JP2019172561A - Granular fertilizer and method of producing granular fertilizer - Google Patents

Abstract

To provide a nitrogen and magnesium-fortified granular fertilizer productivity of which is high, which has favorable characteristics for machine dispersion, and is uniform in elution rate of a fertilizer component.SOLUTION: A granular fertilizer of this invention is formed as secondary particles by integrating particles made practically from a nitrogen fertilizer component (particles A) and particles made practically from a magnesium fertilizer component (particles B). Particles whose diameters are more than 0.1 mm and equal to or less than 2 mm account for 50 wt.% of the particles A and particles whose diameters are more than 0.1 mm and equal to or less than 2 mm account for 50 wt.% of the particles B, and the nitrogen fertilizer component of 50-80 wt.% and the magnesium fertilizer component of 50-20 wt.% are contained in the fertilizer.SELECTED DRAWING: None

Description

  The present invention relates to a granular fertilizer composed of a nitrogen fertilizer component such as ammonium sulfate and a magnesium fertilizer component such as magnesium sulfate as main raw materials, and a method for producing the same.

  Granular fertilizer containing nitrogen fertilizer component and magnesium fertilizer component is known as fertilizer to apply fertilizer to enhance crop leaf growth, with ammonium sulfate as the main component and magnesium sulfate as the main component for magnesium fertilizer . Since it contains a nitrogen fertilizer component and a magnesium fertilizer component, it is useful in the cultivation of soil and tea that lack them. In addition, granular fertilizers are known in various shapes such as spheres and pellets, depending on the application method, but mechanical application using broadcasters etc. is the mainstream especially in fertilization on vast agricultural land. For this reason, spherical fertilizers are required because they have a long reach distance and are easy to apply uniformly.

  On the other hand, in general, fertilizer compositions containing nitrogen fertilizer components and magnesium fertilizer components are difficult to granulate and have low grain hardness after granulation and are easy to powder during storage. Thus, it has been studied to produce a granular fertilizer by combining fertilizer components (Patent Documents 1 to 4). For example, Patent Document 1 proposes a method for producing granular fertilizer in which a mixture of nitrogen fertilizer, magnesium sulfate, and a sufficient amount of water is prepared, and the mixture is press-molded. Patent Document 2 proposes a granulated product produced by mixing a water-soluble inorganic salt such as ammonium sulfate or magnesium sulfate with water and extrusion-molding the resulting mixture. In Patent Document 3, a slurry liquid containing one or more crystalline substances in a supersaturated state is blended with a fertilizer mainly composed of at least one of nitrogen, phosphoric acid, and potash fertilizer elements. Thus, a wet granule production method for granulation has been proposed. Furthermore, in Patent Document 4, at least two kinds selected from a nitrogen fertilizer component, a phosphorus fertilizer component, and a potassium fertilizer component and a magnesium fertilizer are blended under high temperature conditions, and granulation is performed while dissolving a part of the blend with high temperature steam. A method for producing a composite fertilizer granule that is granulated by a machine has been proposed.

JP-A-5-97560 Japanese Patent Laid-Open No. 11-181485 JP-A-61-40890 JP-T-2002-519290

  The characteristics required of granular fertilizers suitable for machine spraying are that the granular material has high crushing strength and is not easily pulverized so that dust generation and clogging in the flow path in the machine do not occur during spraying. It is required that no consolidation occurs. In addition, there is also a demand for a high density so that there is little variation in the flight distance during spraying, and the soil settles immediately after landing in a paddy field or the like and lands on the soil. Furthermore, in order to make the elution rate of the fertilizer component to soil uniform, it is required that the particle size of the fertilizer component contained in the granular fertilizer is uniform.

  However, in the granular fertilizers described in Patent Documents 1 to 4, granulation is performed while dissolving the fertilizer components using a large amount of water and steam, so that the particle size of the fertilizer components contained in the granular fertilizer becomes uneven. was there. Further, if it is attempted to increase the grain hardness or reduce the moisture content in order to prevent caking, a drying process is required and the economic efficiency deteriorates, so that sufficient performance cannot always be obtained.

  As described above, the known technique is not sufficient as a granular fertilizer that is advantageous for machine spraying and has a uniform elution rate of fertilizer components.

  As a result of intensive studies to solve the above problems, the inventors of the present invention integrated particles (particles A) substantially composed of nitrogen fertilizer components and particles (particles B) substantially composed of magnesium fertilizer components. In the granular fertilizer in which secondary particles are formed, the particle A has a particle size of more than 0.1 mm, the particles of 2 mm or less account for 50% by weight or more in the particle A, and the particle B has a particle size of 0.1 mm. More than 2 mm or less particles occupy 50% by weight or more in the particle B, and the fertilizer contains 50 to 80% by weight of nitrogen fertilizer component and 50 to 20% by weight of magnesium fertilizer component. Thus, it was found that a granular fertilizer having a high grain hardness after forming secondary particles, a high fertilizer yield after production, and a uniform elution rate of fertilizer components can be obtained.

  In addition, it has led to the creation of an invention of a granular fertilizer that has been improved in various ways such that it is difficult to cause pulverization even during storage of fertilizer and does not cause caking.

  Moreover, the manufacturing method of the granular fertilizer of this invention integrates the particle (particle A) which consists essentially of a nitrogen fertilizer component, and the particle (particle B) which consists essentially of a magnesium fertilizer component, and makes a secondary particle. In the method for producing granular fertilizer to be formed, the particle A has a particle size of more than 0.25 mm, and particles of 2 mm or less occupy 70% by weight or more in the particle A, and the particle B has a particle size of 0.25 mm. And particles that are 2 mm or less account for 50% by weight or more in the particle B, and the particle A is 50 to 80% by weight and the particle B is 20 to 50% by weight with respect to the total weight of the granular fertilizer. The present invention is intended to be a method for producing a granular fertilizer including a step of mixing in the presence of moisture to obtain a mixture, and a step of forming the mixture to form secondary particles. Created by the inventors.

  According to the present invention, the elution rates of the nitrogen fertilizer component and the magnesium fertilizer component are uniform, the particle hardness after secondary particle formation is high, the fertilizer yield after production is high, and pulverization occurs preferably during fertilizer storage It is possible to obtain a granular fertilizer that is difficult to cause consolidation.

<Nitrogen fertilizer component>
There is no restriction | limiting in particular in the nitrogen fertilizer component used for this invention, The thing which acts as a nutrient for nitrogen content of a plant including a well-known thing can be used. Specific examples of the nitrogen fertilizer component include ammonium sulfate, ammonium chloride, ammonium nitrate, ammonium phosphate, urea, and the like. Of these, ammonium sulfate is particularly preferable because it is excellent in terms of elution and grain hardness when used as a granular fertilizer. For example, ammonium sulfate aqueous solution obtained by bringing coke oven waste gas into contact with sulfuric acid or caprolactam sulfate in the production of caprolactam is obtained by adding caprolactam sulfate and ammonium sulfate to obtain a mixture of caprolactam and ammonium sulfate. From the aqueous ammonium sulfate solution obtained by separating the aqueous solution, it can be used as fine-grain ammonium sulfate obtained by crystallizing ammonium sulfate by crystallization. The separation of the crystal and the mother liquor can be performed by a known method. For example, it is obtained by separating from a liquid by centrifugation and then drying. Fine crystal ammonium sulfate has a crystal structure with a pressure of 10.1 kPa ABS or more because the crystal is rapidly agglomerated and the mother liquor is taken in if the supersaturation degree is too high at the time of crystallization, and the particle size is large, moisture is high, and impurities are increased. By performing the analysis, it is possible to obtain crystal-oriented fine crystal ammonium sulfate. The height of crystallinity can be measured by performing two-dimensional X-ray diffraction, and the degree of orientation obtained from the measurement result is preferably 0.995 or more. More preferably, the degree of orientation is 0.997 or more, and if the degree of orientation is 1.0, the crystallinity is the highest and the most preferable. Further, the proportion of the fine crystal ammonium sulfate containing ammonium sulfate is preferably 95% by weight or more, and if it is 98% by weight or more, it becomes the fine crystal ammonium sulfate having high crystallinity, and is most preferable. The degree of orientation is an index indicating the degree of alignment of crystals. In two-dimensional X-ray diffraction, the following formula (1) is obtained from the half-value width (°) of the orientation peak obtained according to the tilt angle χ (°). ).

    Degree of orientation = (180−full width at half maximum of orientation) / 180 (1)

  The finely-crystallized ammonium sulfate obtained in this way can be used as it is for the particle A which is one of the components of the granular fertilizer of the present invention. In this case, the components other than ammonium sulfate derived from the ammonium sulfate aqueous solution mother liquor are preferably less than 0.3% by weight, more preferably less than 0.2% by weight in the fine-grained crystal ammonium sulfate.

