野外现场铀矿石中铀的快速准确测定方法研究——TOPO萃取α计数法

Rapid and Accurate Determination of Uranium in Uranium Ores in the Field Using TOPO Extraction and α-counting Method

研究了野外现场快速准确测定铀矿石中铀的三辛基氧膦(TOPO)萃取α计数法。目前野外现场铀的测量主要采用γ谱法,即利用铀子体的γ射线强度来计算铀的含量,当样品中铀镭处于不平衡状态时,γ谱法测铀存在着较大的测量误差。本文将铀的核性质与化学性质结合起来,采用密闭酸溶法快速溶解样品中的铀,酸溶后的样品不经分离直接在溶样罐中用TOPO萃取,进而测定样品中铀产生的α射线强度获得铀的含量,避免了γ谱法的不足。方法检出限为铀含量2.41μg/g;当铀含量为大约为100μg/g时,测量相对偏差为5.93%;铀的测定范围为7.23μg/g～n%。密闭酸溶法试剂用量少,溶样速度快,且对环境和操作人员污染小;酸溶后的样品用TOPO萃取2 min后即可达到萃取平衡,铀萃取效率在97%以上;所需的仪器设备可以车载形式用于野外现场铀矿石中铀的准确测定,野外应用操作简单、快速、精密度和准确性较高。

The method of TOPO extraction followed by α-counting has been developed for field determination of uranium in uranium ores.The traditional method of field uranium determination is by spectrometry.The content of uranium using that method is determined by the intensity of the ray,therefore,results have larger errors when uranium and radium are in equilibrium.The method researched by this article combines the nuclear and chemical properties of uranium.The content of the uranium is determined directly by the intensity recorded by an α counter after following dissolution and extraction processes.The detection limit of uranium is 2.41 μg/g.When the content of uranium is about 100 μg/g,the relative standard deviation（RSD） is 5.93%.The determining range of uranium is 7.23 μg/g-n%.The dissolution method requires less reagents,has better dissolving efficiency and less pollution.The extraction method has the advantage and efficiency（97%）.The equipment is portable so consequently can be used in the field where operation is simple and rapid,with higher precision and accuracy than the traditional method.