
Sites 75 and 597, although the average REY contents there are very
high (6REY D 1,530 ppm at Site 75 and 1,630 ppm at Site 597;
Supplementary Table S2 and Fig. 3). At Site 596, 2,000 km west
of these areas, high-6REY mud (2,110 ppm maximum, 1,110 ppm
average) occurs in a layer40mthick below 13.5 mbsf, whereas the
surface sediment has 6REY contents of less than 250 ppm (Figs 2b
and 3; Supplementary Fig. S1).
The REY-rich mud in the North Pacific east and west of the
Hawaiian Islands (320 N;130 W170 E; Fig. 1) has moderate
REY contents (6REY D 4001,000 ppm;6HREE D 70180 ppm).
Deposits in this region are much thicker than those of the
eastern South Pacific, mostly >30m and locally >70m (for
example, Site 1222; Figs 2a, 3 and Supplementary Fig. S1).
Cores from east of the Hawaiian Islands commonly show broad
peaks of REY content that extend deeper than 10 mbsf (for
example, Sites 12151218; Figs 2a, 3 and Supplementary Fig. S1).
West of the Hawaiian Islands, some cores have relatively high
6REY contents, ranging from 680 to 1,130 ppm (Sites 68 and
170). Although the cores are relatively short (less than 20 m)
in the western area, the thickness of the REY-rich mud is
probably comparable to that in the eastern area, considering its
presence deeper than 40 mbsf at Sites 164 and 168 (Fig. 2a and
Supplementary Fig. S1).
REY-rich mud with moderate REY content is also found in the
northeast Pacific, west of the Juan de Fuca Ridge, generally between
5 and 40 mbsf (Fig. 2c and Supplementary Fig. S1). The cores
from Sites 33 and 36 contain significant amounts of terrigenous
material and have low REY contents, which suggests that these
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