氧化还原滴定法测试微米级、纳米级铝粉中单质铝含量

Content determination of elemental aluminum in micro and nano aluminum powder by redox titration method

分别采用水溶剂锰滴法、乙醇溶剂锰滴法和铈滴法3种氧化还原滴定工艺测试了微米级和纳米级铝粉中单质铝的含量,比较各滴定方法的准确度和可靠性并进行误差分析。结果表明:水溶剂锰滴法因为单质铝与水的析氢反应而使结果明显偏低;铈滴法虽然可避免单质铝与质子酸和水的反应且耗时短,但是相同条件多次测量结果浮动较大;乙醇溶剂锰滴法误差小、重复性好,是最值得关注的滴定方法,能否最终形成测试标准,其可靠性还有待验证。

Three different redox titration methods were adopted to test the content of the elemental aluminum in micro and nano aluminum powders, respectively. The accuracy and reliability of the results were compared and the errors were analyzed. The results show that when KMnO2 is used as oxidant and A1 reduces Fe3＋ in aqueous solution, the result of A1 content turns out to be lower due to the reaction between active A1 and H20. The side reaction between A1 and H20 or H＋can be avoided when Ce（SO4）2 is used as oxidant, and the reaction takes much shorter time, however, the results show poor repeatability. When KMnO2 is used as oxidant and A1 reduces Fe3- in ethanol, the results show good accuracy and repeatability, which is the most promising method to be used as testing standard for A1 content in aluminum powders, but the results need to be verified by other methods.