METHOD FOR PRODUCING PURIFIED LACTIC ACID SOLUTION

摘要

The invention is capable of concentrating calcium lactate in a solution containing lactic acid obtained by fermentation in the form of calcium lactate at low cost and reduces the thermal degradation of impurities and the optical isomerization of lactic acid. A calcium lactate-containing solution containing lactic acid obtained by fermentation in the form of calcium lactate is subjected to concentration and purification by a method comprising (1) a step of concentrating calcium lactate by removing water contained in the calcium lactate-containing solution from the solution with a reverse osmotic membrane, (2) a step of separating calcium as calcium sulfate by adding sulfuric acid to the thus obtained concentrated liquid of calcium lactate after the step of concentration with a reverse osmotic membrane, and (3) a step of removing soluble impurities by ion exchange after the step of separation of calcium sulfate.