KINETICS AND REDUCTION CHARACTERISTICS OF HEMATITE-NONCOKING COAL MIXED PELLETS UNDER NITROGEN GAS ATMOSPHERE

Hematite-noncoking coal mixed pellets were reduced isothermally at 900 , 950, 1 000, 1 025 and 1 050-degrees-C under constant flow rate of ni trogen gas. The surface characteristic of the reduced pellets for diff erent time-temperature schedule were examined by a Scanning Electron M icroscope (SEM). Analysis of the data and examination of the SEM micro photographs revealed that the mechanism associated with the reduction changed with increasing temperature and fractional reaction. Activatio n energy values of the reduction at different levels of fractional rea ction were calculated with the help of an Integration Method. The effe ct of Carbon/Hematite molar ratio on the extent of the reduction was a lso investigated. It was found that at temperatures 900 to 1 000-degre es-C fractional reaction increased with increasing carbon content up t o a critical value of the ratio and then decreased. At temperatures ab ove 1 000-degrees-C fractional reaction increased linearly with increa sing carbon content.