DE1938933A1 - Process for the production of fertilizers with slow nutrient release - Google Patents

Description

Method of making fertilizers with slower Nutrient delivery

The invention relates to a method for producing fertilizers with slow release of nutrients to the soil, which is characterized in that a carrier gas with a temperature of at least 20 ^{0 is introduced from below into a truncated cone-shaped container filled with fertilizer granules, the tapered end of which protrudes downwards} C, an aqueous or organic dispersion or solution of one or more film-forming resins is injected into the resulting frustoconical fertilizer fluidized bed from below in "parallel direction" with the carrier gas and the granules, which are coated with several resin layers and dried by the gas flow, are deposited on the fluidized bed deducts as soon as their average Haz cover has reached at least 2 G-ew. $.

It is well known that only part of the soil is added to the soil

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Fertilizer actually absorbed by the plants, among other things because the rainwater washes out the soil and part of the fertilizer in the deeper soil layers, making absorption through the roots of the plants impossible.

To overcome this drawback, an attempt was made the fertilizer granules with a water-insoluble and impermeable organic substance to coat, _r with the specific aim to exploit the action of microorganisms be destroyed by such over time coating, whereby the fertilizer slowly released to the soil will. The effect of the. However, microorganisms turned out to be quite uncontrollable, so that it was impossible to achieve the hoped-for progressive effect. Achieve release.

Another method is that the fertilizer granules coated with resins that are semi-permeable to water. Forms thanks to the soil moisture A saturated fertilizer solution is inside the coating. If now the casing has a low mechanical If there is resistance, it will tear under the action of the osmotic pressure of the solution. In this case the Once started, the fertilizer is released quickly. When the mechanical resistance is better, the fertilizer slowly diffuses through the pores of the coating into the surrounding soil. Through this latter This method allows the intended results to be achieved, i.e. a gradual release of the fertilizer to the soil and in this way less washout by rainwater, creating a supply of nutrients for the plants during of the greater part or even for the entire vegeta-

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_ 3 tiveii cycle is ensured.

However, the coatings made by the latter process are too costly for commercial use. In general, they contain several layers of different resins applied one after the other. The coating on the fertilizer is generally about 10% by weight.

The preparation of each layer is usually done by that on the fertilizer granules ^ for example in a revolver drum, one in an organic one Resin solution dissolved in solvent sprayed on. Such "experience also have the disadvantage that they come with costs related to solvent recovery processes.

The object of the invention is therefore to provide a method for the production of fertilizers, which their nutrients to the Soil to be able to deliver, to deliver, at dc-m die Fertilizer granules in a single operation be coated with a cheap resin. In doing so, small amounts of resin are to be wounded for the production of these coatings will. In addition, you should be able, if necessary, to use organic solvents Avoid dissolved resins in order to exclude the expensive recovery process for the solvents l'iiJ finally seeks to overhaul in a cheap one Device be feasible, which bec-itzt a high production output.

These objects can be achieved by the method according to the invention solve, in which a truncated cone-shaped fertilizer

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is medium-fluidized layer with the aid of a carrier gas having a temperature of at least 2O ⁰ C formed.

A dispersion or an aqueous or organic solution of one or more resins which are _{suitable for producing x} film-forming coatings is applied on the lower part of the layer in the same direction as the carrier gas

icy splashes'.

The fertilizer granules cover each other as a result of their IZ rice course movement, namely by rising upwards around the axis of the layer where they "meet" with the resin dispersion or solution and sinking downwards in the peripheral zone, with successive resin; .; chiohten _f die, when they come into contact with the gas, dry. When their resin coating has reached at least 2 wt. ^, the granules from the device are at co ζ ο gen.

The fluidized bed used in the process according to the invention was already by K.B. MATHUR and P.E. GISHLER in A "i. Inst. Chem. Eng. Journal, Volume 1, No. 2, pp. 157-16 / -. 1955, described.

_f The authors have now explained the use of such a layer for drying eggs.

