著者

村上 浩康 佐藤 比奈子 石山 大三 石原 舜三

出版者

The Society of Resource Geology

雑誌

資源地質 (ISSN:09182454)

巻号頁・発行日

vol.61, no.2, pp.129-137, 2011-05-25

参考文献数

23

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High-grade REE ores containing acid-resistant minerals, which are common in the Nolans Bore REE-P-U deposit, Northern Territory, Australia, were analyzed by ICP-MS after decomposition of two different preparation methods before the analyses; Li-borate-fusion in a commercial laboratory and multi-acid digestion in our organization. The result derived from multi-acid digestion method shows higher values on LREE relative to the other fusion method, yet Y and Zr showed us higher values on the fusion method. The high-grade REE ores are enriched in light-REE, especially Ce, La and Nd, with a maximum total REE value around 7 wt %. The quantitative analysis by multi-acid digestion seems highly reliable for a wide range of REE concentration when using suitable dilution ratio and digestion sequence with several types of acids which could totally dissolve acid-resistant minerals such as monazite. On the other hand, analysis by Li-borate-fusion at a commercial laboratory potentially gives lower values than that of multi-acid digestion; a given sample is extremely concentrated in light REE. It is necessary to examine the upper as well as the lower detection limits by a conventional analytical method in a commercial laboratory.