Solvent Extraction of Radio-Ruthenium as the Thiocyanate Complex

Abstract

The solvent extraction behavior of radioruthenium, as the thiocyanate complex from hydrochloric, sulfuric, and perchloric acid solution was investigated. Ruthenium forms the violet-blue complex on moderate heating with excess thiocyanate as the reductant and the complexing agent. The complex is extractable by liquid amines or oxygenated solvents from acidic solutions. After heating radioruthenium in aqueous 1 mole/l HCl-0.5 mole/l NH/sub 4/NCS solution for 15 min at 70 deg C, it was almost completely extracted by trin-octyl amine hydrothiocyanate in cyclohexane or by trin-butyl phosphate (TBP). Concentration dependences of aqueous acid, thiocyanate, and organic solvents on distribution ratios of radioruthenium were examined and the probable species to be extracted was shown to be cyanate, distribution ratios of radioruthenium were largely enhanced compared with those obtained in mineral acidTBP systems containing no thiocyanate. (auth)