PROGRESS IN THE MATHEMATICAL-MODELING OF LEACHING REACTORS

Leaching reactors have been described using three different approaches . These models are the overall mass balance, the population-balance mo del and the segregated-flow model. Each of these models has been used extensively without the relationship between them being either underst ood or quantified. These models do not only differ in their conceptual basis, but also yield different results for the same reaction conditi ons. The conceptual relationship between the various approaches to the mathematical modelling of continuous leaching reactors is discussed, and it is suggested that the population-balance model is the most appr opriate approach for the modelling of leaching reactors. The populatio n-balance method of the mathematical modelling of leaching reactors is discussed. The population balance incorporates the kinetic parameters obtained from the analysis of the batch experiments. The model is use d to analyse the batch laboratory experiments and to predict the opera tion of the continuous plant. The model accounts for the particle-size distribution of the feed, the residence-time distribution of the reac tor, the leaching kinetics, and the solution mass balance. The model i s used to obtain predictions of the operation of the zinc pressure lea ching reactor at Trail, B.C., and the bacterial leaching of a refracto ry gold ore at Fairview, South Africa. The predictions of the continuo us operation are shown to be in excellent agreement with the data from the plant operation.