Eicso specific layer that with truncated cone or centrifugal layer is referred to, forms in a device formed by a lower frustoconical ,? oil. whose tapered end is gerioh'fcet downwards and is characterized by an upper, cylindrical part. The frustoconical shape of the lower part causes one

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. uneven flow of carrier gas, the speed of which is much greater in the axial zone of the device while it is minimal near the walls. Hence it happens that the particles of the layer with the Axial current come into contact, be dragged upwards. In the upper part of the layer and above, tend the particles, due to the decrease in the velocity of the flow, move towards the walls, as they begin to descend to the bottom. After they have sunk, they are back at the bottom of the Device where they collide again with the axial current. This creates a continuous circulatory movement of the particles within the layer. .

The resins suitable for forming the desired coatings need to be able to. to form film-like coatings when their medium evaporates. Preferably will Water used as the medium. According to the invention, as resins in aqueous dispersions, for example polyvinyl acetate, Polyacrylic esters or butadiene-styrene copolymers, or in aqueous solutions e.g. polyvinyl alcohol use. The use of resins which are dispersed or dissolved in water is from above mentioned reasons particularly useful. The method according to the invention can, however, be used in exactly the same way successful with resins / those in organic solvents solved v / earth, perform. In the latter case, for example, a mixture of maleic resins can be used Nitrocellulose vaw-turn.

Polyvinyl acetate in aqueous dispersion and mixtures of maleic acid resins

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and nitrocellulose in organic solvents. From the From an economic point of view, polyvinyl acetate turned out to be in aqueous dispersion as particularly advantageous. The resin concentration in the dispersion or solution can fluctuate within a wide range. Good results are achieved with both dilute resins, for example 1Ojzi Gew- $ as well as with concentrated resins, for example 50% by weight achieved.

The carrier air or another gas is introduced in allgemipnen into the fluidized bed at temperatures between 20 and 150 ⁰ C, According to a preferred embodiment of the invention dio incoming air has a temperature between 30 Urud 90 ⁰ C. When water is used as the medium, the applied temperature be higher. The more the dispersion or solution is diluted, the higher the temperature will be. With an aqueous dispersion having a concentration of 40 to 50 wt. $, Is preferably carried out at 30 to 80 ° C and in such a case often e.iiiom the air does not need vorerhitztzu ^T .7srde_n since. the heat of compression alone is sufficient to bring the air to 30 to 40 ^° C. On the other hand, if one uses a more dilute, aqueous solution, for example

, 10 Gow. $ Igen ,. Dispersion works, the working temperature is preferably between 70 and 90 ⁰ C.

Optionally, one can improve the production capacity of the Vmrrichtung slightly when higher temperatures, for example, applying between 90 and 150 ⁰ C. In any case, the temperature of the incoming air must not be so high that the resin temperatures are brought close to their softening point, since at this temperature the coated fertilizer granules tend to agglomerate.

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In order to avoid, in the case of polyvinyl acetate "for example, a softening, temperature of the fluidized bed must not be higher than 60 ⁰ C, -. That is, the temperature of the outflow-forming gas 70 ⁰ C does not exceed allowed the temperature of the layer. actually lower than the temperature of the outflowing gases insofar as equilibrium between the layer material and the carrier gas has not yet been reached the solution or dispersion is diluted.

The taper angle of the truncated cone is generally between 55 and 65, preferably about 60 °.

The air or another carrier gas is introduced at the bottom of the device.

The resin dispersion or solution is in the middle part the bottom of the device is introduced by luvende a nozzle concentric to the inlet tube of the carrier gas is arranged. In this way, the injected liquid phase is broken up by the gas flow and on db fertilizer granules that move with their upward movement start being sprayed on. The resin coating on the fertilizer granules dries when it comes into contact with the gas bc-vcr eic again in contact with the liquid jet 1: ο now cn.

~: orzug, sY4Cisc wii-d the dispersion of the liquid phase in the carrier gas is facilitated by suitable aids.

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One can e.g. the resin injection nozzle raises another concentric nozzle through which compressed air is injected.

