分光光度法测定钼萃原液中钼含量的研究

Investigation on Determination of Molybdenum Concentration in Leaching Solution by Spectrophotometry

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%。

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 p（Mo）, and correlation coefficient is 0. 999. Fe3＋ that is existed in solution is reduced by excess amount of SnClz 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 %.