恒电流库仑法测定八氧化三铀中的铀

Constant Current Coulometric Determination of Uranium in U_3O_8

为了对铀产品中的铀含量进行准确定值,建立了用恒电流库仑法测定八氧化三铀中铀的方法。用Fe(Ⅱ)在磷酸介质中还原U(Ⅵ)为U(Ⅳ),用钼作催化剂,用硝酸选择性地氧化过剩的Fe(Ⅱ)后加入略超过铀化学当量的重铬酸钾,把U(Ⅳ)氧化到U(Ⅵ),过量的重铬酸钾用恒电流产生的Fe(Ⅱ)滴定。对250 mg八氧化三铀,精密度优于0.015%。

Constant current coulometric is established to determine uranium in U3O8 in order to correct determination of uranium in uranium product. U （Ⅵ） is reduced to U （Ⅳ） by Fe（ Ⅱ ） in phosphoric acid. Molybdenum is used as catalyzer, the excess Fe（ Ⅱ ） is oxidized by nitric acid selectively. The U（Ⅳ） is oxided to U（Ⅵ） by adding chromium（Ⅵ） that is slightly more than uranium＇s chemical equivalent in sample solution. The excess chromium（Ⅵ） is titrated by Fe（ Ⅱ ） which is produced through constant current. The preci sion is better than 0. 015 % for 250 mg U3O8.