采用硫-磷混酸分解、硫氰酸盐显色分光光度法测定了电解稀土镁中间合金中的杂质钨。本方法改变了常规的碱熔方式,以硫-磷混酸分解合金样品使其中的杂质钨与磷酸形成络合物,再经NaOH溶液转化为钨酸钠,同时将大部分稀土和镁基体沉淀分离,最后通过硫氰酸盐显色后测定钨。采用所确定的方法测定了钆-镁中间合金样品,RSD为2.5%;标准回收实验测得回收率为102%—104%。 Sulfur - phosphorus mixed acid decomposition, thiocyanate color spectrophotometric method for the determination of the impurity rare earth magnesium alloy master alloy tungsten. The method changes the conventional alkali fusion method, decomposes the alloy sample with the sulfur-phosphorus mixed acid to make the impurity tungsten and the phosphoric acid form the complex, and then converts the sodium tungstate into the NaOH solution, and simultaneously precipitates most of the rare earth and the magnesium matrix , The final determination of tungsten by thiocyanate color. The determination of gadolinium-magnesium master alloy samples using the determined method, RSD of 2.5%; standard recovery experiment measured recovery of 102% -104%.