JP2007217231A - Lime nitrogen granular fertilizer and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lime nitrogen granular fertilizer having high hardness to suppress powdering in storage and high cyanamide content. <P>SOLUTION: The lime nitrogen granular fertilizer is granulated with saccharide and has ≥30 mass% powdering residual ratio. It is preferable that the powdering residual ratio is ≥50 mass%. the saccharide is at least one kind selected from sucrose, lactose and glucose, the content of the saccharide is 2-20 mass%, average hardness is 5-15 kg/piece and the powering residual ratio is ≥80 mass%. The method of manufacturing the lime nitrogen granular fertilized is carried out by granulating a powdery mixture of raw material powder of the lime nitrogen fertilizer with the saccharide and heating at a temperature equal to or higher than the melting point of the saccharide. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to a lime nitrogen granular fertilizer and a method for producing the same.

Lime nitrogen is a nitrogen fertilizer mainly composed of calcium cyanamide. Since this cyanamide nitrogen has a pesticide effect and a slow-release nitrogen effect, lime nitrogen is used in anticipation of these effects. For example, if fertilizer containing enough cyanamide is fertilized, it shows herbicidal effect, and the remaining period with ammonia nitrogen is long, and the amount of nitrate nitrogen that is washed away by rainwater is small, so it can be applied to crops over a long period of time. Nitrogen can be supplied.

Powdered lime nitrogen is granulated either alone or in combination with other powdered fertilizers in order to easily spread when sprayed, or for the convenience of being sprayed simultaneously with other fertilizer components such as phosphoric acid and potassium fertilizer. It has been done. Examples of the granulation method include a wet granulation method using water (Patent Document 1) and a dry granulation method using urea or the like as a binder (Patent Document 2).

In the wet method, free lime (CaO) contained in lime nitrogen at a maximum of about 30% by mass is slaked to cause volume expansion and the granulated product is pulverized. It is necessary to mix and age a small amount of water in nitrogen, and calcify a part or all of CaO in lime nitrogen in advance. However, this slaked calcification treatment causes the cyanamide component to volatilize as ammonia or dimerize to denature it into dicyandiamide, resulting in a 20-30% decrease in the angle cyanamide-like nitrogen, and the effectiveness of calcium cyanamide. Sexuality is impaired. In addition, the hardness of the granulated product is small, and there is also a problem that the granulated product is easily broken during transportation or in the storage of fertilizer bags.

In the dry method, reduction of cyanamide nitrogen based on slaked calcification is not observed, but urea-derived nitrogen is included. Therefore, since fertilization to a crop is performed on the basis of the fertilizer component amount, when the nitrogen component is fertilized in the same amount, the amount of cyanamide nitrogen applied is reduced.

Furthermore, in any of the wet method and the dry method, the average particle diameter of the lime nitrogen raw material powder before granulation is 200 to 600 μm, and the average hardness is about 3 kg / piece of low hardness. Only particles could be obtained.
Japanese Patent Laid-Open No. 52-150280 Japanese Patent No. 3484775

An object of the present invention is to provide a lime-nitrogenous granular fertilizer that has high hardness, suppresses pulverization during storage, and has a high cyanamide content.

The present invention is a lime-nitrogenous granular fertilizer that is granulated with saccharides and has a pulverization residual rate of 30% by mass or more. In the present invention, the residual rate of powdering is 50% by mass or more, the saccharide is at least one selected from sucrose, lactose and glucose, the saccharide content is 2 to 20% by mass, and the average hardness Is preferably 5 to 15 kg / piece, and the residual rate of pulverization is 80% by mass or more.

Moreover, this invention is the manufacturing method of the lime nitrogenous granular fertilizer characterized by heating the raw material powder of lime nitrogenous fertilizer, and saccharides, after granulating, and heating above melting | fusing point of saccharides. In this invention, it is also possible that a part or all of the raw material powder of lime nitrogenous fertilizer is replaced with coarse powder of raw material powder of lime nitrogenous fertilizer having an average particle size of 200 to 600 μm.

