JP7330772B2 - fertilizer - Google Patents

Description

The present invention relates to fertilizers. In particular, the present invention relates to fertilizers bearing phosphorus and iron.

A technique for improving soil properties such as soil permeability by mixing charcoal into soil is known. For example, there is known a technique for improving soil properties using carbonized materials obtained by carbonizing biomass such as trees and agricultural products. In such a technique, by heating biomass in a state in which oxygen is shut off, oxygen atoms and hydrogen atoms are desorbed from the biomass to produce carbides composed of carbon and ash.

However, considering the costs involved in producing the above-mentioned charcoal, the use of the charcoal just for soil improvement is not worth the production cost.

On the other hand, carbides are known to be porous and therefore have a very large surface area. Taking advantage of this large surface area, carbides are used as adsorbents for various substances. For example, a technology has been developed in which phosphorus is adsorbed using a calcium-supporting carbide, and the phosphorus-adsorbed carbide is buried in agricultural land, so that the phosphorus-adsorbed carbide is used as a fertilizer.

For example, Patent Document 1 describes a method of using charcoal carrying a water-soluble condensed phosphate as a fertilizer. As described in Patent Document 1, one example of phosphoric acid used as a phosphate fertilizer is in the form of orthophosphoric acid.

JP-A-10-017390

Orthophosphoric acid binds to metals in soil such as calcium, iron, aluminum, etc. to form sparingly soluble salts, resulting in so-called disabling. For this reason, the utilization efficiency of orthophosphoric acid as a fertilizing component for crops of phosphate fertilizer applied to the soil is low at about 10 to 15%, and the remaining about 90 to 85% is poorly soluble in the soil. turn into. Therefore, orthophosphoric acid has a low utilization efficiency as a fertilizer component for crops. Further, even when the technique described in Patent Document 1 is used, since the phosphate of Patent Document 1 is water-soluble, the phosphate is easily water-soluble when buried in soil as a fertilizer. There was a problem that the fertilizing effect does not last because it dissolves in water and flows out.

One embodiment of the present invention has been made in view of the above problems, and an object thereof is to provide a fertilizer capable of using fertilizing components for crops for a long period of time.

A fertilizer according to one embodiment of the present invention is a fertilizer containing a carrier that supports phosphorus and iron, the ratio of citric-soluble phosphoric acid to the total amount of phosphoric acid in the fertilizer is 18% or more, and The ratio of water-soluble phosphoric acid to the total amount of phosphoric acid is 1% or less.

The carrier may be a porous body.

The porous body may contain carbide.

The phosphorus and iron may be present in the pores of the porous body.

A ratio of the iron to the fertilizer may be 1% by mass or more and 50% by mass or less.

A ratio of the total amount of phosphoric acid to the fertilizer may be 1% by mass or more and 20% by mass or less.

A ratio of the citric soluble phosphoric acid to the fertilizer may be 0.03% by mass or more and 15% by mass or less.

The phosphoric acid total amount, the citric acid phosphoric acid, and the water-soluble phosphoric acid may be determined by ammonium vanadomolybdate absorption photometry.

A ratio of soluble phosphoric acid to the fertilizer may be 0.03% by mass or more and 15% by mass or less.

The soluble phosphoric acid may be determined by ammonium vanadomolybdate spectrophotometry.

A ratio of sulfur supported on the carrier to the fertilizer may be 3% by mass or less.

The phosphorus carried on the carrier may include inorganic phosphorus and organic phosphorus.

ADVANTAGE OF THE INVENTION According to one Embodiment of this invention, the fertilizer which can utilize a fertilizing effect component with respect to crops for a long period of time can be provided.

It is a figure which shows the cross-section of the fertilizer which concerns on one Embodiment of this invention. It is a flow chart which shows a manufacturing method of fertilizer concerning one embodiment of the present invention. 1 is a cross-sectional view showing the pore shape of a porous material used for a carrier according to one embodiment of the present invention; FIG.

Hereinafter, a fertilizer and a method for producing the fertilizer according to one embodiment of the present invention will be described with reference to the drawings. However, the fertilizer and method of producing the fertilizer in one embodiment of the present invention can be implemented in many different aspects and should not be construed as limited to the description of the examples given below. In the drawings referred to in the present embodiment, the same parts or parts having similar functions are given the same reference numerals or letters after the same reference numerals, and repetitive description thereof may be omitted.

