<Original Papers>Heat and Mass Transfer in the Reduction of Iron Oxide Pellet with Hydrogen

The reduction rate and the surface temperature change of an iron oxide pellet were measured during the reduction with hydrogen in the temperature range of 800-1,100℃. The surface temperature was measured by using an automatic optical pyroscope. On the other hand, a mathematical model for nonisothermal reaction was developed on the basis of the unreacted core model considering heat and mass transfer. The observed data were compared with the calculated values according to this model. The reduction curves and the surface temperatures calculated by the use of this model almost coincided with observed data. The temperature drop observed during the reduction process was not so large because the heat transfer by radiation played an important role in the rate of heat transfer from the surroundings to the surface of pellet in these experimental conditions. Therefore, the parameters in the rate equation for the reduction of single iron oxide pellet with hydrogen might be determined with sufficient accuracy by analysing the measured data on an assumption that the reaction would proceed isothermally