In the present invention, “lime nitrogenous fertilizer” means a composition composed of lime nitrogen alone or an inorganic fertilizer containing at least 15% by mass of lime nitrogen, and can be coexisted in addition to lime nitrogen. Examples of fertilizers include phosphorus components, potassium components, and bitter earth components. Examples of phosphorus components include superphosphate lime, molten phosphorus fertilizer, calcined phosphorus fertilizer, and calcined heavy fermented phosphorus. Examples of potassium components include sulfated potassium, chlorinated potassium, and silicic acid potassium. Examples of the soil component include magnesium oxide, magnesium sulfate, magnesium hydroxide and the like. Furthermore, trace components such as boron oxide, manganese oxide iron oxide, zinc oxide, copper oxide and the like can be included as trace components necessary for plant growth.

According to the present invention, a lime nitrogen granular fertilizer having high hardness, suppressing pulverization during storage, and having a high cyanamide content is provided.

The saccharide used in the present invention preferably has a melting point of 250 ° C. or lower, and among them, selected from sucrose (for example, melting point 180 ° C.), lactose (for example, melting point 202 to 252 ° C.) and glucose (for example, melting point 86 to 147 ° C.). Preferably, at least one selected from the above is used. Examples of those containing these sugars include granulated sugar, tri-warm sugar, and white sugar. In addition to these saccharides, examples of saccharides that can be used in the present invention include fructose (for example, melting point 102 to 104 ° C.) and maltose (for example, melting point 102 to 103 ° C.).

The reason why at least one saccharide selected from sucrose, lactose and glucose is preferable is that the hardness of the granular fertilizer is increased, it is a solid solid particle at room temperature and easy to handle, and it is a normal granulating binder. For example, it is much safer than polymer binders such as polyvinyl alcohol and methyl acrylate-methacrylic acid copolymer, and is water-soluble and easily decomposed by microorganisms in the soil. It does not remain.

The saccharide content is preferably 2 to 20% by mass, particularly preferably 7 to 12% by mass. If it is less than 2% by mass, granulated particles with high hardness cannot be obtained. Although there is no restriction | limiting in particular in the upper limit of the content rate of saccharides, When it increases, since the fertilizer component will decrease and it will cause the increase of a spreading amount, it is preferable that it is 20 mass%. The average particle diameter is preferably 1 to 5 mm, and the average hardness (Kiya hardness meter) is preferably 5 to 15 kg / piece.

The lime nitrogenous granular fertilizer of the present invention can be produced, for example, by the method for producing the lime nitrogenous granular fertilizer of the present invention. In the production method of the present invention, the mixed powder of lime nitrogenous fertilizer raw material powder and saccharide is compression-molded using a compression molding machine such as a compression molding machine such as tableting, a roll press molding machine, etc. It is heated above its melting point. The particle size of the granulated product before the heat treatment is preferably adjusted to 1 to 5 mm. Moreover, it is preferable that heating temperature is 20 degreeC or more higher than melting | fusing point of saccharides, especially 30-60 degreeC higher temperature. The heating time is, for example, 10 to 120 minutes. The atmosphere for the heat treatment is sufficient in the air.

According to the production method of the present invention, even if the average particle diameter of the lime nitrogenous fertilizer is 200 to 600 μm, it is possible to easily produce a granular material having an average hardness of 5 to 15 kg / piece. In addition, it is possible to effectively utilize coarse powder etc. produced as a by-product in the granulating operation of lime nitrogenous fertilizer. The substitution rate of the raw material powder of the lime nitrogenous fertilizer with coarse powder having an average particle diameter of 200 to 600 μm is preferably 70% by mass or less, particularly preferably 10 to 60% by mass.

