Preconcentration techniques for thorium (IV) analytical determination

Thorium is a natural radioactive element, which wildely exists in various geological conditions, the content of thorium is richer than that of uranium. In this paper, some separation and concentration techniques reported at home and abroad in recent decade are summarized. These techniques are sorted to three types, which is liquid-liquid extraction, solid phase extraction and liquid membrane extraction. The application range and the ability of separation and extraction are mainly discussed, and their advantages and disadvantages are also compared. The prospect of preconcentration technique before the analysis of thorium is proposed. (authors)