JP2001031488A - Production of fertilizer and solid fertilizer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control the content of an accessory component adversely affecting soil such as sulfate radicals to a low value and produce an advanced compound fertilizer improved in hygroscopicity by reacting urea phosphate with a potassium compound in the presence of water. SOLUTION: This solid fertilizer has >=50 wt.% of the sum total of a nitrogen component, a phosphoric acid component and a potassium component and 0.01-10 wt.% content of iron and/or aluminum, especially >=20 wt.% content of the nitrogen component. Urea phosphate prepared by reacting phosphoric acid produced by a wet process with urea is reacted with a potassium compound in the presence of water to provide the solid fertilizer having high contents of NPK components and low hygroscopicity. An advanced compound fertilizer such as 13-35-25 NPK components can be produced. The reaction of the urea phosphate with a potassium compound is an exothermic reaction and proceeds in the presence of water. The molar ratio of the urea phosphate to the potassium is preferably (1:0.5) to (1:1.5). The reactional conditions are preferably 40-100 deg.C, 5-10 min and 2-20 wt.% of the moisture content.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a fertilizer and a solid fertilizer. Specifically, the present invention relates to a method for producing a fertilizer having a large total amount of nitrogen, phosphoric acid and potassium components, which are main components of the fertilizer, and a solid fertilizer thereof.

[0002]

2. Description of the Related Art In recent years, the agricultural population has been declining, and in addition, the average age of the working population has been aging, so that labor has been required to be reduced, and in particular, the fertilization labor has been required to be reduced. Among the components in the fertilizer, the nitrogen component is an important fertilizer component for growing crops such as paddy rice, and the fertilization is required throughout the growing season of the crop, so it is suitable for efficient and labor-saving fertilization. Fertilizer has been sought.

Conventionally, in order to solve such a problem, in order to reduce the number of times of fertilization, nitrogen, phosphoric acid and potassium components (hereinafter may be referred to as "NPK components") per unit weight of fertilizer are contained. So-called advanced chemical fertilizers have been developed in large amounts. In the past, such materials were often liquids, but furthermore, solidification of such materials has led to the development of fertilizers that are lighter than liquid fertilizers (liquid fertilizers).

In the production of advanced chemical fertilizers, nitrogenous fertilizers such as urea, ammonium sulfate and ammonium nitrate, and phosphate fertilizers such as lime superphosphate,
There is a method of producing a potassium fertilizer such as potassium chloride by reacting or mixing. In this production,
By changing the reaction conditions and the mixing ratio of each component,
The component ratio (NPK component ratio) in the NPK component can be changed. An example of this is disclosed in Japanese Patent Laid-Open No. 50-99816.
No. 5,111,8000, etc., there is a description of a method for producing an advanced chemical fertilizer having an NPK component of 60% or more. In addition, advanced chemical fertilizers have a high ratio of fertilizer components (a low ratio of subcomponents), and thus have a tendency that adverse effects on soil, acidification of soil, and the like due to subcomponents such as sulfates are unlikely to occur.

[0005]

However, in many of the conventional methods for producing advanced chemical fertilizers, secondary components such as sulfates and hydrochlorides contained in the raw materials are mixed into the product, so that the content of the NPK component is reduced. It was less than 50%. For example, Japanese Patent Publication No. 59-19909 discloses a method of increasing the content of a nitrogen component. The content of a phosphoric acid and a potassium component is decreased by increasing the nitrogen component. As a result, the NPK component is reduced to 50%. It has become less than. In addition, there is a possibility that the acidification of the fertilized soil may be promoted by the presence of such subcomponents. Also, the aforementioned Japanese Patent Application Laid-Open Nos. 50-99816 and 51-11800.
In the production methods described in Japanese Patent Application Publication No. 0-203, etc., the production conditions are all high, such as 150 ° C. to 800 ° C., so that the production cost is high, and the fertilizer of the final product is extremely expensive. Was. Japanese Patent Laid-Open No. 50-9981
No. 6 also discloses a method for producing fertilizer,
Since expensive potassium metaphosphate is used as a raw material for production, there is also a disadvantage that the fertilizer of the final product becomes very expensive.

