Structural-chemical transformations of alpha-Fe2O3 upon transport reduction

Transient regions between iron oxide crystalline phases were found in vario us stages of alpha -Fe2O3 structural-chemical transformation into FeO by Mo ssbauer spectroscopy. Particle sizes in those regions are less than 8 nm. T he sequence of phase transformations was established for alpha -Fe2O3 reduc tion to iron at temperatures higher and lower than the wustite stability po int (similar to 570 degreesC). Two phases Fe1-xO and FeO were found to form upon the reduction within the wustite stability region (the stoichiometric phase is formed first). It was shown that reduction of hematite into magne tite occurs within temperature range 570-600 degreesC by the multistage mec hanism, while magnetite reduction to wustite occurs by a zonal mechanism, w here three phases Fe3O4, FeO and Fe are present in a sample simultaneously. O 2000 Elsevier Science B.V. All rights reserved.