Phase transition of iron sulphide minerals under hydrothermal conditions and magnetic investigations

Ssu Han Li, Yen Hua Chen, Jey Jau Lee, Hwo Shuenn Sheu

研究成果: Article同行評審

4 引文 斯高帕斯(Scopus)

摘要

Iron sulphide minerals have been used in industrial applications for many years, and more recently there has been increasing interest in the use of iron sulphide nanomaterials because of their useful properties and low cost. Previous studies have mainly focused on the synthesis of iron sulphides, but their phase transition and micro-magnetic properties are still unclear. In this study, iron sulphide minerals were synthesized via a hydrothermal method, and their phase transition mechanisms and magnetic properties were investigated. Ex situ and in situ X-ray diffraction results of the iron–sulphur system under hydrothermal conditions suggested that the transformation sequence followed the order of mackinawite (FeS) → greigite (Fe3S4) → smythite (Fe9S11) → pyrrhotite (Fe9S10). Pure greigite and pyrrhotite were obtained during the synthesis processes, after 1 h at 120 and 160 °C, respectively. Greigite showed a granular morphology with particle diameters around 30 nm, and pyrrhotite comprised stacked hexagonal sheets with thousands of nanometers in width. Pyrrhotite showed anti-ferromagnetic behaviour; however, it did not saturate up to magnetic field of 7 T. Greigite was ferrimagnetic, with a high saturation magnetization of 62.7 Am2 kg−1 and coercive magnetic field of 27.6 mT. Magnetic force microscope measurements of greigite revealed that its magnetic structure belonged to a spin-canted single domain. Overall, this study provides new information on the phase transition mechanism, related reaction formulas, and magnetic properties of iron sulphides, and it emphasizes the important role played by temperature/time in phase transitions.

原文English
頁(從 - 到)27-38
頁數12
期刊Physics and Chemistry of Minerals
45
發行號1
DOIs
出版狀態Published - 2018 一月 1

All Science Journal Classification (ASJC) codes

  • 材料科學(全部)
  • 地球化學與岩石學

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