High-Speed Stirring HSS Method

The solvent extraction process of metal ions inherendy depends on the mass transfer across the interface and the reaction that occurs at the interfacial region. Therefore, the elucidation of the kinetic role of the interface was very important in order to clarify the extraction mechanism and to control the extraction rates. In 1982, Watarai and Preiser invented the high-speed stirring (HSS) method [4,5]. Figure 10.1 shows the schematic drawing of the HSS method [6]. When a two-phase system is vigorously stirred in a... 

The solvent-extraction process for metal ions depends intrinsically on the mass transfer to or across the interface and the chemical reaction in the interfacial region. Therefore, the study of the role of the interface is very important for analyzing the real extraction mechanism and for controlling the extraction kinetics. In the early 1980s, the high-speed stirring (HSS) method was developed by Watarai and Preiser [4,5]. Thereafter, some new methods were proposed in our laboratory, which included the two-phase stopped-flow method [6], the capillary plate method [7], reflection spectrometry [8], the centrifugal liquid membrane (CLM) method [9], and the two-phase sheath flow method... 

Recent research on the solvent extraction mechanism revealed that the role of liquid-liquid interface has to be taken into account for understanding the extraction mechanism, especially in the extraction kinetic mechanism. Breakthrough research has been attained with the invention of a high-speed stirring (HSS) method that made it possible to measure the interfacial concentration of extractant (Lewis base) and extraction rate of the complex. Thus, this technique could determine a rate law for the interfacial reaction for the first time [1],... 

---