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本方法以磷酸溶解金属铀,通空气氧化杂质元素铁、钛、钼等至高价状态,在磷酸和硫酸介质中用标准重铬酸钾溶液将U(IV)氧化至U(VI),过量的重铬酸钾用电解发生的Fe(Ⅱ)进行滴定,以电位法指示终点。观察了电流密度及各种介质的浓度对测定的影响。在3.6 M H_2SO_4-0.74M H_3PO_4-0.023MFe_2(SO_4)_3的溶液中,电流密度为1.4毫安/厘米~2时,U(IV)的测定值与计算值相符。对5毫克铀的测定,精密度为±0.2%。
In the method, U (IV) is oxidized to U (VI) by using phosphoric acid to dissolve uranium metal, and air is used to oxidize impurity elements such as iron, titanium and molybdenum to a high price state by using standard potassium dichromate solution in phosphoric acid and sulfuric acid medium; Potassium dichromate is titrated with Fe (II) generated by electrolysis to indicate the end point by the potential method. The effects of current density and various media concentrations on the assay were observed. In the solution of 3.6 M H 2 SO 4 -0.74 M H 3 PO 4 -0.023M Fe 2 (SO 4) 3, the measured value of U (IV) coincides with the calculated value at a current density of 1.4 mA / cm 2. The determination of 5 mg of uranium, precision of ± 0.2%.