碘化钾分光光度法测定铝合金中铋的含量

Determination of Bismuth in Aluminum Alloy by Potassium Iodide Spectrophotometry

当铝合金样品中的铋质量分数为0.01%~2.5%时,采用碘化钾分光光度法,测定铝合金中铋。将试料用氢氧化钠溶解,加入过氧化氢使硅化物分解,用适量的硝酸酸化,在硫酸介质中,Bi(Ⅲ)与碘化钾反应形成黄色可溶性络合物,在波长465nm处,采用分光光度计测量其吸光度,以此测定铋的质量分数。试验表明:该法操作简便,快速,并有良好的重现性。测定铋的结果的标准偏差在0.0002~0.026,相对标准偏差在1.08%以内,标准加入法的回收率为99.2%~100.2%。

When the mass fraction of bismuth in aluminum alloy samples is 0.01%~2.5%,bismuth in aluminum alloy is determined by potassium iodide spectrophotometry.The method is that the sample is dissolved with sodium hydroxide,the silicide is decomposed by adding hydrogen peroxide,and acidified with nitric acid.In sulfuric acid medium,Bi(Ⅲ)and potassium iodide form a yellow soluble complex,and its absorbance is measured at the wavelength of 465 nm by spectrophotometer,so as to determine the mass fraction of bismuth.Experiments show that the method is simple,rapid and reproducible.The standard deviation of bismuth determination results is 0.0002~0.026,and the relative standard deviation is within 1.08%.The recovery rate of standard addition method is 99.2%~100.2%.