Examples 1-9
The raw material powder and saccharide were mixed in the ratio shown in Table 1. The lime nitrogen fertilizer used is 24.5% total nitrogen and 23.3% internal cyanamide nitrogen. The average particle diameter measured with a laser diffraction particle size distribution analyzer is 120 μm. In Example 2, a tablet molding machine was used and molded into a granular material having a diameter of 10 mm. Except for Example 2, a roll press machine was used to produce a plate-like compression molded product having a length of several to several tens of cm by compression molding. These molded products were pulverized and passed through a granulator having a 1 mm aperture and a 5 mm screen to regulate the particle size to 1 to 5 mm. Put this in a constant temperature and temperature chamber, heat-treat in the atmosphere at 30 ° C higher than the melting point of saccharides for 30 minutes, then use a vibrating screen with a mesh opening of 2 mm to release the fusion between the particles to produce granular fertilizer did.

Example 10
A granular fertilizer was produced in the same manner as in Example 4 except that 50% by mass of the lime nitrogenous fertilizer having an average particle size of 340 μm substituted with coarse powder of lime nitrogenous fertilizer was used.

Comparative Example 1
A granular fertilizer was produced in the same manner as in Example 1 except that no heat treatment was performed after granulation.

Comparative Example 2
A granular fertilizer was produced in the same manner as in Example 4 except that the ratio of glucose was 1% by mass.

Comparative Example 3
10 parts by mass of water was added to 100 parts by mass of the lime nitrogen fertilizer shown in Table 1, and mixed with a mortar mixer for 1 hour. The slaked lime-nitrogen fertilizer, dissolved phosphorus fertilizer, and potassium sulfate were mixed using a Henschel mixer to prepare a raw material powder. This was introduced into a bread granulator rotating at 30 rpm, and tumbling granulated while spraying water appropriately. The obtained granulated material was dried at 110 ° C. with a ventilation constant temperature dryer to produce a granular fertilizer.

Comparative Example 4
A mixed raw material was prepared using a mortar mixer. This was granulated using an extrusion molding machine equipped with a disk die heated to the melting point of urea, and then cooled at normal temperature to produce a granular fertilizer. The total nitrogen of urea used was 46.0%.

The conditions of the roll press are: roll diameter 16 cm, width 6 cm, roll clearance 0.5 mm, roll rotation speed 15 rpm, and compression pressure per roll width 1 cm is 250 MPa. The tablet molding conditions are a compression pressure of 200 MPa and a compression time of 1 minute. The bread-type granulation conditions are a bread diameter of 80 cm and a bread rotation speed of 30 rpm. The extrusion molding conditions are a two-roller type, a disk die diameter of 200 mm, and a diameter of 2.5 mm.

The average hardness, powdered residual rate, cyanamide nitrogen loss rate, ammonia nitrogen concentration after 30 days, and herbicidal effect of the obtained granular fertilizer were measured as follows. The results are shown in Table 1.

(1) Average hardness of granular fertilizer: Using a Kiyama-type hardness meter, compressive fracture of each granular fertilizer particle of 2 to 3 mm diameter, measure the maximum weight at that time, and show the average value of 20 particles It was.
(2) Powdered residual rate of granular fertilizer: 150 × 200 × 0.1 mm ethylene vinyl acetate copolymer bag (moisture permeability 33.3 g / m ² · day, JIS K7129 cup method) 1-5 mm granular 250 g of fertilizer was added and sealed by heat sealing, and left in a constant temperature and humidity chamber of 35 ° C. × 80% RH for 4 days, and then shaken for 10 minutes on a low-tap shaker using a sieve with an opening of 1 mm. The residual rate of the above particles was determined.

(3) Total nitrogen content: Granular fertilizer was pulverized in a mortar and passed through a 0.5 mm sieve as an analytical sample, and measured by Kjeldahl decomposition / steam distillation.
(4) Cyanamide nitrogen content: The amount of cyanamide nitrogen was measured by a silver nitrate / potassium thiocyanate titration method.
(5) Cyanamide nitrogen residual ratio: The amount of cyanamide nitrogen was measured by the silver nitrate / potassium thiocyanate titration method as in (4), and the ratio to the amount of cyanamide originally contained in the lime nitrogen used was calculated.