With the aid of the method according to the invention, very uniform coatings are obtained (with little resin consumption. By varying the residence time of the fertilizer in the device, it is possible _{to overcoat the introduced fertilizer with a predetermined percentage of resin equal to T} r. ' . percentage resin amount required to illuminated to a satisfactory coating depends on dor regularity of the treated ΓΛη · ':;: τ.Lttelgranulate from using regular granules, ¹ C: ii ^ piolsweise substantially spherical as with in Grcrrulatoren. a frusto-conical fluidized bed or uit a yielding layer obtained Verien (spherodiser) ', a 2 wt $ resin coating be sufficient in Fe;... 11 obtained in IlüfTi If-rranulatoren of irregular granules as such, a coating may be selected from c bic IC '/ - resin will be sufficient.

The concentrated aqueous dispersions, for example 40 "οίε 50f-iges polyvinyl acetate or the aqueous or orfanisc-ien Solutions, even the more dilute ones, are often too viscous and therefore difficult to move. When the viscosity of the resin solution or dispersion is greater than 200 to 300 centipoise it was found convenient to foam the dispersion or solution through intimate Mix the dispersion or solution with air to prepare and introducing this much more fluid foam into the coating device rather than the device di / rol: t to be charged with the dispersion or solution.

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It was also found that the above method * namely to inject the foam of a resin dispenser or solution, also with all coating processes where no fluidized bed is used in which the resin dissolved or dispersed in a liquid is applied to the fertilizer granules is sprayed on, gives good results, This method can be used e.g. with lattice fluidized beds, i.e. ' those with a cylindrical cross-section in rotating drums or can be used in disk granulators.

The coating method according to the invention is preferably used carried out discontinuously. One possible embodiment of a batch method is shown below described with reference to the drawing.

A suitable amount of a fertilizer becomes frustoconical through line (9) in the coating apparatus (4) is introduced. The carrier air is pumped in by an electric fan (1) and, if necessary, in a heating device (2) heated. It is introduced into the coating device (4) through line (3). The resin dispersion or solution (5) is introduced into the nozzle (6), while compressed air (7.) is introduced into the nozzle (8) is to promote the atomization of the liquid phase in the fluidizing gas. The nozzles (6) and (8) are concentric arranged to one another, the nozzle (6) being the inner nozzle and both being coaxial with the line (3). The discharge opening of the nozzles is preferably in a notch (15) in the lower part of the coating device arranged »Because the cross-section of the narrower neck of this notch is considerably smaller than that of the line (3) there is a considerable amount due to the Venturi effect Acceleration of the gases with an improved dis-

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permeation of the resin in the gas phase. The cooled and moist air leaves the fluidized bed through line (10) and is then treated in the cyclone (11) to separate the entrained powder which flows out at (12). '

The air that has been purified from the powder flows out of the cyclone at (13). The fine particles that come from the cyclone originate, are preferably returned in the circuit to the coating stage by adding them to (9) together with the fertilizer to be coated in a subsequent process stage.

When the coating of the fertilizer has the desired consistency the resin feed is interrupted and the supply of air can be continued if necessary, to complete the drying of the coated gray matter, and thereafter the coated fertilizer is removed from the device withdrawn, for example by increasing the speed of the swirling gas, to the fluidized bed up to the height of the overflow that is open., bring to.

This further phase of improving the drying of the coated Gm ¹¹¹ XIx ^{6 is} sometimes useful when the apparatus is fed with the resin at a relatively high flow rate.

It is of course also possible to work continuously, by changing the operating conditions accordingly, in such a case one can use the fertilizer continuously through (9) and continuously through

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Subtract overflow (1 * t). The piling speed and Concentration of the resin and the piling speed of the fertilizer are adjusted so that the fertilizer leaving the device has the desired resin content having.

The coatings, according to the method according to the invention treated fertilizer granules, show a remarkable uniformity and a good mechanical strength, the remains unchanged even after long storage.

