Catalytic Kinetic Spectrophotometric Determination of Rhenium in Absorption Solution of Molybdenum Smelting Dust

In a medium of 0.6 mol·L-1 H2SO4-0.002 5 mol·L-1 citric acid solution, heated in a water bath at 50 ℃ for 20 min, the oxidation of SnCl2 by sodium tellurate was remarkably catalyzed by the present of Re(Ⅶ). Based on these facts, a catalytic spectrophotometric method for determination of Re(Ⅶ) in the absorption solution of molybdenum smelting dust was proposed. It was found that if high contents of Mo(Ⅵ) was present in the sample, part of the SnCl2 solution was expended by the redox reaction with Mo(Ⅵ), thus leading to its incomplete reaction with sodium tellurate, and interferred with the determination of rhenium. Howerer, no such interference was observed when the mass ratio of rhenium to the co-existing Mo(Ⅵ) was not large than 1 to 100. Linear relationship between values of absorbance and mass concentration of Re was obtained in the range of 50-1 200 μg·L-1. The proposed method was applied to the determination of Re in absorption solution of molybdenum smelting dust, giving recovery obtained by standard addition method in the range of 97.0%-100.5%.