  In addition, the particle size of the fine crystal ammonium sulfate is preferably 1.7 mm or less because the smaller the particle size in which the crystals are aggregated and the mother liquor is not taken in, the better the consolidation is. More preferably, it is 1.4 mm or less, More preferably, it is 1.18 mm or less. The particle size of the fine crystal ammonium sulfate can be determined by classification with a sieve (aperture 10 mesh = 1.7 mm, 12 mesh = 1.4 mm, 14 mesh = 1.18 mm).

  The content of ammoniacal nitrogen in the fine crystal ammonium sulfate is preferably 20.5% or more, and more preferably 21.0% or more from the viewpoint of fertilizer effect as a nitrogen source per unit weight. The content of ammoniacal nitrogen in the fine-grained ammonium sulfate is a value measured by the formaldehyde method according to the official fertilizer analysis method.

  The moisture content of the nitrogen fertilizer component is preferably 5% by weight or less. More preferably, it is 4 weight% or less, More preferably, it is 3 weight% or less. When the nitrogen fertilizer component is a fine crystal ammonium sulfate, the moisture content is preferably 0.3% by weight or less. More preferably, it is 0.2% by weight or less, further preferably 0.1% by weight or less, and most preferably 0% when the moisture is completely dried. The moisture content of the nitrogen fertilizer component is a value measured by the heat loss method according to the official fertilizer analysis method.

<Particle A>
As will be described later, the granular fertilizer of the present invention is substantially composed of particles composed of nitrogen fertilizer components (sometimes referred to as “particles A”) and particles composed substantially of magnesium fertilizer components (such particles are referred to as “particles B”). To form secondary particles.

  Particle A is a particle substantially composed of a nitrogen fertilizer component. 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 ratio 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 particles A can be obtained by crystallization by crystallization.

  The particles A used in the production of the granular fertilizer of the present invention preferably have 70% by weight or more of the particles A having a particle size of more than 0.25 mm and 2 mm or less. More preferably, particles having a particle size of more than 0.25 mm and 1.7 mm or less are 70% by weight or more of the whole particle A, and more preferably particles having a particle size of more than 0.25 mm and 1.4 mm or less are particles. It is 70 weight% or more of the whole A. When many particles with a particle size exceeding 2 mm are included, the contact area between the particles is small when granulating, and it is difficult to granulate. Arise. When many particles having a particle size of 0.25 mm or less are contained, the bulk density of the particles A is lowered, making it difficult to granulate, and the utilization efficiency of the raw material is lowered. The particle size and the amount of the particles A here are sieves (for example, openings 9 mesh = 2.0 mm, openings 10 mesh = 1.7 mm, 12 mesh = 1.4 mm, openings 60 mesh = 0.25 mm) You can classify by.

  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 or to increase the granulation yield during granulation, the bulk density is more preferably 0.93 g / ml to 1.1 g / ml, more preferably 0.96 g / ml. More preferably, it is 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”.

<Magnesium fertilizer component>
There is no restriction | limiting in particular in the magnesium fertilizer component used for this invention, The thing which acts as a nutrient for a magnesium content of a plant including a well-known thing can be used. Specific examples of the magnesium fertilizer component include magnesium sulfate, magnesium chloride, magnesium nitrate, magnesium hydroxide, magnesium carbonate and the like. Of these, magnesium sulfate is particularly preferable because it is excellent in terms of elution and grain hardness when used as a granular fertilizer. Preferred examples of magnesium sulfate are preferably at least one selected from the group consisting of magnesium sulfate anhydride, magnesium sulfate monohydrate, magnesium sulfate trihydrate, and magnesium sulfate heptahydrate. Since it is advantageous in that it is difficult to powder, it is preferable to use at least one selected from the group consisting of magnesium sulfate anhydride, magnesium sulfate monohydrate and magnesium sulfate trihydrate. It is more preferable to use magnesium sulfate monohydrate (for example, Kiselite (Sumitomo Corporation)). Magnesium sulfate is obtained, for example, by pulverizing raw ore mined from a mine and separating it from potassium chloride or the like by electrolysis, or obtained by neutralization and decomposition with sulfuric acid using lightly burned magnesium as a raw material. The magnesium content in terms of MgO 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 magnesium source per unit weight. The magnesium content of magnesium sulfate in terms of MgO is a value measured by an atomic absorption measurement method according to an official fertilizer analysis method. The magnesium fertilizer component is usually obtained as a granular component, but the particle size is preferably 2 mm or less. More preferably, it is 1.7 mm or less, More preferably, it is 1.4 mm or less. The particle size and amount of the magnesium fertilizer component can be determined by classification with a sieve (aperture 10 mesh = 1.7 mm, 12 mesh = 1.4 mm, 14 mesh = 1.18 mm). The moisture content of the magnesium fertilizer component is preferably 5% by weight or less. More preferably, it is 4 weight% or less, More preferably, it is 3 weight% or less. When the magnesium fertilizer component is magnesium sulfate, the moisture content is preferably 0.3% by weight or less. More preferably, it is 0.2 weight% or less, More preferably, it is 0.1 weight% or less. In addition, the moisture content of a magnesium fertilizer component is the value measured by the heat loss method according to the official fertilizer analysis method.

<Particle B>
Particle B is a particle substantially composed of a magnesium fertilizer component. Here, “being substantially” means that the magnesium fertilizer component content in the particles B is 90% by weight or more on average with respect to the weight of the particles B. The proportion of the particles B containing the magnesium fertilizer component is preferably 95% by weight or more, more preferably 98% by weight or more, and most preferably 100% by weight. The particles B can be obtained by pulverizing raw ore mined from a mine and separating it from potassium chloride or the like by electrolysis.

  The particle B used for producing the granular fertilizer of the present invention preferably has a particle size of more than 0.25 mm and 2 mm or less of 50% by weight or more of the whole particle B. More preferably, the particles having a particle size of more than 0.25 mm and not more than 1.7 mm are 50% by weight or more of the whole particle B, and more preferably, the particles having a particle size of more than 0.25 mm and not more than 1.4 mm are particles. It is that it is 50 weight% or more of the whole B. When many particles having a particle size exceeding 2 mm are contained, the contact area between the particles is small when granulating, and it is difficult to granulate, resulting in a decrease in grain hardness. When the particle B contains a large number of particles having a particle size of 0.25 mm or less, the bulk density of the particle B is reduced, making it difficult to granulate, and the utilization efficiency of the raw material is reduced. The particle size and amount of the particles B here are sieves (for example, an opening of 9 mesh = 2.0 mm, an opening of 10 mesh = 1.7 mm, 12 mesh = 1.4 mm, an opening of 60 mesh = 0.25 mm) You can classify by.

  The bulk density of the particles B used for producing the granular fertilizer of the present invention is 0.95 g / ml or more and 1.10 g / ml or less. In order to prevent scattering during transportation or to increase the granulation yield during granulation, the bulk density is more preferably 0.97 g / ml or more and 1.10 g / ml or less, and 0.99 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 is a granular fertilizer in which particles substantially composed of a nitrogen fertilizer component (particle A) and particles substantially composed of a magnesium fertilizer component (particle B) are integrated to form secondary particles. . That is, in the granular fertilizer, the part of particle A and the part of particle B can be observed using a microscope. In order to obtain such a granular fertilizer, particles A and B as raw materials are mixed in the presence of moisture, and the mixture is molded (also referred to as granulation).

  Mixing particles A and B with a mixer in the presence of moisture, and sequentially performing granulation, pulverization, sizing, and classification to obtain a granular fertilizer having hardness, bulk density, and shape preferable as a fertilizer Can do.

  It should be noted that components other than the particles A and the particles B may be used as long as they do not depart from the gist of the present invention and do not impair the purpose. For example, substances having fertilizing effects on other nutrients, substances that improve shape retention such as binders, and additives such as inorganic fillers and organic fillers can be mentioned.

  The mixing method of the particles A and the particles B is not particularly limited as long as they can be mixed uniformly, and can be a horizontal cylindrical type, vertical type, double cone type or other container rotating type mixer, ribbon type, screw type, Although a container-fixed 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 from 2 minutes to 15 minutes, more preferably from 5 minutes to 10 minutes. When the mixing time is shorter than 2 minutes, the particles A and B are not uniformly dispersed in the mixture, and each particle is biased when granulated. If the mixing time is longer than 15 minutes, the mixer capacity is increased in continuous production of fertilizer, which is economically disadvantageous.

