JPS5917075B2 - Manufacturing method of molten phosphorus fertilizer granules - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing granulated fused phosphorous fertilizer having good disintegratability in water by granulating granulated fused phosphorous fertilizer using an aqueous potassium silicate solution as a binder.

Conventionally, granulation methods for melted phosphorous fertilizers have been known, and various binders have been proposed.

Examples include granulation using pulp waste liquid, granulation using a mixture of the waste liquid and bentonite, granulation using nitrocumic acid, and granulation using bentonite.

By the way, dissolved phosphorous fertilizer is almost insoluble in water, and is a so-called slow-release fertilizer that gradually dissolves from the surface due to acid in the soil or root acid released from plant roots. If the particles become larger and the surface area becomes smaller, the fertilizing effect will deteriorate.

Therefore, technical guidance has been given that granulated products of dissolved phosphorus fertilizer have good water disintegration properties.

On the other hand, because the granules must have sufficient strength to withstand transportation and storage, contradictory properties are required.

However, conventional granulated melted phosphorus fertilizers are not always effective in satisfying these two contradictory characteristics, and in addition, in any case, the granulated melted phosphorus fertilizers have to undergo a further pulverization process. A pulverized product or a mixture of a pulverized product and a pulverized product were used.

Therefore, there were problems in the granulation process, such as generation of dust and bad odor due to pulverization.

In view of the drawback of sloping, the inventors of the present invention have made extensive studies to produce granules that satisfy the above two conflicting properties without further crushing the granulated product of dissolved phosphorus fertilizer. We have arrived at the present invention.

That is, the present invention provides a water-disintegratable starting material characterized in that when a granulated solution of dissolved phosphorous fertilizer is granulated to produce a dissolved phosphorous fertilizer granule, an aqueous potassium silicate solution is used as a binder. This relates to the production of dissolved phosphorus fertilizer granules.

The dissolved phosphorus fertilizer applied to the present invention is a granulated product itself, and does not need to be a pulverized product by further pulverization.

The particle size distribution of this granulated material varies depending on the manufacturing conditions of the dissolved phosphorus fertilizer and the granulation method, but typical examples thereof are as follows.

1.000~2,000μ 10% or less 500~i,
oooμ 10 to 55% 260 to 500μ 10 to 60% 149 to 260μ 2 to 25% 149μ'' 25% or less The purpose is to produce a granulated product with good water disintegration properties, and its feature lies in the use of an aqueous potassium silicate solution as a binder.

When an aqueous potassium silicate solution is added as a binder to the granulated product and the granulated product is granulated, the granulated product satisfies both strength and water disintegration properties.

Moreover, unlike a mere binder, this potassium silicate is suitable as a K fertilizer and a silicate fertilizer, and can be said to be reasonable from the viewpoint of fertilizer effect.

The molar ratio of the potassium silicate aqueous solution used is SiO2/20
1 and 2 are the results of numerous experiments conducted by the present inventors regarding the relationship between the concentration (SiO□ content of 10 to 20) and the water disintegrability and crushing strength of the granules.

Figure 1 shows the water disintegration rate of the granulated product and the molar ratio S102/ at various concentrations of potassium silicate used as a binder.
This is a chart showing the relationship between K20 and water disintegration rate of about 8
If you look for the area above 0%, the molar ratio is approximately 1.9-2.
8 can be said to be a preferred practical range.

The potassium silicate aqueous solution having the following molar ratio and concentration relationship was used as a stock solution.

In addition, in Fig. 1, 1 is the stock solution, 2 is the stock solution: water = 5:
1.3 is the ratio of stock solution: water = 2: 1.4 is the ratio of stock solution: water = 10 nia, which is the case where you want to dilute each with water.

On the other hand, the strength of this granulated product is explained in Figure 2-1, and in the above molar ratio range, the relationship between the pressure strength and the concentration of potassium silicate is approximately 30 to 45% by weight (K2
The crushing strength is approximately 3 at the concentration number ζ (0+SiO2 content)
kg or more, which is preferable as a practical prelude.

