Assessment of Reduction Behaviour of Low-Grade Indian Hematite Iron Ore Pellets by Non-Coking Coal

Studies on isothermal reduction behaviour (with coal) of fired pellets of low-grade hematite iron ore were performed in the temperature range of 1123-1223 K. A rise in temperature considerably improved the reduction rate, and this was sharper up to about 45- 55% reduction. An increase in firing time from 1 to 3 h at 1573 K decreased the degree of reduction in resulting fired iron ore pellets. Fired iron ore pellets made with molasses exhibited slightly higher % of reduction values than those prepared under identical conditions by the addition of bentonite. Abnormal swelling was not observed in any of the reduced pellets. Kinetic model equation, 1 - (1 - f)(1/3) = kt, was noticed to fit well for the experimental results, and computed apparent activation energy values were found to be in the range of 15-16 kJ mol(-) 1, indicating overall reduction rate to be controlled by both the chemical reaction and gaseous diffusion processes.

Automated summary

Studies were conducted on the isothermal reduction behaviour (with coal) of fired pellets of low-grade hematite iron ore in the temperature range of 1123-1223 K. Higher temperature and shorter reduction duration led to improved reduction rate, especially up to about 45- 55% reduction. Fired iron ore pellets made with molasses showed slightly higher reduction values compared to those prepared with bentonite, and no abnormal swelling was observed in any of the reduced pellets. The kinetic model equation, 1 - (1 - f)(1/3) = kt, was found to fit well for the experimental results, with computed apparent activation energy values ranging from 15-16 kJ mol(-) 1, suggesting that the reduction rate was controlled by both chemical reaction and gaseous diffusion processes.