According to the Melchers model, during the initial state of the first stage, steels are oxidized to produce various forms of dissolved ferrous ion or precipitated ferrous hydroxide
. The various forms of ferrous ion are chemically or electrochemically oxidized by oxygen to produce different types of ferric oxyhydroxide, maghemite, or hematite.
The waste stream from the electrochemical cell is pumped to settling pond where precipitated chromium hydroxide and ferrous hydroxide
settles down and chromium free clear water overflow.
Matsunagaa, "Controlled formation of magnetite crystal by partial oxidation of ferrous hydroxide
in the presence of recombinant magnetotactic bacterial protein Mms6," Biomaterials, vol.
The best film is formed at potentials of-950 to -1150 mV (Cu/CuSO4) and is composed of magnetite but--when freshly formed--also contains ferrous hydroxide
which makes the magnetite film poorly conducting.