Method for preparing low-polymerization-degree water-soluble ammonium polyphosphate from ammonium phosphate

Abstract

The invention belongs to the technical field of the production of phosphate in inorganic chemical industry, in particular to a production technology for preparing low-polymerization-degree water-soluble ammonium polyphosphate from ammonium phosphate. The method is used for preparing a solid low-polymerization-degree ammonium polyphosphate product which is good in water solubility by innovatively mixing and heating ammonium phosphate, ammonium phosphate, urea and water which are taken as main raw materials. The method is low in production energy consumption, easy in production control, relatively easy in operation, easy in product package convenient in use and capable of reducing production and transportation costs, and the produced solid low-polymerization-degree ammonium polyphosphate product contains less than 0.15wt% of water-insoluble matters; the solid ammonium polyphosphate product is suitable for preparing a high-quality liquid fertilizer, applicable to airplane spraying forest fire fighting, liquid fertilizer airplane spraying, preparation of other liquid fertilizer and other purposes, and the solid ammonium polyphosphate product can be used for greatly promoting the rapid development of Chinese modern agriculture.

Description

technical field [0001] The invention belongs to the technical field of phosphate production in the inorganic chemical industry, and relates to a production technology for preparing water-soluble ammonium polyphosphate with a low degree of polymerization by using ammonium phosphate. Background technique [0002] Ammonium polyphosphate, also known as ammonium polyphosphate or polycondensed ammonium phosphate (APP for short), is a kind of polyphosphate containing N. The higher the degree of polymerization, the lower the water solubility, and vice versa. According to its structure, it can be divided into crystalline form and amorphous form. The crystalline ammonium polyphosphate is a long-chain water-insoluble salt. The molecular formula of ammonium polyphosphate is (NH 4 ) (n+2) P n o (3n+1) , when n is 2-20, it is water-soluble; when n is greater than 20, it is insoluble. High-purity, high-polymerization degree water-insoluble long-chain ammonium polyphosphate is used to...

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Problems solved by technology

[0006] Aiming at the shortcomings of ammonium polyphosphate currently produced, such as high cost, difficulty in being fully soluble in water, and low yield of ammonium polyphosphate used for agricultural liquid fertilizers, the present invention uses a mixture of ammonium phosphate, phosphorus pentoxide, and ammonium bicarbonate. The method of heating the ammonium polyphosphate solid product with low polymerization degree and good water solubility does not use urea, which can reduce the production cost, and achieve the purpose of good water solubility of the ammonium polyphosphate solid product and small water insoluble matter in the aqueous solution. It is used for aircraft spraying forest fire extinguishing, liquid fertilizer aircraft spraying and other liquid fertilizer preparations, and has the application prospect of realizing low-cost large-scale continuous production