The coated fertilizers slowly release their nutrients to the soil, as shown by the examples below, which serve to explain the invention, is clearly apparent.

example 1

This example concerns the coating of ammonium sulfonitrate with a nitrogen content of 26% by weight with an aqueous solution of 10% by weight of polyvinyl acetate essential! around. In the following, their ^1- inch size distribution is shown:

diameter 3 4 mm mm Wt. Fraction of fo greater than 2 and 4 mm '3 between 1 and 3 mm 10 between and 2 65 between 1 mm 21 less than 1

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The frustoconical part of the coating device has a taper angle of 60 °. The device is charged with 1100 kg of fertilizer and air is introduced at a flow rate of 5000 m- ^ per hour at 75 ° C. The resin dispersion is introduced at a flow rate of 89 kg per hour. After 2 1/2 hours, the feed is interrupted and the ^v fertilizer edium withdrawn from the apparatus. The overdone. Fertilizer has a resin coating that is about $ 2 of its weight.

In order to determine the quality of the coating obtained, ■■ •, ■ the uncoated and the coated fertilizers are subjected to the same rapid permeation tests. For this Ξν / ε-ck, glass tubes with a diameter of 32 mm ui; 1 and a height of 350 mmpi were used. These tubes were filled with quartz granules measuring between 1.58 and 2.37 mm, and 1 g of fertilizer was sprayed onto them and sealed with a glass wool plug. Then water was allowed to percolate at a constant flow rate of 187.5 cm ^ per hour. DiG cluiort liquids were collected in fractions of 50 cm each. The ammonia nitrogen and the nitrate nitrogen were analyzed in each fraction. The most significant results are those shown in Table 1, which shows the ammonia nitrogen and the nitrate nitrogen _ί which were eluted globally in percent with reference to the fraction numbers.

Volume at 0 ° C and 760 mm

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Table 1 with or without Ammonium sulfonitrate with $ 20 wt 8.1 i polyvinyl acetate coating 21.6 Percolation tests determined, determined nitrate 33.5 nitrogen Amniotic nitrogen $ 42.0 Number of fabric $ 80.3 fraction without resin with resin without resin "with resin 88.8 61.7 10.6 47.8 97.6 69.4 26.7 75.9 99.1 1 100.0 39-4 94.8 lOO.O 2 - 50.2 100.0 3 - 89.7- 4th - 98-0 10 - 99-8 16 - 100.0 22nd - - 23 24

It is clear from the table above that the Resin coatings stop the release of ammonia nitrogen as well of nitrate nitrogen slow down very much.

Example 2

This example concerns the coating of a ternary fertilizer 20,10.10 which has the following components in Weight $ contains:

PpO ^ water soluble '$ 9.0

P ₂ O ₁ - soluble in ammonium citrate solution $ 10.0

Nitrate nitrogen $ 7.0

Ammonia nitrogen. $ 13.0

K ₂ O '10, X

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In this case, the coating was carried out with the aid of an aqueous 50% strength by weight polyvinyl acetate dispersion. The dispersion was fluidized in a mixer by injecting compressed air, thereby causing foam formed which was introduced into the device (5).

The fertilizer granules, which are fed to a disk granulator were irregular. Their size distribution was as follows:

Diameter by weight of the fraction

Larger than 4mm $ 0.5

between 3 and 4 mm $ 21.1

between 2 and 3 mm 65,

between 1 and 2 mm x 12.

less than 1mm $ 0.3

The suction device, which is the same as described in Example 1, was charged with 11QD kg of fertilizer. The air was introduced at a FliäBgeschwindigfeeit of 5000 irr per hour at 70 ⁰ C. The resin dispersion was introduced at a flow rate of 66 kg per hour. After 2 hours the feed was stopped and the fertilizer withdrawn from the device. The coated fertilizer had a resin coating equivalent to 8 ° / c of its weight. In order to determine the quality of the coating obtained, the fertilizer with and without coating was subjected to the percolatin tests described in Example 1, the water being fed in at a flow rate of 180 enr per hour enr caught. Any faction

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was based on the content of total sticksotff, water-soluble Phosphorus and potassium analyzed. The more significant results are given in Table 2 in which the gJLobareluted percentages of nitrogen, phosphorus and potassium with reference to fraction numbers are specified.

