Speciation of ruthenium in TBP/TPH organic phases (structure and reactivity)

Abstract

International audienceRuthenium is one of the major fission products and draws attention to it because it is partly extracted with uranium and plutonium during the reprocessing of the used nuclear fuel. The decontamination factors of the recoverable materials are impacted by this unwanted transfer from the nitric acid phase to the tributylphosphate (TBP) phase. During dissolution of used nuclear fuel, ruthenium forms trivalent nitrosyl complexes with nitrate, nitrite, hydroxo and aquo ligands. The admitted general formula is [RuNO(NO$_3$)x(NO$_2$)$_y$(OH)$_z$(H$_2$O)$_{5-x-y-z}$]$^{3-(x+y+z)}$ where x, y, z depend on the chemical conditions. Only the most nitrated complexes must be extracted with a quantitative yield