Method for recycling esterification acid wastewater produced in ethyl cyanoacetate production

The invention discloses a method for recycling esterification acid wastewater produced in ethyl cyanoacetate production, and relates to the technical field of ethyl cyanoacetate production. The method comprises the following steps: (1) adding sodium hydroxide into wastewater, totally transforming sulfuric acid and acidic salt in the wastewater into sodium sulfate, performing ammonia removal treatment to release ammonia gas, and absorbing the ammonia gas with water to obtain ammonia water; (2) decolorizing the ammonia-removed wastewater to obtain a light-colored transparent solution; (3) cooling the decolorized wastewater to be below 0 DEG C, and filtering to obtain a sodium sulfate crystalline solid; (4) dehydrating and concentrating filtrate, and filtering to obtain a sodium chloride solid, wherein residual mother liquor is an ethyl cyanoacetate solution which is recycled for production. The method is simple, and has high adaptability and a good treatment effect; by adopting the method, components in the was