SU1247374A1 - Method of producing double superphosphate - Google Patents

Description

The invention relates to the production of mineral fertilizers and can be used to produce double superphosphate.

The purpose of the invention is to increase the degree of decomposition of phosphate raw materials while improving its quality.

According to the proposed method, the apatite is first decomposed by extraction phosphoric acid for 3-5 minutes and then the resulting pulp is mixed with the sludge of a sewage neutralization station, previously treated with excess sulfuric acid. Sludge composition,%: PjOj 6.0-10.0; CaO 10.0- 15.0; Sic 3.5-6.0; rest. The total humidity of the resulting mixture is 64-68%. Next, the process is carried out according to the traditional technology of producing double superphosphate, first kept in the chamber for 1-1.5 hours, and then in stock. In this case, the total degree of decomposition of apatate and sludge reaches 97-98%, the concentration of 1 Oj / p is 47- 48%, and the degree of removal of fluorine from the mixture is 56-59% of the amount I enter;

The overall degree of decomposition of the raw material increases due to the fact that P, 0j., Introduced with the sludge, is in an easily decomposable form and when decomposed completely goes into an easily decomposable form and when decomposed completely goes into an digestible form, and an excess of sulfuric acid contributes to a more complete decomposition of apatite . The quality improvement of the double superphosphate is due to the reduction of fluorine compounds in it, which is achieved during the treatment of the sludge with sulfuric acid due to aBTOTepMii4ecKOMy heating the mixture.

Thus, the distinguishing features of the invention are the decomposition of apatite in the presence of pulp obtained by treating the sludge from a sewage neutralization station with excess sulfuric acid. The ratio of pulp after decomposition of apatite with phosphoric acid and pulp after treatment of the sludge with sulfuric acid is 1: 0.13-0.43.

The use of the mixture entering the superphosphate chamber, when the ratio of pulp after decomposition to apatite to pulp after decomposition of sludge more than 1: 0.13 is impractical, so

as the amount of fluorophosphate sludge used is reduced and there are no advantages over those achieved in known processes. The use of a mixture of pulp entering the superphosphate chamber, with a ratio of pulps after decomposition of apatite to pulp after decomposition of sludge is less than 1: 0.43

it is also unacceptable because it leads to excessive wetting of the mixture and to obtain a superphosphate mass that does not set.

Example 1. In heat resistant

a glass containing 47 g of sludge from the station for neutralization of wastewater from the Gomel Chemical Plant (GHZ) composition,%: P, 0j 6.8; CaO 11.2; 0 4.0; F 3,0; 75, with vigorous stirring, 10.5 g are introduced.

93% (3% excess of stoichiometry). The temperature of the mixture rises to 80 ° C and, simultaneously with the decomposition of the sludge, intense

Separation of fluorine gases. The decomposition of the sludge is carried out for 25 minutes at a temperature of 80 ° C. In parallel, anaTitTa is decomposed with phosphoric acid in another glass. 50 g of apatite are introduced into a beaker thermostated at 70 ° C and containing 83.3 g of 52% extraction phosphoric acid. After 2-4 minutes, the pulp formed after the decomposition

fluorophosphate sludge sulfuric acid. The ratio of slurries after mixing is 1: 1.43. The resulting mixture is stirred for 2 minutes and then kept without stirring at 95,100 ° C for 1.5 hours. The resulting superphosphate is kept for 6 days and analyzed for P O, jg,

PjOswcg. z sft / p. F no known techniques.

Examples 2-5. Performed analogously to example 1, differ only in the ratio of pulp after decomposition of apatite to pulp after decomposition of sludge and are given in the table, which summarizes the results of the analysis of the resulting double superphosphate.

As can be seen from the table, a comparison of indicators of the process of obtaining double superphosphate according to the prototype and the proposed method provides the possibility of increasing the degree of decomposition of the raw material from 85 to 92.2-97%, as well as obtaining higher quality

product by increasing the content of the water-soluble form of phosphorus from 40-42 to 47.6-48.0%.

The use of the invention in gTro-solutions makes it possible to obtain an additional amount of double

10,5 7,5 5,5 3,3 1.8 0,75

1: 0.43 1: 0.32 1: 0.21 1: 0.13 1: 0.06

(pro (ortho-to-krenne-type) acidic nagny)

Editor N.Kishtulinets

Compiled by T. Dokshina

Tehred I.Popovich M.Samborska Proofreader

Order 4077/24 Circulation 419Subscription

VNIIPI USSR State Committee

for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5

Production and printing company, Uzhgorod, Projecto st., 4

superphosphate and silicofluoric acid by using useful components of fluorophosphate sludge. In addition, the risk of contaminating the environment with toxic compounds, fluorine and phosphorus is reduced.

47,346,72,41,158,997,76 48,948,03,51,056,898,07

48,647,83,40,8759,097,67 48,947,83,050,8356,297.08 45,842,33,310,7157,092.29. 43,841,54,01,525-30. 85,010-il2

Claims (2)

1. Process for the preparation of double superphosphate, comprising treating phosphate rock with sulfuric acid and phosphoric acid, followed by processing the resulting pulp superphosphate, and featuring _a d i c in that, to increase the degree of decomposition of phosphate rock · while improving its quality, pulp, when formed the decomposition of phosphate feedstock with phosphoric acid, subsequent aging of the reaction mass for 1-1.5 hours 2. The method according to claim 1, characterized in that the sludge from the wastewater treatment station is treated with concentrated sulfuric acid in an amount of 2-3 excess of stoichiometric. 1247374 A1 Ί