Effect of precipitation conditions on the phase composition, particle morphology, and properties of iron(III,II) hydroxide precipitates

The phase composition and particle shape of amorphous iron hydroxide-iron o xide precipitates were correlated with the oxidation state of iron in the s tarting solution, Fe2O3 : FeO ratio, and precipitation procedure (coprecipi tation or successive precipitation) using Mossbauer spectroscopy, atomic ab sorption, low-temperature nitrogen BET, and electron microscopy data. A cor relation was established between the amount of iron(II) in the starting sol ution, the amount of the metastable phase gamma-Fe2O3 in the precipitate, p article shape, and the activity of the final heat-treatment products-alpha- Fe2O3 and mixed oxides of iron.