2018年
Discovery of ion-adsorption type deposits of rare earth elements (REE) in southwest Japan with speciation of REE by extended X-ray absorption fine structure spectroscopy
Geochemical Journal
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- 巻
- 52
- 号
- 5
- 開始ページ
- 415
- 終了ページ
- 425
- 記述言語
- 掲載種別
- 研究論文(学術雑誌)
- DOI
- 10.2343/geochemj.2.0531
Copyright © 2018 by The Geochemical Society of Japan. Ion-adsorption type rare earth elements (REE) deposit in weathered granite is the main source of REE essential for high-technology industries. However, this type deposit has not been well surveyed in Japan. In this study, Bulk REE abundances (=REETOT), ion-exchangeable REE (=REEEX) by ammonium chloride solution, and percentage of REEEX relative to REETOT (=REEPER) in fresh and weathered granite samples in Southwest Japan (i.e., Hiroshima and Shimane Prefectures) were determined. The REETOT and REEPER were comparable to those of ion-adsorption type REE deposits in China. This finding indicates that ion-adsorption type REE deposits can also be found in Japan. Furthermore, extended X-ray adsorption fine structure (EXAFS) spectra of yttrium in original samples and samples after the extraction of ion-exchangeable REE showed that (i) REE in samples with high REEPER mainly forms outer-sphere (OS) complexes and (ii) the remaining REE in the rocks after the extraction forms inter-sphere complexes. These findings suggest that ion-exchangeable REE forms OS complexes, which causes the high extraction rate by the ion-exchange reaction.
- リンク情報
- ID情報
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- DOI : 10.2343/geochemj.2.0531
- ISSN : 0016-7002
- SCOPUS ID : 85054857965