JPS6045157B2 - Method for producing chemical fertilizer containing dicyandiamide - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a nitrification-inhibiting stabbed chemical fertilizer, and in particular to a method for producing a nitrification-inhibiting fertilizer using dicyandiamide (hereinafter referred to as Dd).

) Concerning the manufacturing method of containing chemical fertilizers. Conventionally, two methods are known for producing chemical fertilizers using Dd as a nitrification inhibitor.

One of them is a method of adding Dd to slurry during production of chemical fertilizer.

However, in this method, the temperature of the slurry during the production of chemical fertilizer is usually as high as 100 to 110 degrees Celsius.
When Dd is simply added to the slurry, Dd decomposes in the presence of ammonium salt and changes to piganide, guanidine, melamine, etc., depending on the temperature. Furthermore, under acidic conditions, it changes to guanylurea and loses its original nitrification inhibiting function. In order to prevent this decomposition of Dd, when adding Dd, a small amount of an alkaline substance or its salt, such as magnesium oxide, is added at the same time (Japanese Unexamined Patent Application Publication No. 47-1999).
No. 29154) has been proposed. According to this method, the decomposition rate of Dd is, for example, 2 in a slurry of 100 C.
2%, which is the decomposition rate when no magnesium oxide is added.
Although a considerable improvement is recognized compared to 6%, a considerable loss of Dd cannot be avoided. The other method is to use a coating agent to support Dd in chemical fertilizers (Japanese Patent Application Laid-Open No. 48-1989-1).
90850).

In this method, for example, the surface of a granulated fertilizer containing Dd is coated with magnesium oxide or a magnesium phosphate-based sparingly soluble salt containing magnesium hydroxide. Specifically, Dd is added during granulation of a chemical fertilizer. , Dd in the coating
A method of incorporating is disclosed. However, both methods use a coating agent with a complicated composition and require a heating drying process for the Dd-containing chemical fertilizer grains, so the residual rate of Dd is 65 to 70%. The loss is huge. In view of the above problems, the present inventors conducted intensive research on a simple and strong method for supporting Dd, and found that, surprisingly, when Dd is ground and used, it is simply mixed with chemical fertilizer particles. It has been found that the compound adheres firmly to the surface and forms a constant coating.

The present invention is based on these findings and aims to provide a method for producing Dd-containing chemical fertilizers that is simple and does not involve thermal decomposition.

That is, the method for producing a Dd-containing chemical fertilizer of the present invention that achieves the above object is characterized by coating the chemical fertilizer with Dd by mixing the chemical fertilizer with ground Dd.

Also, this grinding process! If Dd is left as it is, there is a risk that it will aggregate and become lumpy, so a small amount of an anti-agglomerating agent such as diatomaceous earth may be added. Although Dd itself is a fine powder, even if it is mixed directly into a chemical fertilizer without using an adhesive or a coating agent, it hardly adheres to the surface of the fertilizer grains and does not form a coating.

On the other hand, when Dd is subjected to grinding treatment, the adhesion rate improves dramatically even when compared to untreated products with particles in the same particle size range, and furthermore, the adhesion rate was determined by a peel test to examine the adhesion strength. 4 will also decrease significantly. Milled D according to the present invention
Although the reason for this amazing adhesion ability and adhesion strength of d is not necessarily clear, it is presumed that it is due to the shape of the surface of the Dd fine particles produced by the grinding process.

Incidentally, according to microscopic observation, the commercially available Dd powder-treated product has a prismatic crystal belonging to the monoclinic system with a smooth surface, whereas the ground Dd of the present invention has an amorphous, acute-angled shape. I can see that you are doing this. The particle size of the ground Dd particles of the present invention is generally desirably smaller from the viewpoint of adhesion amount and adhesion force, but is preferably 250 mesh, more preferably 300 mesh.

Even if the particle size of Dd stops at 250 mesh, it will show a considerable adhesion rate and adhesion strength as long as it is ground and can be put to practical use, but the particle size itself of commercially available Dd untreated products is 170 mesh. Since Bass has a capacity of about 5%, if it is ground, the size of the particles will inevitably become smaller, and it is difficult to obtain a large amount of 250 mesh stop by grinding. Not on target.

On the other hand, if the size of the D attractor is 300 mesh bath, the particles will adhere at about 10 weight percent, and the peeling rate will be about 2 weight percent, which means that the adhesion will be strong, which is most desirable.

For the grinding treatment of Dd, if a large amount is used, for example, an ultrafine grinder manufactured by Fuji Paudal Co., Ltd., may be used, and if a small amount is used, a mortar or the like is sufficient. To coat the surface of the chemical fertilizer granules with the ground Dd, the fertilizer granules are rolled at a temperature of 60°C or less, preferably at room temperature, after passing through the cooling process from the chemical fertilizer granulation drying process. It is only necessary to add a fixed amount of Dd and mix it while moving, which is extremely simple, and there is no need to use an adhesive or the like.

Because the ground Dd has such strong adhesion, if it is not used immediately after the grinding process, it may re-agglomerate within a few hours to a day, leading to a decrease in adhesion and a negative impact on workability. .

