论文部分内容阅读
碱量法测定钨,文献中早有记载,但由于钨酸为难溶弱酸,中和滴定的准确度低,多年来,仅作为一种近似性的方法引用。我们对该法进行了研究,发现加入氯化钡后,可以避免钨酸对滴定的影响,使终点pH有明显的突跃,提高了中和滴定的准确度。用于矿石中钨的测定,获得了较好的结果,且具有简便、快速及无需铂皿等优点,双份测定可在4小时内完成。实验部分 (一)主要试剂 1.钨酸钠溶液:用化学纯Na_2WO_4
Alkalimetric determination of tungsten, the literature has long been documented, but due to the weak solubility of tungstic acid, neutralization titration accuracy is low, over the years, only as an approximation of the method of reference. We have studied this method and found that the addition of barium chloride can avoid the impact of tungstic acid on the titration, the endpoint pH significant jump, increased the accuracy of neutralization titration. It is used for the determination of tungsten in ore with good results. It has the advantages of simplicity, rapidity and no need of platinum dish. The double determination can be completed in 4 hours. Experimental Part (A) of the main reagents 1. Sodium tungstate solution: chemically pure Na_2WO_4