Abstract
Mineralogical alternation of thermally treated siderite in air atmosphere has been systematically analyzed by Mössbauer effects. It was preliminarily estimated from the area of subspectra that 4%, 39% and 62% of magnetite were formed at 410 °C, 490 °C and 510 °C respectively. After being incrementally heated at 530 °C the spectra consist of two sextets of Fe3O4. Sextet of γ-Fe2O3 with hyperfine field of 50T was observed at 550 °C. Spectra at 580 °C consisted of two sextets with hyperfine fields caused by γ-Fe2O3 and α-Fe2O3. Fe3O4 disappeared and the amount of γ-Fe2O3 decreased, while the quantity of α-Fe2O3 increased to 34% and 77% at 640 °C and 690 °C, respectively. During the early stage of decomposition and oxidation, FeO was probably produced but quickly oxidized to magnetite and unidentified in our experiment. These results, in good agreement with the X-ray diffraction analyses and microscopic observation, provide an interpretation to anomalous magnetic property changes of siderite-bearing rock samples.
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Pan, Y., Zhu, R. & Ping, J. Mineralogical alteration of thermally treated siderite in air: Mössbauer spectroscopy results. Chin.Sci.Bull. 44, 1712–1717 (1999). https://doi.org/10.1007/BF03183498
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DOI: https://doi.org/10.1007/BF03183498