In the following embodiments, a configuration in which a carbonized material obtained by carbonizing wood is used as a carrier for phosphorus and iron used in fertilizer will be exemplified, but the configuration is not limited to this. For example, a carbonized material obtained by carbonizing an organic substance other than wood may be used as the carrier. Also, a porous member other than carbide may be used as the carrier. Also, the techniques of different embodiments can be combined unless there is a particular technical contradiction.

In the following embodiments, the pore size of the porous material is referred to as the pore size, and the size of the particulate matter is referred to as the particle size. The pore diameter refers to the size of a pore in a cross section perpendicular to the direction in which the pore extends, unless otherwise specified. However, if the pore does not have a longitudinal dimension, the pore size refers to the size of the pore in any given cross section. The pore diameter may be the circle-equivalent diameter of the pores in any cross-section, or may be the maximum diameter or average diameter in the cross-section. Similarly, the particle diameter may be the equivalent circle diameter of the particulate matter in any cross-sectional view or projection plane, or may be the maximum diameter or average diameter in the cross-sectional view or projection plane.

In the following embodiments, unless otherwise specified, "total amount of phosphoric acid", "citric acid phosphoric acid", "water-soluble phosphoric acid", and "soluble phosphoric acid" are determined by ammonium vanadomolybdate spectrophotometry. Show what you want. Citric-soluble phosphoric acid refers to phosphoric acid that does not dissolve in water but dissolves in a 2% citric acid solution. Citric-soluble phosphoric acid does not immediately dissolve in a weak acid that is about the same as root acid released from the roots of crops, but it dissolves in slightly stronger acids than root acid, so it gradually dissolves from fertilizers and provides long-term fertilizing effects. can. Water-soluble phosphoric acid refers to phosphoric acid that dissolves in water. Since water-soluble phosphoric acid quickly dissolves in water contained in soil and is absorbed by crops, it is possible to obtain a fast-acting fertilizing effect. Soluble phosphoric acid refers to phosphoric acid that does not dissolve in water but dissolves in root acid released from roots. Soluble phosphate is less fast-acting than water-soluble phosphate, but is absorbed by crops faster than citric phosphate. Further, for example, the ratio of the total amount of phosphoric acid to the mass of fertilizer is the total amount of phosphoric acid (P ₂ O ₅ ) mass ratio.

[Ammonium vanadomolybdate spectrophotometry]
The ammonium vanadomolybdate spectrophotometry method is a test method based on Fertilizer Test Methods (2018). The test method for fertilizers, etc. is a test method established by the Ministry of Agriculture, Forestry and Fisheries, and is a test method in which the reagents, equipment, etc. used in the test are specified by JIS standards and the like. The total amount of phosphoric acid, citric acid phosphoric acid, water-soluble phosphoric acid, and soluble phosphoric acid described in the following embodiments are described in the ammonium vanadomolybdate spectrophotometry method of the Fertilizer Test Method (2018). Since it is determined by the method, detailed description is omitted.

[Configuration of Fertilizer 10]
The structure of the fertilizer 10 according to this embodiment will be described with reference to FIGS. 1 and 2. FIG. In this embodiment, a configuration in which a carbonized material (porous body) obtained by carbonizing wood is used as the carrier 100 used for the fertilizer 10 will be described.

FIG. 1 is a diagram showing a cross-sectional structure of fertilizer according to one embodiment of the present invention. The cross-sectional view shown in FIG. 1 is a cross-sectional view perpendicular to the direction in which the holes 200 of the carrier 100 extend. That is, each hole 200 extends in the depth direction of the drawing.

As shown in FIG. 1 , the fertilizer 10 has a carrier 100 , phosphorus-adsorbed iron (hereinafter referred to as “phosphorus-adsorbed iron 600 ”), iron oxide 800 , and/or iron sulfide 900 . The phosphorus-adsorbed iron 600 exists inside the pores 200 (macropores 200 described later) of the carrier 100 . In other words, the carrier 100 carries phosphorus and iron. Phosphorus-adsorbed iron 600 is contained in the inner wall 201 of the pore 200 .

