JP7200960B2 - Granular fertilizer and method for producing granular fertilizer - Google Patents

Description

The present invention relates to a granular fertilizer composed of nitrogenous fertilizer components and trace fertilizer components such as copper sulfate, zinc sulfate, manganese sulfate, iron sulfate and nickel sulfate as main raw materials, and a method for producing the same.

For the normal growth of crops, in addition to the major elements such as nitrogen, phosphorus and potassium, medium abundance elements such as magnesium and trace elements such as copper, zinc, manganese, iron and nickel are required as fertilizers. It is necessary to fertilize the soil with an appropriate amount of such fertilizer elements.

In particular, trace elements in the soil tend to be deficient, but simply adding trace elements alone and fertilizing tends to be excessive, and the actual situation is that the problem cannot be solved.
Therefore, foliar application is carried out to provide liquid fertilizer containing trace elements. However, foliar spraying in large-scale farmland is labor intensive and inefficient, and there is a need for a granular fertilizer containing an appropriate amount of trace elements in grains that can be applied mechanically.

On the other hand, in general, granular fertilizer containing an appropriate amount of trace elements tends to have low grain hardness and is difficult to granulate. In addition, when the grain hardness is low, there is a problem that the grain tends to be pulverized during storage, so granulation by adding substances other than nitrogen fertilizer elements is being studied.

For example, Non-Patent Document 1 proposes a compound fertilizer containing ammonium sulfate and magnesium sulfate in addition to trace fertilizer components such as 0.6% by weight of manganese sulfate. In addition, in Patent Document 1, a granular fertilizer composition having a multi-layer structure in which phosphate particles are used as a base, the particles are coated with a nitrogen fertilizer component such as urea or ammonium sulfate, and the coating is further coated with a trace fertilizer component to cover the coating. things are proposed.

Safety data sheet onodakagaku-14

Japanese Patent Publication No. 2013-521213

Granular fertilizer containing an appropriate amount of trace fertilizer components in grains is required not to cause deficiency of nutrients of the trace fertilizer components in the soil and to have good dissolution properties of the trace fertilizer components after spraying.
Furthermore, in order to prevent the generation of dust and clogging of the flow path in the machine during spraying, the granular fertilizer is required to have a high hardness and be difficult to pulverize, and not to cause caking during storage. Furthermore, it is also required that the particle size is uniform and the bulk density is high so that there is little variation in the flight distance when sprayed, and that it settles and lands on the soil immediately after landing on the water in paddy fields or the like.

However, the granular fertilizer described in Non-Patent Document 1 contains 20 to 25% by weight of other components other than the fertilizer component with respect to the total weight of the granular fertilizer, and the fertilizer is manufactured using a large amount of liquid binder. Since the granules are granulated while dissolving the ingredients, there are problems that the weight ratio of the fertilizer ingredients contained in the granular fertilizer becomes uneven, and trace amounts of fertilizer ingredients remain undissolved in the soil.

In addition, the granular fertilizer composition described in Patent Document 1 has a problem of being immobilized in the soil before being absorbed by crops because it is applied together with phosphate.

Therefore, in view of these problems of the prior art, the present invention provides a granular fertilizer that can be uniformly sprayed with trace fertilizer components without depleting the nutrients of the trace fertilizer components in the soil, and has good dissolution after spraying. The task is to provide fertilizer. Another object of the present invention is to provide a granular fertilizer that can improve the fertilizer yield after production because of its high grain hardness, and that is less likely to be pulverized and less likely to caking during storage of the fertilizer.

That is, the present invention mainly has the following configurations.

Particles (particles A) substantially composed of a nitrogen fertilizer component and particles (particles B) substantially composed of at least one trace fertilizer component selected from copper sulfate, zinc sulfate, manganese sulfate, iron sulfate, and nickel sulfate are integrated. The granular fertilizer that is formed into secondary particles by liquefaction, and the particles (particles A') that are substantially composed of the nitrogen fertilizer component in the granular fertilizer have a particle size of more than 0.1 mm and the proportion of particles of 1 mm or less is the granular fertilizer occupies 50% or more of the particles A' in the granular fertilizer, and the particle B' in the granular fertilizer has a particle size of more than 0.1 mm, and the proportion of particles of 1 mm or less is copper sulfate, zinc sulfate, manganese sulfate, iron sulfate, sulfuric acid At least 60% of the particles (particles B′) substantially composed of at least one trace fertilizer component selected from nickel, and the nitrogen content in the granular fertilizer measured by the combustion method is 13.5 to 45.0% A granular fertilizer, characterized in that the content of at least one metal selected from copper, zinc, manganese, iron and nickel in the granular fertilizer measured by an atomic absorption method is 0.3 to 5.0%.

Particles (particles A) substantially composed of a nitrogen fertilizer component and particles (particles B) substantially composed of at least one trace fertilizer component selected from copper sulfate, zinc sulfate, manganese sulfate, iron sulfate, and nickel sulfate A method for producing a granular fertilizer that integrates to form secondary particles, wherein particles A having a particle size of more than 1 mm and 2 mm or less account for 10% by weight or more and 90% by weight or less of particles A, Particles B having a particle size of more than 1 mm and 2 mm or less account for 10% by weight or more and 40% by weight or less of particles B, and the amount of particles A is 85.0 to 98% with respect to the total weight of the granular fertilizer. A step of mixing 8 parts by weight, 1.2 to 15.0 parts by weight of particles B, and 0 to 4.0 parts by weight of water to obtain a mixture, and molding the mixture to form secondary particles. A method for producing a granular fertilizer, comprising a step of

EFFECTS OF THE INVENTION According to the present invention, it is possible to obtain a granular fertilizer in which the nutrients of the trace fertilizer components are not deficient in the soil, and the trace fertilizer components can be uniformly sprayed, and the elution property after spraying is good. Moreover, since it has a high grain hardness, the fertilizer yield after production can be improved. Furthermore, it is possible to obtain a granular fertilizer that is less likely to be pulverized and less likely to caking during storage of the fertilizer.

Hereinafter, the present invention will be described in detail together with embodiments.

<Particles (particles A) consisting essentially of nitrogen fertilizer components>
Particles A are particles consisting essentially of nitrogenous fertilizer components. Here, "substantially" means that the nitrogen fertilizer component content in the particles A is 90% by weight or more on average with respect to the weight of the particles A. The proportion of the particles A containing the nitrogen fertilizer component is preferably 95% by weight or more, more preferably 98% by weight or more, and most preferably 100% by weight.

The nitrogen fertilizer component used in the present invention is not particularly limited, and any component, including known ones, that acts as a nutrient for the nitrogen content of plants can be used. Specific examples of such nitrogenous fertilizer components include ammonium sulfate, ammonium chloride, ammonium nitrate, diammonium phosphate, and urea. Among these, ammonium sulfate is particularly preferable because it is excellent in dissolution and grain hardness when made into a granular fertilizer.

The particles A can be obtained by, for example, crystallization by crystallization. When the nitrogen fertilizer component in the particles A is ammonium sulfate, the particles A are, for example, an ammonium sulfate aqueous solution obtained by contacting coke oven waste gas with sulfuric acid, or in the production of caprolactam, by adding ammonia to caprolactam sulfate. After obtaining the resulting caprolactam and ammonium sulfate mixed solution, ammonium sulfate can be crystallized from the ammonium sulfate aqueous solution obtained by separating the caprolactam aqueous solution and the ammonium sulfate aqueous solution, which can be used as fine crystalline ammonium sulfate. Separation of crystals and mother liquor can be carried out by a known method. For example, it is obtained by drying after separating from the liquid by centrifugation. If the degree of supersaturation is too high during crystallization, the crystals of the fine-grain ammonium sulfate agglomerate abruptly and take in the mother liquor, resulting in a large particle size, a high water content, and a large amount of impurities. By precipitating, it is possible to obtain fine-grained crystalline ammonium sulfate having crystal orientation and high crystallinity. The degree of crystallinity can be measured by performing two-dimensional X-ray diffraction, and the degree of orientation obtained from the measurement results is preferably 0.995 or more. More preferably, the degree of orientation is 0.997 or more, and the degree of orientation of 1.0 is the highest crystallinity, and is most preferred. The proportion of fine-grain crystalline ammonium sulfate containing ammonium sulfate is preferably 95% by weight or more, and when it is 98% by weight or more, the fine-grain crystalline ammonium sulfate has high crystallinity, which is most preferable. The degree of orientation is an index that indicates the degree of alignment of crystals. ).
Degree of orientation = (180-orientation peak half width)/180 (1)

The content of ammoniacal nitrogen in the fine crystal ammonium sulfate is preferably 20.5% or more, more preferably 21.0% or more, from the viewpoint of the fertilizer effect as a nitrogen source per unit weight. The content of ammoniacal nitrogen in fine-grained ammonium sulfate is a value measured by a combustion method according to the Test Methods for Fertilizers (2019).

When the nitrogen fertilizer component in the particles A is urea, the particles A are prepared by, for example, reacting ammonia and carbon dioxide as raw materials under high-temperature and high-pressure conditions to form a urea-containing solution, and rectifying and drying the urea-containing solution. A prilled urea obtained by The nitrogen content in the prilled urea is preferably 45% or more, more preferably 46% or more, from the viewpoint of the fertilizer effect as a nitrogen source per unit weight. The nitrogen content in prilled urea is a value measured by a combustion method according to the Test Methods for Fertilizers (2019).

In the particles A used for producing the granular fertilizer of the present invention, particles having a particle size of more than 1 mm and 2 mm or less account for 10% by weight or more and 90% by weight or less of the entire particles A. Preferably, particles with a particle size of more than 1 mm and 2 mm or less account for 20% by weight or more and 90% by weight or less of the total particles A, and more preferably particles with a particle size of more than 1 mm and 2 mm or less account for 30% by weight of the total particles A. % or more and 90% by weight or less. If the particle size exceeds 2 mm, classification occurs during mixing, leading to a decrease in component uniformity, and the contact area between the particles is small during granulation, making it difficult to granulate. A decrease in grain hardness occurs due to a decrease in the proportion of the component. When particles having a particle size of 1 mm or less are contained in a large amount, the bulk density of the particles A is lowered, making it difficult to granulate, and the utilization efficiency of raw materials is lowered. The particle size and amount of the particles A can be obtained by classifying them with a sieve (for example, 9-mesh mesh = 2.0 mm, 16-mesh mesh = 1.0 mm).

The bulk density of the particles A used for producing the granular fertilizer of the present invention is preferably 0.90 g/ml or more and 1.1 g/ml or less. In order to prevent scattering during transportation and increase the granulation yield during granulation, the bulk density is more preferably 0.93 g/ml or more and 1.1 g/ml or less, more preferably 0.96 g/ml. It is more preferable that it is more than or equal to 1.1 g/ml or less. The bulk density of the particles A is measured according to "JIS R 1628:1997 Method for measuring bulk density of fine ceramic powder".

