Method for obtaining organic acids from an aqueous mother liquor

A process for obtaining an organic acid from an aqueous solution of the organic acid, wherein the organic acid comprises:

• (i) an aminobenzoic acid of the formula
• in which R is CH3 or H,
• or
• (ii) an aliphatic saturated dicarboxylic acid of the formula
• in which n=1 or 2,
• said process comprising:
• A) preparing the organic acid by a biological process or a chemical reaction, wherein
• α) the organic acid is crystallized from an aqueous medium during or after the preparation, followed by
• 1) removing the fractions of the organic acid that have precipitated in the crystallization by a solid-liquid phase separation to leave a first aqueous solution of the organic acid, and
• 2) optionally depleting the fraction of the inorganic acid dissolved in the first aqueous solution of the organic acid by extracting organic acid with an organic extractant or by adsorbing organic acid on an adsorbent, followed by removing the organic extractant or adsorbent to obtain a second aqueous solution of the organic acid;
• B) treating the first aqueous solution of the organic acid or the second aqueous solution of the organic acid with a metal salt, the metal ions of which include Mn2+, Fe2+ and/or Cu2+, to precipitate a metal compound of the organic acid, followed by removing of the precipitated metal compound of the organic acid by a solid-liquid phase separation;
• C) base treatment of the metal compound of the organic acid that has been removed with an aqueous base solution with precipitation of metal hydroxide and removal of precipitated metal hydroxide by a solid-liquid phase separation to leave a basic aqueous solution containing anions of the organic acid;
• and
• D) crystallizing organic acid out of the basic aqueous solution containing anions of the organic acid that has been obtained in C) by addition of an inorganic acid.