In the electrolytic cell used in this method, an iron vessel acts as the cathode and the anode is made of nickel. First, the electrolysis of N/2 solution of NaOH in ordinary water is done.
About one-fourth of the absolute volume remains, then after distilling it, adding NaOH to the distillate, its concentration is again reduced to N/2 and electrolysis is done again. After repeating this process six times, the water obtained is almost 100% heavy water.