The moisture content of the particles A used for producing the granular fertilizer of the present invention is preferably 5% by weight or less. It is more preferably 4% by weight or less, still more preferably 3% by weight or less. When the particles A are fine crystalline ammonium sulfate, the moisture content is preferably 0.5% by weight or less. It is more preferably 0.4% by weight or less, still more preferably 0.3% by weight or less. In addition, the moisture content of the nitrogen fertilizer component is a value measured by the loss on drying method according to the Test Methods for Fertilizers (2019).

<Particles (Particles B) Substantially Consisting of Trace Fertilizer Components>
Particles B are particles consisting essentially of microfertilizer ingredients. Here, "substantially" means that the content of trace fertilizer components in the particles B is 90% by weight or more on the average with respect to the weight of the particles B. The proportion of the particles B containing the trace fertilizer component is preferably 95% by weight or more, more preferably 98% by weight or more, and most preferably 100% by weight. Such a trace fertilizer component is excellent in terms of handleability when used as a raw material for granular fertilizer, yield of granular fertilizer after production, and elution and grain hardness when made into granular fertilizer. It is at least one selected from copper, zinc sulfate, manganese sulfate, iron sulfate, and nickel sulfate.

The particles B can be obtained by granulating a solute containing trace fertilizer components from a solution containing at least one selected from copper sulfate, zinc sulfate, manganese sulfate, iron sulfate, and nickel sulfate, and separating it from the mother liquor.

When the trace fertilizer component in the particles B is copper sulfate, the particles B are obtained, for example, by refining natural minerals or by a sulfuric acid reaction method in which copper oxide obtained by calcining copper is reacted with dilute sulfuric acid. The content is preferably 15% or more, more preferably 20% or more, and even more preferably 25% or more, from the viewpoint of fertilizer effect as a copper source per unit weight. The copper content of copper sulfate is a value measured by flame atomic absorption spectrometry in accordance with the Test Methods for Fertilizers (2019).

When the trace fertilizer component in the particles B is zinc sulfate, the particles B are obtained, for example, by a sulfuric acid decomposition method in which dilute sulfuric acid is added to a zinc raw material such as zinc or zinc oxide to cause a reaction, and zinc sulfate contains zinc. The ratio is preferably 20% or more, more preferably 30% or more, even more preferably 35% or more, from the viewpoint of fertilizer effect as a zinc source per unit weight. The zinc content of zinc sulfate is a value measured by flame atomic absorption spectrometry in accordance with the Test Methods for Fertilizers (2019).

When the trace fertilizer component in the particles B is manganese sulfate, the particles B are prepared by, for example, mixing pyrolus ore with lime powder or coke and roasting at about 800° C. to obtain manganese monoxide and adding dilute sulfuric acid. The manganese content of manganese sulfate is 20% or more from the viewpoint of the fertilizer effect as a manganese source per unit weight. preferably 25% or more, more preferably 30% or more. The manganese content of manganese sulfate is a value measured by flame atomic absorption spectrometry in accordance with Fertilizer Test Methods (2019).

When the trace fertilizer component in the particles B is iron sulfate, the particles B are obtained, for example, by recovering iron sulfate by-produced when titanium oxide is produced using ilmenite and concentrated sulfuric acid. The iron content of is preferably 15% or more, more preferably 20% or more, even more preferably 25% or more, from the viewpoint of the fertilizer effect as an iron source per unit weight. The iron content of iron sulfate is a value measured by flame atomic absorption spectrometry in accordance with the Test Methods for Fertilizers (2019).

When the minor fertilizer component in the particles B is nickel sulfate, the particles B are obtained, for example, by recovering nickel sulfate that is a by-product of the production of electrolytic nickel, and the nickel content of nickel sulfate is expressed in the unit From the viewpoint of the fertilizer effect as a nickel source per weight, the content is preferably 15% or more, more preferably 20% or more, and even more preferably 25% or more. The nickel content of nickel sulfate is a value measured by flame atomic absorption spectrometry in accordance with the Test Methods for Fertilizers (2019).

It should be noted that such a trace fertilizer component is preferably a hydrous salt from the viewpoint of stability when handled as a raw material and suppression of pulverization when made into a granular fertilizer. Specific examples include copper sulfate hydrate, zinc sulfate hydrate, manganese sulfate hydrate, and iron sulfate hydrate. Among them, copper sulfate pentahydrate, zinc sulfate monohydrate, manganese sulfate monohydrate, ferrous sulfate heptahydrate, and nickel sulfate hexahydrate are preferably used.

In the particles B used for producing the granular fertilizer of the present invention, particles having a particle size of more than 1 mm and 2 mm or less account for 10% by weight or more and 40% by weight or less of the entire particles B. Preferably, particles with a particle size of more than 1 mm and 2 mm or less account for 15% by weight or more and 40% by weight or less of the total particles B, and more preferably particles with a particle size of more than 1 mm and 2 mm or less account for 20% by weight of the total particles B. % or more and 40% by weight or less. If the particle size exceeds 2 mm, classification occurs during mixing, resulting in a decrease in component uniformity, and the contact area between the particles is small during granulation, making it difficult to granulate, resulting in a decrease in grain hardness. When the particle diameter of the particles B is 1 mm or less, the bulk density of the particles B is lowered, making it difficult to granulate, and the utilization efficiency of the raw material is lowered. The particle size and amount of the particles B can be obtained by classifying them with a sieve (for example, 9-mesh mesh = 2.0 mm, 16-mesh mesh = 1.0 mm).

The bulk density of the particles B used for producing the granular fertilizer of the present invention is 0.90 g/ml or more and 1.10 g/ml or less. In order to prevent scattering during transportation and increase the granulation yield during granulation, the bulk density is more preferably 0.93 g/ml or more and 1.10 g/ml or less, more preferably 0.96 g/ml. More preferably, it is 1.10 g/ml or less. The bulk density of the particles B is measured according to "JIS R 1628:1997 Method for measuring bulk density of fine ceramic powder".

<Granular Fertilizer>
The granular fertilizer of the present invention consists essentially of particles (particles A) consisting essentially of nitrogenous fertilizer ingredients and at least one trace fertilizer ingredient selected from copper sulfate, zinc sulfate, manganese sulfate, iron sulfate and nickel sulfate. It is a granular fertilizer in which particles (particles B) are integrated to form secondary particles. In order to obtain such a granular fertilizer, the particles A and B as raw materials are mixed, or the particles A and B are mixed in the presence of water, and the mixture is molded (also called granulation). ). That is, the particles A' and B' are derived from the particles A and B, which are the raw materials of the granular fertilizer, respectively, and the particle size distribution and shape have changed before and after the formation of the granular fertilizer. Particles A' and B' in this granular fertilizer can be discriminated by scanning electron microscope observation-energy dispersive X-ray analysis of the cross section of the granular fertilizer.

Particles A and B as raw materials, and particles A' and B' in the granular fertilizer may be pulverized with a pulverizer before mixing to obtain preferred particle sizes. The type of pulverizer is not particularly limited, and pulverizers such as pin mills, hammer mills, and ball mills can be used, but pin mills are preferably used because the grain size of the pulverized particles can be easily controlled.

Particles A and B are pulverized with a pulverizer as necessary to obtain a preferred particle size, and then mixed with particles A and B with a mixer, or the particles A and B are mixed in the presence of water. By sequentially performing mixing, granulation, pulverization, sizing, and classification, it is possible to obtain a granular fertilizer having a hardness, bulk density, and shape suitable for a fertilizer.

Components other than the particles A and B may be used as long as they do not deviate from the gist of the present invention or impair the purpose. For example, there are other nutrients that have a fertilizing effect, substances that improve shape retention such as binders, and additives such as inorganic fillers and organic fillers.

The method of mixing particles A and particles B is not particularly limited to the type of mixer as long as it can be uniformly mixed, and may be a horizontal cylinder type, V type, double cone type, etc. container rotation type mixer, ribbon type, screw type, Although a fixed container type mixer such as a paddle type can be used, a paddle type mixer is preferably used because continuous processing is possible. The mixing time is preferably 2 minutes or more and 15 minutes or less, more preferably 5 minutes or more and 10 minutes or less. If the mixing time is shorter than 2 minutes, the particles A and B will not be uniformly dispersed in the mixture, and the particles will be uneven when granulated. If the mixing time exceeds 15 minutes, it is economically disadvantageous because the capacity of the mixer is increased in the continuous production of fertilizer.

Water may be present when the particles A and B are mixed. The amount of water is preferably 0 to 4.0 parts by weight when the total weight of the particles A and B is 100 parts by weight. More preferably 0 to 3.0 parts by weight, still more preferably 0 to 2.0 parts by weight. If the amount of water to be present exceeds 4.0 parts by weight and is high, when the mixture is discharged from the mixer and conveyed to the granulator, the amount of adhesion to the equipment increases and the yield decreases, and the granular fertilizer The caking property may deteriorate during storage.

As a molding method, a known method can be used, but compression granulation is preferable, and the compression granulation apparatus may be any of a tablet method, a plate-like method, and a briquette method, but the tablet method has low production efficiency. The briquette method is preferable because it is difficult to mass-produce granular fertilizer due to its low density, and it is difficult to produce spherical granular fertilizer with less burrs using the plate method. As a briquette-type compression granulator, for example, Briquette (registered trademark) BSS type (manufactured by Shinto Kogyo Co., Ltd.) can be preferably used.

There are particular restrictions on the method of supplying a mixture of particles A and B or a mixture of particles A and B in the presence of water (these are also referred to as granulation raw materials) to a compression granulator. However, for example, the mixture is stored in a hopper and supplied directly to the granulator from a conveyor attached to the hopper, or supplied from the hopper conveyor to the granulator via a belt conveyor, bucket conveyor, etc. can be done.

The granulation pressure indicates a value (linear pressure) obtained by dividing the total load applied to the granulated raw material by the effective width, and the effective width indicates the major diameter on the compressor side of the portion where the load is applied to the granulated raw material. For example, in the tablet method, the effective width is the major diameter of the tablet portion, and in the briquette method using rollers, the effective width is the length of the portion where the granulated raw material is compressed by the rollers. Granulation pressure is preferably in the range of 6.0 kN/cm or more and 30.0 kN/cm or less. It is more preferably 7.0 kN/cm or more and 30.0 kN/cm or less, and still more preferably 8.0 kN/cm or more and 30.0 kN/cm or less. When the granulation pressure is less than 6.0 kN/cm, granulation itself of the granulation raw material tends not to occur due to insufficient pressure. If the granulation pressure exceeds 30.0 kN/cm, cracks may occur in the granules obtained due to the excessive pressure, or an excessive load is applied to the compression granulator, resulting in a significant reduction in the life of the device. There is a tendency.

The rotation speed of the granulation roller is the rotation speed of the roller in the briquette method and the plate-like method in which compression granulation is performed using a roller, and is preferably 40 rpm or more. It is more preferably 50 rpm or more, and still more preferably 60 rpm or more. If the rotation speed of the granulation roller is less than 40 rpm, the granulation pressure on the raw material increases, which may cause cracks in the granules and decrease the production amount.

