Studies on the formation of γ-Fe2O3 by thermal decomposition of ferrous malonate dihydrate
1988; Elsevier BV; Volume: 125; Linguagem: Inglês
10.1016/0040-6031(88)87221-6
ISSN1872-762X
AutoresMostafizur Rahman, V. A. Mukhedkar, A. Venkataraman, A.K. Nikumbh, S.B. Kulkarni, A. J. Mukhedkar,
Tópico(s)Minerals Flotation and Separation Techniques
ResumoThe thermal decomposition process of ferrous malonate dihydrate (FeC3H2O4·2H2O) was studied in atmospheres of static air, dynamic dry nitrogen, dynamic dry air, and dynamic air containing water vapour by means of thermal analysis (simultaneous TGA, DTG and DTA), direct current electrical conductivity measurements, infrared spectroscopy, elemental analysis, gas-liquid chromatography and X-ray powder diffraction analysis. The conductivity data in static air and dynamic air are quite complex: nevertheless, the formation of Fe3O4 and α-Fe2O3 with the probable intermediate formation of γ-Fe2O3 has been indicated. In dry nitrogen the step corresponding to dehydration is well resolved in the temperature region 190–260 °C and the formation of FeO and Fe3O4 is also well characterised. A definite indication from the conductivity measurements for the formation of γ-Fe2O3 prior to α-Fe2O3 was found in an atmosphere of dynamic air containing water vapour. Experimental conditions were determined for the formation of γ-Fe2O3 in dynamic air containing water vapour. This compound (γ-Fe2O3) was characterised by X-ray diffraction, magnetic hysteresis, scanning electron microscopy and Mössbauer spectroscopy.
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