PRESSURE LEACHING OF REDUCED ILMENITE - ELECTROCHEMICAL ASPECTS

The anodic dissolution of iron and cathodic reduction of oxygen were s tudied in ammonium chloride solutions over the temperature range 30-15 0 degrees C and at a total pressure up to 780 kPa using the rotating d isc electrode technique. Corrosion current densities determined by the Evans' diagram and linear polarisation method showed that the corrosi on rate increases with increasing temperatures and oxygen partial pres sures, The industrial importance of this reaction is in the production of synthetic rutile via the Becher Process which involves the high te mperature reduction of ilmenite followed by the forced corrosion of me tallic iron from the reduced ilmenite matrix. Results obtained from a series of pressure leaching trials showed that, by carrying out this r eaction at above ambient oxygen partial pressures and at elevated temp eratures, the corrosion rate can be significantly increased above that achieved in the conventional aeration process.