氢化物发生-原子荧光光谱法测定钨矿石、钼矿石中锑

Determination of Sb in tungsten ores and molybdenum ores by hydride generation-atomic fluorescence spectrometry

采用HNO3-HF-H2SO4分解钨矿石,钼矿石,柠檬酸-KI溶液掩蔽干扰,加入硫脲-抗坏血酸溶液还原后,应用氢化物发生-原子荧光光谱法测量溶液中Sb含量。通过优化仪器测定条件和酸度,配合柠檬酸和KI的使用有效地避免了干扰。方法检出限为4 ng/g,RSD为3.9%-8.3%,回收率为90%-106%。经8家实验室对钨钼矿石标准物质样品精密度、准确度验证,精密度满足要求,且方法偏倚不显著。方法可用于钨矿石、钼矿石中Sb的测定。

A conventional method for the determination of Sb in ores is to digest ore samples with aqua regia or mixtures of hydrochloric acid and nitric acid, and then reduces the samples by thiourea and ascorbic acid. Due to the involvement of hydrochloric acid, it is easy to produce volatile SbCl3, possibly resulting in low detection results for Sb. Additionally, when the ores contain a great deal of the metallic elements such as tungsten, molybdenum, copper and so on, the determination results can also be affected during the process of reduction. In this paper, national reference materials - tungsten ores and molybdenum ores were taken as studying objects. The sample was decomposed by HNO3 - HF - H2SO4, and subsequently the citric acid and KI liquor were added to eliminate interference, followed by reduced with addition of thiourea - ascorbic acid, and then determined by HG -AFS. Experimental conditions such as instrumental conditions and pH were optimized and interference was eliminated by using the citric acid and KI solution. The detection limit was 4 ng/g, the relative standard deviations were 3.9% - 8.3% and recoveries were 90% - 106%. The precision and accuracy satisfied the requirements of tungsten ore and molybdenum ore standard materials by eight laboratory determinations. The method is simple and rapid with high sensitivity, and can be used to determine Sb in tungsten ores and molybdenum ores.