Iron can be produced by the direct electrochemical reduction of hematite particles suspended in hot, concentrated NaOH solutions. Because various other iron sources can be considered, the present work was aimed at investigating the electrolytic treatment of the "red mud" generated by Bayer process for alumina preparation from bauxite. Such iron sources contain very high amounts of impurities, in particular silicon and aluminium oxide-based minerals, in addition to other mineral phases. Electrolytic reductive treatment of the industrial red mud sample was shown to be possible but with both lower current density and current efficiency for Fe deposition. After deposition tests at fixed current density, further experiments in simulation tests have been carried out for better understanding: in particular hematite particles were tested, with or without various impurities introduced in the solution. Presence of little soluble impurities at the particle surface appears to hinder the reactivity of the suspended particles at the cathode surface, whereas side-hydrogen efficiency still occurs.