铀矿坑水样中铀电沉积层的表征

Characteristics of Electrodeposited Uranium Films of Uranium Ore Water Samples

描述了硫酸铵溶液中铀矿坑水样品中铀的电沉积层特性。电沉积液为10ml0.8M的硫酸铵溶液,电流密度0.6A/cm2,pH值为2.5,电镀1h。电沉积经化学分离后的水样品和电沉积的纯硝酸铀酰样品进行了比较,并对二者分别做了红外(IR)光谱、扫描电镜(SEM)、元素分析以及α能谱测量。IR谱上铀酰离子的反对称伸缩振动峰在887cm-1附近,使电沉积在不锈钢片上的铀主要以铀酰离子水合物的形式存在,有一部分NH4+以NH3的形式替代水合物中的水,使电沉积层中铀的化合物形式为UO2(OH)2.xNH3.yH2O或者UO2(OH)2-x.(ONH4)x.yH2O,铀酰离子通过链的形式形成聚合结构。SEM照片显示电沉积层均匀,没堆积成团现象出现。α谱表明电沉积层中铀的同位素主要是238U和234U,相应的α能量峰4198和4773keV很显著,没其它峰的干扰。

Characteristics of electrodeposited uranium films of uranium ore water sample in ammonium sulphate was investigated in this work. The optimized electrodeposited conditions were as follows： electro- lyte was ammonium sulphate of 0.8 M, and current density at the cathode was 0.6 A/cm2 , electrolyte pH value was 2.5, the time of plating on the electrodeposition was 1 h. In this situation, the uniform, thin and adheresive films were produced by electrodeposition method. Two samples were made, one electro- deposition of pure uranyl nitrate, and another electrodeposition of uranium ore water sample after chemical separation. Characteristics of electrodeposited uranium films of uranium ore water sample after.chemical separation was studied, making comparisons with electrodeposited films of uranyl nitrate. The analysis of film characteristics was done through infrared （IR） spectrum, scanning electron microscopy（SEM）, ele- ment analysis and spectrum measurment. According to Fourier transform infrared spectra, the asym- metric stretching vibration band of uranyl group is around 887 cm-1. In addition, according to IR spec- trum, we know that uranium exists mainly as the form of hydrated polymeric compound in the film. Elec- trodeposited uranium films also included many NH＋. Polymeric structures of variable composition were present in the electrodeposited samples, with the unit monomeric formula UO2 （OH）2 · xNH3 ·yH2O or UO2 （OH）2 2-x · （ONH4）. · yH2O. Scanning electron microscopy shows that the two samples have similar surface characteristics and no cluster is observed. The samples were also measured by spectrometer equipped with Passivated Implanted Planar Silicon（PiPS） detector. From the a spectrum, we know that isotopes of uranium in the film are 238U and 234U. 2asU is not found in the a spectrum. It also shows that the chemical separation process can isolate uranium from other interfering elements effectively, the result of chemical separation is very satisfactory and electrodeposited process is rather efficient. Source electrode- posited in ammonium sulphate through optimized conditions satisfies the need of high-resolution a spectrum.