SU833931A1 - Method of producing slowly-acting fertilizers - Google Patents

Description

(54) METHOD OF OBTAINING SLOW-AFFECTING FERTILIZER

The invention relates to the chemical industry, in particular, to the production of nitrogen fertilizers, more specifically, to methods for improving the quality indicators of fertilizers.

A known method for producing a slow-acting fertilizer is by introducing formaldehyde into the urea melt as a conditioning additive, followed by granulation of the obtained product. In the production process, unreacted ammonia binds, which reduces the porosity of the resulting granules, this fertilizer nitrogen is absorbed by plants gradually ij.

The disadvantage of this method is an increase in the viscosity of the carbamide melt with the introduction of formaldehyde, which makes granulation difficult.

The closest in technical-. What is the essence and the achieved result to the proposed is a method of obtaining a slow-acting fertilizer by interaction of the urea melt after the second stage of distillation (70% solution of urea) with formalin in the presence of a conditioning additive - polyacrylamide in the amount of

from 0.05 to 5.0% by weight of urea. With the addition of polyacrylamide, the reaction mixture turns into a crumbly crumbly mass or easily solidified melt, which can be easily crushed and dried 2.

The disadvantage of this method is the inability to

0 granulation of the obtained product, in particular, in the air flow.

The purpose of the invention is to obtain a granular product.

five

The goal is achieved by the fact that in the method of producing a slow-acting fertilizer, by reacting the urea melt after the second stage of distillation, with formalin and conditioning agent, as a last resort, soap stock is the waste of alkaline refining of fats and oils, in an amount of 0.02-0 , 23% by weight of urea, and formalin is administered in the amount of 5-15%

5 from the weight of karyamid.

Claims (2)

Soap stock is introduced simultaneously with formaldehyde, i.e., after the second distillation stage, or directly before the granulation stage. Soapstock contains neutral fat 20-23%, sodium fatty acid soaps, water, and various impurities - glycerides, phosphatides, proteins, mucous membranes, resinous and beauty substances. Entering soap stock in the proposed amount allows to reduce the viscosity of the melt, which increases, as a result of the input of formalin, to a value that corresponds to the amount of successful granulation. A formalin concentration of 5-15% is optimal for providing the required strength of the granules and the quantitative content of the fraction with a granule size of 2-3 mm, which is most convenient for transportation and application to the soil. Example 1. To 600 g of 70% molten carbamide after the second distillation step, containing 0.8% of free ammonia, 30 m of formalin with 30-40% of formaldehyde is added. The resulting mixture is sent to the 1st and 2nd steps of evaporation and before the granulation stage is introduced into soap stock in the amount of 0.02% by weight of urea. After granulation in a stream of air (in the granary tower), the product is obtained. -2.0 mm, the strength of the granules is 484 g / granule. Example 2. Repeated example is 1, but formalin is introduced in an amount of 90 ml, and soap stock in an amount of 0.23% by weight of urea. Receive granules of 1.5-2.0 mm and so on. capacity of 786.4 g / granule. Example 3. To 500 g of 70% melted carbs 1Mid after the second distillation stage, containing 0.8% of free ammonia, add 25 m of 30-40% formalin and at the same time soap stock in an amount of 0.02% by weight urea. The resulting mixture is sent for evaporation and then for granulation. Get the product - granules with a size of 1.5-2.0 mm and a strength of 486 g / granule. Example 4. Example 3 is repeated, but formalin is introduced in an amount of 75 ml, and soap stock in an amount of 0.23% by weight of urea. After granulation, granules with a size of 1.5-2.0 mm and a strength of 725 g / granule are obtained. In all cases, the time of sieving of the obtained urea through a sieve with a cell size of 5x5 mm does not exceed 5 s, which is characterized by another positive quality of the product - insignificant caking. Using the proposed method allows to obtain a product with physical properties and agrotechnical properties. The strength of the granules is increased by 14-15%, and the quantitative content of the fraction with a granule size of 2-3 mm - by 15-20%. The invention of the method for producing a slow-acting fertilizer by reacting the urea melt after the second distillation step with formalin and a conditioning additive, is different from the fact that, in order to obtain a granulated product, 0% is used as a conditioner additive. , 02-0.23% by weight of urea, and formalin is administered in the amount of 5-15% by weight of urea. Sources of information taken into account in the examination 1. US patent number 4025329, cl. 71-33, 1970. 2. Authors certificate of the USSR .207241, cl. S.95 D 9/00, 1966 (prototype).