[0006] In addition, as described above, the nitrogen component is important for the growth of agricultural crops.
Further improvement in the nitrogen content of the entire fertilizer was required. However, in order to increase the content of the nitrogen component, many of the methods using inexpensive and high-nitrogen components urea have been studied. Manufacture of fertilizer was difficult. Furthermore, for example, Japanese Patent Publication Nos. 61-5679 and 51-40877 describe methods for producing fertilizers containing iron and / or aluminum. Since salts and the like are simply mixed in the fertilizer production process, quality unevenness in the product has been a problem.

[0007]

Means for Solving the Problems In view of the above-mentioned situation, the present inventors have conducted intensive studies and have found that by reacting inexpensive urea phosphate with a potassium compound in the presence of water, under mild reaction conditions, The present inventors have found that the content of secondary components that adversely affect the soil such as sulfate groups is kept low and that an advanced chemical fertilizer with improved hygroscopicity is produced at low cost, and the present invention has been completed. Preferably, iron and / or
Alternatively, by reacting a potassium compound with a urea phosphate containing aluminum, the phosphate of iron and / or aluminum can be uniformly dispersed as an amorphous solid throughout the reaction system, and the above-described effects can be improved. It became possible to increase. Furthermore, the solid fertilizer of the present invention has a nitrogen content of 20% by containing a specific element.
The present invention provides a solid fertilizer which is the above-mentioned advanced chemical fertilizer and whose hygroscopicity is suppressed, which is lighter than liquid fertilizer and contributes to labor saving in fertilization work.

The gist of the present invention resides in a method for producing a fertilizer, comprising reacting a urea phosphate (hereinafter sometimes abbreviated as UP) with a potassium compound in the presence of water. Further, another gist of the present invention is a nitrogen component,
The total of the phosphoric acid component and the potassium component is 50% by weight or more, and the content of iron and / or aluminum is 0.01%.
-10% by weight of a solid fertilizer, particularly a solid fertilizer characterized in that a nitrogen component is 20% by weight or more. still,
In the present invention, regarding the NPK component ratio (ratio of nitrogen, phosphoric acid, and potassium components) of the fertilizer, each element in the fertilizer is converted into N, P2O5, and K2O, and is expressed as% by weight based on the weight of the fertilizer. I do. For example, when each weight% of the NPK component is 10 weight%, 10-10-10
It is written.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. I: Production Method of Fertilizer In the present invention, NPK is produced by reacting urea phosphate (UP) with a potassium compound in the presence of water.
Manufacture of fertilizer with high components. As the UP used in the present invention, those obtained by any production method such as a method of reacting dry phosphoric acid with urea and a method of reacting wet phosphoric acid with urea can be used. Above all, by using UP obtained by reacting wet phosphoric acid and urea, the fertilizer obtained can be NPK
It becomes a solid fertilizer with high components and low hygroscopicity, such as NPK
The component is preferable in producing a solid advanced chemical fertilizer such as 13-35-25.

In the present invention, the conditions for the reaction between the UP and the potassium compound may be appropriately set. However, in the present invention, since the reaction itself is an exothermic reaction, water is present even without severe conditions such as high temperature and high pressure. The reaction proceeds by causing the reaction, which is industrially advantageous. The reaction conditions are usually 10 to 120 ° C., preferably 40 to 100 ° C., and the reaction time is 2 to 20 minutes, preferably 5 to 10 minutes.
Minutes. The amount of water in the reaction system may be appropriately selected depending on the amount of the UP or potassium compound used, but is usually 0.1 to 80% by weight, preferably 1 to 60% by weight, particularly 2 to 2% by weight.
Preferably, it is in the range of 20% by weight. If the water content is less than 1% by weight, the dry solid UP and the solid potassium compound react violently, and the exothermic reaction may generate ammonia to decompose the UP.
Water may be added to the reaction system by adding each raw material and water separately or by adding each raw material in the form of an aqueous solution or an aqueous slurry. As the urea phosphate to be used, iron and / or aluminum is used in an amount of 0.01 to 20.
It is preferred that the content be contained by weight. For example, iron and / or aluminum may be added in the form of a salt or complex to urea phosphate obtained by reacting orthophosphoric acid and urea, or a desired amount may be added to the reaction raw material. You may. Above all, a method obtained by a reaction between wet phosphoric acid and urea as described below is particularly preferable because iron and / or aluminum in wet phosphoric acid can be used and steps such as addition can be omitted.