The shape of the phosphorus-adsorbed iron 600 is fibrous. Fibrous phosphorus-adsorbed iron 600 is composed of a plurality of linear bodies 610 . One end or both ends of linear body 610 may be attached to inner wall 201 . Alternatively, one end or both ends of linear body 610 may be fixed to inner wall 201 . By fixing one or both ends of the linear body 610 to the inner wall 201 , the phosphorus-adsorbing iron 600 is held inside the hole 200 . A large number of linear bodies 610 are present inside the holes 200, so that the phosphorus-adsorbed iron 600 forms a fibrous shape. That is, in the following description, the filamentous body 610 means part of the fibrous phosphorus-adsorbed iron 600 . For convenience of explanation, the phosphorus-adsorbed iron 600 inside the hole 200 drawn in the lower part of FIG. 1 is omitted.

Since the phosphorus-adsorbed iron 600 inside the hole 200 is fibrous, the interior of the hole 200 is not completely filled with the phosphorus-adsorbed iron 600, and the space where the phosphorus-adsorbed iron 600 does not exist continues in the extending direction of the hole 200. extended. Further, since the phosphorus-adsorbed iron 600 is fibrous, the phosphorus-adsorbed iron 600 exists not only on the inner wall of the hole 200 but also in the space inside the hole 200 . Here, since the hole 200 and the phosphorus-adsorbing iron 600 extend in the depth direction of the figure, when the hole 200 is viewed in the extension direction of the hole 200, the phosphorus-adsorbing iron 600 seems to fill the internal space of the hole 200. looks like

[Proportion of phosphoric acid in Fertilizer 10]
The ratio of citric-soluble phosphoric acid to the total amount of phosphoric acid in the fertilizer 10 (citric-soluble phosphoric acid ratio) is 18% or more, 20% or more, 25% or more, or 30% or more. On the other hand, the ratio of water-soluble phosphoric acid to the total amount of phosphoric acid in the fertilizer 10 (water-soluble phosphoric acid ratio) is 1% or less, 0.8% or less, 0.6% or less, or 0.5% or less. Alternatively, the citric acid ratio is 10 times or more, 15 times or more, 20 times or more, or 30 times or more the water-soluble phosphoric acid ratio. The total amount of phosphoric acid and citric soluble phosphoric acid described above were determined by the ammonium vanadomolybdate absorption photometry method as described above. Thus, the fertilizer 10 according to the present embodiment has a higher citric-soluble phosphoric acid ratio than the water-soluble phosphoric acid ratio.

As described above, citric phosphate is gradually dissolved from the fertilizer, and the fertilizer effect can be obtained for a long period of time. In the fertilizer 10 according to the present embodiment, the citric soluble phosphoric acid ratio is larger than the water-soluble phosphoric acid ratio, so that the fertilizing components of the fertilizer 10 for crops can be used for a long period of time. In addition, when the citric-soluble phosphoric acid ratio is smaller than the above lower limit, it may not be possible to obtain a sufficient fertilizer effect as a fertilizer. In addition, if the water-soluble phosphoric acid ratio is greater than the above upper limit, phosphorus will immediately dissolve and flow out of the fertilizer when the fertilizer is buried in the soil, so the fertilizer effect cannot be sufficiently maintained. Sometimes.

The ratio of iron contained in the phosphorus-adsorbed iron 600 to the fertilizer 10 is 1% by mass or more and 50% by mass or less, 3% by mass or more and 30% by mass or less, 5% by mass or more and 25% by mass or less, 10% by mass or more and 20% by mass or less. is. The mass of iron contained in the fertilizer 10 can be obtained by a method such as an inductively coupled plasma mass spectrometer (ICP-MS). By setting the ratio of the iron contained in the phosphorus-adsorbed iron 600 to the fertilizer 10 within the above range, the content of phosphoric acid in the fertilizer 10 is increased and the carrier is sufficient to enhance the soil improvement effect. It is possible to have a soil improvement effect while enhancing the fertilizer effect.

The ratio of the total amount of phosphoric acid to the fertilizer 10 is 1% by mass to 20% by mass, 3% by mass to 20% by mass, 5% by mass to 20% by mass, and 10% by mass to 20% by mass. Alternatively, the ratio of the iron ratio to the fertilizer 10 and the total phosphate ratio is 5 times or less, 3 times or less, 2 times or less, or 1 in the ratio of the larger ratio value to the smaller ratio value .5 times or less.

