Hematite to magnetite reduction followed by Mössbauer Spectroscopy and x-ray diffraction

JUAN PABLO GAVIRÍA; ANA ESTER BOHÉ; ALBERTO FELIPE PASQUEVICH; DANIEL MIGUEL PASQUEVICH

PHYSICA B: CONDENSED MATTER

C. Karlsson-ELSEVIER

Año: 2007 vol. 389 p. 198 - 201

0921-4526

The aim of the present research is to determine the kinetics of the transformation from hematite (a-Fe2O3) to magnetite (Fe3O4). The procedure consisted of an isothermal heating in a .ow of a H2–Ar mixture at temperatures between 260 and 360 1C. The phase evolution at a given temperature, as a function of the thermal treatment time, was monitored by using room temperature Mo¨ ssbauer spectroscopy and X-ray diffraction analysis (XRD). In the range of temperatures and times studied the only iron oxide that was formed was magnetite. In order to optimize equipment requirements for the quanti.cation of the reaction products a calibration curve was constructed. This allows to estimate the conversion degree (measured as the percentage of magnetite produced) with a short-run XRD pattern. We calculate an apparent activation energy of 9874 kJ/mol from reaction grade–time curves at each temperature.