SU1231046A1 - Method of producing complex fertilizer - Google Patents

Description

Of these, the invention relates to a method for producing a complex fertilizer and can be used in the production of fertilizers by nitric acid processing of phosphate raw materials.

The purpose of the invention is to intensify and simplify the process while reducing the retrogradation of phosphorus pentoxide.

Example. 100 g of Karatau phosphorites decompose 144 g of 55% nitric acid for 60 minutes at 50 ° C. After this, the suspension is separated from a part of the insoluble residue. As a result, 239 g of clarified nitrous acid extract is obtained. 42.9 g of urea-formaldehyde solution is prepared by dissolving urea in formalin at a molar ratio of urea: formaldehyde of 1.8: 1, temperature 40-45 ° C and pH 7.5-8. After the complete dissolution of urea, the solution is kept for 1 hour until complete binding of formaldehyde to methi. lol derivatives, 8.3 g of ammonia gas are introduced into the urea-formaldehyde solution prepared in this way and mixed with nitric acid extract. When this occurs, the reaction mass is heated to 70 ° C, neutralization of acids, polycondensation of the urea-formaldehyde solution, and solidification of the product within 55-60 s.

The composition of the product, may.%: Nitrogen total 20.6; nitrogen water content. 16.3; total 14.4; P, 0j water content. 13.1; uev 14.4; , 7.

Example 2 A nitric acid test and a urea formaldehyde solution were prepared as in Example 1, but the molar ratio of urea: formaldehyde was 2: 1. The amount of urea-formaldehyde hydrate is 68.5 g, and ammonia (gas) 9.1 g. Mixing temperature 80-85 s. The polycondensation and hardening time is 35-40 s. The composition of the product, may.%: Nitrogen total 22.8; nitrogen water content. 18.3; Pjo total 13.9; water management. 10.2; R, ABOUT uev. F3.8; N: P, 05 1: 0.6.

Example 3 A nitric acid extract and a urea formaldehyde solution were prepared as in Example 1, but the urea: formaldehyde molar ratio was 2.5: 1. The amount of urea-formaldehyde solution is 89.1 g, and ammonia is 10.7 g. The mixing temperature is 88-90 C. The polycondensation and solidification time of the reaction mixture is 20-25 seconds.

The composition of the product, May L: nitrogen total.

24.8; nitrogen water content. 19.3; total, 12.4; water management. 11.2; usa. 12.4; ,five.

Ammonia content in the urea-formaldehyde solution in the amount of

3.5-4.5 wt.% Based on the weight of the nitric acid stretch provides neutralization of the nitric acid stretch in the pH range 1.6-2.5 and is obtained only in the form of mono- and dicalcium phosphates. When the amount of ammonia is less than 3.5% by weight of the nitric acid extract, the product hardens slowly, and the amount of ammonia more than 4.5% by weight promotes the formation of

more dicalcium phosphate, In table. Figure 1 shows the dependence of the solidification time of the reaction mass on the amount of ammonia (ratio, 7).

In tab. 2 shows the dependence of the physical state of the product on mixing and temperature.

By combining the processes of neutralization of the nitric acid extraction and polycondensation of the urea-formaldehyde solution, the solidification of the reaction mass at 70–90 ° C for 0.3–1 min is achieved. The time after mixing is less than 20 seconds is not enough for complete bonding of ammonia, and during drying, granulation and granulation, it is observed in the gas phase (see Table 2). Keeping the products of mixing. more than 60 s is undesirable because

this causes thickening of the reactionary mass, which leads to difficulties associated with processing it into a commercial product (Table 2).

Neutralization temperature of nitric acid extract 70-75 ° C. It is impractical to conduct the process of polycondensation and solidification of the reaction mass below 70 ° C. The temperature above 90 ° C leads to the loss of ammonia (see Table 2).

B tab. 3 shows the comparative

characteristics of the known and proposed epoeobov.

Phosphorus retrogradation is performed according to the formulas:

K (% pj05 uev

 Y- PZUS yev. 100.

 f Ti A l “g.

P „GS total ..

% Pt05 ret. IOO-K (Pj0.f ac.).

312310464

where K (Pj05-ycB.) is the percentage of digestible phosphate from urea-formaldehyde phosphorus; a hydrochloric solution containing in its

PiOr total - the total composition of the total ammonia, due to phosphorus; of which a part of the calcium cation is bound

Ra0s Ret. - percentage of phosphorus, with urea-formaldehyde compounds in double salts in the form of calcium nitrate - MFS, and there is a uniform distribution of ammonia over

subjected to retrogradation.

The decrease in phosphorus retrogradation of the proposed method is achieved in

the whole volume of nitric acid solution

by mixing the nitric acid and phosphorus fO.

ten

15

20

.40

60

the whole volume of nitric acid solution

T a b l and c a I

Suspension Ditto

Lipka

weight

Weight

Frozen mass

10 15

20

40 60 10 15

20

40 0.31 The same 60 0.30 urea formaldehyde solution.

.Table

Characteristics Method

Lime Suggested by examples

.1 1 11T11

Neutralization time

nitric acid

stretching for 3-8 h 60 s 40 s -20 s

The solidification time of the mixture of nitrogen-acid pulp and urine

wine formaldehyde

FO solution (duration of full condensation) 5-18 min 60 s 40 s 20 s

Retrogradation

P, Q, wt.% 1-6 Otsut- Otsut- Otsut-

there is

VNIIPI Order 2522/29 Circulation 419 Subscription Proizvodstv.-polygraph, before-e, Uzhgorod, st. Project, 4

1231046

: Continuation of table 2

Suspension

Lipka mass

Frozen mass

Also

Suspension

Frozen mass

Frozen mass

Claims (1)

METHOD FOR PRODUCING COMPLEX FERTILIZER, including decomposition of phosphate feedstock with nitric acid, neutralization of nitric acid extract with gaseous ammonia to pH 1.6-2.5 and mixing with urea-formaldehyde solution, that, in order to intensify the process by reducing the solidification time of the reaction mass while reducing the loss of ammonia and reducing the retrograde of phosphorus pentoxide, ammonia is preliminarily introduced into the urea-formaldehyde solution in an amount of 3.5-4.5% by weight of nitrogen o-acid extract, and mixing and neutralization are simultaneously at 70-90 C for 0.3-1 min. ' SU „„ 1231046 1 I