P. Refait et Jmr. Genin, THE TRANSFORMATION OF CHLORIDE-CONTAINING GREEN RUST ONE INTO SULFATED GREEN RUST 2 BY OXIDATION IN MIXED CL- AND SO42- AQUEOUS-MEDIA, Corrosion science, 36(1), 1994, pp. 55-65
The mechanisms of oxidation of a ferrous hydroxide precipitated by mix
ing a solution of NaOH with a solution containing dissolved ferrous su
lphate and chloride depend on the ratios R = [Fe2+]/[OH-] and A = [SO4
2-]/[Cl-] of the initial conditions. This study is limited to A = 1/4
and R ranging from 0.80 to 1.33 where the oxidation processes are gove
rned by the formation and transformation of green rusts. The overall p
rocess is ferrous hydroxide --> green rust 1 --> green rust 2 --> alph
a and gamma ferric oxyhydroxides. The Pourbaix diagram of iron in chlo
ro-sulphated aqueous media is drawn in the case where A = 1/4.