Kinetics and mechanism of Re(Ⅶ) extraction and separation from
Mo(Ⅵ) with trialkyl amine
(College of Chemistry, Liaoning University, Shenyang 110036, China)
Abstract: The extraction kinetics of rhenium(Ⅶ) or molybdenum(Ⅵ) with trialkyl amine (N235, R3N, R=C8–C10) dissolved in heptane were investigated by constant interfacial cell with laminar flow, which aimed to identify the extraction regime, reaction zone and rate equations. The influence of stirring speed, temperature, specific interfacial area, extraction concentration and chlorine concentration on the extraction of both metals was studied. It is concluded that the extractions of Re(Ⅶ) and Mo(Ⅵ) both take place at the liquid−liquid interface, while the extraction regimes are chemically-controlled for rhenium and mixed controlled for molybdenum, respectively. The extraction rate equations and the rate-determining step were obtained under the experimental conditions, and the extraction rate constant of Re(Ⅶ) or Mo(Ⅵ) with N235 was calculated. These obtained kinetics parameters are different between Re(Ⅶ) and Mo(Ⅵ), which provides better possibilities for Re(Ⅶ) and Mo(Ⅵ) separations at proper conditions.
Key words: extraction; kinetics; separation; N235; rhenium; molybdenum