KINETICS OF REDUCTION OF Fe_2O_3 PARTICLES WITH H_2-CO MIXTURES AT LOW TEMPERATURES

摘要

1. The rate of reduction of particulate hematite with H_2-CO gas mixtures in the temperature range 550 to 650°C decreases as the concentration of carbon monoxide in the gas mixture increases. As an example, at 600°C, the rate of reduction with pure CO represents 51% with respect to that obtained using pure hydrogen. From a practical viewpoint, this conclusion indicates the use of pure hydrogen during reduction of iron ores in a fluidized bed configuration at low temperatures. 2. In the low temperature range investigated only hydrogen can yield complete conversion of iron oxides into metallic iron. Addition of carbon monoxide to the gas mixture contributes to decrease the maximum extent of conversion. The decrease in conversion is not linear with respect to CO, the lowest rate of conversion was found for the gas mixture containing 75% CO. The cause of this behavior is due to a higher rate of carbon deposition. 3. A mixed control mechanism controls the reaction rate for conversions up to 50%.