The invention discloses a method for producing crude
sodium L-ascorbate by recovering crude
vitamin C
mother liquor. The method comprises the steps of: destaining crude
vitamin C
mother liquor through a macroporous adsorption resin, concentrating, crystallizing and centrifuging a destaining solution to obtain a crude
vitamin C
mother liquor recovered product, crushing and
drying the mother liquor recovered product through a micro
powder drying machine, performing
esterification reaction with
methanol, controlling the burdening ratio of mother liquor recovered product (weight) to
methanol (volume) in the
esterification reaction of 1: 7, reacting for 4 hours, wherein the
esterification reaction temperature at the first hour is 68 DEG C, the esterification
reaction temperature at the second hour is 60 DEG C, the esterification
reaction temperature at the third hour is 55 DEG C and the esterification
reaction temperature at the fourth hour is 50 DEG C, adding
sodium bicarbonate with stoichiometric amount to perform
conversion reaction to obtain intermediate crude
sodium L-ascorbate, and then changing over to the production process of normal
vitamin C. The production yield and quality of the crude sodium L-ascorbate are improved, the problem of the accumulation of a mother liquor recovered product is solved, and the production process is simplified.