恒电流库仑法测定八氧化三铀中的铀

Constant Current Coulometric Determination of Uranium in U₃O₈

摘要: 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%。

Abstract: 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 precision is better than 0.015% for 250mg U₃O₈.