  The amount of water that is present when mixing the particles A and the particles B is preferably 0.1 to 1.9 parts by weight when the total weight of the particles A and B is 100 parts by weight. More preferably, it is 0.3-1.7 weight part, More preferably, it is 0.5-1.5 weight part. When the amount of water to be present is lower than 0.3 parts by weight, the binding force between the particles A and B is insufficient during granulation, resulting in a decrease in granulation yield, and the granular fertilizer becomes insufficient due to insufficient hardness during storage. It becomes easy to become. If the amount of water present exceeds 1.7 parts by weight, the amount of water adhering to the equipment increases when the mixture is discharged from the mixer and transported to the granulator, resulting in a decrease in yield or granular fertilizer. The caking property deteriorates 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 a production efficiency. It is preferable to use a briquette system because it is difficult to produce a low-volume granular fertilizer with a low level, and it is difficult to produce a granular fertilizer with a spherical shape and few burrs. As a briquette type compression granulator, for example, a Briquetta (registered trademark) BSS type (manufactured by Shinto Kogyo) or the like can be preferably used.

  There is no particular limitation on the method of supplying a mixture (also referred to as a granulation raw material) in which particles A and particles B are mixed in the presence of moisture to a compression granulator. For example, the mixture is stored in a hopper, It can be directly supplied to the granulator from the accompanying conveyor, or can be supplied from the hopper conveyor to the granulator via a belt conveyor or a bucket conveyor.

  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 axis on the compressor side in the portion where the load is applied to the granulated raw material. For example, in the case of the tablet method, the effective width is the long diameter of the tablet portion, and in the case of the briquette method using a roller, the effective width is the length of the portion where the granulated raw material is compressed by the roller. The granulation pressure is preferably in the range of 6.0 kN / cm to 30.0 kN / cm. More preferably, it is 7.0 kN / cm or more and 30.0 kN / cm or less, More preferably, it is 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 of the granulation raw material itself does not occur due to insufficient pressure. If the granulation pressure is higher than 30.0 kN / cm, the granulated material obtained by excessive pressure will crack, or the compression granulator will be loaded more than necessary, so the device life will be significantly reduced. .

  The number of rotations of the granulation roller is the rotation speed of the rollers in the briquette method and the plate method in which compression granulation is performed using a roller, and 40 rpm or more is preferable. More preferably, it is 50 rpm or more, More preferably, it is 60 rpm or more. When the number of rotations of the granulation roller is less than 40 rpm, the granulation pressure on the raw material is increased, and the granulated material is cracked or the production amount is decreased.

  The burr thickness of the compression granulator indicates the shortest diameter of the granulated raw material at a portion where a load is applied to the granulated raw material. For example, if it is a tablet system, the burr thickness is the short diameter of the tablet part, and if it is a briquette system using a roller, the burr thickness is the length of the plate-like part of the granulated product obtained by granulation. is there. The burr thickness is preferably in the range of 1.0 mm to 2.5 mm, and more preferably in the range of 1.2 mm to 2.0 mm. If the burr thickness is less than 1.2 mm, both the crushing strength and yield of the granular fertilizer tend to decrease. When 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 with, for example, a vibrating sieve using a pulverized ball to make the particle size uniform. In this case, it is not preferable because it causes clogging of the sieve.

  In order to obtain a granular fertilizer with few burrs, strong crushing strength, less dust generation, and hardly caking, the raw material is granulated using a compression granulator, and after compression granulation using a pulverizer It is preferable that the granulated material is crushed, the granulated product is sized using a spherical granulator, and the sized granular fertilizer is classified using a classifier. There are no restrictions on the method of transporting granular fertilizer in each process, but it is possible to use natural fall, conveyor transport, air transport, etc., and after the granulated raw material is transported to the granulator by conveyor transport, it is solved by natural fall. A method of transporting to a crusher, a spherical granulator or a classifier is preferred. For the contact parts of equipment including these transportation equipment, it is preferable to use a material having corrosion resistance for the granular fertilizer, and it is preferable to use SUS316L or resin.

  The granular fertilizer granulated by the compression granulator can be obtained by obtaining a granular fertilizer having hardness, bulk density and shape preferable as a fertilizer by performing crushing, sizing and classification.

  In order to obtain a granular fertilizer having a uniform particle size, it is preferable to crush the granular fertilizer after compression granulation using a crusher. There are no particular limitations on the type of crusher, and various crushers such as a jaw crusher and a roll crusher, various mills such as a roller mill and a cutting mill, and a vibration sieve to which crushing media are added are preferably used. It is also possible to use a combination of these crushers.

  In order to obtain a spherical fertilizer with little burr, it is preferable to use a granulator to regulate the size. There is no particular limitation on the type of the granulator, for example, a high-speed rolling method, an oscillator type, a crushing method, a centrifugal rotating method, or the like is preferably used, and Malmerizer (registered trademark: a high-speed rolling type spherical granulator). It is more preferable to size the granular fertilizer using Dalton).

  The processing time of the granulator is preferably in the range of 0.2 to 5.0 minutes, and more preferably in the range of 0.3 to 3.0 minutes. When the processing time of the granulator becomes lower than the above, the removal of burrs from the granular fertilizer becomes insufficient. When the processing time of the granulator becomes higher 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 the sizing treatment is increased, the yield of granular fertilizer per unit time is also reduced.

  The rotational speed of the granulator is preferably in the range of 50 to 2000 revolutions / minute, and more preferably in the range of 100 to 1500 revolutions / minute. When the rotational speed of the granulator becomes lower than the above range, the burr removal of the granular fertilizer becomes insufficient, and further the time required for the granulation treatment increases, so that the granular fertilizer yield per unit time also decreases. When the rotational speed of the granulator becomes higher than the above range, problems such as an increase in noise and a decrease in equipment life occur.

  In order to obtain a granular fertilizer having a predetermined particle size or more, 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 vibration sieve. The opening of the sieve is not particularly limited as long as a predetermined particle size can be obtained, but preferably 1.8 to 2.2 mm and 3.8 to 4.2 mm. A classification method for obtaining a granular fertilizer having a particle size of 2.0 to 4.0 mm by combining sieves having openings is preferable.

  In the granular fertilizer of the present invention, in the granular fertilizer, the particle A has a particle size of more than 0.1 mm, and the particles of 2 mm or less account for 50% by weight or more in the particle A, and the particle B has a particle size of more than 0.1 mm. Particles of 2 mm or less occupy 50% by weight or more in the particle B, and the granular fertilizer contains 50 to 80% by weight of nitrogen fertilizer component and 50 to 20% by weight of magnesium fertilizer component.

  The amount of nitrogen fertilizer component and magnesium fertilizer component contained in this granular fertilizer is more preferably 55 to 78% by weight of nitrogen fertilizer component and 45 to 22% by weight of magnesium fertilizer component. Is more preferably 60 to 75% by weight and magnesium fertilizer component 40 to 25% by weight. When the nitrogen fertilizer component is less than 50% by weight and the magnesium fertilizer component exceeds 50% by weight, the ratio of the magnesium fertilizer component is large, the grain hardness is lowered, and the powder is easily pulverized. When the nitrogen fertilizer component exceeds 80% by weight and the magnesium fertilizer component is less than 20% by weight, the ratio of the nitrogen fertilizer component and the magnesium fertilizer component in the granular fertilizer is biased, which hinders the growth of the crop. The amount of the nitrogen fertilizer component and the magnesium fertilizer component contained in the granular fertilizer can be set to a desired range by adjusting the blending amount of the particles A and the particles B.

  In the granular fertilizer of the present invention, the particle size of the particles A is more than 0.1 mm and not more than 2.0 mm is 50% by weight or more in the particles A, more preferably more than 0.1 mm and not more than 1.0 mm. The amount is 50% by weight or more in the particle A. When there are many particles A having a particle size exceeding 2 mm, the proportion of the raw material in the granular fertilizer is small, resulting in a decrease in the particle hardness. When there are many particles A having a particle size of 0.1 mm or less, the solidification of the granular fertilizers deteriorates due to pulverization during storage. The particle size of the particle A can be determined by analyzing the cross section of the granular fertilizer by scanning electron microscope observation-energy dispersive X-ray analysis, and identifying particles containing a nitrogen fertilizer component.

  In the granular fertilizer of the present invention, the particle size of the particle B is more than 0.1 mm and 2 mm or less is 50% by weight or more in the particle B, preferably more than 0.1 mm and 1.0 mm or less in the particle B. It is 50% by weight or more. When there are many particles B having a particle size exceeding 2 mm, the ratio of the raw material in the granular fertilizer is small, resulting in a decrease in particle hardness. When there are many particles B having a particle size of 0.1 mm or less, the solidification property between the granular fertilizers deteriorates due to pulverization during storage. The particle size of the particle B can be determined by analyzing the cross section of the granular fertilizer by scanning electron microscope observation-energy dispersive X-ray analysis and identifying particles containing the magnesium fertilizer component.

