Comparing Applicability of the Models to the Powder Reaction Rate Controlled by a One-way Diffusion Process

Abstract

With some powder reactions controlled by a unidirectional diffusion process, the validity of the two models of Ginstling-Brounshtein and Hao-Tanaka was examined by the use of experimental data of conversion with lapse in time. When a suitable model for a specific reaction is required, only the conventional linear plot of the reaction rate data is not sufficient. Theoretical reaction curves should be simulated by these models with the change in particle size as well as the mole ratio.
Actual powder reaction rates of Fe₂O₃-V₂O₅ and Al₂O₃-ZnO systems are quantitatively correlated with the number of the contact points between two component particles. More than 670 diffusing component particles contacted a non-diffusing component particle. In spite of such a large number of diffusing component particles, the traditional spherical shell model of Ginstling-Brounshtein is not valid in both systems.