(6) Ammonia nitrogen concentration after 30 days: In order to evaluate the slow-acting effect, the amount of ammonia nitrogen remaining after 30 days after application to soil was measured. To a 70 ml plastic bottle, 30 g of surface humic black soil and dry soil and water were added. The amount of water added was 60% by mass of the maximum water capacity of the soil. Particulate fertilizer with an amount of nitrogen equivalent to 20 mg was buried almost at the center of the soil, and the upper part of the bottle was covered with aluminum foil. The plastic bottle was stored in a thermo-hygrostat adjusted to saturated humidity at 20 ° C. for 30 days, and then the amount of ammonia nitrogen in the soil was quantified.

(7) Herbicidal effect: The soil collected from the field was air-dried and placed in a planter having a width of 20 cm, a length of 50 cm and a depth of 20 cm. After spraying the granular fertilizer of Example 2 on the soil surface in the ratio of 127.7g per planter (equivalent to 12g as a total nitrogen component amount) to two planters, it left still in the greenhouse where water was irrigated with the sprayer. When the soil surface dries during the stationary period, watering was appropriately performed with a sprayer, and the number of weeds was measured after 30 days. Two planters were used, and the total number of weeds was listed in the table. For the granular fertilizers of Examples 3 to 6 and Comparative Examples 3 and 4 and the commercially available urea fertilizer (reference example), the total nitrogen application amount was sprayed to 12 g on separate planters, and similarly for two planters. The number of weeds was measured. When the urea fertilizer (reference example) was used, 131 weeds were generated.

(8) Comprehensive evaluation: Of three items of average hardness, powdered residual rate, and ammonia nitrogen concentration after 30 days, average hardness is less than 5 kg / piece, powdered residual rate is less than 80% by mass, ammonia nitrogen after 30 days Satisfy all conditions with a concentration of less than 10 mg / 100 g dry soil. ◎ If only one is not reached, ○ Two or more not reached, or even if one is not reached, it is 30 In the case of the ammonia nitrogen concentration after a day, it was set as x.

Table 1 shows the following. The granular fertilizer of the present invention has a higher average hardness than Comparative Examples 1 to 3, and a higher pulverization residual rate than Comparative Examples 1 and 2, and an ammonia nitrogen concentration 30 days after Comparative Examples 3 and 4. Was expensive. Moreover, since urea was not used like the comparative example 4, the ratio of the cyanamide nitrogen which occupies in all the nitrogen was large. For this reason, when nitrogen fertilization of the same quantity is performed, it is excellent in the slow release effect and the herbicidal effect of the fertilizer which are the outstanding properties of cyanamide. Further, as in Example 10, even though the raw material powder of lime nitrogenous fertilizer is a coarse powder having an average particle size of about 340 μm, the average hardness, the residual rate of pulverization, and the residual rate of cyanamide nitrogen are all. Excellent granular fertilizer was produced.

Claims (6)

Lime nitrogenous granular fertilizer which is granulated with saccharides and has a pulverization residual rate of 30% by mass or more. 2. The lime nitrogenous granular fertilizer according to claim 1, wherein the residual rate of pulverization is 50% by mass or more. The lime nitrogenous granular fertilizer according to claim 1 or 2, wherein the saccharide is at least one selected from sucrose, lactose and glucose. The content of saccharides is 2 to 20% by mass, the average hardness is 5 to 15 kg / piece, and the residual rate of pulverization is 80% by mass or more. Granular fertilizer. A method for producing lime-nitrogenous granular fertilizer, comprising granulating a mixed powder of raw material powder of lime-nitrogenous fertilizer and saccharide and then heating at a temperature equal to or higher than the melting point of saccharide. 6. The production method according to claim 5, wherein a part or all of the raw material powder of lime nitrogenous fertilizer is replaced with the raw material powder of lime nitrogenous fertilizer having an average particle size of 200 to 600 [mu] m.