Method and system for producing industrial grade monoammonium phosphate and industrial grade diammonium phosphate from wet process phosphoric acid

Abstract

The invention discloses a method and a system for producing industrial grade monoammonium phosphate and industrial grade diammonium phosphate from wet process phosphoric acid. The method comprises thefollowing steps: (1) mixing a monoammonium phosphate mother liquor, liquid ammonia and the wet process phosphoric acid, reacting the obtained mixture, carrying out solid-liquid separation to obtain the monoammonium phosphate product and a crystallization mother liquor I, mixing the diammonium phosphate mother liquor, liquid ammonia and the wet process phosphoric acid, reacting the obtained mixture, and carrying out solid-liquid separation to obtain the diammonium phosphate product and a crystallization mother liquor II; (2) mixing the crystallization mother liquor I, the crystallization mother liquor II, liquid ammonia and the wet process phosphoric acid, reacting the obtained mixture, carrying out solid-liquid separation to obtain the monoammonium phosphate product and the crystallization mother liquor I, mixing the crystallization mother liquor II, liquid ammonia and the wet process phosphoric acid, reacting the obtained mixture, and carrying out solid-liquid separation to obtain the diammonium phosphate product and the crystallization mother liquor II; and (3) repeating step (2) on the crystallization mother liquor I and the crystallization mother liquor II obtained in step (2), wherein tail gas generated in the neutralization reaction of the diammonium phosphate in the steps (1) and (2) is washed and absorbed by phosphoric acid; and mother liquor balance is realized, and industrial grade monoammonium phosphate and industrial grade diammonium phosphate are coproduced.

Description

technical field [0001] The invention relates to the technical field of chemical industry, in particular to a method and system for producing industrial-grade monoammonium phosphate and industrial-grade diammonium phosphate by wet-process phosphoric acid. Background technique [0002] Industrial grade monoammonium phosphate and diammonium phosphate are widely used in fire protection, drip irrigation fertilizer, medicine and food. At present, the production of industrial grade monoammonium phosphate and diammonium phosphate generally adopts thermal phosphoric acid or purified phosphoric acid process. The disadvantages are high production cost, complicated process, high energy consumption and large pollution. However, the existing wet-process phosphoric acid production process has relatively simple production equipment and production processes, and most of them can only produce industrial-grade monoammonium phosphate or industrial-grade diammonium phosphate, and it is difficult...

AI Technical Summary

Problems solved by technology

At present, the production of industrial grade monoammonium phosphate and diammonium phosphate generally adopts thermal phosphoric acid or purified phosphoric acid process. The disadvantages are high production cost, complicated process, high energy consumption and large pollution.

However, the existing wet-process phosphoric acid production process has relatively simple production equipment and production processes, and most of them can only produce industrial-grade monoammonium phosphate or industrial-grade diammonium phosphate. It is difficult to realize the co-production of industrial-grade monoammonium phosphate and industrial-grade diammonium phosphate

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