Method for producing granular monoammonium phosphate with raffinate

Abstract

The invention provides a method for producing granular monoammonium phosphate with raffinate, wherein, ammonia is neutralized with phosphoric acid to obtain slurry, and the slurry is concentrated and then subjected to spraying granulation to obtain the granular monoammonium phosphate. The method comprises the following steps: (1) mixing wet-process phosphoric acid with the raffinate according to a certain ratio to obtain mixed phosphoric acid, and then lowering the metal ion content in the raw material mixed phosphoric acid; and (2) adjusting the neutralization degree of neutralization reaction between the mixed phosphoric acid and the ammonia to obtain monoammonium phosphate slurry. The granular monoammonium phosphate obtained by the method can meet the requirement for nitrogen nutrients in the product, reach the product strength of no less than 40N, digest the raffinate in a wet-process phosphoric acid purification device, conform to the requirement for the current global recycling economy. The method can improve the concentration of dilute phosphoric acid, reduce steam consumption of a slurrying system, and increase the product strength of the granular monoammonium phosphate.

Description

【Technical field】 [0001] The invention relates to phosphate fertilizers, in particular to monoammonium phosphate, and in particular to a method for producing granular monoammonium phosphate by using raffinate acid from purified wet-process phosphoric acid. 【Background technique】 [0002] As we all know, the purification process of wet-process phosphoric acid has developed in recent years. The quality of purified wet-process phosphoric acid is comparable to that of thermal phosphoric acid, and the production cost is lower. It has a tendency to replace thermal phosphoric acid in the industrial field. In the currently widely used liquid-liquid solvent extraction process to purify wet-process phosphoric acid, raffinate will be produced as a by-product. Raffinic acid is generally used in the manufacture of fertilizers. When using raffinate to produce fertilizer, because of the F in raffinate - , SO 4 2- The content of such anions is reduced, but the metal cations in wet-proce...

AI Technical Summary

Problems solved by technology

[0004] The purpose of the present invention is to digest raffinate acid, ensure the continuous operation of the wet-process phosphoric acid purification device, and at the same time solve the problems of insufficient nitrogen content and excessive water content in the product when using raffinate acid to produce ammonium phosphate fertilizer, and provide a production method using raffinate acid. Method for Granular Monoammonium Phosphate

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