The ratio of citric acid phosphoric acid to fertilizer 10 is 0.03% by mass or more and 15% by mass or less, 0.1% by mass or more and 15% by mass or less, 0.5% by mass or more and 10% by mass or less, and 1% by mass or more and 10% by mass. % by mass or less.

The ratio of soluble phosphoric acid to the fertilizer 10 is 0.03% by mass or more and 15% by mass or less, 0.1% by mass or more and 15% by mass or less, 0.5% by mass or more and 15% by mass or less, and 1% by mass or more and 15% by mass. % or less.

The ratio of sulfur carried on the carrier 100 to the fertilizer 10 is 3% by mass or less, 2% by mass or less, 1% by mass or less, or 0.5% by mass or less. Although the details will be described later, in the method for producing the fertilizer 10, when an iron sulfate aqueous solution is used when iron is supported on the carrier 100, or when the iron compound supported on the carrier 100 is reduced, hydrogen sulfide gas or sulfur dioxide gas is sometimes used. Iron sulfide may be formed on the surface of the fertilizer 10 under the influence of these manufacturing methods, but this iron sulfide does not affect the fertilizer effect. In other words, a relatively small ratio of sulfur to the fertilizer 10 means that the carrier 100 carries relatively large amounts of phosphorus and iron.

Phosphorus carried on the carrier 100 includes inorganic phosphorus and organic phosphorus. Inorganic phosphorus includes orthophosphoric phosphorus and polymerized phosphoric acid. Organic phosphorus includes particulate organic phosphorus and soluble organic phosphorus.

[Configuration of carrier 100]
One configuration of the carrier 100, the phosphorus-adsorbed iron 600, the iron oxide 800, and the iron sulfide 900 will be described in detail with reference to FIG.

The hole diameter of the hole 200 in the cross section orthogonal to the extending direction of the hole 200 is 100 μm or less, 50 μm or less, 30 μm or less, or 20 μm or less.

The length of linear body 610 from one position to the other position on the inner wall of hole 200 is 100 μm or less, 50 μm or less, 30 μm or less, 20 μm or less, or 10 μm or less. The thickness of the linear body 610 (the thickness of the linear body 610 in the cross section perpendicular to the extending direction (or longitudinal direction) of the phosphorus-adsorbing iron 600) is 10 μm or less, 5 μm or less, 3 μm or less, 2 μm or less, or 1 μm. It is below.

The particle size of the carrier 100 in the cross section orthogonal to the extending direction of the hole 200 is 10 mm or less, 5 mm or less, 3 mm or less, or 2 mm or less.

Since it has been confirmed that linear body 610 is crystalline iron, linear body 610 is considered to be formed by crystal growth. That is, unlike, for example, a linear or fibrous metal formed by processing a metal material, the length and thickness are very small as described above.

Iron oxide 800 and/or iron sulfide 900 are present at least on the surface of carrier 100 . Iron oxide 800 is fibrous. Iron sulfide 900 is granular. Iron oxide 800 is formed more extensively than iron sulfide 900. The equivalent circle diameter of iron sulfide 900 is 50 μm or less, 30 μm or less, 20 μm or less, or 10 μm or less.

[Material of each member]
As the carrier 100 used in the fertilizer 10, a carbonized biomass can be used, and typically a carbonized lignocellulose can be used. As lignocellulose, wood, particleboard, sawdust, agricultural waste, sewage, silage, grass, rice husk, bagasse, cotton, jute, hemp, flax, bamboo, sisal, abaca, straw, wheat straw, maize cob, maize sto One or more materials selected from the group consisting of grass, switchgrass, alfalfa, hay, palm hair, seaweed, algae, and mixtures thereof can be used.

The iron oxide 800 on the surface of the carrier 100 may be at least one of wustite, hematite, maghematite, and magnetite. The iron sulfide 900 on the surface of the carrier 100 may be at least one of ferric sulfide, ferrous sulfide, and iron disulfide.

