微量硅的测定方法很多,对于钨中微量硅的测定曾用过光谱法、极谱法以及离子交换分离法,本文采用萃取光度法。当有酒石酸钠存在时,在1mol/LH_2SO_4介质中,用正丁醇萃取,使微量硅与大量基体钨分离,再用混合还原剂在有机相中还原成硅钼蓝。于680nm处测定吸光度,硅浓度0～5μg/ml时符合比尔定律,工作曲线通过原点,250mgWO_3不影响硅的测定。方法简便、灵敏,精密度好,测定高纯钨中硅获得了满意结果。 Determination of trace silicon many ways for the determination of trace silicon in tungsten spectrometry, polarography and ion exchange separation have been used, this article uses extraction spectrophotometry. When sodium tartrate was present, n-butanol was extracted in 1 mol / LH 2 SO 4 medium to separate the trace silicon from the bulk matrix tungsten and then reduced to molybdenum blue in the organic phase using a mixed reducing agent. Absorbance was measured at 680nm. The Beer’s law was obeyed when the concentration of silicon was 0-5μg / ml. The working curve passed the origin and the concentration of 250mgWO_3 did not affect the determination of silicon. The method is simple, sensitive and precise, and satisfactory results have been obtained in the determination of silicon in high-purity tungsten.