HU193954B - Process for production of organic nitrogen fertilizer containing policondensated carbamide - Google Patents

Abstract

The carbamide is heated to about 150 deg. C, when the following is added (wt. %): a catalyst, either 0.1-1.0 CaCO3, or 0.25-2.5 dolomite and 0.001-0.1 active charcoal. The mixt. is then heated to 180 deg. C for 30 minutes. The obtd. partly polymerised carbamide is treated with either sulphuric, phosphoric, nitrous or an organic acid (1-40 wt. % in soln., or 2-10 wt. % solids) at 85-100 deg. C. The product is ground and mixed with a bulk material.

Description

The present invention relates to a process for producing organic nitrogen fertilizers containing polycondensed urea.

As is well known, nitrogen, like phosphorus and potassium, is an essential plant nutrient that is in high quantities.

The nitrogen source of the plants is the absorbable inorganic nitrogen compounds in the soil, in particular the nitrate and ammonium compounds. (As is known, only 78% of the nitrogen in the air can be utilized by root bacteria living with butterflies). Nitrogen supply can be solved by organic fertilization and various nitrogenous fertilizers.

Most of the nitrogen in natural organic matter is insoluble in water. This led to the assumption that they would decompose slowly, so that their nitrogen content would be released over a longer period of time, less leaching losses would occur, and the plants would make better use of the nitrogen content of these fertilizers.

Most of the known nitrogen fertilizers are ammonia derivatives.

Urea, the use of which as a nitrogen fertilizer has increased dramatically in recent years, is an organic nitrogen compound. However, urea, when added to the soil, hydrolyzes very rapidly according to the following reaction:

CO (NH ₂ ) ₂ + 2 H ₂ O - * (NH ₂ ) ₂ CO ₃

Ammonium carbonate is not a stable compound and is decomposed to ammonia and carbon dioxide. The NH ₃ or NH ₄ thus released is adsorbed on the colloidal fraction of the soil and then nitrified. Urea eventually acidifies the soil due to the ammonium ion produced during hydrolysis. Hydrolysis of urea is strongly enhanced by the presence of the urease enzyme to varying degrees in the soil. Urease is present in high concentrations in most soils to rapidly convert urea to NH ₄ and behaves in the same way as other ammonia-shaped nitrogen sources in the form of NH 4. (See SL Tisdale, WL Nelson: Soil Fertility and Fertilization, Agricultural Publisher, Budapest, 1966, p. 130). The degradation of urea by urease is described by Béla Debreceni [Urea fertilization, Hungarian Agriculture 48 (1984)] with the following reaction equation:

CO (NH ₂ ) ₂ 4 -HOH + urease → 2NH ₃ + + CO ₂

Rapid hydrolysis of urea in soil is the cause of ammonia damage to seedlings; this occurs when urea is added together with or too close to the core. Proper placement relative to the core eliminates this hazard.

Urea usage has increased dramatically in recent years as it is considered extremely economical due to its high active ingredient content. However, there are several things to keep in mind when using it:

1. In solid form, it is advisable to use it as a basic fertilizer by incorporation into the soil in order to eliminate nitrogen loss.

2. When applied immediately before or at the time of sowing, its germicidal effect may be exerted.

3. The above effects are more pronounced on acidic or loose soils with poor ammonium binding capacity than on neutral, biologically active, active soils,

4. On heavily calcareous soils, nitrogen loss can be high - due to the disappearance of ammonia.

5. When spraying, the dose should be adjusted to the sensitivity of the crop to be fertilized.

Knowledge of the use of urea is reported in the Agrotrost (Nitrogen, Phosphorus, Potassium Fertilizers) (1983) and NEVIKI (1972) Chemistry of Agriculture, which contains the material from Keszthely.

Free ammonia is toxic to the living organism and is expected to delay the nitrilization process [S.L. Tisdale W.L. Nelson: Fertility and fertilization of soil. Agricultural Publisher 1966.125. side].

Plants take up nitrogen in the form of a dissolved nitrate salt, so nitrate sources are the most common sources of fertilizer.

