REY-Rich Mud: A Deep-Sea Mineral Resource for Rare Earths and Yttrium

Kentaro Nakamura, Koichiro Fujinaga, Kazutaka Yasukawa, Yutaro Takaya, Junichiro Ohta, Shiki Machida, Satoru Haraguchi, Yasuhiro Kato

Research output: Chapter in Book/Report/Conference proceedingChapter

29 Citations (Scopus)


This chapter focuses on newly discovered extensive deposits of deep-sea mud containing high concentrations of rare-earth elements and yttrium (REY). The deep-sea REY-rich muds are found in pelagic region of the Pacific Ocean and very recently also in the Indian Ocean. REY-rich muds are characterized by the following five advantages: (1) tremendous resource potential by virtue of their wide distribution, (2) high REY concentrations with significant heavy REE enrichment, (3) a stratiform distribution that allows relatively simple and cost-effective exploration, (4) very low concentrations of radioactive elements such as Th and U, and (5) ease of extraction of REY by acid leaching. These features demonstrate that the REY-rich mud could constitute a highly promising REY resource for the future. A system to mine REY-rich muds is also presented. This system can be developed based on a system developed and tested for sulfide-rich muds in the Red Sea and manganese nodules in the Pacific Ocean, although pressurized air-lift system will be needed to lift REY-rich muds from very deep water.

Original languageEnglish
Title of host publicationHandbook on the Physics and Chemistry of Rare Earths
PublisherElsevier B.V.
Number of pages49
Publication statusPublished - 2015
Externally publishedYes

Publication series

NameHandbook on the Physics and Chemistry of Rare Earths
ISSN (Print)0168-1273


  • Acid leaching
  • Apatite
  • Development system
  • HREE enrichment
  • Pacific Ocean
  • REY-rich mud
  • Rare-earth elements and yttrium

ASJC Scopus subject areas

  • General Chemistry
  • General Materials Science
  • Geochemistry and Petrology
  • General Physics and Astronomy


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