Synergistic Extraction of Rhenium(VII) and Molybdenum(VI) with Mixtures of Bis-(3,5-dimethylhexyl-4-methylhexyl) Amine and Tributylphosphate

The extraction of rhenium(VII) and molybdenum(VI) from chloride media by mixtures of bis-(3,5-dimethylhexyl-4-methylhexyl) amine N298 and tributylphosphate (TBP) was studied in the present paper. The mixtures had higher synergistic effects on Re(VII) than that of Mo(VI), and the maximal synergistic factor was obtained at a ratio of N298 to TBP of 1 to 9. Re(VII) was extracted as (R₂NH₂Cl)₃·HReO₄·B, whereas Mo(VI) was extracted as (R₂NH₂Cl)_1/2·H₂MoO₄·1/4B by the mixtures, instead of (R₂NH₂Cl)₃·HReO₄ and (R₂NH₂Cl)₃·H₂MoO₄ by N298 alone. Furthermore, the formation constants and extraction mechanism were determined. The possibility of separating rhenium and molybdenum ions by the mixtures according to its synergistic effects and extraction ability was investigated.