JP2926316B2 - Granulated product of nitrogen-containing oxidizing substance and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a raw material for industrial chemicals,
The present invention relates to a granulated product of a nitrogen-containing oxidizing substance used as a fertilizer, a salt bath, and the like, and a method for producing the same.

[0002]

The nitrogen-containing oxidizing substances, such as potassium nitrate, sodium nitrate, ammonium nitrate, calcium nitrate, potassium nitrite, sodium nitrite, ammonium nitrite, calcium nitrite and hydrates thereof are used as nitrogen fertilizers. In addition to being an important compound, in addition to salt bath materials, gunpowder raw materials, fireworks raw materials, dye raw materials,
It is widely used as a raw material for manufacturing industrial chemicals.

[0003] However, these nitrogen-containing oxidizing substances are problematic in that they are dangerous and require great care in production, transportation, storage and handling. More specifically, the nitrogen-containing oxidizing substance reacts violently when it comes into contact with organic substances such as paper, wood chips, cellulose powder, mineral oil, animal and vegetable oils, hydrocarbon-based chemicals, activated carbon, and sulfur compounds, Danger of fire or explosion
Great care must be taken to avoid mixing and contact with these. In addition, it is necessary to provide a vacant lot in the storage place or storage place to enable appropriate digestive activities and prevent fire spread, and to take measures such as bringing together people with sufficient disaster prevention knowledge during transportation, storage and handling.

[0004]

SUMMARY OF THE INVENTION In view of such circumstances, an object of the present invention is to provide a nitrogen-containing oxidizing substance excellent in safety.

According to the present invention, there is provided a granulated product of a nitrogen-containing oxidizing substance containing 90% by weight or more of particles having a particle diameter of 2 mm or more.

Further, according to the present invention, a nitrogen-containing oxidizing substance is granulated using a roll-type compression granulator using a roll having a large number of hemispherical concave portions on the surface, and the obtained granulated product is obtained. And a method for producing a granulated product of a nitrogen-containing oxidizing substance, comprising 90% by weight or more of particles having a particle size of 2 mm or more, characterized by subjecting to a classification treatment.

The granulated product of the nitrogen-containing oxidizing substance of the present invention is excellent in safety and has a markedly reduced ignitability and explosive property when contacted and mixed with an organic substance or the like. It can be said that it greatly contributes to the prevention of accidents.

[0008]

DETAILED DESCRIPTION OF THE INVENTION In the present invention, the nitrogen-containing oxidizing substance is not particularly limited, and conventionally known substances are widely used. Such nitrogen-containing oxidizing substances include, for example, alkali metal nitrate, alkaline earth metal nitrate, ammonium nitrate, alkali metal nitrite, alkaline earth metal nitrite, ammonium nitrite Examples thereof include salts and hydrates thereof, and more specifically, potassium nitrate, sodium nitrate, ammonium nitrate, calcium nitrate, potassium nitrite, sodium nitrite, ammonium nitrite, calcium nitrite and hydrates thereof ( For example, calcium nitrite tetrahydrate) can be exemplified.

In producing the granulated product of the present invention, various conventionally known granulation methods can be employed, for example, various extrusion methods such as a screw type, a roll type, a blade type, a self-molding type, and a ram type. A granulation method using a granulator can be mentioned. The granulated product of the present invention may be granulated by a tumbling granulation method, a spray drying method or the like. Among such granulation methods, a granulation method using an extrusion granulator is preferable from the viewpoint of safety in the granulation step. In the present invention, granulation may be performed by a wet method or a dry method.

[0010] The granulated product of the present invention contains 90% by weight or more of particles having a particle size of 2 mm or more.
It is preferred that the particle size is less than the order. More preferably, it is a granulated material containing 90% by weight or more of particles having a particle size of 2 mm to 30 mm. If the granulated material contains particles having a particle size of less than 2 mm in an amount of 10% by weight or more, sufficient safety may not be ensured, which is inconvenient. Although the larger the particle size, the higher the safety, the practically used granules having a size of about 100 mm or more are not preferable because handling is inconvenient.