  As a method for adjusting the range and amount of the particle diameters of the particles A and the particles B, the particle A or the particle B before molding can be adjusted to a desired range by performing sieving. Therefore, in obtaining the granular fertilizer of the present invention, the particle size is over 0.25 mm, and the particles A having a particle size of 2 mm or less account for 70% by weight or more in the particle A, and the particle size is over 0.25 mm and 2 mm or less. It is possible to preferably employ a mixture of particles B in which the particles occupy 50% by weight or more of the particles B.

  The granular 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 use and transportation. The grain hardness is preferably 2 kgf or more. When the grain hardness is less than 2 kgf, pulverization is likely to occur during storage and transportation of the granular fertilizer, which causes solidification of the granular materials via the powder. Also, when spraying, the grains collapse and uniform fertilization becomes difficult. On the other hand, the upper limit is not particularly limited, but is preferably 5 kgf or less, and if it exceeds 5 kgf, the solubility of the granular fertilizer in the soil is poor, and the fertilization effect may be reduced. More preferably, they are 3 kgf or more and 5 kgf or less, More preferably, they are 3.5 kgf or more and 4.5 kgf or less. In addition, the grain hardness of granular fertilizer measures the grain hardness of 20 granular fertilizers with a Kiyama-type hardness meter, and makes the average value of these grain hardness the grain hardness.

  It is desirable that the elution rate of nitrogen fertilizer and magnesium fertilizer components from granular fertilizer should be the same attenuation rate for the purpose of giving crops the desired fertilization effect, and the initial rate of nitrogen fertilizer and magnesium fertilizer components from granular fertilizer The ratio of the dissolution rate normalized by the amount is preferably 0.8 to 1.2. More preferably, it is 0.9 to 1.1, and 1.0 representing the matching of the attenuation factors is most preferable. The ratio of the elution rate of the nitrogen fertilizer component and the magnesium fertilizer component from the granular fertilizer is as follows: 5 g of granular fertilizer is placed in a 100 ml stoppered glass tube, and 100 ml of water is added and immersed, plugged and sealed at 25 ° C. Leave in a thermostatic bath, remove the glass tube after 5 hours, filter the solution with chemical filter paper and quantitatively analyze the fertilizer components eluted in the water, measure the initial amount, the following formula (3), It is obtained from the equations (4) and (5).

Elution ratio of nitrogen fertilizer component =
(Amount of N component eluted in water) / (Amount of N component contained in 5 g of granular fertilizer) (3)

Elution ratio of magnesium fertilizer component =
(Amount of magnesium in terms of MgO eluted in water) / (Amount of magnesium in terms of MgO contained in 5 g of granular fertilizer) (4)

Ratio of elution rate of nitrogen fertilizer component and magnesium fertilizer component =
Elution ratio of nitrogen fertilizer component / elution ratio of magnesium fertilizer component (5)

  The raw material is granulated using a compression granulator, the granulated product after compression granulation is crushed using a pulverizer, the granulated product is sized using a spherical granulator, and the classifier is The fine powder under the sieve obtained when classifying the granular fertilizer after sizing is recycled and mixed into the raw material and can be used as the raw material. The yield of granular fertilizer is preferably 60% or more in order to reduce the amount of granular fertilizer discarded during granulation and sizing as much as possible, or to recycle to the granulation step without discarding. More preferably, it is 65% or more, further preferably 70% or more, and 100% is most preferable when it can be completely recovered. In addition, a yield is a weight ratio of the granular fertilizer obtained by granulation and sizing with respect to the weight of the granulation raw material thrown into a granulator, and is shown by following formula (6).

Yield = (Weight of granular fertilizer) / (Weight of granulation raw material put into granulator)
× 100 (%) (6)

  The shape of the granular fertilizer is such that the ratio of the major axis diameter to the minor axis diameter (major axis diameter / minor axis diameter) of the granular fertilizer is 1. It is preferably 0 or more and 1.4 or less, more preferably 1.0 or more and 1.3 or less, and further preferably 1.0 or more and 1.2 or less. If the pressed fertilizer has a flat shape, for example, a flat shape, it may adhere to the leaf and will not fall off, resulting in leaf or burn, and the supply of nutrients to the soil may be poor.

  The particle size of the granular fertilizer is preferably 2 mm or more and 4 mm or less occupying 90% by weight or more of the total fertilizer in order to uniformly disperse the fertilizer in mechanical fertilization. More preferably, 2.5 to 3.5 mm occupy 90% by weight or more. The granular fertilizer having a predetermined particle diameter can be obtained by classification using a classifier, and dry classification can be preferably employed. Although there is no restriction | limiting in particular in the kind of dry classifier, It is preferable to use a vibration sieve. The opening of the sieve is not particularly limited as long as a predetermined particle size can be obtained, but preferably 1.8 to 2.2 mm and 3.8 to 4.2 mm. A classification method for obtaining a granular fertilizer having a particle size of 2.0 to 4.0 mm by combining sieves having openings is preferable. It can be determined by classification with a sieve (aperture 5 mesh = 4.0 mm, 6 mesh = 3.5 mm, 8 mesh = 2.5 mm, 9 mesh = 2.0 mm).

  The bulk density of the granular fertilizer is preferably 0.90 g / ml or more and 1.1 g / ml or less so that it can be uniformly sprayed by mechanical fertilization and settles immediately after landing in a paddy field or the like and lands on the soil. More preferably, it is 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 the granular fertilizer is measured according to “JIS R 1628: 1997 Method for measuring bulk density of fine ceramic powder”.

  The moisture content of the granular fertilizer is preferably 2.0% by weight or less from the viewpoint of preventing solidification of the granular fertilizers during long-term storage. More preferably, it is 1.8 weight% or less, More preferably, it is 1.5 weight% or less. Moreover, it is preferable that it is 0.3 weight% or more as a minimum. If the moisture content of the granular fertilizer exceeds 2.0% by weight, the fertilizer components are eluted and solidified at the contact parts of the granular fertilizer when the granular fertilizer is stored. There are things to do. When the moisture content is less than 0.3% by weight, the binding force between the nitrogen fertilizer component and the magnesium fertilizer component contained in the granular fertilizer may decrease, leading to a decrease in the hardness of the granular fertilizer. The moisture content of granular fertilizer is a value measured by the heat loss method according to the official fertilizer analysis method.

  Consolidation is a phenomenon in which the grains cross-link at the contact area and become a lump.When machine spraying, it is difficult or impossible to spread due to the lump. If it cannot be applied, it will adversely affect crop growth. The solidification rate of the granular fertilizer is preferably 20% or less in order to facilitate handling. If the consolidation rate exceeds 20%, fluidity from the hopper may be reduced, and mechanical fertilization may be difficult. More preferably, it is 15% or less, more preferably 10% or less, and most preferably 0% which does not cause any solidification. The solidification rate is determined by placing 750 g of granular fertilizer filled in a plastic sachet at the top and bottom of each dummy fertilizer bag (750 g per bag), placing a wooden board on top of it and depositing it with a 60 kg weight. It is the ratio (%) of the consolidated part weight (g) in the granular fertilizer after one month load, and is represented by the following formula (7).

  Consolidation rate (%) = (weight of consolidated part after loading for one month) / 750 × 100 (7)

The consolidation strength of the granular fertilizer is preferably 1 kg / cm ² or less. When it is 1 kg / cm ² or more, for example, the consolidated portion is difficult to flow out of the flexible container, so that it is not easy to put into the hopper, or the granular fertilizer cannot be uniformly sprayed up to the plant grown in mechanical fertilization. Inferior. More preferably consolidation strength is 0.5 kg / cm ² or less, more preferably 0.2 kg / cm ² or less. Most preferred and ideally 0 kg / cm ² . The consolidation strength is a value measured by pressing the needle portion perpendicularly to the upper surface of the fertilizer using a Yamanaka type soil hardness meter.

  The powdering rate of the granular fertilizer is preferably 1.0% or less in order to prevent caking during storage. If the pulverization rate exceeds 1.0%, it is easy to consolidate during storage through the pulverized powder, and further, the granular fertilizer cannot be sowed up to the plant grown by mechanical fertilization, resulting in poor handling. More preferably, it is 0.5% or less, further preferably 0.3% or less, and most preferably 0% without any powdering. The pulverization rate is the ratio (%) of the granular fertilizer with a weight of 60 kg to 750 g of the granular fertilizer and having a particle diameter of 2 mm or less obtained using a sieve having a mesh opening of 2 mm. Is represented by the following formula (8).