In the reaction between UP and a potassium compound,
The form of the raw material used for each reactant may be appropriately selected, such as a solid or a solution. The solution in the present invention includes not only a solution such as a so-called aqueous solution in which a solute is completely dissolved, but also a dispersion or a slurry-like fluid containing a partially undissolved solute. The reaction between the UP and the potassium compound is usually carried out in an aqueous medium, but the following methods (1) to (3) are preferred. (1) A solution of a solid substance filtered from a reaction mixture of wet phosphoric acid and urea is reacted with a solid potassium compound or a solution thereof. (2) A potassium compound solution is added to and reacted with a solid that has been filtered from the reaction mixture of wet phosphoric acid and urea. (3) The solid substance filtered off from the reaction mixture of wet phosphoric acid and urea is reacted by adding a potassium compound solution.

For example, as one of the methods (1), mainly U
A solid substance (hereinafter, may be simply referred to as a solid substance) filtered from a reaction mixture of wet phosphoric acid and urea, which is P, is converted into a solution using water or an alcohol as a solvent, and is reacted with a potassium compound solution. There is a way to make it happen. This method usually uses
The solid is preferably used as an aqueous solution or an aqueous slurry, and the potassium compound is preferably used as an aqueous solution. Particularly, a solid material is preferable because the reaction proceeds promptly by using an aqueous slurry. According to this method, a large amount of a solvent, preferably water, is present in the reaction system. Therefore, a solid fertilizer can be easily produced by directly spray-drying the reaction product. At this time, it is preferable that the potassium compound solution is slowly added by dropping or the like.

As another method (1), there is a method of reacting a solid solution with a solid potassium compound. In this method, the amount of the solvent, preferably water, present in the reaction system is smaller than that of the above-mentioned method, and the concentration of the fertilizer in the product is high, for example, a viscous gel is obtained.
Therefore, when the solid fertilizer is obtained by drying the solid fertilizer, the solid fertilizer can be easily obtained by means such as a thin film and drying. As still another method, there is a method in which a solid is reacted with a potassium compound solution as it is, as in (2) and (3). In this method, the potassium compound is usually preferably used as an aqueous solution. In this method, the solvent in the reaction system, preferably water, is low as in the previous reaction method, and the concentration of the fertilizer component in the product is high. For example, a viscous gel or a mass with less water is obtained as a mass. . Therefore, drying may not be necessary in this method, but when drying to obtain solid fertilizer,
The same method as described above may be used.

In these methods, (2) a method in which a potassium compound solution is reacted with a solid substance by dropping or the like;
(3) There is a method in which a solid is added to the potassium compound solution to cause a reaction, but UP is less likely to be decomposed due to reaction heat, and the method in (2) is more preferable. Is preferably added little by little. In the present invention, as the wet phosphoric acid, those obtained by a general method such as that obtained by decomposing phosphate rock with sulfuric acid or a mixed acid of sulfuric phosphoric acid can be used, and the production method of urea is also arbitrary. The amount ratio of the wet phosphoric acid to urea is usually 0.1 to 2 mol, preferably 0.5 to 1.5 mol, particularly 0.8 to 1.5 mol per 1 mol of wet phosphoric acid. preferable. The reaction time is usually from 1 to 30 minutes, and it is preferable to carry out the reaction while adjusting the reaction temperature to the urea decomposition temperature or lower.
If the amount of urea is 0.1 mol or less, the reaction rate may be reduced. If the amount of urea is 1.5 mol or more, urea unreacted with phosphoric acid migrates to the mother liquor when the generated UP is filtered out as described later. ,
Yield may deteriorate. The form of urea used for the reaction is arbitrary such as solid, aqueous solution or slurry, but it is preferable to directly react the slurry or solid urea with wet phosphoric acid to shorten the reaction time. When urea is used as a liquid, the reaction time may take 10 minutes or more. When a slurry is used, the reaction time may be 1 to 5 minutes. When solid urea is directly reacted with wet phosphoric acid, the reaction time may be 1 minute.
Minutes or less. In addition, it is preferable to use solid urea from the viewpoint of reducing the amount of mother liquor when filtering generated UP as described later.