The burr thickness of the compression granulator indicates the shortest diameter of the granulated raw material at the portion where the load is applied to the granulated raw material. For example, in the tablet method, the burr thickness is the short diameter of the tablet portion, and in the briquette method using a roller, the burr thickness is the length of the plate-like portion of the granulated product obtained by granulation. be. The burr thickness is preferably in the range of 1.0 mm or more and 2.5 mm or less, and more preferably in the range of 1.2 mm or more and 2.0 mm or less. When the burr thickness is less than 1.2 mm, both the crushing strength and the yield of the granular fertilizer tend to decrease. If the burr thickness exceeds 2.0 mm, the shape of the granular fertilizer becomes unsuitable for fertilizer application, and the granulated granular fertilizer is crushed, for example, by a vibration sieve using a crushing ball to make the particle size uniform. In that case, it is not preferable because it causes clogging of the sieve.

In order to obtain a granular fertilizer with less burrs, high crushing strength, less dust generation, and less caking, the raw material is granulated using a compression granulator, and after compression granulation using a crusher, Preferably, the granules are pulverized, the granules are sized using a spheroidizer, and the sized granular fertilizer is classified using a classifier. There are no restrictions on the method of transporting the granular fertilizer in each process, but it is possible to use gravity, conveyer, or air blowing. A method of transporting to a crusher/spheroidizer/classifier is preferred. It is preferable to use a material having corrosion resistance to granular fertilizers, such as SUS316L or resin, for the powder-contacting parts of equipment including these transportation equipment.

A granular fertilizer granulated by a compression granulator can be crushed, sized and classified to obtain a granular fertilizer having hardness, bulk density and shape suitable for fertilizer.

In order to obtain a granular fertilizer with a uniform particle size, it is preferable to crush the compressed granulated granular fertilizer using a crusher. The type of crusher is not particularly limited, and for example, various crushers such as jaw crushers and roll crushers, various mills such as roller mills and cutting mills, and vibrating sieves containing crushing media are preferably used. It is also possible to use these crushers in combination.

In order to obtain a granular fertilizer with a spherical shape and less burrs, it is preferable to use a granule regulating machine. There are no particular restrictions on the type of grain sizer, and for example, a high-speed rolling method, an oscillator type, a crushing method, a centrifugal rotation method, etc. are preferably used. Dalton) is more preferable for sizing the granular fertilizer.

The treatment time of the grain sizer is preferably in the range of 0.2 to 5.0 minutes, more preferably in the range of 0.3 to 3.0 minutes. If the processing time of the granule sizing machine becomes shorter than the above, burr removal from the granular fertilizer becomes insufficient. If the processing time of the granule regulating machine is longer than the above, the amount of parts other than burrs that are cut increases, and the yield of granular fertilizer decreases. Furthermore, since the time required for sizing treatment increases, the yield of granular fertilizer per unit time also decreases.

The rotation speed of the grain size regulator is preferably in the range of 50 to 2000 rpm, more preferably in the range of 100 to 1500 rpm. If the rotational speed of the granule regulating machine is lower than the above range, burr removal from the granular fertilizer becomes insufficient, and more time is required for the granulation treatment, resulting in a decrease in the yield of granular fertilizer per unit time. If the rotation speed of the grain sizer exceeds the above range, problems such as an increase in noise and a reduction in equipment life will occur.

In order to obtain granular fertilizer having a predetermined particle size or larger, it is desirable to classify the granular fertilizer using a classifier. The type of classifier is not particularly limited as long as dry classification is possible, but it is preferable to use a vibrating sieve. The mesh size of the sieve is not particularly limited as long as it is a size that allows a predetermined particle size to be obtained. A classification method in which sieves having mesh openings are combined to obtain granular fertilizer having a particle size of 2.0 to 4.0 mm is preferred.

In the granular fertilizer of the present invention, particles A' have a particle size of more than 0.1 mm, particles of 1 mm or less account for 50% or more of the particles A', and particles B' have a particle size of 0.1 mm. and particles of 1 mm or less account for 60% or more of the particles B', and the nitrogen content measured by the combustion method is 13.5 to 45.0%, the copper, zinc, manganese measured by the atomic absorption method, The content of at least one metal selected from iron and nickel is 0.3 to 5.0%. Preferably, the granular fertilizer has a nitrogen content measured by a combustion method of 16.0 to 25.0%, and a metal content of at least one selected from copper, zinc, manganese, iron and nickel measured by an atomic absorption method. is 0.7 to 4.0%, more preferably nitrogen content measured by combustion method is 18.0 to 20.0%, copper, zinc, manganese, iron measured by atomic absorption method, The content of at least one metal selected from nickel is 1.0 to 3.0%. When the nitrogen content measured by the combustion method is less than 13.5% and the content of at least one metal selected from copper, zinc, manganese, iron and nickel measured by the atomic absorption method is more than 5.0%, Since the ratio of trace fertilizer components is large, it is likely to cause a local increase in concentration in the soil after application. In addition, the grain hardness decreases, making it easier to pulverize. If the nitrogen content measured by the combustion method exceeds 45% and the content of at least one metal selected from copper, zinc, manganese, iron and nickel measured by the atomic absorption method is less than 0.3%, granular fertilizer An imbalance occurs in the ratio of the nitrogen fertilizer component and the micro-fertilizer component in the soil, which hinders the growth of crops. The nitrogen content in the granular fertilizer and the content of at least one metal selected from copper, zinc, manganese, iron, and nickel are determined by the combustion method according to the Fertilizer Test Method (2019) and the atomic absorption method specified in JIS K 0121. (flame atomic absorption method). The amounts of the nitrogen fertilizer component and the trace fertilizer component contained in the granular fertilizer can be adjusted to a desired range by adjusting the blending amounts of the particles A and B.

In addition, in the granular fertilizer of the present invention, particles A' having a particle size of more than 0.1 mm and 1.0 mm or less account for 50% or more of the particles A', more preferably more than 0.1 mm and 1.0 mm or less. accounts for 60% or more of the particles A'. If many of the particles A' have a particle size of more than 1 mm, natural classification occurs in the raw material during production, causing variations in the content of ingredients in each grain after being made into granular fertilizer. Since the contact area of If many of the particles A' have a particle size of 0.1 mm or less, they are pulverized during storage, and the cohesiveness of the granular fertilizer deteriorates. The particle size of particle A' is determined by analyzing the cross section of the granular fertilizer by scanning electron microscope observation-energy dispersive X-ray analysis, identifying particles containing nitrogen fertilizer components, and randomly selecting 100 particles using image analysis software. are measured, and the ratio of particle diameters exceeding 0.1 mm to 1 mm or less can be obtained by the following formula (2).
Percentage (%) of particles with a particle size of more than 0.1 mm and 1 mm or less = (number of particles with a particle size of more than 0.1 mm and 1 mm or less) / 100 grains × 100 (2)

In the granular fertilizer of the present invention, the particle size of the particles B' is more than 0.1 mm and 1 mm or less, and 60% or more of the particles B' are preferably more than 0.1 mm and 1.0 mm or less. 70% or more in '. If many of the particles B' have a particle size of more than 1 mm, natural classification occurs in the raw material during production, causing variations in the content of ingredients in each grain after being made into granular fertilizer. Since the contact area of If many of the particles B' have a particle size of 0.1 mm or less, they are pulverized during storage, and the cohesiveness of the granular fertilizer deteriorates. The particle size of particle B' is determined by analyzing the cross section of the granular fertilizer by scanning electron microscope observation-energy dispersive X-ray analysis, identifying particles containing trace fertilizer components, and randomly selecting 100 particles using image analysis software. are measured, and the ratio of particle sizes exceeding 0.1 mm to 1 mm or less can be obtained by the following formula (3).
Percentage (%) of particles with a particle size of more than 0.1 mm and 1 mm or less = (number of particles with a particle size of more than 0.1 mm and 1 mm or less) / 100 grains × 100 (3)

The grain hardness of the granular fertilizer after the formation of secondary particles may vary slightly over time from the formation of the secondary particles, but the granular fertilizer of the present invention when distributed as a product assuming the time of use and transportation. Grain hardness is preferably 2 kgf or more. If the grain hardness is less than 2 kgf, powdering is likely to occur during storage or transportation of the granular fertilizer, which causes solidification of the granular materials through the powder. In addition, the granules collapse during spraying, making uniform fertilization difficult. On the other hand, the upper limit is not particularly limited, but it is preferably 5 kgf or less. If it exceeds 5 kgf, the granular fertilizer may have poor solubility in soil, resulting in reduced fertilizer efficacy. It is more preferably 3 kgf or more and 5 kgf or less, and still more preferably 3.5 kgf or more and 4.5 kgf or less. The grain hardness of the granular fertilizer is obtained by measuring the grain hardness of 20 grains of the granular fertilizer with a Kiya type hardness meter, and taking the average value of these grain hardnesses as the grain hardness.

It is desirable that the elution rate of trace fertilizer components from the granular fertilizer is large for the purpose of imparting the fertilizing effect to crops as designed. The dissolution rate normalized by the initial amount is preferably 90% or more. It is more preferably 92%, and most preferably 100%, which indicates that the entire amount has been eluted. The elution rate of trace fertilizer components from granular fertilizer is determined according to the following method. First, as an elution test, put 50 ml of horticultural soil in a 100 ml flowerpot, place about 10 g of granular fertilizer on the horticultural soil after weighing it with a balance, and leave it in a constant temperature and humidity bath at 25 ° C. and 70% RH for 1 day. One 10 ml portion of water was added evenly with an atomizer. After 30 days, the granular fertilizer remaining on the horticultural soil was taken out with tweezers and ground and mixed in a mortar to obtain a sample. An analysis sample is taken from the specimen, and at least one metal content selected from copper, zinc, manganese, iron, and nickel is quantitatively analyzed by atomic absorption spectrometry according to the Fertilizer Test Method (2019), and the metal is divided by the weight of the analysis sample. Fractions were calculated. Similarly, at least one metal selected from copper, zinc, manganese, iron, and nickel contained in the granular fertilizer before the test was taken out with tweezers and mixed while grinding in a mortar. After being used as a specimen, an analysis sample was taken out from the specimen, quantitatively analyzed by atomic absorption spectrometry according to the Fertilizer Test Method (2019), and the metal fraction was calculated by dividing by the weight of the analysis sample. The elution rate of trace fertilizer components from granular fertilizer can be obtained from the following formula (4) using the above measured values.
Elution rate of trace fertilizer components (%) =
(1-((weight of granular fertilizer residue after test) x (metal content in granular fertilizer residue after test))/((weight of granular fertilizer before test) x (granular fertilizer before test) Metal content in))) × 100 (4)

In the case of the test method used for calculating the elution rate of the trace fertilizer components from the granular fertilizer, the nitrogen fertilizer component, the trace fertilizer component, and the constituent components of the granular fertilizer are all eluted into the soil and the elution rate is 100%. is preferably 10 to 30 days, more preferably 10 to 25 days, even more preferably 10 to 20 days. When the elution rate exceeds 30 days, the elution rate of the trace fertilizer component into the soil is slow, and the absorption from the roots of crops becomes slow, which may lead to deficiency. If the elution rate is less than 10 days, the rate of elution of the trace fertilizer component into the soil is too fast, and the local concentration may increase, leading to overdose.

