Ferrate(VI) has the potential to be used as an environmentally friendly treatment for wastewater and drinking water. The electrochemical preparation of ferrate can be considered a "green" and simple approach because it typically involves a one-step reaction without harmful or expensive chemicals for the oxidation of Fe(0) to Fe(VI). The electrolyses are performed in three molten systems (i.e. NaOH-H2O, KOH-H2O and NaOH-KOH-H2O). In the first molten system, soluble ferrate was prepared in relatively low yield and current efficiency for continuous addition to wastewater. In the second system, highly stable ferrate that is easily transported and insoluble is produced with high yield. In the third system, the properties and yield of ferrate depend on the Na/K ratio in the melt. The influence of the anode material, current density and temperature on the electrolysis yield and current efficiency during ferrate preparation is discussed.