Nitrate fertilizers are completely soluble in water, when added to the soil, nitrate ion is readily absorbed by plant roots. On coarse soil soils, nitrate leaching losses may occur in rainy weather. Nitrates can be absorbed by soil microorganisms when decomposing organic residues.

More than 60-70% of the nitrogen in the form of fertilizers is rarely used by cultivated plants. Although some nitrogen losses result from nitrogen and ammonia volatilization, ammonia binding of clay minerals, and bacterial immobilization, the major losses are caused by nitrate leaching. These losses encourage the production of fertilizers that release nitrogen over time, so that nitrates can be continuously absorbed by the branched root system throughout the plant's growing season.

In recent years, some slow-growing nitrogen fertilizers have been developed and marketed for the cultivation of lawns and certain special crops. Products tested include urea formaldehyde compounds, metal ammonium phosphates, oxamide, crotonylidene dicarbamide and

-2193954 There are some other compounds of purely theoretical interest, such as thiourea, urea pyrrolyzate and dicyandiamide. They also dealt with nitrification regulators that inhibit certain bacterial activity. [see

S.L. Tisdale, W L. Nelson: Soil Fertility and Fertilization, Agricultural Publisher, Budapest, 1966]. The disadvantages of the above fertilizers are similar to those of urea fertilizers and their economical industrial production is not solved.

So far, both foreign and domestic attempts have been made to delay the decomposition of urea and to reduce or eliminate the harmful effects of the decomposition. Commercially available PARAMID treated with paraffin and fatty acids, which delays the hydrolysis of urea, [see Pesticides, Fertilizers, Agricultural Publisher, Budapest, 1984].

Numerous studies have confirmed that besides leaching and nutrient extraction of plants, the nitrogen content of the soil is also affected by other losses. These losses occur when nitrogen, nitrous oxide, nitric oxide or ammonia are removed from the soil due to certain biological and chemical processes. Losses are attributed to three processes:

1. Denitrification, which is the biochemical reduction of nitrates under anaerobic conditions.

2. Chemical reactions involving nitrite under aerobic conditions.

3. The disappearance of ammonia (NH) ₃ gas from the surface of alkaline soils.

Thus, in the case of nitrogen supply, many possibilities of losses must be considered and, in certain circumstances, the most economical source of nitrogen must be chosen.

The object of the present invention is to eliminate the adverse effects of the urea fertilizer used in practice and the difficult conditions to be observed during its use.

We have sought to convert urea so that it is no longer affected by urease, thereby delaying the conversion of organic bound nitrogen and favoring the utilization of nitrogen by plants.

The essence of our process is to keep the urea at a high temperature for a certain time, which results in polycondensation.

The macromolecule is reacted with an organic acid. Among the organic acids, saturated organic acids having 1 to 4 carbon atoms and lactic acid are suitable. Most preferred is the use of acetic acid. Its use is justified by its economy (cheap, readily available) and its beneficial effect on soil, the hydrolysis product does not change the pH of the soil due to its low concentration. Acetic acid is a highly dissociating acid, and is best suited to seal the polycondensed urea molecule in the process.

The invention will now be illustrated in more detail by examples.

Example 1

100 g of commercially available urea are heated to 150 ° C to give a clear liquid. To the melt was added 0.1 g of CaCO ₃ , which acts as a catalyst, and vigorous ammonia evolution was observed. Continuous ammonia gas is promoted by the addition of 0.01 g of granular activated carbon.

The melt was heated ^to 200 ° C, then allowed to cool down after 20 minutes to 110 ° C, and 15% lactic acid were added. The total N content of the product thus obtained is 36-37% by weight, and the total N2-2.5% by weight is in the form of biuret. The product has a solid appearance but is not crystalline.

Example 2

The procedure is the same as in the first example, but the melt is kept at 180 ° C for 25 minutes. After the appearance of an opaque color, 2% by weight of 20% acetic acid at 0 ° C was added to the polycondensed urea and 40% by weight of CaCO ₃ at 80 ° C.

The total N content and form of the product obtained is the same as that of Example 1, with 0.5-2.0% of the total N present in biuret form.

