中文摘要：

以721铀矿云际矿石为研究对象，通过室内铀矿石柱浸试验，研究铀矿石在细菌池浸过程中钍浸出特征。试验结果表明，柱浸过程中，水文地球化学条件（pH和Eh）对钍浸出影响不大，随着时间变化，pH值在1．73～1．36发生变化，Eh值在169～592mV变化，但钍浸出量基本稳定在2．2～2．5mg／L。同时试验结果发现，原矿铀浸出率为80．03％，钍浸出率仅约为14．1％，主要原因是U、Th的化学性质不同，Th均以＋4价稳定存在于矿石中，一般不易被溶解而迁移转化。U具有多种价态，在氧化条件下显示＋6价，而这种价态的U性质活泼，易于在环境中迁移转化。

英文摘要：

In this paper, the thorium leaching characteristics is investigated in the bacteria column leaching of uranium ore in Yunji ore deposit of 721 uranium mines. The results show that the hydrogeochemical conditions （pH and Eh） have little effect on the leaching of thorium in the process of column leaching. Although the pH value chan- ges from 1.73 to 1.36, or the Eh value changes from 169 mV to 592 mV, but the last amount of Th leaching is maintain at 2.2-2.5 mg/L. Meanwhile, the experiment results also indicate that the leaching rate of Th reache to 14.1%, while the leaching rate of uranium is 80.03M. The main reason of the results is that U and Th possess dif- ferent chemical properties. The Th （＋4 valence） is difficult to be dissolved, migrated and transformed because of its stability. However, the U has multiple valence states. The ＋6 valence is unusual dynamic and easy to be migra- ted and transformed in the environment.