The HREE concentration process on fish bones.

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K20353
• Research Category: Grant-in-Aid for Research Activity Start-up
• Allocation Type: Multi-year Fund
• Review Section: 0202:Condensed matter physics, plasma science, nuclear engineering, earth resources engineering, energy engineering, and related fields
• Research Institution: Shinshu University
• Principal Investigator: Ejima Terumi 信州大学, 学術研究院理学系, 助教 (70712173)
• Project Period (FY): 2021-08-30 – 2024-03-31
• Keywords: 重希土類元素 / 魚骨 / アパタイト / 有機物 / EPMA

Outline of Final Research Achievements

It has been reported that heavy rare earth elements (HREE) are concentrated in deep-sea sediments to a level several thousand times higher than in terrestrial deposits, attracting attention as a resource. Although it has been elucidated that the host mineral of HREE is apatite, which is a constituent of fish bones, it has not been clarified why the concentration of the HREE in apatite occurred.
Based on the results of previous studies, we focused on the high possibility that the organic matter of fish bone is related to the enrichment mechanism of HREE. In this study, experiments on the concentration of HREE in fish bones were investigated, and it was found that HREE were more easily concentrated in organic matter than in inorganic apatite, which is a constituent of fish bones, and that some organic matter are more easily concentrated than others.

Free Research Field

鉱物学

Academic Significance and Societal Importance of the Research Achievements

魚類起源アパタイトの重希土類元素の濃集メカニズムを解明するには、アパタイト中の重希土類元素の存在状態を明らかにすることが重要である。先行研究では、重希土類元素はアパタイト中の構造にCaを置換して存在、またはアパタイト結晶の表面に吸着し錯体として存在することが報告されてきた。本研究では、これまでに検討されなかった魚の骨がもつ有機物に着目した。その結果、有機物が重希土類元素の濃集に関わる可能性が高いことが明らかになった。今後、魚類起源アパタイトの重希土類元素の濃集のより詳細なメカニズムが明らかになれば、深海底泥からの効率的な重希土類元素回収や固定回収技術の開発への発展も期待できる。