The raw material is granulated using a compression granulator, the granules after compression granulation are crushed using a crusher, the granules are sized using a spherical granulator, and a classifier is used. The fine powder under sieves obtained when the granular fertilizer after sieving is classified using the sieving method can be recycled and mixed into the raw material and used as the raw material. The yield of the granular fertilizer is preferably 50% or more in order to reduce the amount of granular fertilizer discarded during granulation and sizing as much as possible, or to recycle it to the granulation process without discarding it. It is more preferably 55% or more, and still more preferably 60% or more. The yield is the weight ratio of the granular fertilizer obtained by granulation and sizing with respect to the weight of the granulated raw material put into the granulator, and is expressed by the following formula (5).
Yield (%) = (weight of granular fertilizer)/(weight of granulated raw material to be fed into granulator) x 100 (5)

The shape of the granular fertilizer is such that the ratio of the diameter of the major axis to the diameter of the minor axis (diameter of the major axis/diameter of the minor axis) of the granular fertilizer is 1.0 so that when fertilizer is applied mechanically, it does not adhere to the leaves of crops and falls into the soil. It is preferably 0 or more and 1.4 or less, more preferably 1.0 or more and 1.3 or less, and even more preferably 1.0 or more and 1.2 or less. If the leaf fertilizer is not spherical, for example flat, it may stick to the leaves and not fall off, resulting in leaf scorch and insufficient supply of nutrients to the soil.

In mechanical fertilization, the grain size of the granular fertilizer is preferably 2 mm or more and 4 mm or less, and accounts for 90% by weight or more of the total fertilizer in order to spread the fertilizer uniformly. More preferably, those having a thickness of 2.5 mm or more and 3.5 mm or less account for 90% by weight or more. A granular fertilizer having a predetermined particle size can be obtained by classification using a classifier, and dry classification can be preferably employed. Although the type of dry classifier is not particularly limited, it is preferable to use a vibrating sieve. The mesh size of the sieve is not particularly limited as long as it is a size that allows a predetermined particle size to be obtained. A classification method in which sieves having mesh openings are combined to obtain granular fertilizer having a particle size of 2.0 to 4.0 mm is preferred. It can be obtained by classifying with a sieve (5 meshes = 4.0 mm, 6 meshes = 3.5 mm, 8 meshes = 2.5 mm, 9 meshes = 2.0 mm).

The granular fertilizer preferably has a bulk density of 0.90 g/ml or more and 1.1 g/ml or less so that it can be uniformly applied in mechanical fertilization and settles on the soil immediately after it reaches water in a paddy field or the like. It is more preferably 92 g/ml or more and 0.98 g/ml or less, and further preferably 0.94 g/ml or more and 0.96 g/ml or less. The bulk density of granular fertilizer is measured according to "JIS R 1628:1997 Method for measuring bulk density of fine ceramics powder".

The moisture content of the granular fertilizer is preferably 5.0% by weight or less from the viewpoint of preventing solidification of the granular fertilizer during long-term storage. It is more preferably 4.0% by weight or less, still more preferably 3.0% by weight or less. Also, the lower limit is preferably 1.0% by weight or more. If the moisture content of the granular fertilizer exceeds 5.0% by weight, during storage of the granular fertilizer, the fertilizer components are eluted and solidified at the contact points between the granular fertilizers, causing the grains to cross-link and agglomerate, resulting in poor handling. I have something to do. If the moisture content is less than 1.0% by weight, the bonding strength between the nitrogen fertilizer component and the trace fertilizer component contained in the granular fertilizer may be reduced, leading to a reduction in the hardness of the granular fertilizer. The moisture content of the granular fertilizer is a value measured by the loss-on-drying method according to the Test Methods for Fertilizers (2019).

Caking is a phenomenon in which granules are bridging at their contact points to form clumps. Failure to spray will adversely affect the growth of crops. The solidification rate of the granular fertilizer is preferably 20% or less for easy handling. When the solidification rate exceeds 20%, the fluidity from the hopper is lowered, and mechanical fertilization may become difficult. It is more preferably 15% or less, still more preferably 10% or less, and most preferably 0% where there is no caking. The solidification rate was determined by placing 750 g of granular fertilizer filled in a small plastic bag on the top and bottom of each dummy fertilizer bag (750 g per bag), placing a wooden board on top of it, and accumulating with a weight of 60 kg. It is the ratio (%) of the solidified portion weight (g) in the granular fertilizer after loading for one month, and is shown by the following formula (6).
Solidification rate (%) = (weight of solidified portion after loading for one month)/750 x 100 (6)

The compaction strength of the granular fertilizer is preferably 1 kg/cm ² or less. If it is 1 kg/cm ² or more, for example, since the solidified portion is difficult to flow out of the flexible container, it is not easy to put it into a hopper, or in mechanical fertilization, the granular fertilizer cannot be uniformly spread to the growing plants. Inferior. More preferably, the consolidation strength is 0.5 kg/cm ² or less, and still more preferably 0.2 kg/cm ² or less. Most preferably and ideally, it is 0 kg/cm ² . The caking strength is a value measured by pressing the needle vertically into the upper surface of the fertilizer using a Yamanaka soil hardness tester.

The pulverization rate of the granular fertilizer is preferably 1.0% or less to prevent caking during storage. If the pulverization rate exceeds 1.0%, the pulverized powder is likely to be caking during storage, and the granular fertilizer cannot be spread to the plants to be grown in mechanical fertilization, resulting in poor handleability. It is more preferably 0.5% or less, still more preferably 0.3% or less, and most preferably 0% where there is no dusting. The pulverization rate is the ratio (%) of particles having a particle size of 2 mm or less obtained by using a sieve with an opening of 2 mm among the granular fertilizers after loading for one month with a weight of 60 kg for 750 g of the granular fertilizer. , is represented by the following formula (7).
Pulverization rate (%) = (weight (g) of particles with a particle size of 2 mm or less) / 750 x 100
... (7)

After pulverizing, mixing, granulating, pulverizing, sizing, and classifying to produce a granular fertilizer, talc, clay, kaolin, bentonite, polyethylene glycol, metal stearate, and lauryl are added to the granular fertilizer as anti-caking agents. At least one selected from metal sulfate, calcium carbonate, silicon oxide, calcium terephthalate, aluminum oxide, titanium oxide, calcium phosphate, and lithium fluoride can be coated on the surface of the granular fertilizer to obtain a granular fertilizer. As a method of coating, the granulated raw material is granulated and sized, and after classifying with a classifier, if it is uniformly coated, it may be added at the exit of the classifier, or mixed and coated using a mixer. Alternatively, the coating may be carried out by spraying on a belt conveyor.

The amount of the anti-caking material added to the granular fertilizer is preferably 0.05 to 3.0 parts by weight per 100 parts by weight of the granular fertilizer. 0.1 to 0.3 parts by weight per 100 parts by weight of the granular fertilizer composition is more preferable in order to obtain a fertilizer with no adverse effects and good solubility as a fertilizer. 0.15 to 0.25 parts by weight per 100 parts by weight of the granular fertilizer is more preferable in order to reduce adhesion loss to the apparatus.

When using the granular fertilizer of the present invention, it may be either a single fertilizer or a bulk blend fertilizer obtained by dry-blending other granular fertilizers. Since this mixed fertilizer can be blended at any ratio, blending corresponding to each crop can be performed.

The aspects of the present invention will be described more specifically below using examples, but the present invention should not be construed as being limited to the following examples.

The methods for measuring physical properties and the like are as follows. In addition, unless otherwise specified, 10 samples were measured, and the arithmetic average was obtained.

(1) Particle Size Ratio of Particle A and Particle B before Molding The particle size ratio of Particle A and Particle B before molding is 9 mesh = 2.0 mm and 16 mesh = 1 Using a 0.0 mm sieve, the ratio of particle sizes exceeding 1.0 mm to 2 mm or less was calculated according to the following formula.
Percentage of particles with a particle size of more than 1 mm and 2 mm or less (% by weight) = (weight of particles with a particle size of more than 1 mm and 2 mm or less) / (weight of particles before sieving) x 100

(2) Particle A' and Particle B' Grain Size Ratio after Granular Fertilizer Molding Analyzed by type X-ray analysis, particles containing nitrogen fertilizer components and particles containing trace fertilizer components were distinguished, and the particle sizes of 100 grains were measured at random using image analysis software. The ratio of particle diameters exceeding 1 mm to 1 mm or less was calculated.
Percentage (%) of particles with a particle size of more than 0.1 mm and less than or equal to 1 mm = (number of particles with a particle size of more than 0.1 mm and less than or equal to 1 mm) / 100 grains × 100

(3) Moisture Content of Particle A and Particle B Before Molding The moisture content of Particle A and Particle B before molding was measured by weight measurement after drying Particle A or Particle B at 130° C. for 3 hours before drying. It is a value obtained from the loss on drying at the time of drying, and was calculated by the following formula.
Moisture content of particles A (% by weight) = ((weight of particles A before drying) - (weight of particles A after drying)) / (weight of particles A before drying) x 100
Moisture content of particles B (% by weight) = ((weight of particles B before drying) - (weight of particles B after drying))/(weight of particles B before drying) x 100

(4) Grain hardness after secondary particle formation of granular fertilizer Grain hardness after secondary particle formation (after molding) of granular fertilizer is measured by measuring the grain hardness of 20 granules with a Kiya hardness meter. It is the average hardness.
A higher grain hardness indicates that a granular fertilizer with higher hardness is obtained.

(5) Yield of Granular Fertilizer The yield of granular fertilizer is the weight of granular fertilizer obtained by granulation and sizing with respect to the weight of granulated raw material put into the granulator, and was calculated by the following formula. .
Yield (%) of granular fertilizer = (weight of granular fertilizer) / (weight of granulated raw material) x 100

(6) Particle size of granular fertilizer The particle size of granular fertilizer is calculated using sieves with openings of 9 mesh = 2.0 mm and 5 mesh = 4.0 mm, and the ratio of particles with a particle size of 2 mm or more and 4 mm or less according to the following formula. was calculated.
Percentage (% by weight) of granular fertilizer with a particle size of 2 mm or more and 4 mm or less = (weight of particles with a particle size of 2 mm or more and 4 mm or less) / (weight of granular fertilizer before sieving) x 100

(7) Nitrogen content in granular fertilizer The nitrogen content in granular fertilizer is measured by a total nitrogen measuring device (Gerhardt Japan Co., Ltd. Dumaserm ) was used. First, a test and a blank test were performed using ethylenediaminetetraacetic acid (purity of 99% by weight or more) as a standard for a calibration curve, and a calibration curve was created by plotting the indicated value of the total nitrogen measuring device and the amount of nitrogen. Subsequently, the granular fertilizer sample is pulverized to a particle size of 0.5 mm or less to obtain a pulverized material, and about 100 mg is measured from the pulverized material to the order of 0.1 mg to obtain an analysis sample, which is placed in a combustion vessel. The measurement was carried out by inserting it into the combustion method total nitrogen measuring device. The indicated value after the measurement was read, and the weight of nitrogen was calculated using the calibration curve. The nitrogen content in the granular fertilizer was calculated by dividing the calculated weight of nitrogen by the weight of the analysis sample.

