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铁矿石中全铁的测定,大多采用盐酸溶矿,二氯化锡还原,二氯化汞消除过量二氯化锡,重铬酸钾滴定的经典方法.因为使用剧毒的汞盐,国内外分析化学工作者多年来对无汞测定全铁做了大量工作.其中对不用汞盐的重铬酸钾容量法研究较多的是用SnCl_2或SnCl_2TiCl_3还原Fe(Ⅲ),而选择一种合适的指示剂用来准确辨认Fe(Ⅲ)的还原终点.但这些方法操作都比较麻烦;由于使用了二次指示剂,也影响测定的准确度.本文利用HClO_4热时有强氧化性,释稀并冷却时氧化性消失的特性,用HClO_4代替HgCl_2,在SnCl_2—TiCl_3完全还原Fe(Ⅲ)之后,
The determination of total iron in iron ore, most of the use of hydrochloric acid dissolved ore, tin dichloride reduction, mercury dichloride eliminate excess tin dichloride, potassium dichromate titration of the classic method.Because the use of toxic mercury salts, domestic and foreign analysis For many years, chemists have done a great deal of work on the determination of total iron without mercury, of which the study on the capacity of potassium dichromate without mercury salts is more about the reduction of Fe (Ⅲ) with SnCl_2 or SnCl_2TiCl_3 and choosing a suitable indicator Agent is used to accurately identify the reduction end point of Fe (Ⅲ), but these methods are troublesome to operate, and the accuracy of the determination is also affected by the use of the secondary indicator.In this paper, when the HClO_4 is hot, When the disappearance of the oxidation properties, with HClO_4 instead of HgCl_2, SnCl_2-TiCl_3 complete reduction of Fe (Ⅲ)