CS235883B1 - Method of principal stabilized np-suspension preparation - Google Patents

Abstract

The purpose of the invention was to prepare highly concentrated sulfur-containing NI suspension % to 5 wt. This goal is achieved by ammoniacalization phosphoric acid mixtures; \ t ammonium sulfate to a pH in the range of 6.5 to 7. After ammoniacalization, the reaction mixture it is cooled and stabilized by the addition of bentonite dispersion.

Description

The invention relates to a process for preparing a basic stabilized NP suspension.

Sulfur deficit in industrialized countries with developed industry of combined NPK and NPK fertilizers based on phosphoric acid extraction is eliminated by using liquid and suspension fertilizers, which are a good carrier medium for incorporating this macro-nutrient ·

The need for fertilizer sulfur in some agricultural areas of the Czechoslovak Socialist Republic is covered by technical crystalline ammonium sulphate from coking plants, caprolactam production plants and in the production of iron pigments. The disadvantage of this solid nitrogen fertilizer is the low nutrient content (19.0 to 19.5 wt% N, 22 to 24 wt% S) of considerable caking, due to an unbalanced granulometric composition (a significant proportion of the dust fraction), caused by gravity at application by spreaders.

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Ammonium sulphate is a component of liquid and suspension N fertilizers and liquid NP fertilizers. Liquid fertilizer plants produce next door

N solutions based on urea and ammonium nitrate as well as a basic nitrogen solution with a sulfur content of 20,55-O-Ot5 »8 S with a composition of 23,75% by weight of ammonium sulphate, 25,7% by weight of. % urea and 0.95 wt. ammonium nitrate. The advantage of this clear, liquid nitrogen fertilizer is its good cryoscopic properties - crystallization temperature = -21 ° G. The disadvantage is the low nitrogen concentration - 20.55% by weight, caused by the low solubility of ammonium sulfate in the solution of urea and ammonium nitrate. A further disadvantage of this liquid fertilizer is its limited miscibility with the basic NP solutions based on ortho and ammonium polyphosphates 8-24-0 and 10-34-0 in the preparation of NP mixed and NPK liquid clear fertilizers.

The low nutrient content is eliminated by introducing an N suspension based on urea and ammonium sulfate.

a process for preparing a stabilized suspension fertilizer

29-0-0-5 S, stabilized 1.5 wt. This suspension is prepared by ammoniacalizing concentrated sulfuric acid solutions (93% HgSO4) while diluting the reaction mixture with urea solution and additional water to cover the evaporation of the boiling water. The hot solution was cooled rapidly from 116 ° C to 38 ° C over 10 minutes in order to eliminate fine ammonium sulfate crystals by disturbed crystallization. Powdery attapulgite clay is added to the cooled N slurry to suppress nucleation and crystallization and sedimentation of the precipitated crystals. This procedure is described in the US publication: Production of Urea - Ammonium Sulfate Suspension, 12 ^ ¹¹ Demonstration, October 18-19 »1978, New Developments in Pertilizer Technology, US, National Pertilizer Development Center, Muscle Schoals Alabama, USA, 61-63 , 1978.

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In MS. No. 204,790 describes a process for the preparation of a basic stabilized N suspension containing 25 to 30 wt. % nitrogen and 0.5 to 5 wt. open. A reaction mixture is prepared from granulated urea, solution or solid ammonium sulfate and optionally water at 70-90 ° C, which is stabilized at a temperature below 60 ° C by addition of a natrified bentonite dispersion so that the product contains 30 to 20 ° after cooling. C 1 to 2 wt. bentonite.

DC Young, in U.S. Pat. No. 3,046,105 (1962), protects the process for preparing NP ammonium sulfate solution type fertilizers. The preparation of this NP liquid fertilizer consists in neutralizing pure phosphoric acid (54% by weight ^and aspic acid (96% by weight HgSO4), diluted with the calculated amount of water, ammonia gas or ammonia water). The neutralization is conducted so that the temperature of the reaction mixture is less than 93.3 ° C due to ammonia losses, and the phosphoric acid is neutralized to the neutralization stage characterized by compound (NH 4) ₁ γΗΗPO 2. for optimum solubility of both - (NH4) · ^ γΗ ^ ^ PO ^ and (NH4) ₂ SO4, based on the mixture and it is possible to prepare NP fertilizers of solution type with crystallization temperature lower than 0 ° C and following »Beige composition:

Type Composition NP fertilizer (NH4) ^ γίί ^ ^ PO ^ (NH4gSO4HgO) NP content N-PgO ^ -KgO-S% wt% wt% components% wt% wt% flow ·

1. 5-10-0-2 WITH 17.9 8.3 73.8 26.2 2. 8- 9-0-6, 5 14.3 24.8 60.9 39.1 3. 9-22-0-2 WITH 39.4 8.3 52.3 47.7 4. 9-11-0-6 with 19.7 24.8 55.5 44.5

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The disadvantage of the process is the relatively low concentration of nutrients (15-31% by weight) and the need to use pure or purified acids, i.e. sulfuric acid and phosphoric acid.