Example 3

In the same manner as in the first example, the melt is heated for 30 minutes at 180 ° C, then at 110 ° C, 10% by weight of 10% acetic acid is added and allowed to cool to 70 ° C with constant stirring. and then 30 w / ^ dolomite (MgCO ₃ + CaCO ₃₎ was added.

After cooling, the product is ground and used as fertilizer.

The product has the same appearance, nitrogen and dry matter content as the product of Examples 1 and 2.

Small plot fertilization with polycondensed urea based fertilizer! experiment.

Urea was used as a control fertilizer. Our aim was to prove the absence of harmful factors when using urea fertilizers.

Our experiments were carried out on cereals and maize (See Table 1). It was found that nitrogen loss was lower and nitrogen immobilization was more favorable, which increased the nitrogen content of vegetative and generative parts of the plant.

The use of nitrogen active substance per 1 t of yield proved to be favorable. Particularly striking is the comparative values obtained using known fertilizers. (See Table 2). It can be seen that the amount of product obtained by the application of the fertilizer produced according to the invention is higher than that obtained with the known fertilizers.

-3193954, Table

Application of Nitrogen and Use of Nitrogen Fertilizers According to the Invention

Urea (Szentlőrinci State Economy, Tarcsapuszta, 1984) Polycondensed Urea (1984) Maize average yield kg / ha 10650 11310 1 ha applied N active ingredient (kg) 135 120 Per 1 t of crop N active ingredient (kg) 12.6 10.6 Wheat average yield kg / ha 6410 6580 1 ha applied N active ingredient (kg) 60 58 Per 1 t of crop N active ingredient (kg) 9.3 8.8

Table 2

Nitrogen drug application and crop yield changes with known nitrogen fertilizers *

Bábolnai Agricultural combine No. 15 table No. 16 table 1981 1982 1981 1982

Maize average yield kg / ha 10620 9620 8400 8800 Per 1 t of crop N active ingredient (kg) 17 21.6 26 21 N active ingredient applied per 1 ha (kg) 182 208 218 182

* Data by Róza Molnár dr. ' They are from his work The True Reserve of Nutrition Management (Farming 1984/9).

The beneficial effects of polycondensed urea on maize are presented in Tables 3 and 4 (the tests were performed by the Szekszárd Corn Growing System upon request).

Table 3 shows that the amount of grain harvested (kg / ha) is significantly higher for polycondensed urea (PKK) than for urea.

Table 4 shows the evolution of maize yields using urea and polycondensed urea. It can be seen that polycondensed urea also has a favorable effect on the growth of the number of fruit plants 4.

Table 5 shows the effect of urea biuret content on wheat yield. It can be seen that the effect of biuret is unfavorable, contrary to polycondensed urea. The biret content of the θθ fertilizer produced according to the invention does not reach these adverse concentrations.

Table 6 shows the effect of winter wheat fertilization with different fertilizers and different dosages on the number of cereals and the _6g yield average. For plots 1 and 2, the entire amount of fertilizer weasel 4193954 was applied in autumn; for plots 3 and 4, 50% of the applied active ingredient was applied in the autumn and 50% in the spring, and on these plots the head fertilization was carried out on 12 May; the

For plots 5 and 6, 75% of the total fertilizer demand was applied in the fall, no additional active ingredient was added, and no head fertilization was applied. (The area of the experimental plots is 1000 m ² each).

It can be seen from the table that using polycondensed urea, both in terms of the number of corns and the average yield, gives a better result than the conventionally applied urea, except when the whole amount of fertilizer is added to the soil in autumn (plots 1 and 2). ), the results can be considered the same. Our results are even more convincing that the active ingredient in urea treatment always slightly exceeds the active ingredient in the form of polycondensed urea.