[0015] The obtained UP is obtained by filtering the mother liquor. At the time of this filtration, secondary components of fertilizer such as sulfate groups can be separated together with the mother liquor. Next, in the present invention, the UP obtained by the above method is reacted with a potassium compound in the presence of water to produce a fertilizer. As the potassium compound used in the present invention, any potassium compound can be used, for example, potassium alkoxides such as potassium hydroxide, potassium methoxide and potassium ethoxide, potassium carbonate such as potassium carbonate, potassium hydrogen carbonate, potassium chloride and potassium sulfate. And the like. Among them, potassium carbonate, potassium bicarbonate, and potassium hydroxide are preferable. Particularly, potassium hydroxide has a high reaction rate and the reaction proceeds with a small amount of use, and the resulting fertilizer is effective for plants and has little adverse effect on soil. Is preferred.

The amount of the potassium compound used is usually UP
0.1 to 2.0 mol, especially 0.5 to 1.5 mol, in terms of the molar ratio of potassium in the potassium compound to 1.0 mol.
Mol, particularly preferably 0.8 to 1.2 mol.
If it is less than 0.1 mol, the resulting product may not be solid (or gel-like) and may not be suitable for producing solid fertilizer. If the amount exceeds 2.0 mol, the product may not be solid (or gel-like) but may be a brown liquid. In addition, these liquid products can be used as a raw material of liquid fertilizer (liquid fertilizer).

In the present invention, an advanced chemical fertilizer having a higher NPK component can be produced by further adding a nitrogen component to the fertilizer obtained by the above-described method. For example, by adding a nitrogen component to a product obtained by the above-described reaction of the UP with the potassium compound, preferably a viscous gel or lump product and drying the product, the NPK component is higher and the desired The solid fertilizer having a nitrogen component ratio can be produced. The nitrogen component to be added may be appropriately selected from conventionally known ones. For example, urea, dicyandiamide, ureaform, oxamide, I
BDU (registered trademark), clotomilidene urea (2-oxo-4-methyl-6-ureidohexahydropyrimidine), guanylurea, guanidine, urea-Z, glycoluril, furfural urea compounds, cyanuric acid, ammelide, ammeline , Melamine compounds, triazone compounds and the like. Among them, urea, dicyandiamide, guanidine, ammelide, melamine compounds, and triazone compounds are preferable in order to obtain a solid fertilizer having a nitrogen component of 20% or more in the finally obtained advanced chemical solid fertilizer. Furthermore, urea, dicyandiamide, and guanidine are preferable in view of the fertilizer surface of the solid fertilizer.

The state of the nitrogen component to be added may be appropriately selected. The nitrogen component is used as a solid core material such as a granular tablet, a tableting tablet by extrusion, or a powder, and is obtained by a reaction between UP and a potassium compound. It is preferable to coat with a solid material, preferably a viscous gel or lump solid material. The fertilizer thus obtained is, for example, when the nitrogen component to be added is a quick-acting nitrogen component such as urea,
It is preferable because the fertilizing effect can be controlled and the advanced chemical solid fertilizer can be slowed down. The amount and film thickness of the coating at the time of coating may be appropriately adjusted by a known method according to the desired performance of the fertilizer. Further, in addition to the nitrogen component, polyphosphorus, polyanthracene, dianthine, etc. may be added as a phosphorus component.