Therefore, if storage is required for industrial implementation, a small amount of anti-flocculant such as diatomaceous earth, talc,
It is recommended to add bentonite, kaolin, acid clay, etc. It is sufficient that the amount of anti-aggregation agent added is about 2 to 20% by weight based on Dd. If the amount added is less than 2% by weight, the agglomeration prevention effect will not be sufficient, and if it exceeds 2% by weight, it will not be economical considering the effect. The timing of adding the anti-aggregation agent is Dd
It may be done before or after the grinding process, but it is preferable to do it before the process to prevent secondary agglomeration during the grinding process. Addition after treatment also has the disadvantage of requiring additional mixing work. Note that any chemical fertilizer to which the present invention is applied may be used, and examples include Phosphorus Agari (16-10-14, 18-11-
11,15-15-1), phosphorus sulfate (12-16-1
4, 14-10-1) etc.

In summary, according to the present invention, a strong coating can be formed on the surface of the chemical fertilizer particles by simply grinding the Dd used and simply mixing it with the chemical fertilizer particles. Also,
Since the coating work can be carried out at room temperature, there is no fear of thermal decomposition of Dd. Furthermore, since no adhesive or coating is used, there is no adverse effect on the nitrification suppressing function of Dd, making it extremely practical. Note that one mesh used in the present invention is defined as a JIS standard mesh sieve. Examples of the present invention will be described below, but the present invention is not limited thereto.

In the examples, percentages are by weight unless otherwise specified. Example 1 After granulation and drying, 1 (1) part of phosphorus sulfate Ankali grains was sieved into a 5 mesh bath to 16 mesh stop, and Ddl part (phosphorus sulfate Ankali as Dd-nitrogen) was ground in a mortar and sieved in advance. (equivalent to 10% of the nitrogen component) in a 250ml container, mixed by tumbling for 2 minutes at room temperature, and passed through a 60 mesh sieve.
The adhesion rate of d was calculated.

Note that Dd was manufactured by Nippon Carbide Co., Ltd.
Example 2 After granulation and drying, 1 (1) part of phosphorus sulfate and potassium granules were sieved to a 5-mesh bath to 16-mesh stop, and 0.1 part of Ddl and diatomaceous earth were ground in a mortar and sieved in advance. was placed in a 250 mt container, treated in the same manner as in Example 1, and the adhesion rate of Ddl diatomaceous earth was calculated.

Example 3 Drum diameter 300rT1/m, internal volume 31.7e
Using a rotary rotary machine, granulate the porosity to 80%, dry it, and then put 7 kg of phosphorus-based potassium granules (16-10-14), which had been sieved into a 5-mesh bath to a 16-mesh stop, into a drum. Dd7Og and 10 g of diatomaceous earth were added while rolling the drum, and the adhesion rate of Dd and diatomaceous earth was calculated in relation to the drum rotation speed and rotation time.

Next, put the above sample 5k9 in a plastic chloride bag (36CTf1).
It was packed and sealed in a size (length x 26 cm width x 5 CW 1 thickness) and dropped 10 times from eye level (approximately 160C71) (7 times in the table).
3 times) was sieved with a 60-mesh sieve, and the peeling rate was calculated using the amount of peeled particles that fell through the sieve mesh.

These results are shown in Table 1. In addition, the Dd grinding processed product is
A commercially available Dd untreated product (average particle size: 170 mesh) was ground using an ultrafine grinder (Umizer) manufactured by Fuji Paudal Co., Ltd., and a 300 mesh bath was used.

Reference Example 1 A mixture of Dd from a 350 mesh bath obtained by grinding commercially available Dd and an agglomeration inhibitor in a mortar was left to stand for one day, and then sieved through a sieve.Those that passed through the sieve were considered to be free of agglomeration, and the sieve passage rate was determined. was calculated.

These results are shown in Table 2.

Note that the diatomaceous earth used was Kureha Chemical's product name 1 Silica Flower, and the talc used was Kishida Chemical's 1 Talc.

Claims (1)

[Scope of Claims] 1. A method for producing a dicyandiamide-containing chemical fertilizer, which comprises coating the chemical fertilizer with ground dicyandiamide. 2. The method for producing a dicyandiamide-containing chemical fertilizer according to claim 1, wherein the size of the dicyandiamide particles is 250 mesh pass. 3. The method for producing a dicyandiamide-containing chemical fertilizer according to claim 1, wherein the size of the dicyandiamide particles is 300 mesh pass. 4. The method for producing a dicyandiamide-containing chemical fertilizer according to claim 1, wherein the dicyandiamide contains at least one anti-aggregation agent selected from the group consisting of diatomaceous earth, talc, bentonite, kaolin, and acid clay. 5. The method for producing a dicyandiamide-containing chemical fertilizer according to claim 4, wherein the anti-aggregation agent is diatomaceous earth. 6. The method for producing a dicyandiamide-containing chemical fertilizer according to claim 4 or 5, wherein the content of the agglomeration inhibitor is 2 to 20% by weight based on dicyandiamide. 7. The method for producing a dicyandiamide-containing chemical fertilizer according to claim 4 or 5, characterized in that the anti-aggregation agent is added before the grinding treatment of dicyandiamide. 8. The method for producing a dicyandiamide-containing chemical fertilizer according to claim 1, characterized in that the coating treatment with dicyandiamide is carried out at a temperature of 60° C. or lower. 9 The particle size of dicyandiamide is 300 mesh pass, and diatomaceous earth is added to the dicyandiamide at a ratio of 2 to 2.
10. The method for producing a chemical fertilizer containing dicyandiamide according to claim 1, wherein the coating treatment is carried out at room temperature.