TPR data regarding the effect of sulfur on the reducibility of alpha-Fe2O3

The temperature programmed reduction (TPR) method has been used to study th e effect of residual sulfur on the reducibility of alpha-Fe2O3 prepared bot h using iron(II) and iron(III) sulfate. The values of the kinetic parameter s characteristic of the reduction of the hematite to magnetite, of the magn etite to metallic iron, as well as of the processes involved in the elimina tion of the sulfate anions, were evaluated by simulation of the TPR curves. The effect on the reducibility of alpha-Fe2O3 is reflected in the values o f the kinetic parameters when the sulfur is dispersed into the sample's bul k. If the sulfur exists only on the surface, its influence on the reducibil ity of the sample is mainly due to the fact that the reduction of the hemat ite starts only after the elimination of the sulfate anions begins. (C) 199 9 Elsevier Science B.V. All rights reserved.