  Powdering rate (%) = (weight (g) of a particle size of 2 mm or less) / 750 × 100 (8)

  After granulating, pulverizing, sizing and classifying to produce a granular fertilizer, talc, clay, kaolin, bentonite, polyethylene glycol, stearic acid metal salt, lauryl sulfate metal salt, The granular fertilizer surface can be coated with at least one selected from calcium carbonate, silicon oxide, calcium terephthalate, aluminum oxide, titanium oxide, calcium phosphate, and lithium fluoride. As a coating method, the granulated raw material is granulated and sized, and after being classified by a classifier, if it is uniformly coated, it may be added at the outlet of the classifier, or mixed and coated using a mixer. Alternatively, it may be coated by spraying on a belt conveyor.

  The addition amount of the anti-caking material to the granular fertilizer is preferably 0.05 to 3.0% by weight with respect to 100% by weight of the granular fertilizer, and the loss due to adhesion to the device or the fertilizer component content per unit weight In order to obtain a fertilizer having no influence and good solubility as a fertilizer, 0.1 to 0.3% by weight is more preferable with respect to 100% by weight of the granular fertilizer composition. In order to reduce the adhesion loss to the apparatus, 0.15 to 0.25% by weight is more preferable with respect to 100% by weight of the granular fertilizer.

  In using the granular fertilizer of this invention, it is good also as any of the bulk blend fertilizer obtained by dry blending a simple fertilizer or another granular fertilizer. Since this mixed fertilizer can be blended at an arbitrary ratio, blending corresponding to each crop can be performed.

  The embodiment of the present invention will be described more specifically with reference to the following examples. However, the present invention should not be construed as being limited to the following examples.

  Measuring methods for physical properties and the like are as follows. Moreover, unless otherwise indicated, it measured about 10 samples and calculated | required as arithmetic average.

(1) Particle size before molding of particle A and particle B The particle size of the particle A and particle B at the stage before molding is a sieve having an opening of 9 mesh = 2.0 mm and an opening of 60 mesh = 0.25 mm. Was used to calculate the ratio of particle diameters exceeding 0.25 mm and not more than 2 mm according to the following formula.
Ratio of particles exceeding 0.25 mm and not more than 2 mm (% by weight) = (weight of particles exceeding 0.25 mm and not more than 2 mm) / (weight of particles before sieving) × 100.

(2) Particle size of particles A and B after molding of granular fertilizer Particle size of particles A and particle B in the granular fertilizer is determined by scanning electron microscope observation-energy dispersive X-ray analysis of the cross section of the granular fertilizer. Analysis was performed, and particles containing a nitrogenous fertilizer component and particles containing a magnesium fertilizer component were identified, and 100 particle sizes were measured at random.

(3) Moisture content before molding of particles A and B The moisture content before molding of particles A and B was measured by heating the particles A or B before heating at 130 ° C. for 3 hours. It was a value obtained by heating loss at the time, and was calculated by the following formula.
Moisture content (% by weight) of particles A = ((weight of particles A before heating) − (weight of particles A after heating)) / (weight of particles A before heating) × 100
Moisture content of particles B (% by weight) = ((weight of particles B before heating) − (weight of particles B after heating)) / (weight of particles B before heating) × 100.

(4) Grain hardness after formation of secondary particles of granular fertilizer Grain hardness after formation of secondary particles of granular fertilizer (after molding) is measured by measuring the particle hardness of 20 granules with a Kiyama-type hardness meter. The average hardness is obtained.

(5) Yield of granular fertilizer The yield of granular fertilizer is the weight of the granular fertilizer obtained by granulation and sizing with respect to the weight of the granulation 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) × 100.

(6) Particle size of granular fertilizer The particle size of the granular fertilizer is a ratio of particles having a particle size of 2 mm or more and 4 mm or less according to the following formula using a sieve having an opening of 9 mesh = 2.0 mm and 5 mesh = 4.0 mm. Was calculated.
Ratio (% by weight) of granular fertilizer having a particle size of 2 mm or more and 4 mm or less = (weight of particle size of particle size of 2 mm or more and 4 mm or less) / (weight of granular fertilizer before sieving) × 100.

(7) Content of nitrogen fertilizer component and magnesium fertilizer component after molding of granular fertilizer The content of nitrogen fertilizer component and magnesium fertilizer component in the granular fertilizer is as follows: Particle A before molding, Particle B before molding, and granular fertilizer Is analyzed by the official fertilizer analysis method, the N content is measured by the combustion method, the magnesium content in terms of MgO is measured by the atomic absorption method, and the nitrogen fertilizer component and the magnesium fertilizer component in the granular fertilizer are expressed by the following formulas The content at was calculated.
Content of nitrogen fertilizer component after granulated fertilizer molding (% by weight) = (content of N content of granular fertilizer) / (content of N content before molding of particle A) × 100.
Content of magnesium fertilizer component after molding of granular fertilizer (% by weight) = (content of MgO in granular fertilizer) / (content of MgO before molding of particle B) × 100.

(8) Ratio of elution rate of nitrogen fertilizer component and magnesium fertilizer component from granular fertilizer (ratio of decay rate)
The ratio of the elution rate normalized with the initial amount of nitrogen fertilizer component and magnesium fertilizer component from granular fertilizer is as follows: 5 g of granular fertilizer is put into a 100 ml stoppered glass tube, 100 ml of water is added and immersed. And leave it in a constant temperature bath at 25 ° C., take out the glass tube after 5 hours, filter the solution with chemical filter paper and quantitatively analyze the fertilizer components eluted in the water, and each of the nitrogen fertilizer components and magnesium fertilizer components The elution amount was calculated, and the initial amount was measured and calculated according to the following formula.
Elution ratio of nitrogen fertilizer component = (amount of N component eluted in water) / (amount of N component contained in 5 g of granular fertilizer)
Elution ratio of magnesium fertilizer component = (amount of magnesium in terms of MgO eluted in water) / (amount of magnesium in terms of MgO contained in 5 g of granular fertilizer)
Ratio of elution rate of nitrogen fertilizer component and magnesium fertilizer component = elution ratio of nitrogen fertilizer component / elution ratio of magnesium fertilizer component.

(9) Ratio of major axis diameter and 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 determined by measuring the major axis diameter and minor axis diameter with an image analysis type particle size measuring device using a photographed image of the granular fertilizer, and converting the major axis diameter to the minor axis. Calculated by dividing by diameter.

(10) 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 ceramic powder”.

(11) Moisture content of granular fertilizer The moisture content of granular fertilizer is a value obtained by weight loss after heating the granular fertilizer before heating at 130 ° C. for 3 hours, and was calculated by the following formula.
Moisture content (% by weight) of granular fertilizer = ((weight of granular fertilizer before heating) − (weight of granular fertilizer after heating)) / (weight of granular fertilizer before heating) × 100.

(12) Solidification rate of granular fertilizer The solidification rate of granular fertilizer is determined by placing 750 g of granular fertilizer filled in a plastic sachet one dummy fertilizer bag at the top and bottom and placing a wooden board on top of it. The ratio of the solidified part weight (g) of the granular fertilizer after being loaded with a 60 kg weight for one month, and calculated by the following formula.
Solidification rate of granular fertilizer (%) = (weight of consolidated part after one month load) / 750 × 100

(13) Consolidation strength of granular fertilizer The solidification strength of granular fertilizer is a value measured by pressing the needle portion perpendicularly to the upper surface of the fertilizer using a Yamanaka soil hardness meter.

(14) Pulverization rate of granular fertilizer The pulverization rate of granular fertilizer is obtained by using a sieve having a mesh opening of 2 mm among the granular fertilizer composition after being loaded with a weight of 60 kg for one month with respect to 750 g of granular fertilizer. The particle diameter is a ratio of 2 mm or less, and was calculated by the following formula.

  Pulverization rate of granular fertilizer (%) = (weight (g) of particle size of 2 mm or less) / 750 × 100.

  In Examples 1 to 10 and Comparative Examples 1 to 6, particles substantially composed of nitrogen fertilizer components shown in Table 1 (indicated in the table as particle A) and particles substantially composed of magnesium fertilizer components (in the table) A granular fertilizer was produced by molding particles B).

