Iron (III) Oxide Fabrication From Natural Clay With Reference to Phase Transformation γ- → α- Fe2O3

  • Aleksandra Šaponjić University of Belgrade - Vinča Institute of Nuclear Sciences
  • Đorđe Šaponjić University of Belgrade - Vinča Institute of Nuclear Sciences
  • Violeta Nikolić University of Belgrade - Vinča Institute of Nuclear Sciences
  • Maja Milošević University of Belgrade - Faculty of Mining and Geology
  • Milena Marinović-Cincović University of Belgrade - Vinča Institute of Nuclear Sciences
  • Stanislav Gyoshev Institute of Information and Communication Technologies, Bulgarian Academy of Sciences
  • Marina Vuković University of Belgrade - Institute for Multidisciplinary Research
  • Maja Kokunešoski University of Belgrade - Vinča Institute of Nuclear Sciences

Abstract

Amorphous iron (III) oxide was obtained from clay, using ammonium hydroxide as a precipitating agent. Influence of freeze drying under vacuum, as a drying method, on particle size, chemical composition, and crystallinity of obtained iron (III) oxide powder was investigated. After freeze drying, precipitate was annealed in air at 500 oC and 900 oC. X-ray diffraction, particle size analysis, scanning electron microscopy, energy dispersive spectrometry, Fourier transform infrared spectroscopy, thermogravimetric and differential thermal analysis were used to characterize obtained iron (III) oxide powder. All of three powders obtained by freeze drying and annealing, have low crystallinity and particles with irregular layered shape. Narrow particle size distribution was given by an average diameter value of around 50 μm for all observed powders. Iron-bearing materials like α-Fe2O3 and γ-Fe2O3 are obtained. Differential thermal analysis curve of obtained samples showed endothermic reaction at 620 oC which could be ascribed to phase transition from cubic form γ- → α- Fe2O3. Thermal transformations of iron (III) oxide, obtained from clay as a natural source, is suitable to explore in the framework of materials chemistry, and opens the possibility to synthesize materials based on Fe2O3 with specific magnetic behavior.

Published
2017-12-13
Section
Articles