A MASS-TRANSFER MODEL FOR THE AUTOCATALYTIC DISSOLUTION OF A ROTATING COPPER DISK IN OXYGEN SATURATED AMMONIA SOLUTIONS

A mathematical model of mass transfer processes during autocatalytic dissolution of metallic copper in oxygen-containing ammonia solutions using the rotating disc technique is presented. The model is based on the equations of steady state convective diffusion with volumetric mass generation terms and boundary conditions of the third kind, in more generalized form, at the disc surface and of the first kind in the bulk solution. The boundary value problem was solved numerically using the finite difference method with variable mesh spacing. Comparison of calculated and experimental results indicates that the model quantitatively represents the measurements. The rate of the reaction Cu(II)+Cu→2Cu(I) determines the overall rate of the process. © 1990 Chapman and Hall Ltd.