Example 1
80 parts by weight of ammonium sulfate particles (particle A) having a particle size of more than 0.25 mm and not more than 2 mm are 77% by weight and magnesium sulfate monohydrate particles having a particle size of more than 0.25 mm and not more than 2 mm are 69% by weight ( Particle B) 20 parts by weight and 0.7 part by weight of water 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 as a granulator to Briquetta (registered trademark) BSS-IV type (manufactured by Shinto Kogyo), the effective roll width is 185 mm, the roll pressure is 8.3 kN / cm, the burr thickness is 1.70 mm, After granulating at a pocket size of Φ3.9 mm × 0.94 mm and a roller rotation speed of 50 rpm, and crushing with a crusher, three-stage crushing with sieves with openings of 6.7 mm, 5.2 mm, and 2.2 mm The mixture was put into a sieve (manufactured by Kowa Kogyo) and crushed with a crushing media (200 nylon hard ball balls, 200 lower balls). Subsequently, the granulated product was put into a marumerizer (Dalton), and the pulverized product on a sieve was put in, and after granulating for 20 seconds at a rotation speed of 225 rpm, a circular vibrating sieve having a sieve with an opening of 2 mm (Dalton) ) And classified, and a sieved product having a mesh opening of 2 mm was recovered as a granular fertilizer. The yield of granular fertilizer is 80%, the ratio of the particle size of 2 mm to 4 mm is 95%, the major axis diameter is 3.9 mm, the minor axis diameter is 3.55 mm, and the ratio of major axis diameter to minor axis diameter (Major axis diameter / minor axis diameter) is 1.10, particle A in the granular fertilizer having a particle size of more than 0.1 mm and less than 2 mm is 61% by weight, and particle B having a particle size of more than 0.1 mm and less than 2 mm is 60% by weight. %, Ammonium sulfate content was 79% by weight, and magnesium sulfate content was 20% by weight. The ratio of the elution rate of the nitrogen fertilizer component and the magnesium fertilizer component is 1.18, the granular fertilizer has a grain hardness of 3.3 kgf, a bulk density of 0.96 g / ml, a moisture content of 1.0% by weight, One month after the consolidation test, the consolidation rate was 0%, the consolidation strength was 0 kg / cm ² , and the powdering rate was 0.2%.

(Example 2)
70 parts by weight of ammonium sulfate particles (Particle A) having a particle diameter of more than 0.25 mm and 2 mm or less are 71 wt% and magnesium sulfate monohydrate particles having a particle diameter of more than 0.25 mm and 2 mm or less are 65 wt% ( Particle B) A granular fertilizer was produced by mixing, granulating, crushing, sizing, and classifying in the same manner as in Example 1 except that 30 parts by weight and 0.9 part by weight of water were used. The yield of granular fertilizer is 79%, the ratio of the particle size of 2 mm to 4 mm is 95%, the major axis diameter is 3.9 mm, the minor axis diameter is 3.55 mm, and the ratio of major axis diameter to minor axis diameter (Major axis diameter / minor axis diameter) is 1.10, particle A having a particle size of more than 0.1 mm and less than 2 mm in the granular fertilizer is 54% by weight, and particle B having a particle size of more than 0.1 mm and less than 2 mm is 58% by weight. %, The ammonium sulfate content was 69% by weight, and the magnesium sulfate content was 30% by weight. Further, the ratio of the elution rate of the nitrogen fertilizer component and the magnesium fertilizer component is 1.12, the granular hardness of the granular fertilizer is 2.7 kgf, the bulk density is 0.95 g / ml, the moisture content is 1.2% by weight, One month after the consolidation test, the consolidation rate was 0%, the consolidation strength was 0 kg / cm ² , and the powdering rate was 0.3%.

(Example 3)
60 parts by weight of ammonium sulfate particles (particle A) having a particle size of more than 0.25 mm and not more than 2 mm are 75% by weight and magnesium sulfate monohydrate particles having a particle size of more than 0.25 mm and not more than 2 mm are 72% by weight ( Particle B) A granular fertilizer was produced by mixing, granulating, crushing, sizing and classifying in the same manner as in Example 1 except that 40 parts by weight and 1.2 parts by weight of water were used. The yield of granular fertilizer is 74%, the ratio of particle diameter is 2% or more and 4mm or less is 95%, the major axis diameter is 3.9mm, the minor axis diameter is 3.55mm, the ratio of major axis diameter to minor axis diameter (Major axis diameter / minor axis diameter) is 1.10, particle A having a particle size of more than 0.1 mm and less than 2 mm in the granular fertilizer is 58% by weight, and particle B having a particle size of more than 0.1 mm and less than 2 mm is 68% by weight. %, Ammonium sulfate content was 59% by weight, and magnesium sulfate content was 39% by weight. Moreover, the ratio of the elution rate of the nitrogen fertilizer component and the magnesium fertilizer component is 1.14, the granular hardness of the granular fertilizer is 2.4 kgf, the bulk density is 0.95 g / ml, the moisture content is 1.5% by weight, One month after the consolidation test, the consolidation rate was 0%, the consolidation strength was 0 kg / cm ² , and the powdering rate was 0.3%.

(Example 4)
50 parts by weight of ammonium sulfate particles (particle A) having a particle diameter of more than 0.25 mm and not more than 2 mm are 73 wt% and magnesium sulfate monohydrate particles having a particle diameter of more than 0.25 mm and not more than 2 mm are 67 wt% ( Particle B) A granular fertilizer was produced by mixing, granulating, crushing, sizing and classifying in the same manner as in Example 1 except that 50 parts by weight and 1.5 parts by weight of water were used. The yield of granular fertilizer is 72%, the ratio of the particle size of 2mm to 4mm is 95%, the major axis diameter is 3.9mm, the minor axis diameter is 3.50mm, the ratio of major axis diameter to minor axis diameter (Major axis diameter / minor axis diameter) is 1.11, the particle A in the granular fertilizer having a particle size exceeding 0.1 mm and 2 mm or less is 55% by weight, and the particle B having a particle size exceeding 0.1 mm and 2 mm or less is 59% by weight. %, Ammonium sulfate content was 49% by weight, and magnesium sulfate content was 49% by weight. Further, the ratio of the elution rate of the nitrogen fertilizer component and the magnesium fertilizer component is 1.09, the granular hardness of the fertilizer is 2.1 kgf, the bulk density is 0.95 g / ml, the moisture content is 1.8% by weight, The consolidation rate after 1 month of the consolidation test was 0%, the consolidation strength was 0 kg / cm ² , and the powdering rate was 0.6%.

(Example 5)
70 parts by weight of ammonium sulfate particles (particle A) having a particle diameter of more than 0.25 mm and not more than 2 mm are 75% by weight and magnesium hydroxide particles having a particle diameter of more than 0.25 mm and not more than 2 mm are 55% by weight (particle B) A granular fertilizer was produced by mixing, granulating, crushing, sizing, and classifying in the same manner as in Example 1 except that 30 parts by weight and 0.9 parts by weight of water were used. The yield of granular fertilizer is 74%, the ratio of the particle size of 2mm to 4mm is 95%, the major axis diameter is 3.9mm, the minor axis diameter is 3.50mm, the ratio of major axis diameter to minor axis diameter (Major axis diameter / minor axis diameter) is 1.11, particle A having a particle size of more than 0.1 mm and less than 2 mm in the granular fertilizer is 60% by weight, and particle B having a particle size of more than 0.1 mm and less than 2 mm is 54% by weight. %, Ammonium sulfate content was 69% by weight, and magnesium hydroxide content was 30% by weight. Further, the ratio of the elution rate of the nitrogen fertilizer component and the magnesium fertilizer component is 0.95, the granular hardness of the granular fertilizer is 2.3 kgf, the bulk density is 0.94 g / ml, the moisture content is 1.3% by weight, One month after the consolidation test, the consolidation rate was 0%, the consolidation strength was 0 kg / cm ² , and the powdering rate was 0.4%.

(Example 6)
70 parts by weight of ammonium sulfate particles (particle A) having a particle size of more than 0.25 mm and 2 mm or less are 71 wt% and magnesium chloride particles (particle B) 30 having a particle size of more than 0.25 mm and 2 mm or less are 61 wt% A granular fertilizer was produced by mixing, granulating, crushing, sizing and classifying in the same manner as in Example 1 except that the amount was 0.9 parts by weight and water. The yield of granular fertilizer is 71%, the ratio of particle size of 2mm to 4mm is 95%, the major axis diameter is 3.8mm, the minor axis diameter is 3.40mm, the ratio of major axis diameter to minor axis diameter (Major axis diameter / minor axis diameter) is 1.12, particle A having a particle size of more than 0.1 mm and less than 2 mm in the granular fertilizer is 53% by weight, and particle B having a particle size of more than 0.1 mm and less than 2 mm is 57% by weight. %, Ammonium sulfate content was 69% by weight, and magnesium chloride content was 30% by weight. The ratio of the elution rate of the nitrogen fertilizer component and the magnesium fertilizer component is 1.06, the granular hardness of the fertilizer is 2.2 kgf, the bulk density is 0.94 g / ml, the moisture content is 1.2% by weight, One month after the consolidation test, the consolidation rate was 0%, the consolidation strength was 0 kg / cm ² , and the powdering rate was 0.5%.

