Influence of Urotropin on the Precipitation of Iron Oxides from FeCl_3 Solutions

摘要

Precipitations of iron oxides from FeCl_3 solutions in the presence of urotropin at 90 deg. C were monitored using the Fourier transform infrared spectroscopy, Mossbauer spectroscopy, X-ray diffraction and transmission electron microscopy. Urotropin was used as a generator of OH~- ions. The precipitation processes depended on the concentrations of FeCl_3 and urotropin and the time of aging. After 1 day of aging the precipitation systems up to pH ≈ 2, the β-FeOOH phase was precipitated, while in the region of 5 < pH < 6 the mix- tures ofβ-FeOOH, α-FeCl_3 and α-FeOOH were precipitated, and at pH >6 the mixtures ofα-FeCl_3 and α-FeOOH were observed.