A process for preparing a basic stabilized NP suspension containing up to 5 wt. Sulfur according to the present invention, characterized in that the aqueous suspension of the phosphoric acid / ammonium sulfate mixture is neutralized with ammonia to a pH of 6.5 to 7.0, whereupon the reaction mixture is immediately cooled below 50 ° C and stabilized by addition of a bentonite dispersion.

The advantage of the present method lies in the possibility of converting a relatively available feedstock, ie phosphoric acid, into a highly concentrated fertilizer. Due to its discontinuity, the process itself is simple both technologically and in terms of production equipment. The process according to the present invention makes it possible to prepare basic stabilized, highly concentrated, sulfur-containing NP suspensions in the form of ammonium sulphate with satisfactory storage, application and cryoscopic properties.

It should also be borne in mind that it allows the utilization of waste solutions of ammonium sulfate as well as crystalline ammonium sulfate as they are dispensed with in caprolactam, coke oven and pigment production plants.

©

The realization of the invention consists, for example, in the preparation of a basic unstabilized NP suspension having a composition of 7-15.4-0 to 7

13,2-25,5-0 by ammoniacalization of extraction phosphoric acid in a mixture with dissolved technical ammonium sulphate or solutions of extraction phosphoric acid mixed with aqueous solutions

235 883 ammonium wound. Ammoniacalization with a gaseous or aqueous ammonia solution is carried out to a pH of 6.5 to 7 at a temperature of about 60 to 103 ° C, which is the boiling point of the reaction mixture. NP-stabilized suspension is quickly cooled to 40 C and ⁹ immediately or after dilution with a calculated amount of water stabilizes under cooling navážky.předem prepared by dispersing 15% natrifikované bentonite dispersion at a concentration of 1.5 to 3% by weight. bentonite such that the resulting temperature of the basic stabilized NP slurry was 20-25 ° C.

It was found that the magnesium content in ammonium sulfate solutions in a concentration range of 0.5 to 5% by weight. magnesium sulfate does not affect the deterioration of the physico-chemical and storage properties of the NP suspensions. In ammoniacalization, some of the magnesium precipitates as ammonium magnesium phosphate, which does not increase viscosity, solid phase content and sedimentation rate. The presence of this component only slightly decreases the content of the water-soluble component PgO ^ ·

It is not recommended by the method of the invention to produce a suspension with a sulfur content above 5% by weight, i.e. with an ammonium sulfate content above 25% by weight, as the flow and storage properties of the NP stabilized suspension will sharply deteriorate due to the increase in solids.

Dispersion and homogeneous mixing of swollen bentonite particles in the NP suspension prevents nucleation, crystallization and sedimentation of ammonium sulfate crystals, ammonium phosphates, ammonium magnesium phosphate and impurities.

The thus prepared stabilized NP suspensions have good storage and application properties and with a sulfur content of up to 5% by weight. may contain up to 12 wt. % N and 22 wt. P ₂ 0 ^.

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They are suitable for direct fertilization and can also be used as a leaf fertilizer after dilution with water or as a NP fertilizer with sulfur content when mixing NT mixed fertilizers with DAM 390 30-0-0 basic nitrogen solution or preparing NPK suepensive fertilizers in cold mixing plants.

Example 1

Into a stirred reactor located at the strain gauge scales, equipped with double-action with a paddle stirrer and water condenser was weighed 4316 kg extraction of phosphoric acid (51 wt.% Ρ ₂ 0, ρ and 4316 kg of ammonium sulphate solution at 20 ° C containing 18.53% by weight This mixture is neutralized by cooling 4028 kg of aqueous ammonia (25% NH3) to pH = 6.9 so that the average temperature of the reaction mixture after 60 minutes of neutralization was 60 C.

To 12660 kg of the basic unstabilized NP suspension of 7,92-17,40-0, cooled to 40 ° C, add 1948 kg of a preformed 15 ^L % 21 ° C natrified bentonite dispersion and disperse with cooling and stirring ( 1500 rpm) for 15 minutes. 14608 kg of a stabilized NP suspension having a composition of 6.83-15.07-0 and a 93.9% water-solubility of the component θ2θ5 → ⁰ 20 ° C and containing 2.0 wt. bentonite.

