Kinetics and Mechanisms of Reactions in Iron Ore/Coal Composites

The present work is a fundamental study of reduction in mixtures of iron ore concentrate and pulverized coal by indirect heating. Cylindrical steel crucibles, 118 mm i.d. and 150 mm height, with full-load of mixtures were placed in a muffle furnace which was controlled to be at a constant temperature of 1200°C for predetermined times of reaction. The profile of temperature and degree of reduction, and distribution of residual carbon were measured by embedded tiny thermocouples during the course of reaction and sampling and chemical analysis of reacted solids. It has been found that reducing gas generated in higher temperature regions by devolatilization and Boudouard reaction plays a role in convective heat transfer and indirect reduction for benefits of interior regions. The likely rate-controlling step of the overall reaction is considered to be heat transfer.