The invention discloses a two-stage negative-pressure 
evaporation, concentration and purification treatment process and a device for food-grade waste 
phosphoric acid. The invention belongs to the technical field of waste 
phosphoric acid treatment. Food-grade waste 
phosphoric acid is treated by a triple-effect negative pressure 
evaporation concentration and single-effect negative pressure 
evaporation concentration purification technology; the recovered regenerated phosphoric acid is high in purity, the 
mass concentration is greater than or equal to 85%, and no 
adverse effect is generated on a production process when the recovered regenerated phosphoric acid is returned to a workshop for use, so that economic and efficient treatment of food-grade waste phosphoric acid and maximum recycling of phosphoric acid resources are realized; the 
steam heating average distribution coefficient is high, so that the repeated 
utilization rate is high; the characteristics of 
high heat transfer efficiency, short 
heating time and the like are realized; according to the process and the device, the total steam consumption of food-grade waste phosphoric 
acid treatment is 1 / 3 of that of common evaporationequipment, the total operation power is 1 / 2 of that of traditional evaporation equipment, the process and the device have the advantages of 
energy conservation, consumption reduction, low steam consumption, low cooling 
water circulation amount and the like, wet and 
latent heat is fully utilized, the raw steam consumption is reduced, and the operation cost is reduced.