A method of recovering terephthalic acid and, if any, of soda from sodium terephthalate solution

The invention concerns a method for recuperating from saponification products of alkylene polyterephthalate with soda, both terephthalate ions in acid form and sodium ions in the form of soda and for optimising the recuperation process. The invention is characterised in that the sodium terephthalate solution resulting from dissolving these saponification products are subjected to a step of electrochemical pre-acidification to bring it to a pH of 4 to 7, then an electrochemical acidification by electrolysis to precipitate the terephthalic acid in the anode section and recuperate in the cathode the soda which can be recycled, if required, after being previously concentrated, to the step of saponification.