1993 Volume 33 Issue 7 Pages 735-739
Hematite-noncoking coal mixed pellets were reduced isothermally at 900, 950, 1000, 1025 and 1050°C under constant flow rate of nitrogen gas. The surface characteristic of the reduced pellets for different time-temperature schedule were examined by a Scanning Electron Microscope (SEM). Analysis of the data and examination of the SEM microphotographs revealed that the mechanism associated with the reduction changed with increasing temperature and fractional reaction. Activation energy values of the reduction at different levels of fractional reaction were calculated with the help of an Integration Method.
The effect of Carbon/Hematite molar ratio on the extent of the reduction was also investigated. It was found that at temperatures 900 to 1000°C fractional reaction increased with increasing carbon content up to a critical value of the ratio and then decreased. At temperatures above 1000°C fractional reaction increased linearly with increasing carbon content.