化学形态分析在铀工艺中的应用

Application of Speciation Analysis Method in Uranium Technology

运用新的化学形态分析软件CHEMSPEC研究了铀工艺溶液中游离酸浓度的测定和UF6转化中的问题,探讨了化学形态分析在铀工艺中的应用。研究结果表明,通过化学形态分析可以较准确地给出测定游离酸浓度的滴定终点,与实验结果一致;在UF6转化方法方面,直接水解需要精确地控制最终的pH值,还原水解法需要寻找合适的还原剂,而用Al(Ⅲ)掩蔽F-后萃取U(Ⅵ)则在低pH值范围内是可行的。化学形态分析可以为精确地控制铀工艺实验的进行提供帮助。

Chemical speciation analysis method is used in the field of uranium technology. The method contains two aspects, experimental analysis and theoretical calculation. CHEMSPEC is a newly developed speciation code. In this work, CHEMSPEC is used to determine the free acid concentration in the presence of uranium（Ⅵ） and the conversion channels of UF6. Three conversion channels are considered： direct hydrolysis, reduction hydrolysis and extraction after F- is coupled by Al^3＋. The results indicate that the titration endpoint of the acid solution can be precisely determined by the CHEMSPEC and consist with the results of titration experiments. In the conversion of UF6, the pH value must be strictly controlled when the direct hydrolysis channel is applied, reduction hydrolysis channel needs suitable reducing agents, while when F- is coupled by Al^3＋, the extraction channel may applicable in low pH value solutions. These may suggest that speciation analysis method could be helpful in the field of uranium technology.