In the granulation step, it is preferable to adopt a method in which no binder component is added. By employing this method, it is possible to obtain a granulated material having excellent solubility in water and other solvents as well as fine crystals. Examples of such a granulation method include a method of granulating a nitrogen-containing oxidizing substance using a roll-type compression granulator using a roll having a large number of hemispherical concave portions on the surface. In such a production method, the nitrogen-containing oxidizing substance powder before granulation contains about 5 to 20,000 ppm of water (excluding crystallization water when the nitrogen-containing oxidizing substance is a hydrate). It is desirable. By using a raw material having such a water content, a small amount of the contained water substantially acts as a binder and a good granulated product can be obtained without newly adding a binder component.
At that time, if the water content is less than 5 ppm, it is not preferable because the granulated material may be embrittled. On the other hand, when the water content exceeds 20,000 ppm, the solubility of the obtained granules in water or the like may be adversely affected, and the use in applications that dislike water is restricted, which is not preferable.

[0012] Since the granules produced by the above steps are not always formed into granules having a constant shape, it is preferable to sort the granules having a desired particle size by further classifying. Such a classification method is not particularly limited, and conventionally known methods can be widely used.
It is preferable to employ a method of collecting intermediate components by performing a sieving operation using a lower sieve having a diameter of at least mm and an upper sieve having a larger opening.

[0013]

The present invention will be described in more detail with reference to the following Examples and Comparative Examples.

Example 1 Commercially available industrial potassium nitrate (average particle diameter 0.5 mm, water content 0.01 to 0.02% by weight) was rolled on a two-roll (150φ × 250 m) having a large number of hemispherical concave portions having a diameter of 5 mm.
In m), the roll interval was set to 1.3 mm and supplied from the top. The sheet-like material including the 5 mm spherical material extruded downward is put into a horizontal vibrating sieve having an upper stage of 8 mm and a lower stage of 3.5 mm to be crushed into granules, and the granules on the 3.5 mm sieve are collected. Thus, a potassium nitrate granulated product was obtained.

Example 2 An ammonium nitrate granulated product was obtained in the same manner as in Example 1 except that ammonium nitrate (average particle size: 0.4 mm, water content: 0.2 to 0.3% by weight) was used instead of potassium nitrate. .

Example 3 A granulated product of potassium nitrite was prepared in the same manner as in Example 1 except that potassium nitrite (average particle size: 0.5 mm, water content: 0.1 to 0.2% by weight) was used instead of potassium nitrate. Obtained.

Example 4 Sodium nitrite (average particle diameter 0.8 mm, water content 0.1 mL)
2 to 0.3% by weight) were supplied from the top with two rolls (150 φ × 250 mm) having a large number of hemispherical concave portions having a diameter of 8 mm, with a roll interval set to 1.5 mm. The sheet-like material containing the spherical material of 8 mm extruded downward is put into a horizontal vibrating sieve of 13 mm in the upper stage and 4.0 mm in the lower stage to be broken into granules, and the granules on the 4.0 mm sieve are collected. A sodium nitrite granulation was obtained.

Example 5 Ammonium nitrite granulation was carried out in the same manner as in Example 4 except that ammonium nitrite (average particle diameter: 0.3 mm, water content: 0.1 to 0.3% by weight) was used instead of sodium nitrite. I got something.

Example 6 Calcium nitrite was prepared in the same manner as in Example 4 except that calcium nitrite (average particle size: 0.4 mm, water content: 0.2 to 0.4% by weight) was used instead of sodium nitrite. A granulated product was obtained.

Example 7 Nitrite was prepared in the same manner as in Example 4 except that calcium nitrate tetrahydrate (average particle size: 0.5 mm, attached water: 1 to 1.5% by weight) was used instead of sodium nitrite. A calcium tetrahydrate granulated product was obtained.

Example 8 Commercially available industrial potassium nitrate (average particle size: 0.5 mm, water content: 0.01 to 0.02% by weight) was mixed with 30 cm × 30 c
m and pressurized at 4 kg / cm ² , thickness 5 mm
Into a sheet. The sheet was taken out, placed on rubber, a mold with a 10 mm lattice-shaped blade was overlaid and pressed to obtain a granulated product of 10 mm × 10 mm × 5 mm. A sieve having an opening of 20 mm was sieved to remove a portion of the powder to obtain a potassium nitrate granule.