The NP suspension has the following physicochemical and storage properties at 25 ° 0: density = 1190 kg.m, viscosity at shear rate 243 s = 34 »8 mPa.s, pH = 6.88, solid phase content = 13.52 wt., residue after flow test * 1.24 wt. The edimentation volumes after storage periods of 24, 72 and 144 hours amounted to 97.7, 92.3 and 90.1 vol%, respectively. The NP suspension contains 1.40 wt. % of sulfur and 0.054 wt. magnesium. The solidification temperature of the NP suspension is -20.2 ° C.

Example 2

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Weigh 5492 kg of extractive phosphoric acid (39.5% by weight of PgO4) at 20 ° C and 2941 kg of ammonium sulphate solution at 25 ° C into a stirred reactor, placed on a strain-gauge balance equipped with a double-action paddle stirrer with water cooler and ammonia gas distributor. This mixture is neutralized with cooling 967 kg of ammonia gas to pH = 6.85 so that the average temperature of the reaction mixture after 60 minutes of neutralization was 60 DEG C. To 9400 kg of the unstabilized NP slurry of 10.27-23.08-0, cooled to 40 DEG C., was added 1446 kg of a preformed 15% sodium bentonite dispersion at 20 DEG C. and dispersed with cooling and stirring (1500 rev / min) for 15 min. give 10846 kg NP stabilized basic slurry composition 8,90-20,0-0 and about 93.0% water solubility component PGO ^, ⁰ at 25 ° C and containing 2.0% bentonium by weight The NP slurry exhibits the following physicochemical and storage properties at 25 ° C: density = 1269 kg.m, viscosity at shear rate 243 s ”= $ 4.87, solid phase content = 26.0 wt. %, the residue after flow test X 2.53 wt. The sedimentation volumes after storage periods of 24, 72 and 144 hours were 98.1, 96.2 and 96.1% by volume respectively. % sulfur and 0.192 wt. magnesium. The solidification temperature of the NP suspension is -16.5 ° C.

Example 3

Weigh 6756 kg of extractive phosphoric acid (32% by weight P ₂ O 4) and 659 kg of clarified water into a stirred tank mounted on a strain-gauge balance equipped with a double-action paddle stirrer, water condenser and ammonia gas distributor. In the present phosphoric acid, 1010 kg of technical ammonium sulfate having a composition of 79.21 wt. (NH4 ^ SO4a)

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10.15% wt. % MgSO4 and 10.64 wt. humidity. This mixture was neutralized with 975 kg of ammonia gas to pH = 6.70 with cooling so that the average neutralization temperature after 60 minutes of neutralization was 60 ° C. To 9400 kg of a 10,33-23,00-0 base non-stabilized NP suspension, cooled to 40 ° C, add 1044 kg of a pre-prepared 15% natriated 25 ° C bentonite dispersion and disperse with cooling and stirring (1500 ° C). rpm) for 15 minutes. Give 10444 kg NP stabilized basic slurry composition of 9,30-20,70-0 and 93.7% water solubility ingredients PGO ^ ⁰ the resulting temperature »of 25 ° C and containing 1.5% by weight. The bentonite.NP suspension exhibits the following physicochemical and storage properties at a temperature of 25 ° C: density = 1259 kg.m, viscosity at shear rate 243 s ¹ = 49.9 mPa.s, solid phase content = 24.15 wt. , residue after flow test = 0.94 wt. The sedimentation volumes after storage periods of 24, 72, 144 hours were 98.0, 97.5 and 97.4% by volume respectively. % of sulfur and 0.198 wt. magnesium. The solidification temperature of the NP_ suspension is -16.5 ° C.

Example 4

Weigh 4638 kg of phosphoric acid (54% by weight PgO4) ^and 442 kg of clarified water into a stirred tank mounted on a strain gauge, equipped with a double-action paddle stirrer, water cooler and ammonia gas distributor. 4970 kg of a solution of ammonium sulphate at a temperature of 25 ° C and a composition of 35.41 wt. The resulting mixture is neutralized with 1182 kg of ammonia gas to a pH of < 6.80 without cooling in the temperature range of 25 to 103 ° C. 103 ° C over a period of 25 to 6 minutes to evaporate 1182 kg of water from the neutralizer To 10050 kg of the 14.38-24.92-0 14.48-24.92-0 unstabilized suspension, cooled to 40 ° C, add 386 kg of clarified water. temperature 25 ° 0 and 1160 kg in advance at 9

