Iron ore sintering involves the movement of a flame front down a particulate bed, and a series of physico-chemical reactions over a large temperature range. In the literature simple and more sophisticated iron ore sintering models have been reported. In this paper a more comprehensive numerical model which incorporates most of the significant processes and heat transfer modes proposed in earlier models is given. Therefore, sub-models are available to describe the relationship between airflow rate through the bed and flame front speed, the evaporation and condensation of water ahead of the front, the calcination of fluxes nearer to the front, the reactions that occur in the front and cooling of the bed with the departure of the front. Improvements were made to several areas -such as coke combustion, and the melting and solidification processes -to more accurately quantify the phenomena involved. More recent progress in understanding the fundamentals of sintering from BHP Billiton studies have also been incorporated into the model. To date, twelve sinter pot tests have been used for validation studies. Reasonably good agreement was obtained between predicted and measured results -in areas such as bed temperature profiles and waste gas temperature and compositions. Work is continuing to further improve the model, and broaden the validation work to include other bed temperature profile parameters.

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A new numerical iron ore sintering model was developed recently. It takes into account most of the significant physico-chemical processes in sintering. In this study results from the model are compared with experimental results from twenty five sinter pot tests. Results indicate that the model can simulate the iron ore sintering process, as reasonable correlations between predicted and measured results were obtained in many areas. The good comparisons also indicate that the key sub-models, which have significant effects on results, viz., coke combustion, fluxes calcination, drying and condensation as well as heat and mass transfer, describe the sub-processes well. The phenomena of steady-state waste gas composition (SSWGC) and steady-state waste gas temperature (SSWGT) were simulated and analyzed by the model. A total of nine important input variables were identified and their influence on sintering time and three critical parameters which determine heat transfer during sintering were considered in the sensitivity studies. Results showed that bed bulk density, solid and gas thermal capacities, coke level and diameter and post-ignition airflow rate have the greatest influences on sintering time and the temperature profile parameters. This paper also gives suggestions on how the model can be improved.

It is well established that flame front speed is an important factor influencing sinter productivity, sinter quality and fuel rate. In this work, the effect of suction, coke addition and mix moisture on flame front speed was studied in a pilot-scale sinter pot and also using a recently developed theoretical model. Airflow through the bed has a large influence on flame front speed. It was found that increasing sintering airflow rate will lead to increased flame front speed, but the increases become smaller at higher airflow rates. Sinter pot test results showed that increasing coke addition decreased green bed permeability and increased flame front temperature, which resulted in increased flame front resistance and decreased flame front speed. Studies also showed that green bed properties are sensitive to sinter mix moisture level. The changes in green bed properties further influence the flame front properties.