SU494379A1 - The method of obtaining nitrogen-phosphorus fertilizer - Google Patents

Description

The invention relates to a method for producing nitrogen-phosphate fertilizers and can be carried out in mineral fertilizer plants.

Methods are known for producing nitrogen-phosphate fertilizers by reacting natural phosphates with mineral acids and then neutralizing the mixture with ammonia.

According to such methods, it is economically unprofitable to use low concentrated phosphates, for example, phosphorite flour.

A known method for producing nitrogen-phosphorus fertilizer by mixing carbamate / a nitrate and phosphates during the production process.

However, this method does not allow to obtain fertilizers with good physical and agrochemical properties due to the presence of hygroscopic calcium nitrate salts in it. In addition, during the process a large amount of harmful gases (B mainly fluoride compounds) is released, which complicates the process.

In order to convert P2O5 natural phosphate into a plant-digestible form, near the decomposition stage, and to eliminate the release of harmful gases in the proposed method, mixing is carried out with dry (percent moisture from 2 to 4) urea nitrate at a weight ratio between JPsOe and CO (LH2) 2 -NMO,

equal to 1: 5-5.5, followed by the addition of a urea-formaldehyde resin in an amount of 4 to 5i% of the total weight of the mixture, granulation of the mixture obtained to a granule size of 2-4 mm and drying at 65-75 ° C.

The proposed method was tested in laboratory conditions at the Ionava Nitrogen Fertilizer Plant, and an agrochemical evaluation of the obtained fertilizer was carried out at the Lithuanian Agricultural Academy in vegetation experiments with oats.

In soil, under the action of moisture on fertilizer granules, carbamide nitrate is hydrolyzed to release free nitric acid, which decomposes natural phosphate and turns it into an absorbable plant form.

Example 1: Preparation of nitrogen phosphate fertilizer under laboratory conditions.

At 600 g of urea, they act with nitric acid (57%) at a molar ratio of 1: 1, they are displaced for 10 minutes and are present.

Natural phosphate, for example phosphate of the Maardu deposit (21.0% PaOz). mixed with the obtained dry product - carbamide nitrate (moisture percentage from 2 to 4) with a weight ratio between P2O5 and CO (NH2) 2-HNO3 equal to 1: 5-5.5. Then from 4 to 5% of the total weight is added to the mixture.

the urea-formaldehyde resin mixture is mixed well, granulated and dried in a drum granulator at 65-75 ° C for 20 minutes. The resulting product contains 18.6% N and 10.1% PrOb.

The hygroscopic point of the fertilizer obtained by the proposed method is 77-%, caking 0.13 kg / cm, while in the known fertilizer these indicators are respectively 70% and 0.18 kg / cm. The obtained fertilizer is well soluble in water: 80% PaOs and 95-97% nitrogen dissolve at room temperature for 24 hours.

Example 2. Agrochemical evaluation of fertilizer obtained by the proposed method.

In the Lithuanian Academy of Agriculture, vegetation experiments were carried out with oats in Mitscherlich vessels. The fertilizer obtained by the proposed method was compared with a mixture of granulated superphosphate and urea with an equal amount of nutritious ingredients. Fertilizers were applied at the rate of 0.1 g of nutrients per 1 kg of dry soil. The results of the experiments are given in the table.

Note. The accuracy of the experiments: R, 53,67

Note. Accuracy: Rgs 3.67.

From the results of the experiments it is clear that the proposed fertilizer (experiment 4) even slightly exceeds the mixture of superphosphate and urea (experiment 3) in its agrochemical properties.

In the process of producing fertilizer according to the proposed method, no harmful gases are emitted, which simplifies the production process. In addition, a urea-formaldehyde additive with ion-exchange properties improves the agrochemical properties of the fertilizer and binds the release of yyfi fluorine at the beginning of the growing season.

In the fertilizer obtained by the proposed method, there are no hygroscopic calcium nitrate salts (which increase caking), which significantly improves

physical and agrochemical properties of fertilizer and provides reliable storage.

Subject invention

A method of producing nitrogen-phosphorus fertilizer by mixing natural phosphates with urea nitrate, characterized in that, in order to transform the natural phosphate PgOs into a plant-digestible form, mine decomposition stage, and eliminate the generation of harmful gases, mixing is carried out with a dry (percentage of moisture from 2 to 4) carbamide nitrate with a weight ratio between PrOb and CO (NH2) 2-HNO3 equal to 1: 5-5.5, followed by the addition of urea-formaldehyde resin in an amount of 4 to 5% of the total weight of the mixture, granulating the resulting mixture up to granule size 2-4 mm and drying at 65-75 ° C.