铀尾矿中铀、钍及部分金属的模拟淋浸实验初探

Preliminary study on uranium,thorium and some other metals leached from uranium tailings under simulated natural environmental conditions

模拟广东某地区降雨的几种要素,对该地某铀矿区的两种粒径(<0.45 mm和>6 mm)的铀尾矿,分别采用1 h及24 h的初始浸泡时间、pH=3.0及pH=6.0的淋浸剂,以开放体系,进行7周的半动态淋滤实验,初步考察铀尾矿中铀钍的释放规律及其与金属元素Al、K、Mg释放行为的相关性.结果表明:(1)对铀尾矿释放铀能力的影响作用依次为:粒径>pH>浸泡时间;对钍释放能力的影响作用依次为:pH>粒径>浸泡时间.(2)pH、粒径和浸泡时间的改变将影响U与Th、Al、K和Mg的释放相关性.

Under simulated natural environmental conditions, a semi-dynamic leaching test was cameo out Ior studying the release behaviors of uranium and thorium and their correlations with those of A1, K and Mg in uranium tailings. The uranium tailings were exposed to an open system over seven weeks, with two different tailing particle size （ 〈 0.45 mm and 〉 6 mm）, two different soaking time （ 1 h and 24 h） and soaking solutions in two different acidity （pH = 3 and 6）. Based on the analysis of the experimental data and the correlation relationships, the factors influencing uranium release in sequence are as follows： uranium tailing particle size 〉 the acidity of socking solutions 〉 socking time. The influential factors in sequence on thorium release are the acidity of socking solutions 〉 uranium tailing particle size 〉 socking time. The changes of the acidity of socking solutions, tailing particle size and socking time would affect the correlation relationships among U, Th, A1, K and Mg as well. This study would be of high reference values for better understanding the geo-environmental and chemical behaviors of uranium and thorium from uranium tailings under naturally environmental conditions.