EXAMPLE 9 500 g was added to 10 kg of commercially available industrial potassium nitrate (average particle diameter: 0.5 mm, water content: 0.01 to 0.02% by weight).
Was added to a solution prepared by dissolving 15 g of polyvinyl alcohol in water, and the mixture was sufficiently mixed with a kneader. The mixture was put into a pre-extrusion-type granulator having an inner diameter of 5 mm, extruded and granulated, dried at 110 ° C. for 5 hours, and a powder portion was removed with a sieve having an opening of 20 mm to obtain a granulated product of potassium nitrate.

Test Example 1 100 g of the potassium nitrate granules obtained in Example 1 was placed in a sieve having a mesh size of 2 mm, subjected to vibration and rotation 160 times per minute, and vibrated for 30 minutes to reduce the passing amount. The measured value was 4.5 g. That is, those having a particle diameter of 2 mm or more are 95.
It was 5% by weight.

The amount of 100 g of the sodium nitrite granules obtained in Example 4 measured through a sieve with a mesh size of 2 mm in the same manner as described above was 3.5 g. That is, those having a particle size of 2 mm or more were 96.5% by weight.

Further, about 100 g of the granulated potassium nitrate obtained in Example 8, the mesh
The amount passed through the sieve was 5.6 g.
That is, those having a particle diameter of 2 mm or more were 94.4% by weight.

In addition, about 100 g of the potassium nitrate granules obtained in Example 9,
When the amount passed through a sieve of mm was measured, it was 7.3 g.
That is, those having a particle size of 2 mm or more were 92.7% by weight.

Commercially available industrial potassium nitrate (average particle diameter 0.5 mm, water content 0.01 to 0.02% by weight) 100
The amount of g passed through a sieve having a mesh size of 2 mm was 99.1 g.

Test Example 2 For each of the granules obtained in Examples 1 to 9, according to the method described in the Dangerous Goods Confirmation Test Implementation Manual (Supervised by the Fire and Disaster Management Agency Dangerous Goods Regulation Division, New Japan Regulations Publication (1989)). A mass combustion test was performed. For comparison, a similar test was performed on commercially available industrial potassium nitrate. Table 1 shows the results.

Test Example 3 For each of the granules obtained in Examples 1 to 9, according to the method described in the Dangerous Goods Confirmation Test Implementation Manual (Supervised by the Fire and Disaster Management Agency Dangerous Goods Regulation Division, New Japan Regulations Publication (1989)). An iron tube test was performed. The results are shown in Table 1.

[0030]

[Table 1]

As is evident from Table 1, commercially available industrial potassium nitrate was determined to be dangerous in a large-scale combustion test, because the combustion time was shorter than that of potassium perchlorate as a standard substance. Therefore, it is understood that the granulated product of the present invention has higher safety than commercially available industrial potassium nitrate.

Test Example 4 The potassium nitrate granules obtained in Example 1, the potassium nitrate granules obtained in Example 9, and commercially available industrial potassium nitrate were examined for solubility in water. That is, 500m
300 g of deionized water was placed in a 1-liter beaker, 30 g of each of the above granulated products or industrial potassium nitrate was put into a place where stirring was performed at 20 ° C. and 90 rpm, and the time required for dissolution was examined. As a result, the granulated potassium nitrate obtained in Example 1 was 18.3 minutes, the granulated potassium nitrate obtained in Example 9 was 43.2 minutes, and the commercially available potassium nitrate was 16.1 minutes. .

Claims (2)

(57) [Claims] 1. It has a water content of 5 to 20,000 ppm
After granulating potassium nitrate under pressure, classify the obtained granules
A granulated product of potassium nitrate, containing 90% by weight or more of particles having a particle size of 2 mm or more obtained by the treatment . 2. The lower sieve having a mesh size of 2 mm or more.
Perform the sieving operation using the upper sieve with a large aperture.
1 obtained by a classification process of collecting intermediate components.
The granulate as described.