Metal Ionic Diffusivity: Measurement and Application

Diffusivity of metal compounds in aqueous solutions is a very important parameter in hydrometallurgical processes. In metal extraction using a hydrometallurgical method or in the case of solvent extraction, diffusion of metal ions through various medium frequently plays a controlling role. Therefore, correct information on diffusivity of the relevant species is necessary in order to understand the mechanism of the unit process in question. In this paper, various techniques used in measurement of diffusivity of metal compounds in solution are reviewed. A detailed discussion on the practical applicability of the diaphragm cell technique is given, since this technique is regarded as an easy and reliable technique in measuring diffusivity of species dissolved in aqueous media. Also reviewed are theoretical approaches to diffusivity in aqueous media.