Toward a More Complete Quantitative Model of Recarburizer Dissolution in Liquid Iron

Abstract It is shown that the combination of the uniformly shrinking particle model with the classic diffusion layer model of dissolution can be used to predict the dissolution curve for a recarburizer. The method utilizes a transformation of the mass distribution of particle size into a number distribution, thereby allowing the initial interfacial surface area to be estimated. The shrinking particle model then permits the continuously changing surface area to be quantified for the duration of the dissolution process, enabling an analytical solution to the Nernst–Brunner equation. The applicability of the method is demonstrated for a hypothetical addition of graphite to a ductile iron melt. The results are consistent with published experimental data for graphite dissolution in molten iron. The practical implications of the model for recarburizer additions are discussed, including the effects of particle size, agitation, temperature, nature of the recarburizer, and production practices in the foundry.