分光光度法测定钼萃原液中钼含量的研究

在HNO3体系中,用SnCl2将Mo(Ⅵ)还原为Mo(Ⅴ),NaSCN与Mo(Ⅴ)形成橙红色配合物,该配合物在460nm处产生最大吸收,吸光度和钼质量浓度在0.0~2.0 mg/L范围内呈线性关系,线性方程式为A=0.008 2+0.117 3ρ(Mo),相关系数R=0.999。利用过量的SnCl2还原Fe3+形成Fe2+消除了Fe3+对Mo(Ⅴ)测定的影响,由此建立钼浓度测定方法,当测量体系中钼质量浓度为2 mg/L、铁质量浓度为1.0~3.0 mg/L时,对测定钼的干扰可忽略。对实际钼萃原液进行稀释测定,发现样品中钼质量浓度为3.0g/L时,进行加标回收试验测得平均回收率为103.5%。

Investigation on Determination of Molybdenum Concentration in Leaching Solution by Spectrophotometry

In HNO3 system,Mo (Ⅵ) is reduced to Mo (Ⅴ) by SnCl2,and NaSCN complex with Mo(Ⅴ) forms an orange-red complex which has maximum absorption at 460 nm.The absorption has linear relationship with Mo concentration in the range of 0.0～ 2.0 mg/L and linear equation is A=0.008 2+0.117 3 ρ(Mo),and correlation coefficient is 0.999.Fe3+ that is existed in solution is reduced by excess amount of SnCl2 to Fe2+,therefore,the influence of Fe3+ to measure Mo(Ⅴ) is prevented.The method of measuring molybdenum in leaching solution is built.If Fe3+ concentration is between 1～3 mg/L and molybdenum concentration is 3.0 g/L in the solution,interference of Fe3+ to measurement of molybdenum can be neglected.Molybdenum in real leaching solution is determined with pre-dilution procedure.If molybdenum concentration is 3.0 g/L in the solution,average added standard recovery of molybdenum is 103.5 ％.