Verfahren zum Elektrodialysieren von Fluessigkeiten

This new method is used for the electrodialysis of fluids, accompanied by water electrolysis. Fluid containing a salt undergoes monopolar electrodialysis. Concentrate flowing from this stage is then subjected to bipolar electrodialysis. A novel feature of this process is that the concentrate stream undergoing bipolar electrodialysis, is mixed with fluid which has been reduced in concentration by bipolar electrodialysis, i.e. resultant dilutate. Also claimed is the equipment to carry out the procedure. This includes monopolar and bipolar electrodialysis units (6, 11), each with one or more electrodialysis stacks, with a circuit (15, 10) for cyclic electrodialysis of the dilutate. The new feature is connection of the concentrate chamber (s) (9) of the monopolar dialysis to the dilutate circuit (15, 10). USE - To electrolyse salts, producing a high product concentration. ADVANTAGE - This process wins the acid and alkaline products in higher concentration, for lower energy consumption than required in comparable prior art. The dilutate concentration may be made very low. The example of sodium lactate processing is described, producing lactic acid and sodium hydroxide. In a process example included, graphs clearly illustrate the changes in dilutate and concentrate concentrations, with time and with total electrical charge passed.