II: Solid Fertilizer The solid fertilizer of the present invention contains 50% by weight or more of NPK component and 0.01 to 10% by weight of iron and / or aluminum.
, Especially a solid fertilizer characterized in that the nitrogen component is 20% by weight or more. The solid fertilizer of the present invention contains iron and / or aluminum in the solid fertilizer in an amount of 0.01%.
By adding up to 10% by weight, it is possible to solidify the fertilizer while it is an advanced chemical fertilizer, and to solve the problem of hygroscopicity which was a problem of the conventional advanced chemical fertilizer, to have excellent disintegration in water, and to further improve NPK. 20 nitrogen components
It is an excellent solid fertilizer that could be improved to more than weight%. The iron and / or aluminum content in the solid fertilizer is 0.01 to 10% by weight, and especially 0.01 to 10% by weight.
It is preferably contained in an amount of 3.0% by weight, more preferably 0.01 to 2.5% by weight, particularly preferably 0.02 to 1.5% by weight.
If it is less than 0.01% by weight, the hygroscopicity of the solid fertilizer increases, and if it exceeds 10% by weight, the solid fertilizer becomes powdery and is not economical. In the present invention, either iron or aluminum is contained in 0.01 to 10%.
% By weight, but preferably contains iron and aluminum, and the weight ratio is from 1: 9 to 9:
1, more preferably from 4: 6 to 6: 4. The method for producing the solid fertilizer of the present invention is optional, and any conventionally known method may be used. For example, iron and / or aluminum may be added to the raw materials as a compound such as a salt or a complex. It is preferred to be manufactured by the method described in (I). This is to produce a fertilizer by chemically reacting the raw material, iron and / or aluminum in the fertilizer takes the form of a salt such as phosphate, which is an amorphous solid,
This is because the solid fertilizer has excellent effects of solidifying, reducing hygroscopicity, and disintegrating in water.

[0020]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the present invention is limited to the following Examples without departing from the scope of the invention.

Example 1 A wet method containing 44.1% by weight of a phosphoric acid component as P ₂ O ₅ , 0.29% by weight of Al, and 0.26% by weight of Fe (all converted to atomic weight%) 87 g of a 55% aqueous urea solution was added to 161 g of phosphoric acid, and the mixture was stirred for 3 to 10 minutes.
Thus, 76 g of urea phosphate (UP) crystals and 172 g of mother liquor were obtained. The slurry was filtered under reduced pressure to separate crystals and mother liquor. To this total amount of crystals, 159 g of a 52% saturated solution of UP prepared in a similar manner in a separate system was added, and
A new slurry was made. While stirring the slurry, 120 g of a 56% aqueous solution of potassium hydroxide was dropped in over 5 minutes to cause a reaction, and about 355 g of a water-containing gel-like substance was reacted.
I got The reaction temperature was 95 ° C. at the highest temperature.

The gel material is dried at 50 ° C. for about 8 hours, and the NPK component ratio is 13-35-25, and Al is 0.03%.
A solid fertilizer containing 1% by weight and 0.032% by weight of Fe was obtained. The solid fertilizer after drying was 196 g. Similarly, after obtaining 355 g of a gel-like substance, 56 g of solid urea was mixed and stirred with this gel-like substance, and dried at 50 ° C. for about 8 hours, whereby the NPK component was 20-27-19 and the Al content was 0.0%.
252 g of a solid fertilizer containing 17% by weight and 0.018% by weight of Fe were obtained. This solid fertilizer is heated at 23 ° C and 80% RH.
Was left in the incubator for 19 hours, and the amount of increase in water due to moisture absorption was measured. As a result, the rate of weight increase of the solid fertilizer of the present invention was 49%, and the rate of weight increase due to moisture absorption was low.

