SU363676A1 - - Google Patents

Description

Method of producing ammonium polyphosphates

one

This invention relates to a process for the preparation of complex fertilizers based on polyphosphoric acids.

A known method of producing ammonium polyphosphates by ammonizing polyphosphoric acid with gaseous am.miama to pH 5-6 while simultaneously hydrolyzing with water vapor, injected in an amount of 100-300% of the theoretically necessary to convert all PjOs into pyro form. The resulting mixture is kept at 125–200 ° C, water and NHs (up to pH 7) are added to the resulting melt at 25–110 ° C and a suspension is obtained, which is processed by nitrogen and phosphorus fertilizer.

However, the known method is characterized by the need for hydrolysis of the water of MGA. With steam and the formation of melt in the first stage of amization.

To simplify the process and improve the quality of the product according to the proposed method / 5 parts of the starting polyphosphoric acid is ammoniated with ammonia gas at 70-80 ° C to a pH of 8-8.5 for 30-120 minutes, followed by pre-ammoniation of the resulting solution and the remaining part of the polyphosphorus acid on the surface of the particles of the finished product.

Example. 100 g of polyphosphoric acid concentration of 80% P2O5, containing,% of

Р20506Щ ; 16 ORTHOPHORIC ACID,

40 pyrophosphoric acid, 24 trinolyphosphoric acid and 20 acids of a higher degree of condensation are divided into two

parts in the ratio of 1.5: 1. Most of it is loaded into a reactor equipped with a water jacket, where it is ammoniated at 75 ° C for 60 minutes to pH 8 while 40 g of water are introduced. The resulting solution

and the remaining part of the original acid is loaded into the granulator together with the previously obtained product m, where water is removed by ammonizing the fresh portion of the acid for 10-15 minutes at 70 ° C,

injected with a solution. The resulting product corresponds to the composition of 20.7-57,5-O and contains,% of P205; 32 ammonium orthophosphates, 49 pyrophosphates and 19 tripolyphosphates.

20

Subject invention

The method of producing ammonium polyphosphates by ammonizing polyphosphoric acid with gaseous am.Miac, characterized in that, in order to simplify the process and improve the quality of the product, 5 hours of starting polyphosphoric acid is ammoniated with ammonia gas at 70-80 ° C to pH 8- 8.5 during 34

30–120 min with subsequent polyphosphoric acid on the surface by scaling of the resulting solution and the remaining particles of the finished product.

363676