In this way, by granulating the dissolved phosphorus fertilizer as it is without pulverizing it using an aqueous potassium silicate solution as a binder, a granulated product with moderate strength and good disintegration properties in water, that is, granules, can be obtained. It is an effective granulated product because it can be used as a fertilizer and the binder itself is also used as a preferred fertilizer.

In particular, potassium silicate aqueous solution has a molar ratio of 1.9 to 2.
．． 80, and a concentration in the range of 30 to 45% by weight is practical and preferred.

The amount of potassium silicate aqueous solution used is 1
The appropriate amount is approximately 10 to 25 parts by weight per 00 parts by weight (calculated as anhydride). During granulation, while or after adding potassium silicate aqueous solution to the granulated material, a known desired amount is added. The product can be granulated to a desired thickness using a granulator such as a dish-type granulator, and then dried to obtain a granulated product.

The average particle size of the granules is generally in the range of approximately 0.5 to 3 mm.

Example 1 Melted phosphorus fertilizer hydrate (2,000-1,000μ: 3%.

500-1,000μ: 37%, 260-500μ: 3
5%, 149-260μ: 10%, 149μ pass: 15
%) 100 parts by weight (anhydrous equivalent) to 5in2/202
．． 60, granulated with a rotating plate granulator while adding a potassium silicate aqueous solution having a concentration of 33% by weight in the form of a mist, and then at a temperature of 60%.
It was dried at ~110°C for 1 hour to obtain granular dissolved phosphorus fertilizer.

The yield of 0.5 mrn or more of the obtained granules is 93%.
When this material was measured for water disintegration and strength using the test method shown below, the water disintegration rate was 98%.
The crushing strength is 3.5! It was 9.

Example 2 Melted phosphorus fertilizer hydrate (2,000-1,000 μ: 10%,
500-1,000μ: 45%, 260-500μ=3
5%, 149-260μ: 4%.

149 μ pass = 6%) 810 to 100 parts (anhydrous equivalent)
2/ Using 12 parts of a potassium silicate aqueous solution of K202.30 and a concentration of 42.5% by weight, granulation was carried out under the same operation and conditions as in Example 1 to produce a granular dissolved phosphorus fertilizer.

The yield of 0.5 ml or more of the obtained granules is 9
0%, water disintegration rate is 99%, and crushing strength is 3.6k.
It was g.

〔Test method〕

1. Water disintegrability... Weigh 100 granules with a particle size of 2 mm or more, and immerse them in water overnight in a sieve with a sieve opening of 2 mm.

Next, the material on the sieve is taken out, dried at a temperature of 100° C. for 1 hour, and then its weight is measured.

The disintegration weight is obtained by subtracting the remaining weight from the initial weight, and the ratio to the initial weight is expressed as a percentage.

2. Crushing strength... The crushing strength of 10 grains with a grain size of 2 to 4 mm was measured using shell grain hardness, and the average value was used to express the results.

[Brief explanation of drawings]

Figure 1 shows the molar ratio (S
iO□/K20) is a diagram showing the relationship between the second
The figure is also a diagram showing the relationship between crushing strength and concentration of potassium silicate aqueous solution.

Claims (1)

[Scope of Claims] 1 Disintegration in water, characterized in that the granulation is carried out using an aqueous solution of potassium silicate as a binder when producing a granulated solution of dissolved phosphorous fertilizer by granulating a granulated solution of dissolved phosphorous fertilizer. A method for producing dissolved phosphorus fertilizer granules with good properties. 2 molar ratio S i 02 /20 1.90-2.8
0, 10 to 10 parts by weight of potassium silicate aqueous solution with a concentration of 30 to 45% by weight per 100 parts by weight of fused phosphorus fertilizer granules (anhydrous equivalent)
Production island of melted phosphorus fertilizer granules according to claim 1, characterized in that 25 parts by weight are used.