A composite model for computational analysis of the Corex process of ironmaking has been developed. The model combines a set of common material and heat balance equations. Taking user specified inputs, the model is capable of determining the consumption of raw materials and fluxes, the volume and composition of the slag and the volume and composition of reducing gases from the melter-gasifier. The accuracy of the prediction of Corex operational parameters is competitive, and the model enables computation of changes in process pathways induced by a modification of Corex raw materials, slag composition, hot metal chemistry and other parameters. The model allows optimisation of the operational parameters of the Corex process.