Two-stage negative-pressure evaporation, concentration and purification treatment process and device for food-grade waste phosphoric acid

Abstract

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.

Description

technical field [0001] The invention belongs to the technical field of waste phosphoric acid treatment, and in particular relates to a two-stage negative pressure evaporation, concentration and purification treatment process and device for food-grade waste phosphoric acid. Background technique [0002] Phosphoric acid (H 3 PO 4 ) is an important inorganic acid, the acidity is a medium-strong acid, and it is an important intermediate product in the production of chemical fertilizers. It is mainly used in chemical fertilizers, industrial phosphates, feed-grade phosphates, medical phosphates, food phosphoric acid and electronic-grade phosphoric acid. etc. production. [0003] Phosphoric acid is a kind of relatively stable protonic acid catalyst, which can make the protonated carbonyl easier to attack the reagent with nucleophilic group, thereby accelerating the reaction, avoiding the occurrence of disproportionation reaction, and reducing the occurrence of side reactions The...

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Problems solved by technology

[0015] Furthermore, the source of phosphoric acid at home and abroad is divided into thermal method and wet method according to the production process conditions: because the raw material of phosphoric acid produced by thermal method is yellow phosphorus, the cost of yellow phosphorus is high, and in addition, because yellow phosphorus produces phosphoric acid, the environmental pollution is serious, so , the production of phosphoric acid by thermal method cannot be produced in large quantities; the production of phosphoric acid by wet method is due to high price, complicated purification process, high equipment investment and other reasons, which lead to the continuous increase in the price of phosphoric acid produced by wet method

[0016] However, the above three waste phosphoric acid treatment methods all have certain disadvantages: the first waste phosphoric acid treatment method has a low utilization rate of phosphorus resources and can only be used to produce phosphate fertilizers and some low-grade phosphate products, making its application The scope is greatly limited; the second waste phosphoric acid treatment method requires the introduction of sedimentation agent, decolorizer and heavy metal scavenger, as well as extraction, back extraction, and secondary concentration. The third waste phosphoric acid treatment method adopts membrane separation technology or ion exchange resin to adsorb and purify waste phosphoric acid, which also leads to high recovery cost of phosphoric acid and poor economy

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