Table 3

The yields of maize hybrids are different

When using N forms and doses (1986)

Hybrids tested

Harvested grain kg / ha

300 kg / ha N 200 kg / ha N Carb. PKK carb. PKK Pi 3925 SC 7337.15 9775.51 8407.38 9103.23 Isela / X 0047 / SC 7584.48 10141.29 9303.34 9121.51 Pi 3737 SC 9947.04 11947.63 10628.80 10461.16 NKPX 9283 SC 9117.04 10949.07 9289.47 9472.66 Pi 3707 SC 8625.01 10262.41 9188.19 9302.92 Pi 3475 SC 9773.77 10975.54 9475.97 9026.29 Average: 8730.75 10675.24 9382.19 9464.69 4th Spreadsheet Different N shapes and doses effect on corn

growth rate

Date of population count: 19 B 6. 06/10/10

Lake number / dt./10 fm / treatment

Hybrids tested Spring to fall

300 kg / ha N. 700 kg / ha N. Effective at 100 kg / ha N.

Urea PK-carb. Kírbamid PK-carb. Carbamic PK. carb. Pi 3925 SC 34.5 54.8 48.2 55.2 52.7 X 0047 SC 31.25 47.5 44.5 45.0 42.75 Pl 3737 SC 42.50 59.0 53.0 55.75 57.25 NKPX 9283 SC 38.25 60.5 51.25 58.0 58.75 Pi 3707 39.25 56.5 44.5 58.5 56.0 Pi 3475 SC 36.75 51.5 42.5 50.0 48.0 Average: 37.25 55.04 47,48 53.75 51.58 Plant density db / ha 49 013 72 426 62 474 70 714 69 184

-5193954

Table 5

Effect of urea biuret content on winter wheat stock

fertilizer biuret % In% of stock a kg / ha N the control is specified at doses X 10 20 40 Ammonium nitrate - 95.6 id;., 3 8B, 0 Ammonium nitrate 2.5 94.2 81.9 83.5 Urea 2 Λ 80.4 67.3 26.4 Urea 5.0 60.7 42.0 19.9 Urea 10.0 41.5 28.3 9.1

Control: Buret-free urea

Table 6

Parcel: First Second Third 4th 5th 6th PKK 139 kg N / ha in Autumn - 70 kg N / ha + fall 70 kg N / ha in the spring - 102 kg N / ha in Autumn - Karbami d - 142 kg N / ha in Autumn - 76 kg N / ha + fall 76 kg N / ha in the spring - 112 kg N / ha in Autumn Cereals / m ² Rating kai; 524, 535 s z h á n y á s 528 after 484 580 492 Average crop yield t / ha Worthwhile 5.0 5 1 and a letter; 5.2 saving in 5.2 □ r 4.0 6.5 4.0

The slower decomposition and other unexplained mechanism of action of the nitrogen fertilizer containing polycondensed urea of the present invention is more advantageous than conventional urea. As can be seen from the results, both the plant number and the yields are improved with the fertilizers produced according to the invention compared with the known use of urea.

The fertilizers produced according to the invention can be used as basic and head fertilizers for cultivating crop plants, horticultural plants, fruit 60 and vineyards, meadows and pastures, sports grounds and parks.

The preparation is not hygroscopic. It can be produced without the extra investment of ec chemical plants currently producing urea fertilizers.

Claims (3)

A process for preparing an organic nitrogen fertilizer containing polycondensed urea, optionally in combination with a known carrier, characterized in that the urea is heated to 170 to 200 ° C, preferably to 180 ° C, by heating at 145 to 150 ° C with respect to urea. 1 to 1.0% by weight of calcium carbonate or 0.25 to 2.5% by weight of dolomite as catalyst and, if desired, 0.001 to 0.1% by weight of activated carbon, heating for 20 to 40 minutes, preferably for 30 minutes and polycondensed urea obtained at a temperature of 100-110 ° C is added with 0.1-2.0% by weight of saturated organic acid having 1 to 4 carbon atoms, preferably 5-20% by weight aqueous acetic acid or 10-20% by weight of lactic acid, followed by the product is ground or, if desired, admixed with 30 to 50% by weight of dolomite or calcium carbonate, based on the carbamide, and ground together. 2. The method of claim 1, wherein ¹⁰ characterized in that after the heating is 15% by weight of lactic acid were polycondensed urea. The process according to claim 1, wherein after heating, 2% by weight of 20% acetic acid is added to the poly15 condensed urea.