(8) Content of at least one metal selected from copper, zinc, manganese, iron and nickel in granular fertilizer The content of at least one metal selected from copper, zinc, manganese, iron and nickel in granular fertilizer is It was measured according to the atomic absorption method (frame atomic absorption method) defined in JIS K 0121 according to Equal Test Methods (2019).

(9) Elution Rate of Trace Fertilizer Components from Granular Fertilizer The elution rate of trace fertilizer components from granular fertilizer normalized by the initial amount is obtained according to the following method. First, as an elution test, put 50 ml of horticultural soil in a 100 ml flowerpot, place about 10 g of granular fertilizer on the horticultural soil after weighing it with a balance, and leave it in a constant temperature and humidity bath at 25 ° C. and 70% RH for 1 day. One 10 ml portion of water was added evenly with an atomizer. After 30 days, the granular fertilizer remaining on the horticultural soil was taken out with tweezers and ground and mixed in a mortar to obtain a sample. An analysis sample is taken from the specimen, and at least one metal content selected from copper, zinc, manganese, iron, and nickel is quantitatively analyzed by atomic absorption spectrometry according to the Fertilizer Test Method (2019), and the metal is divided by the weight of the analysis sample. Fractions were calculated. Similarly, at least one metal selected from copper, zinc, manganese, iron, and nickel contained in the granular fertilizer before the test was taken out with tweezers and mixed while grinding in a mortar. After being used as a specimen, an analysis sample was taken out from the specimen, quantitatively analyzed by atomic absorption spectrometry according to the Fertilizer Test Method (2019), and the metal fraction was calculated by dividing by the weight of the analysis sample. The elution rate of trace fertilizer components from granular fertilizer was calculated according to the following formula using the above measured values.
Elution rate of trace fertilizer components (%) =
(1-((weight of granular fertilizer residue after test) x (metal fraction contained in granular fertilizer residue after test))/((weight of granular fertilizer before test) x (granular fertilizer before test) Metal fraction contained in))) × 100 (4)
A higher dissolution rate indicates that a granular fertilizer with better dissolution after spraying is obtained.

(10) Number of days required for 100% elution rate of nitrogen fertilizer components and trace fertilizer components from granular fertilizer Put 10 g of granular fertilizer on top of the gardening soil, place it in a constant temperature and humidity tank at 25 ° C and 70% RH, add 10 ml of water evenly with a sprayer once a day, and remain on the gardening soil. It was defined as the number of days elapsed from the start of the test when no more granular fertilizer was found.

(11) Ratio of major axis diameter to minor axis diameter of granular fertilizer (major axis diameter/minor axis diameter)
The ratio of the major axis diameter to the minor axis diameter of the granular fertilizer is obtained by measuring the major axis diameter and the minor axis diameter with an image analysis type particle size measuring device using a photographed image of the granular fertilizer. Calculated by dividing by the diameter.

(12) Bulk Density of Granular Fertilizer The bulk density of granular fertilizer was measured according to "JIS R 1628:1997 Method for measuring bulk density of fine ceramics powder".

(13) Moisture Percentage of Granular Fertilizer The moisture percentage of the granular fertilizer is a value obtained from the weight loss on drying after drying the granular fertilizer before drying at 130° C. for 3 hours, and was calculated by the following formula.
Moisture content of granular fertilizer (% by weight) = ((weight of granular fertilizer before drying) - (weight of granular fertilizer after drying)) / (weight of granular fertilizer before drying) x 100

(14) Solidification rate of granular fertilizer The solidification rate of granular fertilizer was measured by placing 750g of granular fertilizer in plastic bags, placing dummy fertilizer bags at the top and bottom, and placing a wooden board on top of each bag. , is the ratio of the solidified portion weight (g) in the granular fertilizer after being loaded with a weight of 60 kg for one month, and was calculated by the following formula.
Solidification rate of granular fertilizer (%) = (weight of solidified portion after loading for one month)/750 x 100
A lower caking ratio indicates that a granular fertilizer with less caking is obtained.

(15) Cohesion Strength of Granular Fertilizer The cohesion strength of granular fertilizer is a value measured by pressing the needle into the upper surface of the fertilizer perpendicularly using a Yamanaka soil hardness tester.
A lower value of caking strength indicates that a granular fertilizer with less caking is obtained.

(16) Powderization rate of granular fertilizer The powderization rate of granular fertilizer is obtained by using a sieve with an opening of 2 mm among the granular fertilizer compositions after loading with a weight of 60 kg for 750 g of granular fertilizer for one month. It is the ratio of particles having a grain size of 2 mm or less, and was calculated by the following formula.
Pulverization rate (%) of granular fertilizer = (weight (g) of particles with a particle size of 2 mm or less)/750 x 100
A lower pulverization rate indicates that a granular fertilizer that is less pulverized can be obtained.

In Examples 1 to 19 and Comparative Examples 1 to 7, particles substantially composed of the nitrogen fertilizer components shown in Tables 1 to 3 (denoted as particles A in the tables) and particles substantially composed of trace fertilizer components (table A granular fertilizer was produced by molding the powder (denoted as particle B in the drawings).

(Example 1)
98 parts by weight of ammonium sulfate particles (particles A) containing 57 wt. Parts by weight were supplied to a Dow Mixer (manufactured by Shin-Nichinan Co., Ltd.) as a mixer and mixed for 10 minutes. Next, the mixture was supplied to a Briquette (registered trademark) BSS-IV type (manufactured by Shinto Kogyo Co., Ltd.) as a granulator. Granulation was performed with a pocket size of Φ3.9 mm × 0.94 mm and a roller rotation speed of 50 rpm, and after crushing with a coarse crusher, three-stage sieving with sieves with openings of 6.7 mm, 5.2 mm, and 2.2 mm. The mixture was placed in a sieving machine (manufactured by Kowa Kogyosho) and crushed with crushing media (200 nylon hard balls in the upper stage and 200 in the lower stage). Subsequently, the granulated product was put into a Marumerizer (manufactured by Dalton) and subjected to sieving treatment for 20 seconds at a rotation speed of 225 rpm. ) and classified, and a sieve with an opening of 2 mm was collected as granular fertilizer. The yield of granular fertilizer is 55%, the ratio of particle size between 2 mm and 4 mm is 95%, the major axis diameter is 3.9 mm, the minor axis diameter is 3.6 mm, and the ratio of the major axis diameter to the minor axis diameter is (major axis diameter / minor axis diameter) is 1.08, 65% of particles A' having a particle size of more than 0.1 mm and 1 mm or less in the granular fertilizer, and 87% of particles B' having a particle size of more than 0.1 mm and 1 mm or less. %, the nitrogen content was 20.7%, the copper content was 0.5%, and the moisture content was 0.9% by weight. Further, the elution rate of trace fertilizer components was 100%, and the number of days required for 100% elution rate was 10 days. The granular fertilizer had a grain hardness of 3.4 kgf, a bulk density of 0.96 g/ml, a caking rate of 0%, a caking strength of 0 kg/cm ² and a pulverization rate of 0%.

(Example 2)
95 parts by weight of ammonium sulfate particles (particles A) containing 57 wt. A granular fertilizer was produced by mixing, granulating, pulverizing, sizing, and classifying in the same manner as in Example 1, except that parts by weight were used. The yield of granular fertilizer is 59%, the ratio of particle size between 2 mm and 4 mm is 95%, the major axis diameter is 3.9 mm, the minor axis diameter is 3.6 mm, and the ratio of the major axis diameter to the minor axis diameter is (major axis diameter / minor axis diameter) is 1.08, 61% of particles A' having a particle size of more than 0.1 mm and 1 mm or less in the granular fertilizer, and 81% of particles B' having a particle size of more than 0.1 mm and 1 mm or less. %, the nitrogen content was 20.0%, the copper content was 1.2%, and the moisture content was 2.1% by weight. Further, the elution rate of trace fertilizer components was 100%, and the number of days required for 100% elution rate was 12 days. The granular fertilizer had a grain hardness of 3.2 kgf, a bulk density of 0.96 g/ml, a caking rate of 0%, a caking strength of 0 kg/cm ² and a pulverization rate of 0%.

(Example 3)
90 parts by weight of ammonium sulfate particles (particles A) containing 57 wt. A granular fertilizer was produced by mixing, granulating, pulverizing, sizing, and classifying in the same manner as in Example 1, except that parts by weight were used. The yield of granular fertilizer is 57%, the ratio of particle size between 2 mm and 4 mm is 95%, the major axis diameter is 3.9 mm, the minor axis diameter is 3.6 mm, and the ratio of the major axis diameter to the minor axis diameter is (major axis diameter / minor axis diameter) is 1.08, 69% of particles A' having a particle size of 0.1 mm or more and 1 mm or less in the granular fertilizer, and 83% of particles B' having a particle size of 0.1 mm or more and 1 mm or less. %, the nitrogen content was 19.0%, the copper content was 2.5%, and the moisture content was 3.2% by weight. Further, the elution rate of trace fertilizer components was 100%, and the number of days required for 100% elution rate was 19 days. The granular fertilizer had a grain hardness of 2.6 kgf, a bulk density of 0.95 g/ml, a caking rate of 0%, a caking strength of 0 kg/cm ² and a pulverization rate of 0%.

(Example 4)
86 parts by weight of ammonium sulfate particles (particles A) containing 57 wt. A granular fertilizer was produced by mixing, granulating, pulverizing, sizing, and classifying in the same manner as in Example 1, except that parts by weight were used. The yield of granular fertilizer is 54%, the ratio of particle size between 2 mm and 4 mm is 95%, the major axis diameter is 3.9 mm, the minor axis diameter is 3.5 mm, and the ratio of the major axis diameter to the minor axis diameter is (major axis diameter / minor axis diameter) is 1.11, 73% of particles A' having a particle size of more than 0.1 mm and 1 mm or less in the granular fertilizer, and 89% of particles B' having a particle size of more than 0.1 mm and 1 mm or less. %, the nitrogen content was 18.2%, the copper content was 3.5%, and the moisture content was 4.2% by weight. Further, the elution rate of trace fertilizer components was 100%, and the number of days required for 100% elution rate was 25 days. The granular fertilizer had a grain hardness of 2.1 kgf, a bulk density of 0.94 g/ml, a caking rate of 0%, a caking strength of 0 kg/cm ² and a pulverization rate of 5%.