235 883 of a treated 15% natrified bentonite dispersion at 25 ° C and dispersed with cooling and stirring (1500 rpm) for 15 minutes. This results in a base stabilized NP slurry having a composition of 11.60-21.60-0 at 25 ° C with a 91.8% water-insolubility of the P ₂ O 4 component, stabilized with 1.5 wt. bentonite. The NP suspension exhibits the following physicochemical and storage properties: density = 1326 kg.m,, viscosity at shear rate 243 s ^-1 83 83.9 mPa.s, solid phase content = 43.8% by weight, residue after flow test = 1.39% wt. The sedimentation volumes after storage periods of 24, 72 and 144 hours were: 97.7, 96.5 and 96.3% v / v of the NP slurry containing 4.21% w / w. % sulfur and 0.400 wt. magnesium. The solidification temperature of the NP suspension is -20.4 ° C.

Example 5

Weigh 4384 kg of extraction phosphoric acid (54% by weight of total PgO4) ^and 921 kg of clarified water at 25 ° C into a stirred reactor placed on a strain gauge, equipped with an impeller stirrer, water cooler and aqueous ammonia distributor. 897 kg of technical ammonium sulphate having a content of 20.1% by weight are dissolved in the present dilute acid. N. The resulting mixture was neutralized with 3848 kg of 25.0 wt.% Ammonia water. NH ~ to pH = 6.85 with cooling so that the neutralization temperature does not exceed 60 C. The neutralization time is 60 minutes. To 10Q50 kg of the base unstabilized NP suspension of 9.67-23.55-0, cooled to 40 ° C, add 1117 kg of a preformed 15% natrified 25 ° C bentonite dispersion and disperse with cooling and stirring (1500 ° C). rpm) for 15 minutes. 11167 kg of a stabilized NP suspension having a composition of 8.70-21.1-0 and a 93.9% water-solubility of the PgOcj component at 25 ° C are obtained, stabilized by 1.5 wt. in bentonite. The NP suspension has the following physicochemical and storage properties at 25 ° C: Density «1253 kg.m» / \ viscosity at speed 10

235 883 three shear deformations 243 s * ^ = 48.8 mPa.s, solid phase content 23.65 wt.%, Remainder after flow test = 0.97 wt. The sedimentation volumes after storage for 24, 72, 144 hours were 97.6, 97.4 and 97.3% by volume respectively. open. The solidification temperature of the NP suspension is ^ 15.8 ° C.

Example 6

A 43S4 kg extraction phosphoric acid (54 wt% total PgO 2) and 673 kg clarified water at 25 ° C were weighed into a stirred tank mounted on a strain gauge, equipped with a double-action paddle stirrer, water cooler and ammonia gas distributor. Weigh 4993 kg of ammonium sulphate solution containing 40.0% by weight of the dilute phosphoric acid solution. (NH 4) 2 SO 4 at 25 ° C. The resulting mixture was neutralized with 897 kg of ammonia gas to pH 6 6.80 without cooling over a temperature range of 25 to 103 ° C for 60 minutes. During the neutralization between 25 and 60 minutes at the boiling point NP solution (101 to 103 C, ^b) the evaporation of 897 kg water from the neutralizer. To 10050 kg of the unstabilized 11.55t23.55-O NP suspension, cooled to 40 ° C, add 1117 kg of a pre-prepared 15% natrified 25 ° C dispersion and disperse with cooling and stirring (1500 rpm) ) for 15 minutes. 11167 kg of a basic stabilized NP suspension having a composition of 10.40-21.20-0 and 94.9% water-solubility of the BgO2 component at a temperature of 25 [deg.] C., stabilized by 1.5 wt. bentonite. The NP suspension exhibits the following physicochemical and storage properties: density «1355 kg.m» ^, viscosity at shear rate 243 s » ¹ » 79 mPa.s, pH »6.90, solid phase content« 47.9% by mass · %, the remainder of the flow test < 4.05 wt. The sedimentation volumes after storage for 24, 72 and 144 hours were 97.9, 94.7% and 94.2% by volume respectively. open. The solidification temperature of the NP suspension is -19.9 ° C.

Claims (1)

SUBJECT OF THE INVENTION 235 883 Process for preparing a basic stabilized NP suspension containing up to 5 wt. The aqueous suspension of the phosphoric acid / ammonium sulfate mixture is neutralized with ammonia to a pH of 6.5 to 7, then the reaction mixture is immediately cooled below 50 [deg.] C. and stabilized by the addition of a bentonite dispersion.