The modelling of dissolution of active substances contained in the underground depository of industrial waste materials

In the paper, the problems of dissolution and migration of active substances contained in the underground depository of industrial waste materials have been considered. From the physicochemical point of view, the dissolution of active substances dispersed in the underground depository is very similar to leaching phenomenon encountered in hydrometallurgical processes. The dissolution process is regarded as a heterogeneous reaction for the two-phase solid-liquid system. The progressive conversion, unreacted core and shrinking core models of the dissolution phenomenon have been considered. The modifications of the dissolution kinetics equations by the solubility product effects have been elicited. The author presents the discontinuous, single wave type solutions of the differential equations describing the migration of dissolved active substance in the depository. Finally, the modifications of the concentration wave by the diffusion and dispersion phenomena have briefly been discussed.