(Example 5)
95 parts by weight of ammonium sulfate particles (particles A) containing 57% by weight of particles having a particle size of more than 1 mm and 2 mm or less and 5 parts by weight of copper sulfate anhydride particles (particles B) containing 37% by weight of particles having a particle size of more than 1 mm to 2 mm A granular fertilizer was produced by mixing, granulating, pulverizing, sizing and classifying in the same manner as in Example 1, except that 3 parts by weight of and water were used. The yield of granular fertilizer is 50%, the ratio of particle size between 2 mm and 4 mm is 95%, the major axis diameter is 3.9 mm, the minor axis diameter is 3.4 mm, and the ratio of the major axis diameter to the minor axis diameter is (major axis diameter / minor axis diameter) is 1.15, 52% of particles A' having a particle size of more than 0.1 mm and 1 mm or less in the granular fertilizer, and 88% of particles B' having a particle size of more than 0.1 mm and 1 mm or less. %, the nitrogen content was 19.5%, the copper content was 1.9%, and the moisture content was 3.4% by weight. Further, the elution rate of trace fertilizer components was 100%, and the number of days required for 100% elution rate was 11 days. The granular fertilizer had a grain hardness of 1.3 kgf, a bulk density of 0.94 g/ml, a caking rate of 0%, a caking strength of 0 kg/cm ² and a pulverization rate of 13%.

(Example 6)
95 parts by weight of urea particles (particles A) containing 57% by weight of particles having a particle size of more than 1 mm and 2 mm or less and 5 copper sulfate pentahydrate particles (particles B) containing 37% by weight of particles having a particle size of more than 1 mm and 2 mm or less A granular fertilizer was produced by mixing, granulating, pulverizing, sizing, and classifying in the same manner as in Example 1, except that parts by weight were used. The yield of granular fertilizer is 55%, the ratio of particle size between 2 mm and 4 mm is 95%, the major axis diameter is 3.9 mm, the minor axis diameter is 3.5 mm, and the ratio of the major axis diameter to the minor axis diameter is (major axis diameter / minor axis diameter) is 1.11, 87% of particles A' having a particle size of more than 0.1 mm and 1 mm or less in the granular fertilizer, and 81% of particles B' having a particle size of more than 0.1 mm and 1 mm or less. %, the nitrogen content was 44.3%, the copper content was 1.2%, and the moisture content was 2.3% by weight. Further, the elution rate of trace fertilizer components was 100%, and the number of days required for 100% elution rate was 20 days. The granular fertilizer had a grain hardness of 2.2 kgf, a bulk density of 0.94 g/ml, a caking rate of 0%, a caking strength of 0 kg/cm ² and a pulverization rate of 2%.

(Example 7)
85 parts by weight of urea particles (particles A) containing 57% by weight of particles having a particle size of more than 1 mm and 2 mm or less and 15 copper sulfate pentahydrate particles (particles B) containing 37% by weight of particles having a particle size of more than 1 mm and 2 mm or less A granular fertilizer was produced by mixing, granulating, pulverizing, sizing, and classifying in the same manner as in Example 1, except that parts by weight were used. The yield of granular fertilizer is 51%, the ratio of particle size between 2 mm and 4 mm is 95%, the major axis diameter is 3.9 mm, the minor axis diameter is 3.4 mm, and the ratio of the major axis diameter to the minor axis diameter is (major axis diameter / minor axis diameter) is 1.15, 78% of particles A' having a particle size of 0.1 mm or more and 1 mm or less in the granular fertilizer, and 83% of particles B' having a particle size of 0.1 mm or more and 1 mm or less. %, the nitrogen content was 39.6%, the copper content was 3.8%, and the moisture content was 4.9% by weight. Further, the elution rate of trace fertilizer components was 100%, and the number of days required for 100% elution rate was 28 days. The granular fertilizer had a grain hardness of 1.4 kgf, a bulk density of 0.94 g/ml, a caking rate of 9%, a caking strength of 3 kg/cm ² and a pulverization rate of 9%.

(Example 8)
92 parts by weight of ammonium sulfate particles (particles A) containing 57 wt. A granular fertilizer was produced by mixing, granulating, pulverizing, sizing, and classifying in the same manner as in Example 1, except that parts by weight were used. The yield of granular fertilizer is 51%, the ratio of particle size between 2 mm and 4 mm is 95%, the major axis diameter is 3.9 mm, the minor axis diameter is 3.4 mm, and the ratio of the major axis diameter to the minor axis diameter is (major axis diameter / minor axis diameter) is 1.15, 69% of particles A' having a particle size of more than 0.1 mm and 1 mm or less in the granular fertilizer, and 85% of particles B' having a particle size of more than 0.1 mm and 1 mm or less. %, the nitrogen content was 19.4%, the zinc content was 2.9%, and the moisture content was 0.9% by weight. Further, the elution rate of trace fertilizer components was 100%, and the number of days required for 100% elution rate was 18 days. The granular fertilizer had a grain hardness of 1.5 kgf, a bulk density of 0.94 g/ml, a caking rate of 0%, a caking strength of 0 kg/cm ² and a pulverization rate of 5%.

(Example 9)
96 parts by weight of ammonium sulfate particles (particles A) containing 57 wt. A granular fertilizer was produced by mixing, granulating, pulverizing, sizing, and classifying in the same manner as in Example 1, except that parts by weight and water were changed to 2 parts by weight. The yield of granular fertilizer is 59%, the ratio of particle size between 2 mm and 4 mm is 95%, the major axis diameter is 3.9 mm, the minor axis diameter is 3.6 mm, and the ratio of the major axis diameter to the minor axis diameter is (major axis diameter / minor axis diameter) is 1.08, 66% of particles A' having a particle size of more than 0.1 mm and 1 mm or less in the granular fertilizer, and 86% of particles B' having a particle size of more than 0.1 mm and 1 mm or less %, 19.9%, the zinc content was 1.4%, and the moisture content was 2.1% by weight. Further, the elution rate of trace fertilizer components was 100%, and the number of days required for 100% elution rate was 12 days. The granular fertilizer had a grain hardness of 2.8 kgf, a bulk density of 0.95 g/ml, a caking rate of 0%, a caking strength of 0 kg/cm ² and a pulverization rate of 0%.

(Example 10)
92 parts by weight of ammonium sulfate particles (particles A) containing 57 wt. A granular fertilizer was produced by mixing, granulating, pulverizing, sizing, and classifying in the same manner as in Example 1, except that parts by weight and water were changed to 2 parts by weight. The yield of granular fertilizer is 64%, the ratio of particle size between 2 mm and 4 mm is 95%, the major axis diameter is 3.9 mm, the minor axis diameter is 3.6 mm, and the ratio of the major axis diameter to the minor axis diameter is (major axis diameter / minor axis diameter) is 1.08, 72% of particles A' having a particle size of 0.1 mm or more and 1 mm or less in the granular fertilizer, and 83% of particles B' having a particle size of 0.1 mm or more and 1 mm or less. %, the nitrogen content was 19.1%, the zinc content was 2.8%, and the moisture content was 2.6% by weight. Further, the elution rate of trace fertilizer components was 100%, and the number of days required for 100% elution rate was 17 days. The granular fertilizer had a grain hardness of 2.3 kgf, a bulk density of 0.95 g/ml, a caking rate of 0%, a caking strength of 0 kg/cm ² and a pulverization rate of 0%.

(Example 11)
88 parts by weight of ammonium sulfate particles (particles A) containing 57 wt. A granular fertilizer was produced by mixing, granulating, pulverizing, sizing, and classifying in the same manner as in Example 1, except that parts by weight and water were changed to 2 parts by weight. The yield of granular fertilizer is 55%, the ratio of particle size between 2 mm and 4 mm is 95%, the major axis diameter is 3.9 mm, the minor axis diameter is 3.6 mm, and the ratio of the major axis diameter to the minor axis diameter ( Long axis diameter / short axis diameter) is 1.08, particles A' with a particle size of more than 0.1 mm and 1 mm or less in the granular fertilizer are 74%, and particles B' with a particle size of more than 0.1 mm and 1 mm or less are 81%. , the nitrogen content was 18.2%, the zinc content was 4.2%, and the moisture content was 3.4% by weight. Further, the elution rate of trace fertilizer components was 100%, and the number of days required for 100% elution rate was 23 days. The granular fertilizer had a grain hardness of 2.1 kgf, a bulk density of 0.94 g/ml, a caking rate of 0%, a caking strength of 0 kg/cm ² and a pulverization rate of 0%.

(Example 12)
92 parts by weight of ammonium sulfate particles (particles A) containing 57 wt. A granular fertilizer was produced by mixing, granulating, pulverizing, sizing and classifying in the same manner as in Example 1, except that the parts by weight and water were changed to 5 parts by weight. The yield of granular fertilizer is 43%, the ratio of particle size between 2 mm and 4 mm is 95%, the major axis diameter is 3.9 mm, the minor axis diameter is 3.4 mm, and the ratio of the major axis diameter to the minor axis diameter is (major axis diameter / minor axis diameter) is 1.15, 65% of particles A' having a particle size of more than 0.1 mm and 1 mm or less in the granular fertilizer, and 78% of particles B' having a particle size of more than 0.1 mm and 1 mm or less. %, the nitrogen content was 18.5%, the zinc content was 2.7%, and the moisture content was 5.9% by weight. Further, the elution rate of trace fertilizer components was 100%, and the number of days required for 100% elution rate was 15 days. The granular fertilizer had a grain hardness of 2.4 kgf, a bulk density of 0.95 g/ml, a caking rate of 12%, a caking strength of 2 kg/cm ² and a pulverization rate of 0%.

(Example 13)
92 parts by weight of ammonium sulfate particles (particles A) containing 57 wt. A granular fertilizer was produced by mixing, granulating, pulverizing, sizing and classifying in the same manner as in Example 1, except that the parts by weight and the 50% by weight aqueous molasses solution were changed to 3 parts by weight. The yield of granular fertilizer is 56%, the ratio of particle size between 2 mm and 4 mm is 95%, the major axis diameter is 3.9 mm, the minor axis diameter is 3.5 mm, and the ratio of the major axis diameter to the minor axis diameter is (major axis diameter / minor axis diameter) is 1.11, 68% of particles A' having a particle size of more than 0.1 mm and 1 mm or less in the granular fertilizer, and 79% of particles B' having a particle size of more than 0.1 mm and 1 mm or less. %, the nitrogen content was 19.2%, the zinc content was 2.8%, and the moisture content was 2.9% by weight. Further, the elution rate of trace fertilizer components was 81%, and the number of days required for 100% elution rate was 34 days. The granular fertilizer had a grain hardness of 2.9 kgf, a bulk density of 0.96 g/ml, a caking rate of 9%, a caking strength of 2 kg/cm ² and a pulverization rate of 0%.