Tabel 2 ternary Fertilizer 13.2 io an_ elu
ied sol
lichen Phos
phor
ο. H. π. H. 8.6 20.10. 11.6 Percolation tests of a without polyvinyl acetate coating 35.7 36.8 15.6 28.9 with and Fraction ^ of eluted
Total stick
material
dme H. with H. 56.2 59.3 38.1 " 46.3 Kr. The 35.Q 80.7 86.9 61.9 .10 70.6 1 70.1 88.3 95 '. 7th 76.7 83-7 3 81.1 94.0 97.8 86_, 0- io to eluier
tem potassium
o. H. Li. H. 89.9 5 91.2 98.1 98.9 91.7 .37.2 94.1 10 95.6 100.0 99.4 96.6 76.1 97.4 15th 98.6 - -100.0 98.8 88.1 99.0 20th 99.5 - 100.0 96.6 100.0 25th 100.0 98.2 30th - 99.0 35 - 99.5 40 100.0 - -

From Table 2 it can be clearly seen that the resin coating is the Release of each of the nutrients is greatly slowed down.

Example 3

This example relates to a coating that consists of a

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Mixing a maleic acid resin with nitrocellulose aiii one ternary fertilizers. 20.10.10 was produced with the same composition as described in Example 2 This fertilizer, however, was in a frustoconical shape Granulator granulates and bites the Jörn * from very regular granules that are essentially spherical in shape was. The particle size distribution of the granules was as follows;

Dia eater
Greater than
between
between
ζ v / i see
less than

4 mm

3 and 4 mm 2 and 3 mm 1 and 2 mm

1 mm

Yes, by weight of the fraction

3.0 i * 16.0 # 74.0 #

7.0 ^

0.0? Δ

The resins are followed in a transparent lacquer mixture Composition include:

Nitrocellulose (Nitrocotton) 16 wt. $

T.Ialeic resin x 23 "wt lutyl phthalate 5,3 Gev, ·. '/

Different solvents 54.5% by weight oilikonöl 1 Gc'.v. 7?

Un to obtain a solution with an appropriate fluidity, the mixture of equal amounts of a ^T "was - ?. rdünnungsmittGls below Zurnrncnr.-vLzur.g-diluted:

43 wt. 4. ■ 57

aromatic solvents

sr-.ucrstofi-

?. "ltifres solvent

The coating device was the same as in

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. "and was charged with 1100 kg of fertilizers. The air was introduced at a flow rate of 5000 m" per hour at 55 ° C. The resin solution was introduced at a flow rate of 288 kg per hour. After 20 minutes the feed was stopped and the fertilizer was withdrawn from the device. The coated fertilizer had a resin coating equal to 2% - its weight. In order to determine the quality of the suction obtained, the uncoated and the coated fertilizer were subjected to the percolation tests described in Example -1, the water being introduced at a rate of 180 cm per hour. The eluted substances were removed in fractions of 25 cm each.

The total nitrogen content was determined in each fraction '.v-T-soluble phosphates and potassium analyzed. the The most significant results are shown in Table 3 below, in which the content of total eluted Nitrogen, phosphorus and potassium in percentages under reference "i-iTteo on the fraction numbers.

Table 3

_ / 20.10.10.

PerTi-olation test of a ternary fertilizer with or ob.no nitrocellulose coating ;

IT:?, The fraction fo an eluted fo an elu fo an eluting

Total embroidered solution, potassium material borrowed phosphorus without resin with H. o.H. m.H. Oh. ra.H.

1 30.3 0.7 26.6 1.1 30.2 3 «2nd

3 85.4 8.5 90-0 5.4 94.8 13-4

5 90.2 25.7 95-3 11.0 98.6 24.4

0 92.0 64.7 97.9 30.1 99.7 55.0

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ITr. the fraction ic an eluted ^ an elu $ an eluent

Totally embroidered solder potassium

material
without resin with - H. borrowed
phor
Oh Phos-
mH ο.Η • 9 >, κι.-H 15th 95-6 90 .1 99.0 49-5 99 .0 77.9 20th 100.0 98 .8th 99.6 69.0 100 . 90.5 25th - 100 .0 100.0 85.6 - "- ■ ■ 95.5 30th - - - 99.0 - 97.5 40 - - - 100.0 - 99.2 50 - - - - - 100.0

In this case, too, it can be clearly stated that the resinous substance greatly reduces the release of each of the nutrients slowed down,

Example 4

The ability of the fertilizers treated according to the invention ^ The delayed and controlled release of the nutrients was made possible by field trials / related to the cultivation of Tomatoes. Explains. The tests were carried out on a muddy sandy, over-alkaline & n soil, the one Average content of total lime, absorbable: Potassium and in total nitrogen and phosphorus and sufficient absorbable phosphorus. .

