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一、引言重量法测定三氧化钨,耗时长,手续繁,且需贵重铂皿,不适于厂矿实验室的日常检验。近年来很多厂矿实验室在容量法上进行新的探索和研究。容量法测定三氧化钨,文献上有很多介绍,但一直没有得到普遍推广和采用。主要原因是存在一定困难和问题。近来介绍较多的是电位滴定法。一般厂矿限于设备,很难普遍采用。酸碱滴定法必须首先分离出纯净钨酸,手续繁复,根据我们实验结果,误差很大。沉淀滴定法中,有以氯化钙沉淀成钨酸钙,过滤后用EDTA滴定滤液中的钙,从而计算钨的含量;有以
I. Introduction Gravimetric determination of tungsten trioxide, time-consuming, complicated procedures, and the need for expensive platinum dish, not suitable for daily inspection of factories and mines laboratories. In recent years, many factories and mines laboratories in the capacity method to conduct a new exploration and research. Volumetric determination of tungsten trioxide, the literature has a lot of introduction, but has not been widely promoted and adopted. The main reason is that there are some difficulties and problems. More recently introduced potentiometric titration. General factory is limited to equipment, it is difficult to commonly used. Acid-base titration must first separate the pure tungstic acid, procedures complicated, according to our experimental results, a great error. Sedimentation titration, with calcium chloride precipitation into calcium tungstate, filtered with EDTA after titration of calcium in the filtrate to calculate the tungsten content; with