The current yield for the anodic oxidation of a pure iron (99.95%) electrode to ferrate(VI) ions in 14 M NaOH between 30 and 60 degrees C using a sinusoidal alternating current (a.c.) at amplitudes in the range 38-88 mA cm(-2) and frequencies in the range 0.5 mHz to 5 kHz superimposed on direct current (d.c.) of 16 mA cm(-2) was measured under conditions of bubble induced convection in a batch cell. The current yield for ferrate(VI) synthesis exhibited a complex dependence on temperature and a.c. frequency, but generally a maximum was observed in a frequency range 2-50 Hz depending on the a.c. amplitude. A global maximum current yield after 180 min of electrolysis of 33% was reached at the following conditions: a.c. amplitude of 88 mA cm(-2), a.c. frequency of 50 Hz and temperature of 40 degrees C. At the optimum conditions the highest d.c. electrolysis yield was 23%. Thus, operation with the a.c. component leads to an increase in the yield by 43% with respect to d.c. electrolysis alone.