The purposes of the tests were twofold. The first was the one to determine if the fertilizers were coated actually were able to make better use of the To ensure nutrients on the parts of the plant and consequently to get a bigger harvest. The second purpose was the one that slowed the release of nutrients to the

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To prove soil. For this purpose one made the well-known destructive effect of NCU -A-nions take advantage of the germination of plants by using ζ. Z. the Sow large quantities of the NO ^ -containing fertilizer. In the case of the coated fertilizer, the destruction effect should necessarily be lower in, due to the slower release of these anions.

For this purpose, the bottom pin was 6 rows of 10 each Divided into fields with a size of 24 m. At the time of sowing, 1,00j2,00j 4.0Of6, OO and 8.00 Qt / ha of the ternary fertilizer 20.10. 10, which was coated with 6 wt. ^ Polyvinyl acetate, such as described in Example 2, scattered. On the rest of them

Equal amounts of uncoated fertilizer were spread over 5 fields in each series.

According to the specific requirements of the person to be examined Cultivation method: each field is fertilized 3 times in a row: pinned from the 2nd to the 6th month after the statement, i.e. from February to May with a total of 5.66 Qt / ha ammonium nitrate with a nitrogen content of $ 26 to $ 27. The ammonium nitrate was in none of the cases coated as it was intended to be consumed immediately by the growing plants.

Table 4 shows the average harvests for the

6 rows in kg / field during the 3 months of the main harvest season.

Table 4

Attempts at the tomato harvest Qt (quintal) = 100 kg

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fertilizer
10/20/10
Qt / ha picked
kg.
without resin in May
with H. picked
in June
kg
ο. H. m. H. 97.60 picked
in July
kg
oHmH 128.07 1.00 18.49 20.17 83.51 99.39 117.Q9 134.45 2.00 20.45 23.28 80.15 83.62 -133Γ27 114.69 4.00 02/12 14.48 77.82 89.56 102.17 121.72 6.00 6.68 17. 7 65.13 72.00 96.23 99.17 8.00 8.13 11.62 59-34 90.30

The results in Table 4 clearly show that a better harvest was always achieved with the coated fertilizers. In addition, proof of the fact that the destruction ■ effect of larger amounts of fertilizer is essential / rrößer in cases of non-coated fertilizer ⁴ / that the delivery of NO-y-ions has been slowed by the resin coating.

Example 5

This example relates to growing rice in a rice field. The fertilizer used was a ternary fertilizers 10.10.10 the following percentage Composition:

PpO _R water-soluble 5.5% by weight

F ₀ Op; in an ammonium citrate solution * "'soluble 10 wt." p

F. ITitr-1stickstoff 4.5 wt. '

Ammonia nitrogen 5.5 wt. $

K ₂ O 10 wt. $

This fertilizer was made in a frustoconical shape Fluidized bed granulator and had very even

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• moderate, essentially spherical granules. The size distribution of the granules was as follows:

diameter 3 4 mm mm Wt. Jo of the parliamentary group greater than 2 and 4 mm 1.5 1 » ζ v / i see 1 and 3 mm 12.0 % between and 2 80.0 f ζ v / i see 1 mm 6.5 1o less than $ 0.0

The fertilizer was coated with a 10% strength by weight polyvinyl acetate layer coated, proceeding according to Example 2, * starting from a 20% resin dispersion. The rice trial field consisted of 2 rows of basins, each row containing 4 basins that were stepped around to simplify the water cycle. The basins had the following dimensions; Height 50 cm, length 200 cm and width 120 cm. They were made of loamy, coarse-grained, over-alkaline earth with an average content of total lime, absorbable Potassium and nitrogen and a scanty level of absorbable phosphorus, the rice plants were planted in the basins 45 days after sowing. The soil was fertilized with the fertilizer in an amount of 10 qt / ha, on one of the two Rows of basins. Covered fertilizer scattered and the others were sprinkled with the same uncoated fertilizer. A few days later the water supply began with a constant piling speed of 2 l / ha / sck. The water ran into the bottom of the first basin, filled the same to the edge and then overflowed into the next basin and in the same way into the other basins.

