Abstract

PALACIOS, P. R.; DE LOS SANTOS VALLADARES, L.; BUSTAMANTE, A.  and  GONZALEZ, J.C.. Study of the dehydroxylation in the hydrated ferric oxide named limonite. Rev. Soc. Quím. Perú [online]. 2012, vol.78, n.3, pp.198-207. ISSN 1810-634X.

We completed the previous characterization of the compound named limonite (FeO[OH].nH₂O) with the analysis of thermal behavior at temperatures from ambient to 1000°C, as well as their chemical analysis through the measurements of energy dispersive X-ray and the study in the infrared region in energy range from 600 to 4000cm^-1. The results show a sharp endotherm peak around 264°C, it corresponds to the structure change of the orthorhombic goethite (Pbnm) to rhombohedra hematite (R3c) Moreover, we found three inflexion points in the percentage of mass loss at temperatures of 50, 190 and 290°C. These changes are closely related to the deshydroxylation of limonite to goethite, α -FeO(OH), phases and subsequently to hematite, α -Fe₂O₃.

Keywords : hydrated ferric oxide; infrared spectroscopy; thermogravimetric analysis; differential thermal analysis.

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