Process for reclaiming 2-keto-L-gulonate by salting out method

The invention relates to a method for reclaiming 2-Keto-L-gulonic sodium by a salting out method. The crystallized mother liquor of 2-Keto-L-gulonic sodium or the extracted mother liquor of 2-Keto-L-gulonic sodium is heated to 30 to 40 DEG C, then inorganic sodium salt is added into the mother liquor while being stirred, then the temperature of the mother liquor is reduced to 10 to 15 DEG C, the temperature is kept for 2 to 10 h until 2-Keto-L-gulonic sodium is no longer separated out, and the separated educt is 2-Keto-L-gulonic sodium, wherein the pH value of the crystallized mother liquor of 2-Keto-L-gulonic sodium is adjusted to 5-7 before being heated. The method reclaims 2-Keto-L-gulonic sodium in discharged waste liquor, and has the advantages that the method is simple, the operation is convenient, the recovery rate is more than 70 percent, and simultaneously the pollution of organic substances in the discharged waste liquor is reduced.