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络合滴定法测定钨已有Sousa和王承宪等的间接法。前者是析出钨酸钙后借EDTA滴定其中的钙;后者是以钨酸钡形式沉淀后亦以EDTA滴定过量的氯化钡,均曾用之于矿石分析。在本文中作者提出以钨酸铅状态析出钨,用络合滴定与钨当量的铅以作间接容量法测定钨;而络合滴定铅优于滴定钙或钡。曾采用沉淀钼酸铅的条件下同时析出钨、钼,作者从实验中观察到钼酸铅与钨酸铅的沉淀条件不完全一致,尤其在酸度上。由于未找到有关钨酸铅沉淀条件的详尽报告,故又对钨酸铅沉淀条件进行研究。
Complexometric titration of tungsten has been Sousa and Wang Chengxian indirect method. The former is the precipitation of calcium tungstate by EDTA titration of which calcium; the latter is precipitated in the form of barium tungstate also EDTA titration excessive barium chloride, have been used in ore analysis. In this paper, the authors propose that tungsten be precipitated with lead tungstate, tungsten should be measured by complexometric titration with tungsten equivalent to make indirect capacity method, and complexometric titration of lead is superior to titration of calcium or barium. The precipitated molybdic acid lead has been used under the conditions of simultaneous precipitation of tungsten, molybdenum, the authors observed from the experiment lead molybdate and lead tungstate precipitation conditions are not exactly the same, especially in the acidity. Since no detailed report on lead tungstate precipitation conditions has been found, the lead tungstate precipitation conditions were studied.