Process for purifying lactic acid characterised by the initial removal of ionic substances

摘要

Lactic acid is purified from a fermentation medium in a process essentially comprising the following steps: 1) Elimination of the ion loads capable of catalysing the lactic acid condensation, using solid or liquid ion exchange resins; 2) Concentration of lactic acid to 70 to 90 % by evaporation at a low temperature and under reduced pressure; 3) Post concentration of the lactic acid using a mechanically shaken thin-film evaporator or short-path evaporator 4) Purification of the lactic acid by distillation.