铀、钼分离工艺中铀和钼的测定(Ⅱ).钼的测定

Determination of Uranium and Molybdenum in Separation Process of Uranium and Molybdenum (Ⅱ):Determination of Molybdenum

介绍了铀、钼提取工艺各种样品中钼的测定方法及其应用。铀钼矿及其浸出渣样品 ,首先用混酸分解 ,然后在硝酸介质中 ,用二氯化锡将钼 ( )还原到钼 ( )。钼 ( )与硫氰酸盐反应形成橙红色配合物 ,可用分光光度法测定 ;淋浸液、吸附淋洗夜和反萃取液中的钼可直接采用光度法测定 ;离子交换树脂中的钼 ,需在加热条件下 ,用氢氧化钠溶液浸取 ,然后以快速光度法测定 ;铀产品 (化学浓缩物 )和高含量铀样品中的微量钼 ,在硫酸介质中 ,钼 ( )与硫氰酸盐反应形成可溶性配合物 ,可用异戊醇萃取分离、光度法测定 ;对钼产品 (多钼酸铵 )中高含量的钼 ,则采用氢氧化钠溶液溶解样品 ,以 EDTA容量法测定。在 p H2～ 5的硫酸溶液中 ,用盐酸羟胺将钼 ( )还原到钼 ( ) ,钼 ( )与 EDTA反应形成 (1∶ 1 )配合物 ,过量的 EDTA用铋盐反滴定。简述了各种方法的基本原理 ,最佳测定条件 ,应用范围和操作步骤。经大量样品的例行分析证实 ,所得结果均准确可靠 ,而且操作简便快速。各方法的精密度和准确度较好 ,精密度优于 5 % ,标准加入回收率为 98.5 %～ 1 0 4%。

Determination methods of Molybdenum in various sample in separation process have been developed.The moluranite and leaching residue are dissolved with mixed acid.In nitric acid medium,the molybdenum(Ⅵ)is reduced to molybdenum(Ⅴ) with stannoces dihydrate,and Mo(Ⅴ) combines with ammonium thiocyanate to orange red complex which can be determined by spectrophotometry. The molybdenum in leaching solution,absorbed or eluted solution and stripping solution can be directly determined by spectrophotometry.Molybdenum in ion exchange resins can be rapid spectrophotometric determination after being leached with sodium hydroxide solution at heating condition. Trace Mo in uranium product (chemical concentrate) and high U content samples can be spectrophotometric determined in sulfate acid medium by extracted separation with iso penfanol. Mo in molybdenum product can be determined by EDTA volumetry.In sulfate acid solution of pH2.0,Mo(Ⅵ)is reduced to Mo(Ⅴ) by hydroxylammonium chloride.Mo(Ⅴ)with EDTA forms 1∶1 complex.The excess EDTA can be trititrated by bismuth nitrate. The principle,optimum conditions,operation steps,applied range are introduced.The methods are simple and rapid,and can be used to determine Mo in separation process of uranium and molybdenum.The precision of analysis is less than 5%,and percent recovery is 98.5%～104%.