REDUCTION BEHAVIOURS OF PELLET BY HYDROGEN AND CARBON MONOXIDE ATMOSPHERES USING IN-SITU XRD AND THERMOGRAVIMETRIC ANALYSISES

摘要

Canadian hematite acid pellet with low magnetite content were isothermally reduced with hydrogen and carbon monoxide at 600 to 1000 °C . The course of reduction was investigated by measuring the oxygen weight loss as a function of time using thermogravimetric analysis. Macroscopic and microscopic examination, in-Situ X-ray diffraction and carbon analyses were also used to elucidate the mechanisms of reduction of pellet. For CO atmospheres, CO can increase carbon deposition behaviors in pellet reduction and carbon deposition leads to the fracture of pellet at the low temperature. Reduction of Fe_2O_3 to Fe_3O_4 by CO or H2 atmospheres has the fastest reaction ratio. Pellet reduced by CO has porous structures, while pellet reduced by H2 has a dense product layer on the surface.