Precipitation and dissolution of iron oxide in high temperature water

In this work, a series of experiments were carried out to electrochemically deposit magnetite, hematite or a mixture of magnetite and hematite on a Pt coupon from FeSO4 solution. The techniques of scanning electron microscopy (SEM), X-Ray diffraction (XRD), and energy dispersive x-ray (EDX) were used to characterize the magnetite and hematite deposited on the Pt coupon.;In the dissolution experiment, a mixture of magnetite and hematite was first electrochemically deposited on platinum, in which part of the iron was irradiated to Fe59. A laboratory program was devised to investigate the electrochemical dissolution of the magnetite and hematite from the surface of the Pt coupon. The experiment was undertaken at open circuit potential and at several applied potentials (-0.145 V to -1.012V vs. standard hydrogen electrode (SHE)) with a potentiostat. It was found that the "dissolution" process involved the dissolution of iron oxides and the departure of particulate from the Pt coupon. Potential could affect the "dissolution" process significantly.