钼蓝光度法测定铝及铝合金中硅的含量

介绍了用钼蓝光度法测定铝及铝合金中硅含量的方法。铝合金样品用氢氧化钠分解,硝酸酸化。在弱酸性溶液中,加入钼酸铵,使硅酸根离子与钼酸根离子形成黄色络合物,在硫酸介质中用抗坏血酸还原成硅钼蓝,测定其吸光度。结果表明：该方法操作简单,测定铝及铝合金中硅的含量范围广（0.1%～12%）。方法的稳定性、重现性和准确性都良好,能满足铝及铝合金中硅含量的分析检测要求。

Determination of Silicon Content in Aluminium and Aluminium-alloy by Molybdate Blue Spectrophotometric Method

The means of determining silicon content in aluminium and aluminium-alloy by molybdate blue spectrophotometric method was introduced in this article.The aluminum alloy specimens are fused with sodium hydroxide and are acidized with nitric acid.In the weak acid liquor,adding ammonium molybdate,silicic acid ion and molybdic acid ion are taken shape the yellow complex compound,in the sulphuric acid medium the yellow complex compound is reduced into the silicon molybdete blue by the ascorbic acid,moreover ascertaining the photoabsorption degree.The results showed that,this method is simple in manipulation,the measured silicon content range is wider（0.1% ～ 12%） in aluminium and aluminium-alloy.The stability,reappearing and accuracy of this method are well,it is able to meet a demand for analysis and examination of the silicon content in aluminium and the aluminium-alloy.