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: Contribution to journalArticle

9 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
Pages (from-to)79-127
Number of pages49
JournalUnknown Journal
Publication statusPublished - 2015
Externally publishedYes



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

ASJC Scopus subject areas

  • Geochemistry and Petrology
  • Chemistry(all)
  • Materials Science(all)
  • Physics and Astronomy(all)

Cite this

Nakamura, K., Fujinaga, K., Yasukawa, K., Takaya, Y., Ohta, J., Machida, S., Haraguchi, S., & Kato, Y. (2015). REY-Rich Mud: A Deep-Sea Mineral Resource for Rare Earths and Yttrium. Unknown Journal, 46, 79-127.