采用电位滴定法测定合金钢中高含量钼的研究

Molybdenum Content Determination of Alloy Steel With High Molybdenum Content by Potentiometric Titration

钼是钢中重要的合金元素,准确分析钢中的钼元素含量具有重要意义。分析了反应体系磷酸浓度、硫酸的加入量和硫酸亚铁铵的加入量对电位滴定法测定钼含量准确度的影响,在此基础上优化了反应体系酸度,引入干扰系数校正了钒对测定结果的影响,并通过对复合铂环电极进行预处理,消除了三价铁对突跃电位的影响。采用该优化方案对实际样品进行钼含量测定,加标回收试验显示回收率为99%~101%。该方案能用于钼的质量分数为8.00%~62.00%的镍基高温合金、中低合金钢(如刀具钢)、钼铁等金属材料中钼含量的准确测定,能够满足材料检验重复性和再现性的要求。

Molybdenum is an important alloying element in steel,and to analyze its content accurately is of much importance.Analysis was carried out on the effects of phosphoric acid concentration,sulfuric acid addition and ammonium ferrous sulfate addition on the determine accuracy of molybdenum content using potentiometric titration.Based on this,the acidity of the reaction system was optimized,and the interference coefficient was introduced to adjust the effect of vanadium on the determination results.Furthermore,the influence of ferric iron on the titration jump potential was eliminated by pretreatment on the composite platinum ring electrode.Adopting this optimized scheme,the content determination of molybdenum in actual specimens was carried out,and corresponding recovery test showed that the results were in range of 99%~101%.For the metal material with molybdenum content range of 8.00%~62.00%,such as nickel-based superalloys,medium-low alloy steels(e.g.cutting tool steel),ferromolybdenum and other materials,this method can be used in molybdenum content determination with high accuracy,and can meet the repeatability and reproducibility requirements of material inspection.