The chemical and structural properties of Fe-oxides formed
from FeS04 solutions are strongly dependent on the [Fe2+]/[OH-]
concentration ratio at the beginning of the precipitation process,·
on the rate of oxygenation, the time of precipitation, the temperature,
and the kind of alkali (NH40H or NaOH). Goethite (a-FeOOH) of varyingcrystallinity and/er substoichiometric magnetite (Fe3-\u27 04) were precipitated at 90 -c. Differences in the crystallinity of a-FeOOH were revealed by Mossbauer spectroscopy, as well as by X-ray diffraction. The stoichiometry of Fe3_x04 varied from Fe2.9104 to the one close to Fe2.6704. The X-ray diffraction showed only the presence of Fe3-x04, but not of maghemite (y-Fe203). The formation of hematite (a-Fe203), under specific experimental conditions, was also observed. Amorphous iron(III) hydroxyde precipitated at room temperature. The mechanism of precipitation of Fe-oxides from FeS04 solution is discussed