Example 2 To 161 g of wet phosphoric acid used in Example 1 was added 60 g of powdery solid urea, and the mixture was stirred.
132 g of UP having a PK component ratio of 17-44-0 and mother liquor 89
g was obtained. This UP was filtered under reduced pressure, and 5.
After adding 6 g of water, 56 g of a 56% aqueous solution of potassium hydroxide was added with stirring to obtain about 193.5 g of a water-containing gel-like substance. Solid urea 56
g was mixed and stirred, and dried at 50 ° C. for about 8 hours. The NPK component ratio was 22-27-16, and Al was 0.02%.
250 g of a solid fertilizer containing 0% by weight and 0.021% by weight of Fe were obtained. When a moisture absorption test was performed on this solid fertilizer in the same manner as in Example 1, the weight increase rate was 51%.

Example 3 The reaction was carried out in the same manner as in Example 1 to obtain 355 g of a water-containing gel-like substance. 74 g of solid urea and 10 g of solid dicyandiamide were mixed and stirred, and dried at 50 ° C. for about 8 hours. As a result, 280 g of a solid fertilizer having an NPK component ratio of 23-24-17 and containing 0.014% by weight of Al and 0.014% by weight of Fe was obtained. When a moisture absorption test was performed on this solid fertilizer in the same manner as in Example 1, the weight increase rate was 54%.

[Comparative Example 1] When solid potassium hydroxide was similarly added to the UP obtained in the same manner as in Example 1 without adding any water, the mixture reacted violently and smelled ammonia. And the obtained product was a brown liquid.

Comparative Example 2 A moisture absorption test was conducted in the same manner as in Example 1 using 1 g of urea powder (a product having passed through a 710 μm mesh). As a result, the weight increase rate of urea was 73%.

Comparative Example 3 21% urea, 2 potassium chloride
A moisture absorption test was carried out in the same manner as in Example 1 using 1 g of a solid fertilizer containing 8% and having an NPK component ratio of 16-16-16 (a product passed through a 710 μm mesh). As a result, the weight increase rate of this solid fertilizer was 98%. The results of these Examples and Comparative Examples are summarized in Tables 1 and 2 below.

[0028]

[Table 1]

[0029]

[Table 2]

*: The NPK ratio was expressed as NP ₂ O ₅ -K ₂ O (% by weight). As is clear from Tables 1 and 2, the method for producing a fertilizer of the present invention can be used efficiently as a component of a fertilizer without decomposition of raw materials in the production process, and the fertilizer of the product is also solid. Thus, a high NPK component of 60% or more can be obtained.

Example 4 A urea phosphate was reacted with an aqueous solution of potassium hydroxide in the same manner as in Example 1, and the obtained gel was dried at 50 ° C. for about 8 hours to obtain a substance (N
PK component ratio: 13-35-25: 0.031% by weight of Al and 0.032% by weight of Fe. That is, the content of each element in terms of phosphate is 0.14% by weight and 0.14% by weight, respectively). The solution is left in a desiccator at 30 ° C. and 70% RH for 800 hours to increase the water content by moisture absorption. The amount was measured. As a result, the weight increase rate was 35.0%.

Example 5 AlPO ₄ was added to a phosphoric acid aqueous solution containing 71.0% by weight of a phosphoric acid component as P ₂ O _{5 in an amount} of 0.02%.
15 g of solid urea was added to a mixture (7 g) containing 7 wt% and 0.07 wt% of FePO ₄ .nH ₂ O, and the mixture was stirred for 3 to 10 minutes. Then, 30 g of a 56% aqueous potassium hydroxide solution was added for 3 minutes. The reaction was carried out by dropping the gel-like substance 8
2 g were obtained. This material was dried at 50 ° C. for 8 hours and dried in Example 4.
When the same hygroscopicity evaluation was performed, the weight increase rate was 4
2.7%.

Example 6 The same phosphoric acid as in Example 5 was added to Al
0.14% by weight of PO ₄ and FePO ₄ .nH ₂ O
Was added to 0.14% by weight (37 g) of Example 5 and
In the same manner as in the above, solid urea and an aqueous solution of potassium hydroxide were reacted and dried, and the hygroscopicity was evaluated. As a result, the weight increase rate was 35.0%.