(Example 7)
70 parts by weight of urea particles (particle A) having a particle size of more than 0.25 mm and not more than 2 mm are 86 wt% and magnesium sulfate monohydrate particles having a particle size of more than 0.25 mm and not more than 2 mm are 70 wt% ( Particle B) A granular fertilizer was produced by mixing, granulating, crushing, sizing and classifying in the same manner as in Example 1 except that 30 parts by weight and 0.5 part by weight of water were used. The yield of granular fertilizer is 70%, the ratio of the particle size of 2 mm to 4 mm is 95%, the major axis diameter is 3.8 mm, the minor axis diameter is 3.40 mm, and the ratio of major axis diameter to minor axis diameter (Major axis diameter / minor axis diameter) is 1.12, particle A having a particle size of more than 0.1 mm and less than 2 mm in the granular fertilizer is 73% by weight, particle B having a particle size of more than 0.1 mm and less than 2 mm is 65% by weight, The urea content was 70% by weight and the magnesium sulfate content was 29% by weight. Moreover, the ratio of the elution rate of the nitrogen fertilizer component and the magnesium fertilizer component is 1.11, the grain hardness of the granular fertilizer is 2.1 kgf, the bulk density is 0.92 g / ml, the moisture content is 1.2% by weight, One month after the consolidation test, the consolidation rate was 0%, the consolidation strength was 0 kg / cm ² , and the powdering rate was 0.9%.

(Example 8)
70 parts by weight of ammonium sulfate particles (particle A) having a particle diameter of more than 0.25 mm and 2 mm or less are 73% by weight and anhydrous magnesium sulfate particles (particle B having a particle diameter of more than 0.25 mm and 2 mm or less are 62% by weight) ) A granular fertilizer was produced by mixing, granulating, crushing, sizing and classifying in the same manner as in Example 1 except that 30 parts by weight and 1.5 parts by weight of water were used. The yield of granular fertilizer is 65%, the ratio of the particle size of 2 mm to 4 mm is 95%, the major axis diameter is 3.9 mm, the minor axis diameter is 3.50 mm, and the ratio of major axis diameter to minor axis diameter (Major axis diameter / minor axis diameter) is 1.11, particle A having a particle size of more than 0.1 mm and not more than 2 mm in the granular fertilizer is 60% by weight, and particle B having a particle size of more than 0.1 mm and not more than 2 mm is 59% by weight. %, The ammonium sulfate content was 69% by weight, and the magnesium sulfate content was 30% by weight. The ratio of the elution rate of the nitrogen fertilizer component and the magnesium fertilizer component is 1.04, the granular hardness of the granular fertilizer is 2.5 kgf, the bulk density is 0.95 g / ml, the moisture content is 1.7% by weight, One month after the consolidation test, the consolidation rate was 0%, the consolidation strength was 0 kg / cm ² , and the powdering rate was 0.5%.

Example 9
70 parts by weight of ammonium sulfate particles (particle A) having a particle diameter of more than 0.25 mm and not more than 2 mm are 71 wt% and magnesium sulfate trihydrate particles having a particle diameter of more than 0.25 mm and not more than 2 mm are 64 wt% ( Particle B) A granular fertilizer was produced by mixing, granulating, crushing, sizing and classifying in the same manner as in Example 1 except that 30 parts by weight and 0.5 parts by weight of water were used. The yield of granular fertilizer is 62%, the ratio of the particle size of 2 mm to 4 mm is 95%, the major axis diameter is 3.8 mm, the minor axis diameter is 3.40 mm, and the ratio of major axis diameter to minor axis diameter (Major axis diameter / minor axis diameter) is 1.12, particle A in the granular fertilizer having a particle size of more than 0.1 mm and less than 2 mm is 54% by weight, and particle B having a particle size of more than 0.1 mm and less than 2 mm is 52% by weight. %, Ammonium sulfate content was 67% by weight, and magnesium sulfate content was 29% by weight. Moreover, the ratio of the elution rate of the nitrogen fertilizer component and the magnesium fertilizer component is 1.13, the grain hardness of the granular fertilizer is 2.1 kgf, the bulk density is 0.95 g / ml, the moisture content is 2.1% by weight, One month after the consolidation test, the consolidation rate was 0%, the consolidation strength was 0 kg / cm ² , and the powdering rate was 0.7%.

(Example 10)
70 parts by weight of ammonium sulfate particles (particle A) having a particle size of more than 0.25 mm and not more than 2 mm are 72% by weight and magnesium sulfate heptahydrate particles having a particle size of more than 0.25 mm and not more than 2 mm are 69% by weight ( Particle B) A granular fertilizer was produced by mixing, granulating, crushing, sizing and classifying in the same manner as in Example 1 except that 30 parts by weight and 0.2 parts by weight of water were used. The yield of granular fertilizer is 60%, the ratio of particle size of 2mm to 4mm is 95%, the major axis diameter is 3.8mm, the minor axis diameter is 3.40mm, the ratio of major axis diameter to minor axis diameter (Major axis diameter / minor axis diameter) is 1.12, particle A having a particle size of more than 0.1 mm and less than 2 mm in the granular fertilizer is 52% by weight, and particle B having a particle size of more than 0.1 mm and less than 2 mm is 50% by weight. %, The ammonium sulfate content was 66% by weight, and the magnesium sulfate content was 26% by weight. The ratio of the elution rate of the nitrogen fertilizer component and the magnesium fertilizer component is 1.19, the granular hardness of the fertilizer is 2.0 kgf, the bulk density is 0.95 g / ml, the moisture content is 2.7% by weight, One month after the consolidation test, the consolidation rate was 0%, the consolidation strength was 0 kg / cm ² , and the powdering rate was 0.9%.

(Comparative Example 1)
40 parts by weight of ammonium sulfate particles (particle A) having a particle size of more than 0.25 mm and not more than 2 mm are 77% by weight and magnesium sulfate monohydrate particles having a particle size of more than 0.25 mm and not more than 2 mm are 69% by weight ( Particle B) A granular fertilizer was produced by mixing, granulating, crushing, sizing and classifying in the same manner as in Example 1 except that 60 parts by weight and 0.7 parts by weight of water were used. The yield of granular fertilizer is 51%, the ratio of particle size between 2mm and 4mm is 95%, the major axis diameter is 3.8mm, the minor axis diameter is 3.30mm, the ratio of major axis diameter to minor axis diameter (Major axis diameter / minor axis diameter) is 1.15, particle A having a particle size of more than 0.1 mm and less than 2 mm in the granular fertilizer is 63% by weight, and particle B having a particle size of more than 0.1 mm and less than 2 mm is 61% by weight. %, The ammonium sulfate content was 39% by weight, and the magnesium sulfate content was 60% by weight. Moreover, the ratio of the elution rate of the nitrogen fertilizer component and the magnesium fertilizer component is 1.18, the grain hardness of the granular fertilizer is 0.9 kgf, the bulk density is 0.95 g / ml, the moisture content is 0.9% by weight, The consolidation rate after one month of the consolidation test was 8.1%, the consolidation strength was 1.8 kg / cm ² , and the powdering rate was 11.3%.

(Comparative Example 2)
70 parts by weight of ammonium sulfate particles (particle A) having a particle diameter of more than 0.25 mm and 2 mm or less are 41 wt% and magnesium sulfate monohydrate particles having a particle diameter of more than 0.25 mm and 2 mm or less are 45 wt% ( Particle B) A granular fertilizer was produced by mixing, granulating, crushing, sizing, and classifying in the same manner as in Example 1 except that 30 parts by weight and 0.9 part by weight of water were used. The yield of granular fertilizer is 59%, the ratio of the particle size of 2mm to 4mm is 95%, the major axis diameter is 3.8mm, the minor axis diameter is 3.50mm, the ratio of major axis diameter to minor axis diameter (Major axis diameter / minor axis diameter) is 1.09, the particle A in the granular fertilizer having a particle size of more than 0.1 mm and less than 2 mm is 35% by weight, and the particle B having a particle size of more than 0.1 mm and less than 2 mm is 40% by weight. %, The ammonium sulfate content was 69% by weight, and the magnesium sulfate content was 30% by weight. Moreover, the ratio of the elution rate of the nitrogen fertilizer component and the magnesium fertilizer component is 1.19, the grain hardness of the granular fertilizer is 1.5 kgf, the bulk density is 0.95 g / ml, the moisture content is 1.2% by weight, The consolidation rate after one month of the consolidation test was 4.8%, the consolidation strength was 1.5 kg / cm ² , and the powdering rate was 1.8%.

