Effect of Denitration on Ruthenium Volatilization
The volatilization of Ru depends on the compound in which the element is fixed. The ruthenium that dissolves in nitric acid solutions of fuel reprocessing plants exists principally as complexes of nitrosyl ruthenium with the general formula, RuNO(NO3)xOH3−x·yH2O. As the molarity of the HNO3 is increased, the concentration of trinitrato-complexes increases. After the denitration of RuNO(NO3)3 with HCHO in 8 M HNO3 solution, heating in the temperature range of 130–200°C caused all denitrated ruthenium compounds to decompose to stable ruthenium dioxide. The volatility of RuO2 in air is 1–2% up to 1050°C in contrast to elemental Ru.
KeywordsNitric Acid Solution High Level Liquid Waste Raschig Ring Ruthenium Tetroxide Nitrosyl Ruthenium
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