Example 7 0.28% by weight of AlPO ₄
A gel-like substance was obtained in the same manner as in Example 5 except that the amount of FePO ₄ .nH ₂ O was changed to 0.28 and the hygroscopicity was evaluated. As a result, the weight increase rate was 38.2%.

Example 8 A gel-like substance was obtained in the same manner as in Example 5 except that AlPO ₄ was 0.7% by weight and FePO ₄ .nH ₂ O was 0.7% by weight, and the hygroscopicity was evaluated. As a result, the rate of weight increase was 40.0%.

Example 9 37 g of phosphoric acid as in Example 5
In the same manner as in Example 5, solid urea and an aqueous solution of potassium hydroxide were reacted and dried to evaluate the hygroscopicity. As a result, the rate of weight increase was 46.0%. As is clear from Examples 4 to 9, the fertilizer obtained by the production method of the present invention and the fertilizer of the present invention are excellent in moisture absorption resistance, and in particular, by containing iron and / or aluminum, more excellent resistance. Shows hygroscopicity.

[0037]

According to the method for producing a fertilizer component of the present invention, by reacting an inexpensive UP with a potassium compound in the presence of water, the production cost can be reduced without pressurizing or heating, and the production of sulfates and the like can be suppressed. This makes it possible to produce a high-component fertilizer that does not contain sub-components. In addition, the raw material can be effectively used as a fertilizer component without the raw material being decomposed during the manufacturing process.
It is an excellent manufacturing method. Further, by adding a nitrogen component, it is possible to produce a solid fertilizer component having an NPK component of 50% or more, in which the nitrogen component is adjusted to 20% or more, or the fertilizing effect of nitrogen is adjusted. The solid fertilizer of the present invention is a solid fertilizer containing a specific amount of iron and / or aluminum, which is a highly chemical fertilizer while solidifying, reducing moisture absorption, and being excellent in disintegration in water.

Claims (15)

[Claims] 1. A method for producing a fertilizer, comprising reacting a urea phosphate with a potassium compound in the presence of water. 2. The method according to claim 1, wherein the urea phosphate contains 0.01 to 20% by weight of iron and / or aluminum. 3. The production method according to claim 1, wherein the urea phosphate is obtained by reacting wet phosphoric acid with urea. 4. The method according to claim 3, wherein the urea is solid urea. 5. The reaction between a urea phosphate and a potassium compound is a reaction between a solid substance filtered from a reaction mixture of wet phosphoric acid and urea and a potassium compound solution,
The method according to any one of claims 1 to 4, wherein the method is performed by any one of the following methods (1) to (3). (1) A solution of a solid substance filtered from a reaction mixture of wet phosphoric acid and urea is reacted with a solid potassium compound or a solution thereof. (2) A potassium compound solution is added to and reacted with a solid that has been filtered from the reaction mixture of wet phosphoric acid and urea. (3) A solid substance filtered from a reaction mixture of wet phosphoric acid and urea is added to a potassium compound solution and reacted. 6. The method according to claim 5, wherein the solid solution is in the form of a slurry. 7. The process according to claim 1, wherein the molar ratio of urea phosphate to potassium is 1: 0.5 to 1: 1.5. 8. The water content in the reaction system is 0.5 to 60% by weight.
The method according to any one of claims 1 to 7, wherein 9. The method according to claim 1, wherein the potassium compound is selected from the group consisting of potassium hydroxide, potassium alkoxide and potassium salt. 10. A method for producing a fertilizer, further comprising adding a nitrogen component to the fertilizer obtained by the method according to any one of claims 1 to 9. 11. The method according to claim 10, wherein the nitrogen component is urea, dicyandiamide or guanidine. 12. The method according to claim 10, wherein a nitrogen component is used as a core material, and the core material is coated with a fertilizer. 13. The method according to claim 1, wherein the fertilizer is a solid fertilizer. 14. A solid fertilizer containing a nitrogen component, a phosphoric acid component and a potassium component in a total amount of 50% by weight or more and containing 0.01 to 10% by weight of iron and / or aluminum. 15. The solid fertilizer according to claim 14, wherein the total nitrogen component is 20% by weight or more.