SU543250A1 - Method of producing slowly acting fertilizers - Google Patents

Description

I

A known method of producing nitrogenous slow-acting fertilizer by condensation of urea with formaldehyde gas in the presence of catalysts at elevated temperatures yj.

However, a complete conversion of the original carbamide to a new form of fertilizer, which is the condensation product, significantly reduces the relative nitrogen content; In addition, the need for drying at 10 ° -15 ° C and the introduction of a stabilizer into the system are also undesirable.

A method is known for producing a slow-acting granulated fertilizer with an adjustable rate of nutrient dissolution by applying fertilizer to the granules with an aqueous emulsion of polymers with the addition of other components 2.

The disadvantage of this method is the need to preliminarily obtain a half-peace material used for ii-morfMinq on fertilizer granules, as well as a stage of drying the emulsion applied to the fertilizer.

A method is known for producing a slow-acting fertilizer containing polymers by radiation treatment of fertilizers with monomers in the liquid phase and NK followed by drying (.

However, the complexity of speed control: the dissolution of nutrients, as well as the implementation of the process in several stages and the long stage of drying, complicate the process,

According to the proposed method, fertilizer granules are treated with monomers or a mixture of monomers in a vapor state at a ratio of monomer vapor pressure to monomer saturated vapor pressure at a solid body temperature equal to O, OO1-1.

According to the proposed method, the fertilizer is pretreated with a fine filler,

Claims (3)

These differences make it possible to accelerate the polymerization process and to obtain fertilizers with coatings of various thickness and effectiveness in terms of slowing the dissolution of fertilizers. The resulting coatings are stable when stored in air. Fertilizers with coatings do not clot or crush. Example 1: 0.03 g of A-175 Aerosil grade is loaded into a glass ampoule, and 3 g of technical granulated urea (KA) with a grain size of 1–2 mm are dated. The ampoule is shaken for 15-2 minutes before the aerosil layer and its distribution disappear on the surface of the granules. After the air has been removed from the system, the sample is brought into contact with methyl methacrylate (MMA) vapors and subjected to gamma irradiation at 60 ° C. and vapor pressure MMA 10O mm Hg. Art. (, 5) with continuous mixing of the granules for 1 h at a dose rate of 2 Mrad / h. At the end of the irradiation, the ampoule is opened and the granules are weighed. The weight of the granules is 3.144 g. The kinetics of dissolution of the obtained granules (O, 2 g per 200 ml of water) is determined at room temperature (22 ° C) under stirring conditions. The average dissolution rate of the obtained sample is 1.5.10 -2.10® times less, than that of the initial spacecraft. When a sample is dissolved, an induction period of dissolution is observed (the time from the moment the sample is immersed in water until the dissolution begins) about half an hour. The content of the polymer-filled coating is 4.6% by weight (determined by the weight of the capsules remaining after the CA has completely dissolved). All the nitrogen in the resulting sample is in water-soluble form. Example 2. A sample of KA with a polymer coating obtained similarly to Example 1, containing 1.7 wt.% Of coatings (O, 3% aerosil and 1.4% polymethyl methacrylate), is subjected to repeated coating with polymethylmethacrylate of AP 55 ° C and pressure Vapor MMA 1OO mm RT. Art. (P / 1 | - O, 5). Irradiation is continued for 1.5 hours at a dose rate of 2 Mrad / h. The resulting sample contains 15% coating (0.3% aerosil and 14.7% polymethyl methacrylate). The average dissolution rate of the sample is 1.10-1.5.10 times (depending on the depth of dissolution) less than that of the original spacecraft. The duration of the induction period of dissolution is about 5 hours. Example. 3. A sample of technical carbammofoski (CAFC) with an hour size of 0–1–2 mm, after application of A-175 aerosil (0.3 wt.%) And irradiation in MMA vapor for 1.5 h under the conditions of Example 1 , contains 8.3 wt.% of the coating (0.3% aerosil, 8% polymethyl methacrylate) and has an average dissolution rate in water 50O-90O times less than the original. The whole useful part of the fertilizer is in water-soluble form. Example 4. Fine magnesium oxide powder (1 wt.%) Was applied to a sample of a technical KA in example 1 of aerosil; After removal from the air system, the sample is brought into contact with a mixture of vapor of MMA (7 O mol%) and ethylacrylate (EA) at a total pressure of 70 mm Hg. Art. and subjected to gamma-radiation at 43 C and a dose rate of 2 Mrad / h for 4 hours. The sample obtained contains 6.5% of coating (1% of magnesium oxide and 5.5% of MMA and EA copolymer) and has an average dissolution rate in water in 2.5.10 - 5.10 times smaller than the original. The duration of the induction period of dissolution is 4 hours. Example 5. A 1 wt.% A-175 Aerosil prepared in Example 1 is applied to a sample of a technical KA, after which the sample is irradiated in pairs of a mixture of MMA and EA under the same conditions as as in example 4. The resulting sample contains © wt.% coating (1% aerosil and 8% MMA and EA copolymer) and has an average dissolution rate in water 2.5.10-4.5.10 times less than the original. The inductive period of dissolution is 3 hours. Example 6. A sample of urea subjected to irradiation under the conditions specified in Example 1 was maintained at an experimental temperature and a methyl methacrylate vapor pressure of 8 mm after termination of irradiation. Hg Art. for 4 hours without irradiation. The samples obtained have an average dissolution rate in water 80O-120O times less than the initial ones. The content of the polymer shell is 2%, of which 0.8% was obtained in the absence of irradiation (due to the post-polymerization reaction). Example 7. A granular granular carbamide (KA) with granules of 1-2 mm in size is loaded into a glass ampoule and, after removal of the air system, brought into contact with methyl methacrylate (MMA) vapors. After this, the sample is subjected to gamma irradiation for 2 hours at a dose rate of 2 Mrad / h, a temperature of 50 C, and an MMA vapor pressure of 80 mm Hg with continuous stirring of the granules. Art. {P / R 2J O, 6) After the end of the irradiation, the ampoule is opened and the SV is weighed. Get 3, 039 g KA, covered with ggolimetilmetakrilat. The kinetics of dissolution in water of the obtained granules of the coated KA (0.2 g per 2OO ml of water) is determined at the temperature under stirring conditions. The average dissolution rate of the obtained sample is 4OO-700 times (depending on the depth of dissolution) less than that of the original spacecraft. The content of the polymeric shell, determined from the weight of the capsules remaining after the complete dissolution of the CA, is 1.2%. All nitrogen of a coated SC is in a water-soluble form. Claim 1. Method for producing slow-acting fertilizers containing polymers 506 by radiation treatment of fertilizers in the presence of monomers, characterized in that, in order to control the dissolution rate of nutrients, fertilizers are treated with monomers or a mixture of monomers in the vapor state at the ratio of monomer vapor pressure to monomer vapor pressure at a solid temperature equal to O, OO1-1. 2. A method according to claim 1, characterized in that, in order to accelerate the polymerization process and to improve the efficiency of the resulting polymer coatings, the fertilizer is pretreated with a fine filler. Sources of information taken into account in the examination 1.Patent of Germany. No. 1132159, cl. 16 B 9 / O2, 1967. 2. The patent of Germany No. 1592655, cl. 16 E 9 / GS, 1970. 3. Japanese Patent No. 100ОЗ / 72, j 4 А 2, 1972.