1986 Volume 19 Issue 6 Pages 575-580
Soluble substances contained in various solids such as plastics, bitumen and concrete slowly migrate into surrounding liquids. These phenomena are analyzed by a modified particulate dispersion model proposed by the authors in this paper. The model is based on the assumption that a part of a solute initially forms a solid solution in the continuous phase of the solids, and the remainder is dispersed particulately.
Basic equations based on this model have been solved numerically. The adequacy of the model was determined by a comparison of calculated curves with experimental results. Leaching of metal compounds from three kinds of plastics using dilute nitric acid was carried out. It was confirmed that the mass fraction of solid solution of solute governed the curve features in the early stage of leaching and the volume fraction of particulate solute was preferential in the later stage.