(Example 14)
92 parts by weight of ammonium sulfate particles (particles A) containing 57% by weight of particles having a particle size of more than 1 mm and 2 mm or less and 8 parts by weight of anhydrous zinc sulfate particles (particles B) containing 41% by weight of particles having a particle size of more than 1 mm to 2 mm A granular fertilizer was produced by mixing, granulating, pulverizing, sizing and classifying in the same manner as in Example 1, except that 3 parts by weight of and water were used. The yield of granular fertilizer is 51%, the ratio of particle size between 2 mm and 4 mm is 95%, the major axis diameter is 3.9 mm, the minor axis diameter is 3.4 mm, and the ratio of the major axis diameter to the minor axis diameter is (major axis diameter / minor axis diameter) is 1.15, 54% of particles A' having a particle size of 0.1 mm or more and 1 mm or less in the granular fertilizer, and 81% of particles B' having a particle size of 0.1 mm or more and 1 mm or less. %, the nitrogen content was 18.9%, the zinc content was 3.1%, and the moisture content was 3.1% by weight. Further, the elution rate of trace fertilizer components was 100%, and the number of days required for 100% elution rate was 18 days. The granular fertilizer had a grain hardness of 1.1 kgf, a bulk density of 0.94 g/ml, a caking rate of 0%, a caking strength of 0 kg/cm ² and a pulverization rate of 16%.

(Example 15)
92 parts by weight of ammonium sulfate particles (particles A) containing 57 wt. A granular fertilizer was produced by mixing, granulating, pulverizing, sizing, and classifying in the same manner as in Example 1, except that parts by weight were used. The yield of granular fertilizer is 55%, the ratio of particle size between 2 mm and 4 mm is 95%, the major axis diameter is 3.9 mm, the minor axis diameter is 3.5 mm, and the ratio of the major axis diameter to the minor axis diameter is (major axis diameter / minor axis diameter) is 1.11, 65% of particles A' having a particle size of more than 0.1 mm and 1 mm or less in the granular fertilizer, and 88% of particles B' having a particle size of more than 0.1 mm and 1 mm or less. %, the nitrogen content was 19.4%, the zinc content was 1.8%, and the moisture content was 3.2% by weight. Further, the elution rate of trace fertilizer components was 100%, and the number of days required for 100% elution rate was 17 days. The granular fertilizer had a grain hardness of 2.4 kgf, a bulk density of 0.95 g/ml, a caking rate of 0%, a caking strength of 0 kg/cm ² and a pulverization rate of 0%.

(Example 16)
93 parts by weight of ammonium sulfate particles (particles A) containing 57% by weight of particles having a particle size of more than 1 mm and 2 mm or less and manganese sulfate monohydrate particles (particles B) containing 35% by weight of particles having a particle size of more than 1 mm and 2 mm or less (7) A granular fertilizer was produced by mixing, granulating, pulverizing, sizing, and classifying in the same manner as in Example 1, except that parts by weight were used. The yield of granular fertilizer is 52%, the ratio of particle size between 2 mm and 4 mm is 95%, the major axis diameter is 3.9 mm, the minor axis diameter is 3.4 mm, and the ratio of the major axis diameter to the minor axis diameter is (major axis diameter / minor axis diameter) is 1.15, 68% of particles A' having a particle size of 0.1 mm or more and 1 mm or less in the granular fertilizer, and 87% of particles B' having a particle size of 0.1 mm or more and 1 mm or less. %, the nitrogen content was 19.7%, the manganese content was 2.2%, and the moisture content was 0.8% by weight. Further, the elution rate of the nitrogen fertilizer component was 100%, the elution rate of the trace fertilizer component was 100%, and the number of days required for the elution rate of 100% was 15 days. The granular fertilizer had a grain hardness of 1.3 kgf, a bulk density of 0.94 g/ml, a caking rate of 0%, a caking strength of 0 kg/cm ² and a pulverization rate of 7%.

(Example 17)
93 parts by weight of ammonium sulfate particles (particles A) containing 57% by weight of particles having a particle size of more than 1 mm and 2 mm or less and manganese sulfate monohydrate particles (particles B) containing 35% by weight of particles having a particle size of more than 1 mm and 2 mm or less (7) A granular fertilizer was produced by mixing, granulating, pulverizing, sizing, and classifying in the same manner as in Example 1, except that parts by weight and water were changed to 2 parts by weight. The yield of granular fertilizer is 62%, the ratio of particle size between 2 mm and 4 mm is 95%, the major axis diameter is 3.9 mm, the minor axis diameter is 3.6 mm, and the ratio of the major axis diameter to the minor axis diameter is (major axis diameter / minor axis diameter) is 1.08, 74% of particles A' having a particle size of more than 0.1 mm and 1 mm or less in the granular fertilizer, and 83% of particles B' having a particle size of more than 0.1 mm and 1 mm or less %, the nitrogen content was 19.3%, the manganese content was 2.2%, and the moisture content was 2.3% by weight. Further, the elution rate of trace fertilizer components was 100%, and the number of days required for 100% elution rate was 15 days. The granular fertilizer had a grain hardness of 2.1 kgf, a bulk density of 0.95 g/ml, a caking rate of 0%, a caking strength of 0 kg/cm ² and a pulverization rate of 0%.

(Example 18)
90 parts by weight of ammonium sulfate particles (particles A) containing 57% by weight of particles having a particle size of more than 1 mm and 2 mm or less and ferrous sulfate heptahydrate particles (particles B) containing 27% by weight of particles having a particle size of more than 1 mm and 2 mm or less ) A granular fertilizer was produced by mixing, granulating, pulverizing, sizing, and classifying in the same manner as in Example 1, except that the content was 10 parts by weight. The yield of granular fertilizer is 63%, the ratio of particle size between 2 mm and 4 mm is 95%, the major axis diameter is 3.9 mm, the minor axis diameter is 3.5 mm, and the ratio of the major axis diameter to the minor axis diameter is (major axis diameter / minor axis diameter) is 1.11, 55% of particles A 'with a particle size of more than 0.1 mm and 1 mm or less in the granular fertilizer, and 72% of particles B 'with a particle size of 0.1 mm and 1 mm or less %, the nitrogen content was 19.5%, the iron content was 1.9%, and the moisture content was 2.8% by weight. Further, the elution rate of trace fertilizer components was 100%, and the number of days required for 100% elution rate was 11 days. The granular fertilizer had a grain hardness of 2.9 kgf, a bulk density of 0.95 g/ml, a caking rate of 0%, a caking strength of 0 kg/cm ² and a pulverization rate of 0%.

(Example 19)
97 parts by weight of ammonium sulfate particles (particles A) containing 57 wt. A granular fertilizer was produced by mixing, granulating, pulverizing, sizing, and classifying in the same manner as in Example 1, except that parts by weight were used. The yield of granular fertilizer is 60%, the ratio of particle size between 2 mm and 4 mm is 95%, the major axis diameter is 3.9 mm, the minor axis diameter is 3.5 mm, and the ratio of the major axis diameter to the minor axis diameter is (long axis diameter / short axis diameter) is 1.11, 63% of particles A 'with a particle size of more than 0.1 mm and 1 mm or less in the granular fertilizer, and 75% of particles B 'with a particle size of 0.1 mm and 1 mm or less %, the nitrogen content was 19.9%, the nickel content was 0.6%, and the moisture content was 2.2% by weight. Further, the elution rate of trace fertilizer components was 100%, and the number of days required for 100% elution rate was 13 days. The granular fertilizer had a grain hardness of 2.4 kgf, a bulk density of 0.95 g/ml, a caking rate of 0%, a caking strength of 0 kg/cm ² and a pulverization rate of 0%.

(Comparative example 1)
80 parts by weight of ammonium sulfate particles (particles A) containing 57 wt. A granular fertilizer was produced by mixing, granulating, pulverizing, sizing, and classifying in the same manner as in Example 1, except that parts by weight were used. The yield of granular fertilizer is 35%, the ratio of particle size between 2 mm and 4 mm is 95%, the major axis diameter is 3.9 mm, the minor axis diameter is 3.4 mm, and the ratio of the major axis diameter to the minor axis diameter is (major axis diameter / minor axis diameter) is 1.15, 63% of particles A' having a particle size of more than 0.1 mm and 1 mm or less in the granular fertilizer, and 79% of particles B' having a particle size of more than 0.1 mm and 1 mm or less. %, the nitrogen content was 16.9%, the copper content was 5.1%, and the moisture content was 5.9% by weight. Further, the elution rate of trace fertilizer components was 85%, and the number of days required for 100% elution rate was 32 days. The granular fertilizer had a grain hardness of 1.8 kgf, a bulk density of 0.95 g/ml, a caking rate of 15%, a caking strength of 3 kg/cm ² and a pulverization rate of 4%.

(Comparative example 2)
95 parts by weight of ammonium sulfate particles (particles A) containing 8 wt. A granular fertilizer was produced by mixing, granulating, pulverizing, sizing, and classifying in the same manner as in Example 1, except that parts by weight were used. The yield of granular fertilizer is 41%, the ratio of particle size between 2 mm and 4 mm is 95%, the major axis diameter is 3.9 mm, the minor axis diameter is 3.3 mm, and the ratio of the major axis diameter to the minor axis diameter is (major axis diameter / minor axis diameter) is 1.18, 37% of particles A' having a particle size of more than 0.1 mm and 1 mm or less in the granular fertilizer, and 55% of particles B' having a particle size of more than 0.1 mm and 1 mm or less. %, the nitrogen content was 20.0%, the copper content was 1.2%, and the moisture content was 1.6% by weight. Further, the elution rate of trace fertilizer components was 63%, and the number of days required for 100% elution rate was 43 days. The granular fertilizer had a grain hardness of 0.8 kgf, a bulk density of 0.94 g/ml, a caking rate of 17%, a caking strength of 2 kg/cm ² and a pulverization rate of 13%.

(Comparative Example 3)
95 parts by weight of urea particles (particles A) containing 13 wt. A granular fertilizer was produced by mixing, granulating, pulverizing, sizing, and classifying in the same manner as in Example 1, except that parts by weight were used. The yield of granular fertilizer is 36%, the ratio of particle size between 2 mm and 4 mm is 95%, the major axis diameter is 3.9 mm, the minor axis diameter is 3.2 mm, and the ratio of the major axis diameter to the minor axis diameter is (major axis diameter / minor axis diameter) is 1.22, 42% of particles A' having a particle size of 0.1 mm or more and 1 mm or less in the granular fertilizer, and 48% of particles B' having a particle size of 0.1 mm or more and 1 mm or less. %, the nitrogen content was 44.3%, the copper content was 1.2%, and the moisture content was 2.3% by weight. Further, the elution rate of trace fertilizer components was 59%, and the number of days required for 100% elution rate was 45 days. The granular fertilizer had a grain hardness of 0.6 kgf, a bulk density of 0.93 g/ml, a caking rate of 45%, a caking strength of 5 kg/cm ² and a pulverization rate of 21%.