(Comparative Example 3)
70 parts by weight of ammonium sulfate particles (particle A) having a particle size of more than 0.25 mm and not more than 2 mm are 77% by weight and magnesium sulfate monohydrate particles having a particle size of more than 0.25 mm and not more than 2 mm are 11% by weight ( Particle B) A granular fertilizer was produced by mixing, granulating, crushing, sizing and classifying in the same manner as in Example 1 except that 30 parts by weight and 0.7 parts by weight of water were used. The yield of granular fertilizer is 45%, the ratio of particle size of 2mm to 4mm is 95%, the major axis diameter is 3.8mm, the minor axis diameter is 3.55mm, the ratio of major axis diameter to minor axis diameter (Major axis diameter / minor axis diameter) is 1.07, particle A having a particle size of more than 0.1 mm and less than 2 mm in the granular fertilizer is 65% by weight, and particle B having a particle size of more than 0.1 mm and less than 2 mm is 15% by weight. %, Ammonium sulfate content was 70% by weight, and magnesium sulfate content was 29% by weight. The ratio of the elution rate of the nitrogen fertilizer component and the magnesium fertilizer component is 0.67, the granular hardness of the fertilizer is 1.7 kgf, the bulk density is 0.95 g / ml, the moisture content is 1.0% by weight, One month after the consolidation test, the consolidation rate was 0%, the consolidation strength was 0 kg / cm ² , and the powdering rate was 0.8%.

(Comparative Example 4)
70 parts by weight of ammonium sulfate particles (particle A) having a particle size of more than 0.25 mm and not more than 2 mm are 9% by weight and magnesium sulfate particles monohydrate having a particle size of more than 0.25 mm and not more than 2 mm is 66% by weight ( Particle B) A granular fertilizer was produced by mixing, granulating, crushing, sizing and classifying in the same manner as in Example 1 except that 30 parts by weight and 0.7 parts by weight of water were used. The yield of granular fertilizer is 31%, the ratio of the particle size of 2 mm to 4 mm is 95%, the major axis diameter is 3.6 mm, the minor axis diameter is 3.3 mm, and the ratio of the major axis diameter to the minor axis diameter (Major axis diameter / minor axis diameter) is 1.09, particle A in the granular fertilizer having a particle size of more than 0.1 mm and less than 2 mm is 25% by weight, and particle B having a particle size of more than 0.1 mm and less than 2 mm is 57% by weight. %, The ammonium sulfate content was 69% by weight, and the magnesium sulfate content was 30% by weight. The ratio of the elution rate of the nitrogen fertilizer component and the magnesium fertilizer component is 1.64, the granular hardness of the fertilizer is 1.0 kgf, the bulk density is 0.94 g / ml, the moisture content is 1.0% by weight, The consolidation rate after one month of the consolidation test was 2.4%, the consolidation strength was 1.2 kg / cm ² , and the powdering rate was 5.4%.

(Comparative Example 5)
Mixing and granulating in the same manner as in Example 1 except that 100 parts by weight of ammonium sulfate particles (Particle A) having a particle diameter of more than 0.25 mm and 2 mm or less were 74 parts by weight and water was 0.7 parts by weight. Granular fertilizer was produced by crushing, sizing and classification. The yield of granular fertilizer is 65%, the ratio of the particle size of 2mm to 4mm is 96%, the major axis diameter is 3.9mm, the minor axis diameter is 3.55mm, the ratio of major axis diameter to minor axis diameter The (major axis diameter / minor axis diameter) was 1.10, and the particle A having a particle diameter of more than 0.1 mm and not more than 2 mm in the granular fertilizer was 62% by weight. The granular fertilizer has a grain hardness of 2.8 kgf, a bulk density of 0.96 g / ml, a moisture content of 1.0% by weight, a consolidation rate after one month of consolidation test of 3.8%, and a consolidation strength of The powdering rate was 0.5% at 0.5 kg / cm ² .

(Comparative Example 6)
The same method as in Example 1, except that 100 parts by weight of magnesium sulfate monohydrate particles (particles B) having a particle size of more than 0.25 mm and 2 mm or less were 0.7% by weight and water was 0.7 parts by weight. A granular fertilizer was produced by mixing, granulating, crushing, sizing and classifying. The yield of granular fertilizer is 41%, the ratio of the particle size of 2 mm to 4 mm is 94%, the major axis diameter is 3.6 mm, the minor axis diameter is 3.0 mm, and the ratio of the major axis diameter to the minor axis diameter The (major axis diameter / minor axis diameter) was 1.20, and the particle B having a particle diameter exceeding 0.1 mm and not more than 2 mm in the granular fertilizer was 60% by weight. The granular fertilizer has a grain hardness of 0.8 kgf, a bulk density of 0.95 g / ml, a moisture content of 0.9 wt%, a consolidation rate after 1 month of consolidation test of 0%, and a consolidation strength of 0 kg / cm ² , and the powdering rate was 27.6%.

  The results are shown in Table 1.

  As explained above, the particle size distribution of particles (particle A) substantially composed of nitrogen fertilizer components as raw materials and particles (particle B) substantially composed of magnesium fertilizer components, and the quantitative ratio of particles A and particles B In a predetermined range, the elution rate of the nitrogen fertilizer component and the magnesium fertilizer component is uniform, the particle hardness after secondary particle formation is high, the fertilizer yield after production is high, and the fertilizer is spherical and fertilizer It can be seen that it is possible to obtain a granular fertilizer that is not easily pulverized during storage and does not cause consolidation.

The granular fertilizer according to the present invention is not pulverized and solidified during storage and does not deteriorate in fluidity, and can be applied not only to fertilization by humans on a small farm but also to machine spraying on a large farm. . Moreover, since it can be made into the bulk blend fertilizer which dry blended granular fertilizer with other granular fertilizers in arbitrary ratios according to a use and the objective, it can be used for growth of rice, vegetables, fruits, etc.

Claims (16)

A granular fertilizer in which particles substantially composed of a nitrogen fertilizer component (particle A) and particles substantially composed of a magnesium fertilizer component (particle B) are integrated to form secondary particles, and the particle A has a particle size Particles greater than 0.1 mm and less than or equal to 2 mm occupy 50% by weight or more in particle A, particle B has a particle size greater than 0.1 mm and particles less than or equal to 2 mm account for greater than 50% by weight in particle B, and A granular fertilizer comprising 50 to 80% by weight of a nitrogen fertilizer component and 20 to 50% by weight of a magnesium fertilizer component in the granular fertilizer. The granular fertilizer according to claim 1, wherein 0.3 to 2.0% by weight of water is contained in the granular fertilizer. The granular fertilizer according to claim 1, wherein the granular fertilizer has a grain hardness of 2 kgf or more after forming secondary particles. The granule according to any one of claims 1 to 3, wherein a ratio of a major axis diameter to a minor axis diameter (major axis diameter / minor axis diameter) of the granular fertilizer is 1.0 or more and 1.4 or less. fertilizer. The granular fertilizer according to any one of claims 1 to 4, wherein a bulk density of the granular fertilizer is 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 the nitrogen fertilizer component is at least one selected from ammonium sulfate, ammonium chloride, ammonium nitrate, ammonium phosphate, and urea. The granular fertilizer according to any one of claims 1 to 6, wherein the magnesium fertilizer component is at least one selected from magnesium sulfate, magnesium chloride, magnesium nitrate, magnesium hydroxide, and magnesium carbonate. The magnesium sulfate is at least one selected from the group consisting of magnesium sulfate anhydride, magnesium sulfate monohydrate, magnesium sulfate trihydrate, and magnesium sulfate heptahydrate. The described granular fertilizer. A method for producing a granular fertilizer in which particles (particle A) substantially composed of a nitrogenous fertilizer component and particles (particle B) substantially composed of a magnesium fertilizer component are integrated to form secondary particles. A having a particle size of more than 0.25 mm and not more than 2 mm accounts for 70% by weight or more in particle A, and particle B has a particle size of more than 0.25 mm and not more than 2 mm in particle B The process which occupies 50 weight% or more and mixes particle | grain A with 50-80 weight% and particle | grain B with 20-50 weight% in presence of a water | moisture content with respect to the whole weight of a granular fertilizer, and obtains a mixture A method for producing granular fertilizer, comprising a step of forming the mixture to form secondary particles. The method for producing granular fertilizer according to claim 9, wherein the granular fertilizer is molded so that a ratio of a major axis diameter to a minor axis diameter of the granular fertilizer is 1.0 or more and 1.4 or less. The method for producing a granular fertilizer according to claim 9 or 10, wherein the granular fertilizer is molded so that a bulk density is 0.9 g / ml or more and 1.1 g / ml or less. The method for producing granular fertilizer according to any one of claims 9 to 11, wherein a molding method for forming the secondary particles is compression granulation. The method for producing granular fertilizer according to claim 12, wherein the compression granulation is performed by a briquette method using a pair of rollers. The method for producing granular fertilizer according to claim 12 or 13, wherein the compression granulation has 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 9 to 14, wherein as the molding step, compression granulation is performed to obtain a granulated product, and then granulated. The method for producing a granular fertilizer according to claim 15, wherein the sizing is a rotary sizing method.