重铬酸钾自动电位滴定法测定渣样中低含量氧化亚铁的不确定度评定

来源期刊：冶金分析2010年第10期

论文作者：闻向东 陈士华 李玉芬

文章页码：74 - 78

关键词：不确定度评定； 自动电位滴定法； 渣样； 氧化亚铁

Key words：uncertainty evaluation； automatic potentiometric titration method； slag specimen； ferrous oxide

摘    要：分析了自动电位滴定法测定渣样中低含量氧化亚铁的检测过程,建立了测量过程分量的数学模型,讨论和比较了检测过程中各种不确定度因素,发现各不确定度因素中测量重复性的不确定度贡献最大,其次是滴定体积的不确定度。对一个低含量氧化亚铁的渣样用两种浓度的标准溶液进行了测定,采用浓的标准溶液滴定时自动电位滴定仪消耗重铬酸钾标准溶液小体积读数体积的不确定度,远远大于采用稀的标准溶液滴定时大体积读数分析的体积不确定度,并比较了总的不确定度大小,为采用较好的检测方案提供了依据。

Abstract: The determination process of low-content of ferrous oxide in slag sample by automatic potentiometric titration method was discussed.A mathematical model of measurement component was established to compare the uncertainty factors during measurement process.It was found that the uncertainty of measurement repeatability had maximal contribution,and the uncertainty of titration volume was in the second place.One slag sample with low-content of ferrous oxide was determined with two standard solutions in different concentrations.The results showed that the uncertainty of small volume of consumed potassium dichromate standard solution in high concentration was much larger than that of large volume of consumed potassium dichromate standard solution in low concentration.The total uncertainty was also compared,which provided the basis for selecting a better determination scheme.