Simultaneous determination of different ruthenium species by rate differential kinetic spectrophotometry

Abstract

With increasing nuclear fuel burning up, the yield of fission products increases and the reaction of high-yield fission products comparatively stands out. The precious metal ruthenium is one of the main fission products and a very important indicator in reprocessing and recovery, but the removal of this metal in the first co-decontamination step of plutonium uranium recovery by extraction is difficult. To rapidly determine the ruthenium concentrations in a uranium purification cycle and radioactive waste treatment processes, a simple and sensitive differential kinetic spectrophotometry that allows the simultaneous determination of ruthenium and nitrosyl ruthenium in a complex system is proposed. Based on the determination of the initial apparent rate constant, the reaction order in terms of the Ru3+ and [Ru(NO)]3+ concentrations, the equilibrium constant for the reaction of bipyridyl with Ru3+ and [Ru(NO)]3+ in the presence of hydroxylamine hydrochloride, and the measurement of the initial formation rate and equilibrium concentration of products [Ru(bipy)3]2+, Ru3+, and [Ru(NO)]3+ in the complex system were analyzed using mathematical models, obtaining satisfactory results. The recovery rates ranged from 95.5% to 105%, and the relative standard deviations ranged from 2.9% to 4.3%.