An auto-layering model for the granulation of iron ore fines

Abstract

An auto-layering mechanism for the granulation of iron ore fines and similar materials is proposed. It is phenomenologically consistent in the sense that large particles are explicitly excluded from depositing in relatively thin layers around the nuclei. Given appropriate inputs, such as the feed size distribution and the moisture-layer thickness relationship, the model is capable of calculating size distributions of granules and of their constituent particles, as well as partition coefficients which classify feed particles into nuclei or layering material. In addition, the model elucidates and reconciles the controversial role of intermediate size particles in the granulation process. The model is implemented by a novel sequential size interval-by-size interval calculation scheme that is tailored for its structure. The theoretical results are in reasonable agreement with published data.