A GENERAL-MODEL FOR LEACHING OF ONE OR MORE SOLID REACTANTS FROM POROUS ORE PARTICLES

A general, unsteady-state model for leaching of one or more solid reactant species from a nonreactive, porous, spherical pellet is derived in dimensionless form for the interpretation of leaching data and for use in the design of coarse-ore leaching processes. Numerical solutions of the model equations are obtained with implicit finite difference approximations. The effects of diffusion rate, chemical reaction rate, and competition between multiple solid reactants are examined using the concept of the effectiveness factor. The importance of deposits of solid reactants on the pellet surface is ascertained. It is shown that the model is capable of simulating both 'reaction-zone'' and 'homogeneous'' kinetics, depending on the choice of parameters. The model is also capable of simulating leaching from a distribution of particle sizes, and techniques for the modification of model parameters for this purpose are discussed.