(Comparative Example 4)
92 parts by weight of ammonium sulfate particles (particles A) containing 8% by weight of particles having a particle size of more than 1 mm and 2 mm or less and 8 zinc sulfate monohydrate particles (particles B) containing 3% by weight of particles having a particle size of more than 1 mm and 2 mm or less A granular fertilizer was produced by mixing, granulating, pulverizing, sizing, and classifying in the same manner as in Example 1, except that parts by weight and water were changed to 2 parts by weight. The yield of granular fertilizer is 38%, the ratio of particle size between 2 mm and 4 mm is 95%, the major axis diameter is 3.9 mm, the minor axis diameter is 3.2 mm, and the ratio of the major axis diameter to the minor axis diameter is (major axis diameter / minor axis diameter) is 1.22, 33% of particles A' having a particle size of 0.1 mm or more and 1 mm or less in the granular fertilizer, and 36% of particles B' having a particle size of 0.1 mm or more and 1 mm or less. %, the nitrogen content was 19.1%, the zinc content was 2.8%, and the moisture content was 2.6% by weight. Further, the elution rate of trace fertilizer components was 100%, and the number of days required for 100% elution rate was 8 days. The granular fertilizer had a grain hardness of 0.5 kgf, a bulk density of 0.92 g/ml, a caking rate of 5%, a caking strength of 1 kg/cm ² and a pulverization rate of 8%.

(Comparative Example 5)
95 parts by weight of ammonium sulfate particles (particles A) containing 57% by weight of particles having a particle size of more than 1 mm and 2 mm or less and 5 magnesium sulfate monohydrate particles (particles B) containing 27% by weight of particles having a particle size of more than 1 mm and 2 mm or less A granular fertilizer was produced by mixing, granulating, pulverizing, sizing, and classifying in the same manner as in Example 1, except that the parts by weight and water were 1 part by weight. The yield of granular fertilizer is 55%, the ratio of particle size between 2 mm and 4 mm is 95%, the major axis diameter is 3.9 mm, the minor axis diameter is 3.6 mm, and the ratio of the major axis diameter to the minor axis diameter is (major axis diameter / minor axis diameter) is 1.08, 73% of particles A' having a particle size of more than 0.1 mm and 1 mm or less in the granular fertilizer, and 81% of particles B' having a particle size of more than 0.1 mm and 1 mm or less %, the nitrogen content was 19.2%, the magnesium content was 2.1%, and the moisture content was 1.7% by weight. Further, there was no elution of trace fertilizer components, and the number of days required for the elution rate of 100% was 8 days. The granular fertilizer had a grain hardness of 2.8 kgf, a bulk density of 0.95 g/ml, a caking rate of 0%, a caking strength of 0 kg/cm ² and a pulverization rate of 0%.

(Comparative Example 6)
95 parts by weight of ammonium sulfate particles (particles A) containing 57 wt. Parts by weight and 20 parts by weight of a 50% by weight molasses aqueous solution were supplied to a Dow Mixer (manufactured by Shin Nichinan Co., Ltd.) as a mixer and mixed for 10 minutes. Next, the mixture is supplied to a pan-type granulator as a granulator, and granulated at a pan diameter of 30 cm and a pan rotation speed of 20 rpm for 5 minutes. (manufacturer) and classified, and a sieve with an opening of 2 mm was collected as granular fertilizer. The obtained granular fertilizer was dried at 200° C. for 1 hour using a tray dryer. The yield of granular fertilizer is 46%, the ratio of particle size between 2 mm and 4 mm is 95%, the major axis diameter is 3.9 mm, the minor axis diameter is 3.8 mm, and the ratio of the major axis diameter to the minor axis diameter is (major axis diameter / minor axis diameter) is 1.03, 14% of particles A' having a particle size of more than 0.1 mm and 1 mm or less in the granular fertilizer, and 3 particles B' having a particle size of more than 0.1 mm and 1 mm or less %, the nitrogen content was 18.5%, the copper content was 1.0%, and the moisture content was 2.2% by weight. Further, the elution rate of trace fertilizer components was 51%, and the number of days required for 100% elution rate was 59 days. The granular fertilizer had a grain hardness of 2.2 kgf, a bulk density of 0.96 g/ml, a caking rate of 3%, a caking strength of 1 kg/cm ² and a pulverization rate of 0%.

(Comparative Example 7)
99 parts by weight of ammonium sulfate particles (particles A) containing 57 wt. A granular fertilizer was produced by mixing, granulating, classifying and drying in the same manner as in Comparative Example 6, except that the parts by weight and the 50% by weight molasses aqueous solution were changed to 20 parts by weight. The yield of granular fertilizer is 43%, the ratio of particle size between 2 mm and 4 mm is 95%, the major axis diameter is 3.9 mm, the minor axis diameter is 3.8 mm, and the ratio of the major axis diameter to the minor axis diameter is (major axis diameter / minor axis diameter) is 1.03, 21% of particles A' having a particle size of 0.1 mm or more and 1 mm or less in the granular fertilizer, and 5 particles B' having a particle size of 0.1 mm or more and 1 mm or less %, the nitrogen content was 19.2%, the copper content was 0.2%, and the moisture content was 2.4% by weight. Further, the elution rate of trace fertilizer components was 79%, and the number of days required for 100% elution rate was 38 days. The granular fertilizer had a grain hardness of 2.6 kgf, a bulk density of 0.96 g/ml, a caking rate of 5%, a caking strength of 2 kg/cm ² and a pulverization rate of 0%.

The results are shown in Tables 1-3.

As described above, the particle size distribution of the particles (particles A) substantially from the raw material nitrogen fertilizer component and the particles (particles B) substantially from the trace fertilizer component, and the quantitative ratio of the particles A and the particles B is within a predetermined range, it is possible to suppress excess symptoms because the concentration of the trace fertilizer component is not locally increased, and because it has good elution properties, it does not remain in the soil, and is evenly distributed with the nitrogen fertilizer component. To obtain a granular fertilizer that can be sprayed, has a high grain hardness after secondary particle formation and a high yield of fertilizer after production, and is spherical to prevent pulverization and caking during storage of the fertilizer. It turns out that it is possible.

The granular fertilizer according to the present invention does not cause the soil to become deficient in the nutrients of the micro-fertilizer components, allows uniform application of the micro-fertilizer components in concentration, and provides a granular fertilizer with good dissolution properties after application. can be done. In addition, it does not become pulverized and hardened during storage to reduce fluidity, and can be used not only for manual fertilization in small-scale farms but also for mechanical spraying in large-scale farms. In addition, since the bulk blended fertilizer can be prepared by dry-blending the granular fertilizer with other granular fertilizers in an arbitrary ratio according to the application and purpose, it can be used for growing rice, vegetables, fruits, and the like.

Claims (15)

Particles (particles A) substantially composed of a nitrogen fertilizer component and particles (particles B) substantially composed of at least one trace fertilizer component selected from copper sulfate, zinc sulfate, manganese sulfate, iron sulfate, and nickel sulfate are integrated. The granular fertilizer that is formed into secondary particles by liquefaction, and the particles (particles A') that are substantially composed of the nitrogen fertilizer component in the granular fertilizer have a particle size of more than 0.1 mm and the proportion of particles of 1 mm or less is the granular fertilizer occupies 50% or more of the particles A' in the granular fertilizer, and the particle B' in the granular fertilizer has a particle size of more than 0.1 mm, and the proportion of particles of 1 mm or less is copper sulfate, zinc sulfate, manganese sulfate, iron sulfate, sulfuric acid At least 60% of the particles (particles B′) substantially composed of at least one trace fertilizer component selected from nickel, and the nitrogen content in the granular fertilizer measured by the combustion method is 13.5 to 45.0% A granular fertilizer, characterized in that the content of at least one metal selected from copper, zinc, manganese, iron and nickel in the granular fertilizer measured by an atomic absorption method is 0.3 to 5.0%. The granular fertilizer according to claim 1, characterized in that the moisture content in said granular fertilizer is 1.0-5.0% by weight. The granular fertilizer according to claim 1 or 2, wherein the granular fertilizer has a grain hardness of 2 kgf or more after forming secondary particles. The granular fertilizer according to any one of claims 1 to 3, characterized in that the ratio of major axis diameter to minor axis diameter (major axis diameter/minor axis diameter) is 1.0 or more and 1.4 or less. granular fertilizer. The granular fertilizer according to any one of claims 1 to 4, characterized in that said granular fertilizer has a bulk density of 0.9 g/ml or more and 1.1 g/ml or less. The granular fertilizer according to any one of claims 1 to 5, wherein said nitrogen fertilizer component is at least one selected from ammonium sulfate, ammonium chloride, ammonium nitrate, diammonium phosphate and urea. 2. A granular fertilizer according to claim 1, characterized in that said trace fertilizer component is a hydrous salt. Particles (particles A) substantially composed of a nitrogen fertilizer component and particles (particles B) substantially composed of at least one trace fertilizer component selected from copper sulfate, zinc sulfate, manganese sulfate, iron sulfate, and nickel sulfate A method for producing a granular fertilizer that integrates to form secondary particles, wherein particles A having a particle size of more than 1 mm and 2 mm or less account for 10% by weight or more and 90% by weight or less of particles A, Particles B having a particle size of more than 1 mm and 2 mm or less account for 10% by weight or more and 40% by weight or less of particles B, and the amount of particles A is 85.0 to 98% with respect to the total weight of the granular fertilizer. A step of mixing 8 parts by weight, 1.2 to 15.0 parts by weight of particles B, and 0 to 4.0 parts by weight of water to obtain a mixture, and molding the mixture to form secondary particles. A method for producing a granular fertilizer, comprising a step of The method for producing a granular fertilizer according to claim 8, wherein the granular fertilizer is molded so that the ratio of the major axis diameter to the minor axis diameter is 1.0 or more and 1.4 or less. The method for producing a granular fertilizer according to claim 8 or 9, wherein the granular fertilizer is molded so that the bulk density of the granular fertilizer is 0.9 g/ml or more and 1.1 g/ml or less. The method for producing a granular fertilizer according to any one of claims 8 to 10, wherein the molding method for forming the secondary particles is compression granulation. 12. The method for producing granular fertilizer according to claim 11, wherein the compression granulation is performed by a briquetting method using a pair of rollers. The method for producing a granular fertilizer according to claim 11 or 12, wherein the compression granulation is performed at a granulation pressure of 6.0 kN/cm or more and 30.0 kN/cm or less. The method for producing a granular fertilizer according to any one of claims 8 to 13, characterized in that compression granulation is performed as said molding step to obtain granules, and then granules are regulated. 15. The method for producing a granular fertilizer according to claim 14, wherein the sizing is a rotary sizing method.