Note that the iron 601 inside the pores 200 of the carrier 100 is crystalline iron, the iron oxide 800 on the surface of the carrier 100 is crystalline iron oxide, and the iron sulfide 900 on the surface of the carrier 100 is crystalline. may be iron sulfide having

As described above, the fertilizer 10 according to the present embodiment can be formed by causing the crystalline fibrous iron 601 existing inside the pores 200 of the carrier 100 to adsorb phosphorus. That is, the fertilizer 10 has crystalline fibrous phosphorus-adsorbed iron 600 inside the pores 200 of the carrier 100, and has crystalline iron oxide 800 and iron sulfide 900 on the surface of the carrier 100. may be A detailed manufacturing method of the fertilizer 10 will be described later, but it is necessary to perform a high-temperature heat treatment (reduction treatment) in order to form the zerovalent iron 601 for adsorbing phosphorus inside the holes 200 . If the iron 601 inside the holes 200 is oxidized or sulfided by this reduction treatment, the adsorption performance of phosphorus to the iron 601 is lowered. As a result, the total amount of phosphoric acid in the carrier 100, especially the amount of citric-soluble phosphoric acid, is reduced. Therefore, it is preferable to suppress oxidation or sulfurization of the iron 601 inside the holes 200 during the reduction treatment.

In addition, since the phosphorus-adsorbed iron 600 inside the holes 200 of the carrier 100 is fibrous, the surface area of the phosphorus-adsorbed iron 600 inside the holes 200 can be increased, and the total amount of phosphoric acid contained in the fertilizer 10 is increased. can be made In addition, since the phosphorus-adsorbed iron 600 is fibrous, it takes time for the phosphoric acid to dissolve from the phosphorus-adsorbed iron 600 present in the deep position of the hole 200. can be

Fertilizer 10 contains, in addition to phosphorus, iron and sulfur, other components such as nitrogen, potassium, calcium, magnesium, boron, chlorine, manganese, zinc, copper, molybdenum, nickel and other essential plant nutrients, flavonoids, organic acids, Amino acids, peptides, nucleosides, nucleotides, nucleobases, sugars, monohydric alcohols, nonionic surfactants, food additives, microbial extracts, plant hormones, nod factors or lipo-chitooligosaccharides, synthetic lipo-chitooligosaccharides, chitooligos It may be used in combination with one or more selected from sugars, chitinous compounds, linoleic acid or derivatives thereof, linolenic acid or derivatives thereof, karrikin, acyl-homoserine lactone derivatives, betaine compounds, phenolic compounds and the like.

[Manufacturing method of Fertilizer 10]
A method for manufacturing the fertilizer 10 according to the present embodiment will be described with reference to FIGS. 2 and 3. FIG. In this embodiment, as a method of introducing the iron compound into the pores of the carbide, a method of immersing the carbide in a solution containing iron is used, and the iron compound adhering to the pores of the carbide is reduced. The manner in which the zerovalent iron particles are placed in the pores of the carbide is described.

FIG. 2 is a flow chart showing a method for producing fertilizer according to one embodiment of the present invention. FIG. 3 is a cross-sectional view showing the pore shape of the porous material used for fertilizer according to one embodiment of the present invention.

As shown in FIG. 2, organic matter is carbonized in step S101. In this embodiment, wood is used as the organic material. Carbonization of the organic matter is performed by heat treatment in an atmosphere having a lower oxygen ratio than the air atmosphere.

There are two main types of carbonization furnaces: a carbonization furnace that supplies heat necessary for carbonization from the outside is called an external heat type, and a furnace that secures heat from materials is called an internal combustion type. The external heat type cuts off oxygen for carbonization, and the internal combustion type supplies the oxygen necessary for combustion to secure the minimum amount of heat necessary for carbonization. So basically the process of heating at high temperature under reducing conditions is called carbonization. When organic matter is heated under reducing conditions, composition decomposition in the organic matter begins during the temperature rise (for example, about 280° C.), and oxygen and hydrogen in the organic matter are converted into gases such as carbon dioxide, carbon monoxide, hydrogen, and hydrocarbons. As it evaporates, it changes to amorphous carbon with a high carbon content. By continuing to heat at a higher temperature, oxygen and hydrogen in the organic matter are further reduced, forming a carbide composed of high-purity fixed carbon and ash. Such a change turns the organic matter into a carbide. Moisture and constituent components in the organic matter are desorbed as volatile gases, etc., and a certain amount of carbon remains. Therefore, a large number of continuous pores of various sizes are formed in the carbide formed by the carbonization of the organic matter. As the carbonization temperature rises, the carbonization progresses and the carbide formed has heat resistance (fire resistance), adsorptivity, and conductivity. A char formed by charring organic matter is an example of the carrier 100 . In this case, carrier 100 is electrically conductive.