* but from.

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The nutrient levels of the .from the last. Basin draining Water were analyzed. The tests were carried out for 3 months and then continued until the rice harvest.

Table 5 shows the amount of nutrients that are globally by the flowing water after the first, the second and the third month had been removed. The percentage Data concern the total amount of nutrients used at the time was added to the fertilization.

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Table 5

Tents rait a ternary fertilizer 10.10.10 with and without a polyvinyl acetate coating; nutrients carried away by the running water of the experimental rice field

co

co

CO OO

cn

CD

cn

fertilizer
without resin
fertilizer
with resin Nitrogen i » nd2.
month nd3
month in ammonium citrate potassium $
i «-solar phosphorus nd2.
month nd3.
month nd1.
month nd2.
month nd3.
month iach 'that
1 month 67.5
44.3 94.5
87.6 After this
1 month 56.2
40.6 84.6
75.2 42.5
30.5 71.4
50.2 96.3
90.1 40.2.
24.5 31.4
21.3

ro u »

S. §

CD CO CO CD GO

The data relating to the harvest are given in the .bulle'6 below.

• l section 6

TeGts with a ternary fertilizer 10.10.10 with and without polyvinyl acetate coating; Jienge of harvested Iteis on the reverse trial field

Number in Amount of Amount of straw per pelvis Rice grains when harvesting right gc- when harvesting pro Beckeri reaped per basin line Ears of wheat line fertilizer without resin 4900 9.80 kg 7.85 kg riingcraittcl with resin 5570 10.40 kg 7.50 kg

Table 5 shows quite clearly that also in underwater plantings the coated ones manufactured according to the invention Fertilizers release their nutrients slowly. From Table 6 it can be seen that those with the "coated Fertilizer yielded yield absolutely superior to that obtained with uncoated fertilizer i .- 't.

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Claims (9)

PATENT CLAIMS 1. A process for the production of fertilizers with slow nutrient release to the soil, characterized in that a carrier gas with a temperature of at least 20 ⁰ C is introduced from below into a truncated cone-shaped container filled with fertilizer granules, the tapered end of which protrudes downwards , an aqueous or organic dispersion or solution of one or more film-forming resins is injected from below in the same direction as the carrier gas into the resulting, frustoconical fertilizer fluidized bed and the granules, which are coated with several resin layers and dried by the gas stream, are removed from the fluidized bed as soon as they are average resin coating at least 2 wt. '?' has reached, 2. The method according to claim 1, characterized in that the resin is in the form of an aqueous dispersion initiates. 3. The method according to claim 1 and 2, characterized in that that he. uses polyvinyl acetate as resin. 4c method according to claim 1, characterized in that a mixture of a maleic acid resin and nitrocellulose used in an organic solution, 5, method according to one of the preceding claims, d- ^Q - the. characterized in that the fertilizer is made from vortex 909886/1166 layer is withdrawn as soon as the average resin coating a value between 2 and 10 percent by f.. has reached _. 6 = Method according to one of the preceding claims, characterized in that a dispersion of a solution with a resin content of 10 to 5 % by weight is used. 7. The method nsch one of the preceding claims, characterized in that one introduces the carrier gas at 20 to 15O ⁰ C. 8. The method according to claim 7, characterized by gelmnseichnet, that one introduces the carrier gas at 30 to 90 C. 9. The method according to any one of the preceding claims, characterized characterized because ^ one is the solution or dispersion carefully mixed with air and in the form of foam initiates, - if their viscosity at room temperature is more than 200 bic 300 centipoise. Fir: oI.XAT ooc.Inu. Catanese o.p.A. Kechtsanvi & _t BAD ORIGINAL 9098 86/1166