关于稀土中钍的去除问题

现有稀土湿法冶金过程中对钍的去除，不论是酸法或碱法，一般采用选择性沉淀（ｐＨ１．０５）法，萃取法或分级沉淀分级结晶法，其原理基于钍与稀土在特定条件下分配系数Ｋ的区别，但不足之处是钍在过程中多处分布，并影响环境保护和稀土产品质量。本综合分析了钍的特性及其有阴阳离子交换树脂上的行为后，提出了用离子交换色层工艺可将钍除掉的新方案。

Problem of the Removal of Thorium from Rare Earths

In the current hydrometallurgy processing of rare earths, the methods, such as selected precipitation (pH1.05), (liquid) extraction, or fractional precipitation-fractional crystallization, are usually ed to remove thorium. regardless of the acid or the alkaline proeess. The principle of there methods is based on the difference in partition value K between thorium and rare earths. The insufficiency of above methods in processing is that the thorium partitioned into several parts, may impair the purity of certain final individual rare earth product and environmental protection. In order to improve the removal of thorium from rare earth, the character of thorium and its behaviour on cation and anion ion exchanger are analyzed. On the basis of above analysis the cation and anion ion exchange chromatography is proposed as a new technology in rare earth hydrometallurgy processing for better removal of thoritum from rare earth.