Modeling of reactions governing metal composition and experimental studies of carbon pickup for the cupola melting furnace.

The cupola is a coke-fueled shaft furnace used as a primary melting unit in iron foundries. Control of chemical composition of the iron tapped from the cupola is a key factor in productivity and quality control. In an effort to develop a control model for the cupola, a fundamental approach based on physical and chemical principles has been taken to describe the melting process. This work has provided a computer-implemented model of the chemical reactions occurring in the cupola which predicts the composition of metal tapped from a cupola. This modeling effort has been supported further by an experimental investigation of transfer of carbon from a packed bed of coke particles to liquid iron-base metal droplets trickling through the bed. Oxidation of the solid charge in the stack of the cupola has been studied. Sulfidation of the charge materials by sulfur-bearing components released to the furnace gases from the coke has been described. Carburization of metal droplets of iron and of steel in separate molten streams has been characterized. Also, an experimental investigation of the carbon pickup phenomenon has been conducted to examine the influence of parameters such as carbon content of charge material, residence time of metal droplets, various types of carbon sources and temperature. Finally, reactions with alloying elements in the hearth (well) of the furnace have been defined. These process reactions and their interdependence have been considered for the first time in a modeling approach to obtain an in-depth understanding of various inter-linked phenomena occurring in the cupola melting furnace. These reactions have been described in a computer-implemented model developed to predict the composition of the iron tapped from the cupola. The model has utilized the thermodynamics and kinetics of the oxidation, sulfidation, and carburization reactions, including temperature and physical aspects, in the various zones of the melting unit. The model has been validated by comparing the composition of tapped metal streams in an industrial cupola with model predictions. Excellent agreement between modeling results and plant operations has been obtained. The model developed in this study therefore can be used with confidence to predict and control the composition of metal tapped from an industrial cupola.PhDMaterials Science and EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/103301/1/9308436.pdfDescription of 9308436.pdf : Restricted to UM users only