Instrumental Neutron Activation Analysis of Tungsten Content in Mineralized and Non-mineralized Granite.

OGATA Takeyuki, MIZUTA Toshio, ISHIYAMA Daizo, TAKADA Jithuya

doi:10.5188/jsmerj.15.29

Bibliographic Information

Other Title

中性子放射化分析法による鉱化および非鉱化の花こう岩中のタングステンの定量
チュウセイシホウシャカブンセキホウニヨルコウカオヨビヒコウカノカコウガンチュウノタングステンノテイリョウ

Search this article

Abstract

Tungsten content in granitic rocks is precisely determined by an instrumental neutron activation analysis method (INAA) using several standard samples. Natural geostandard rocks are GSJ geostandard of JG-1, JG-1a, JG-2, JR-2 and JR-3, and artificial standard materials of JR-2 with added scheelite powder and tungsten-doped quartz sand were employed for the analysis. Each sample (100mg) was irradiated for short time (1min, 2min and 3min) at thermal neutron flux 2.8×10¹³n/cm²/s and for long time (60min) at thermal neutron flux 2.3×10¹³n/cm²/s. Gamma-ray spectrum of ¹⁸⁷W at 685.72keV was used for the tungsten analysis in geostandards. The ¹⁸⁷W gamma-ray spectrum was not recognized for Na-rich JG-1 (W concentration=1.5ppm), while the gamma spectrum of that was recognized for JR-2 (1.8ppm). S/N ratios of ¹⁸⁷W for geostandards that irradiated for 3min and after cooling for 6 day were higher than those of another irradiation conditions. The analytical error of tungsten in geostandards with the confidential limit of 95% was ± 4.7ppm. This INAA with 3min irradiation is the most suitable method for the tungsten-bearing samples was successfully applied to wide range of tungsten (i. e. low W concentration of non-mineralized granites to high W concentration of mineralized granite and scheelite-bearing ore).

Journal

Journal of the Society of Materials Engineering for Resources of Japan

Journal of the Society of Materials Engineering for Resources of Japan 15 (2), 29-35, 2002

The Society of Materials Engineering for Resources of JAPAN

Keywords

Details 詳細情報について

Export