硫氰酸盐分光光度法测定电解稀土-镁中间合金中钼

来源期刊：冶金分析2010年第5期

论文作者：胡珊玲 魏友利 林燕

文章页码：72 - 75

关键词：稀土-镁中间合金； 硫氰酸盐； 分光光度法； 钼

Key words：rare earth magnesium master alloy； thiocyanate； spectrophotometry； molybdenum

摘    要：提出用硫氰酸盐分光光度法快速测定电解稀土-镁中间合金中杂质钼方法。取大样(2g)溶解于盐酸(1+1)和H₂O₂中,样品溶解完全并定容后,分取部分试液在1.0～1.8 mol/L硫酸介质中室温下显色,若室温低时加入Fe(Ⅲ)溶液加快显色反应。然后,在分光光度计460 nm波长处测定溶液的吸光度。Fe(Ⅲ)和W(Ⅵ)对钼的测定有干扰,但可分别用抗坏血酸和柠檬酸消除;基体元素稀土和镁以及其他杂质元素对钼测定无干扰,因此不需要预先分离而直接进行测定。本法对钇-镁、钆-镁合金中的钼进行测定,RSD小于1.5%,加标回收率在99%～102%范围。

Abstract: The determination of molybdenum in rare earth magnesium master alloy by thiocyanate spectrophotometry was developed.About 2 grams of alloy sample were dissolved in hydrochloric acid (1+1) and hydrogen peroxide,then diluted to the mark with water.Appropriate solution was sampled to conduct the chromogenic reaction at the room temperature in the medium of 1.0-1.8 mol/L sulfuric acid.Fe(III) was added to speeden the reaction especially when room temperature was low.Then,the Absorbency was measured at 460 nm on spectrophotometer.Fe(III) and W(Ⅵ) had interference in the determination of molybdenum,but they could be eliminated by ascorbic acid and citric acid.The matrix elements of rare earth,magnesium and other impurities were showed interference-free,thus pre-separation step could be omitted.The method obtained has been applied to determine molybdenum contents in yttrium-magnesium and gadolinium-magnesium alloys,with the RSD below 1.5% and the recovery rate obtained by standard addition method in the range of 99%-102%.