A kind of preparation method of fully water-soluble solid ammonium polyphosphate

Abstract

The invention belongs to the technical field of phosphate production, and particularly relates to a preparation method of full water-soluble solid ammonium polyphosphate. The invention aims at providing the preparation method of full water-soluble solid ammonium polyphosphate. The method comprises the following steps that 1, ammonium dihydrogen phosphate is fused to obtain fused slurry; 2, the fused slurry obtained in the first step is added to urea and stirred for a reaction, reacted slurry is obtained, the reacted slurry is added to water-soluble solid ammonium polyphosphate for a reaction, a polymerized and cured substance is obtained after the reaction is completed, and the temperature of a reaction system is decreased to 80 DEG C or below in the reaction process; 3, smashing and packing are conducted, wherein the polymerized and cured substance obtained in the second step is smashed and packed in a sealed mode, and full water-soluble solid ammonium polyphosphate is obtained. According to the preparation method of full water-soluble solid ammonium polyphosphate, the ammonium dihydrogen phosphate raw material is used, the processing steps are reduced, the requirement of process materials to equipment materials is improved, the preparation method is friendly to the environment, and the prepared product is good in fluidity, not prone to moisture absorption, good in subsequent processing performance and particularly suitable for major element water-soluble fertilizers, and a wide application prospect is achieved.

Description

technical field [0001] The invention belongs to the technical field of phosphate production, and in particular relates to a preparation method of fully water-soluble solid ammonium polyphosphate. Background technique [0002] Ammonium polyphosphate (APP) is a polyphosphate containing N and P. According to its degree of polymerization, it can be divided into low-polymerization, medium-polymerization and high-polymerization. The higher the degree of polymerization, the lower the water solubility, and vice versa. Big. The molecular formula of ammonium polyphosphate is (NH4) n+2 P n o (3n+1) , when n≤20, it is water-soluble, and when n>20, it is insoluble. High-purity, high-polymerization degree water-insoluble long-chain ammonium polyphosphate is used to prepare advanced fire-resistant coatings and flame-retardant plastics. Water-soluble products with a low degree of polymerization can be used as flame retardants, and can also be used in high-concentration slow-release ...

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Problems solved by technology

[0005] The weak point of above-mentioned technology is: above-mentioned method 1, adopts the method for thermal method phosphoric acid production, and cost is too high; above-mentioned method 2, the method in Chinese patent document CN101613095A, adopts ammonia neutralization phosphoric acid to filter, can produce a large amount of white manure, The value of phosphorus resources is not reflected, and its concentration and polymerization time are too long (greater than 11 hours) at the same time, and the energy consumption is high; the method in the above-mentioned method 3, Chinese patent document CN104528682A, due to the water-soluble ammonium polyphosphate solid product in the production process control requirements high, the continuity is not high, and it is very easy to produce products with high hygroscopicity, so the Chinese patent document CN104528682A and the aforementioned TVA process in the United States can only prepare ammonium polyphosphate aqueous solution, but the aqueous solution product is easy to crystallize during low-temperature storage Unfavorable factors such as high precipitation, storage and transportation costs, high freight (according to effective components)

[0006] Aiming at the problems of high cost, high moisture absorption rate, and poor continuity in the production of water-soluble ammonium polyphosphate solid products at home and abroad, the present invention specially studies the use of monoammonium phosphate (that is, the commonly used name for ammonium dihydrogen phosphate in this field) to prepare fully water-soluble ammonium polyphosphate. Ammonium polyphosphate solid product with low degree of polymerization, in order to reduce production costs and avoid unfavorable factors such as storage and transportation difficulties in preparation of liquid products, the product has low moisture absorption rate, and can realize continuous industrialized large-scale production

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