Abstract
Rare earth elements (REE) are used in various high-performance industrial products in recent years, but there are supply risks due to their uneven regional distribution. Ion Adsorption Deposits (IAD) are excellent in that REEs can be extracted at room temperature, they are rich in heavy REEs with high resource value, and their environmental impact is relatively small. In the REE concentrations in the IAD, the extraction rate is considered to be high due to the weak adsorption of REE as exospheric complexes on weathered clay minerals, and such clay minerals tend to be formed in temperate regions where the degree of weathering is moderate. Therefore, in this study, we used weathered granite samples generated from weathering granites of different ages in temperate Japan (six sites in total in Japan: Osumi Peninsula, Kagoshima Prefecture, Otake City, Hiroshima Prefecture, Tanakama-Yama, Shiga Prefecture, Kofu City, Yamanashi Prefecture, Ishikawa-machi, Fukushima Prefecture, and Taiheizan, Akita Prefecture) to discuss IAD formation process and factors regulating it.
