Multiple reactions and the vapor transport of solids

Abstract

The method of Lever, which has enabled calculation of the steady-state diffusion limited rate of transport of solid for the case of a single chemical equilibrium, is generalized to include the situation in which several equilibria are simultaneously operating. This is accomplished for the case of N equilibria by the introduction of (N-1) "coupling parameters," so defined that the steady-state conditions become formally identical to those given previously. Following Lever, the results of these operations are combined with the usual thermodynamic relations for the temperature dependence of the equilibrium constants, finally resulting in a set of (N-1) linear simultaneous equations in (N-1) unknowns, the "coupling parameters." These equations can be solved, in general, in terms of the ratios of (N-1) dimensional determinants. On the basis of the above, a straightforward procedure is devised for the calculation of the rate of transport of solid, based on knowledge of initial conditions as well as thermodynamic and diffusion coefficient data.