engleski

Precipitation of oxide phases from concentrated Fe(No3)3 solutions

Concentrated Fe(NO3)3 solutions (final concentration of Fe3+ corresponded to 1M) were completely or partially neutralized with the addition of concentrated NaOH solution and then aged in dependence on temperature and time. The precipitates were investigated using Mössbauer spectroscopy and transmission electron microscopy (TEM). In highly alkaline medium, a-FeOOH as a single phase was obtained at RT, while a-Fe2O3 crystallized at 333 K as a second phase. After 90% of 1M Fe(NO3)3 solution was neutralized, the lemon-shape a-Fe2O3 particles were obtained at 398 K for 6 or 24 h. Mössbauer spectra were dependent on the microstructure of the oxide phases obtained. The nature of the formation of a FeOOH and a-Fe2O3 was discussed.

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