The tremendous potential of deep-sea mud as a source of rare-earth elements

Yutaro Takaya, Kazutaka Yasukawa, Takehiro Kawasaki, Koichiro Fujinaga, Junichiro Ohta, Yoichi Usui, Kentaro Nakamura, Jun Ichi Kimura, Qing Chang, Morihisa Hamada, Gjergj Dodbiba, Tatsuo Nozaki, Koichi Iijima, Tomohiro Morisawa, Takuma Kuwahara, Yasuyuki Ishida, Takao Ichimura, Masaki Kitazume, Toyohisa Fujita, Yasuhiro Kato

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    Abstract

    Potential risks of supply shortages for critical metals including rare-earth elements and yttrium (REY) have spurred great interest in commercial mining of deep-sea mineral resources. Deep-sea mud containing over 5,000 ppm total REY content was discovered in the western North Pacific Ocean near Minamitorishima Island, Japan, in 2013. This REY-rich mud has great potential as a rare-earth metal resource because of the enormous amount available and its advantageous mineralogical features. Here, we estimated the resource amount in REY-rich mud with Geographical Information System software and established a mineral processing procedure to greatly enhance its economic value. The resource amount was estimated to be 1.2 Mt of rare-earth oxide for the most promising area (105 km2 × 0-10 mbsf), which accounts for 62, 47, 32, and 56 years of annual global demand for Y, Eu, Tb, and Dy, respectively. Moreover, using a hydrocyclone separator enabled us to recover selectively biogenic calcium phosphate grains, which have high REY content (up to 22,000 ppm) and constitute the coarser domain in the grain-size distribution. The enormous resource amount and the effectiveness of the mineral processing are strong indicators that this new REY resource could be exploited in the near future.

    Original languageEnglish
    Article number5763
    JournalScientific Reports
    Volume8
    Issue number1
    DOIs
    Publication statusPublished - 2018 Dec 1

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    ASJC Scopus subject areas

    • General

    Cite this

    Takaya, Y., Yasukawa, K., Kawasaki, T., Fujinaga, K., Ohta, J., Usui, Y., Nakamura, K., Kimura, J. I., Chang, Q., Hamada, M., Dodbiba, G., Nozaki, T., Iijima, K., Morisawa, T., Kuwahara, T., Ishida, Y., Ichimura, T., Kitazume, M., Fujita, T., & Kato, Y. (2018). The tremendous potential of deep-sea mud as a source of rare-earth elements. Scientific Reports, 8(1), [5763]. https://doi.org/10.1038/s41598-018-23948-5