Reduction and melting model of carbon composite ore pellets

A numerical model for the process of reduction and meltdown of iron ore-carbon pellets has been developed. The model covers the devolatilisation of coal, a set of gaseous reduction reactions by carbon monoxide and hydrogen and reactions for the formation of reducing gases. Carburisation of reduced iron and its subsequent meltdown is an important high temperature feature of the model. Transport of heat and gases is included, the latter using a specific isobaric approach. Model computations have been applied to a number of test cases with variable ore-reductant combinations and temperatures. Computed results match reasonably well with the results of laboratory tests. The reactions are found to occur in a complex sequence with main steps as follows: devolatilisation and gas evolution, gaseous reduction and Boudouard reaction, carburisation of solid iron and finally formation of liquid iron. The limits and potential use of the model are discussed.