Here, the pore shape of the carrier 100 when carbide is used as the carrier 100 will be described with reference to FIG. As shown in FIG. 3, carrier 100 has macropores 200 (corresponding to pores 200 in FIG. 1), mesopores 210 and micropores 220 . Macropores 200 are pores connected to the surface of carrier 100 . Inside the carrier 100 , the macropores 200 are subdivided to form mesopores 210 , and the mesopores 210 are subdivided to form micropores 220 . The size of the macropores 200 is 100 μm or less, 50 μm or less, 30 μm or less, or 20 μm or less. The size of the mesopores 210 is about 2 nm or more and 50 nm or less. The size of the micropores 220 is approximately 0.5 nm or more and 2 nm or less.

As shown in FIG. 2, apart from the carbonization of organic matter in step S101, a solution 120 containing iron or iron compounds is prepared in step S103. In this embodiment, an aqueous solution containing iron is used as the solution 120 . Specifically, the solution 120 includes a ferrous chloride aqueous solution (FeCl ₂ ), a ferric chloride aqueous solution (FeCl ₃ ), a ferrous nitrate aqueous solution (Fe(NO ₃ ), in which inorganic iron or an inorganic iron compound is dissolved). ₂ ), an aqueous ferric nitrate solution (Fe(NO ₃ ) ₃ ), an aqueous ferrous sulfate solution (FeSO ₄ ), or an aqueous ferric sulfate solution (Fe(SO ₄ ) ₃ ) is used. Alternatively, as the solution 120, a solution in which heme iron bound to protein as an organic iron compound is dissolved can also be used. Waste products such as animal blood containing heme iron may also be used. When these solutions are not particularly distinguished, they may simply be referred to as iron solutions. The solution 120 is not limited to the above iron solution, and may be a solution containing iron other than the above. Moreover, the solvent of the solution is not limited to water, and organic solvents such as methanol, ethanol, phenol, benzene, and hexane may be used.

At step S105, the carbide formed at step S101 is immersed in the solution 120 formed at step S103.

In step S107, with the carrier 100 immersed in the solution 120, the atmosphere in which these are placed is decompressed (degassed). Alternatively, the atmosphere may be decompressed while the carrier 100 is arranged, and then the solution 120 may be injected to immerse the carrier 100 in the solution 120 . Alternatively, a method of pressurizing after immersing the carrier 100 and reducing the pressure may be adopted. This decompression process can eliminate the phenomenon that air bubbles remain inside the holes. If such a phenomenon does not occur, or if such a phenomenon does not greatly affect the properties of the fertilizer 10, this depressurization process can be omitted.

In step S109, the atmosphere pressure-reduced in step S107 is returned to atmospheric pressure, and the carrier 100 is taken out of the solution 120. FIG. As a method for removing the carrier 100 from the solution 120, a known method such as liquid removal by centrifugation can be used. In step S111, the carrier 100 impregnated with the solution 120 is dried. This drying removes the liquid contained in the solution 120 . This drying also deposits the iron compound 111 in the pores of the carrier 100 and on its surface. This drying is performed while heating the carrier 100 . Further, when drying the carrier 100, the humidity of the environment in which the carrier 100 is arranged may be adjusted. This drying may be carried out at the same time as the heat treatment of the reduction process in the next step.

In step S113 of FIG. 2, reduction treatment of the iron compound 111 adhering to the inside of the pores of the carrier 100 and its surface is performed. In other words, the iron compound 111 is reduced while adhering to the inner wall of at least one of the macropores 200 , mesopores 210 and micropores 220 . The reduction treatment is performed by heat treatment in a reducing gas atmosphere. By this reduction treatment, the bivalent or trivalent iron compound 111 is reduced to zerovalent iron. Note that part of the iron compound 111 is thermally decomposed by the above heat treatment, and iron oxide and/or iron sulfide are formed. A portion of the iron oxide and/or iron sulfide is then reduced to metallic iron. Thus, the pre-stage adsorbent of the fertilizer 10 according to the present embodiment is manufactured.

At step S115 in FIG. 2, phosphorus is adsorbed onto the iron contained in the adsorbent. Specifically, the iron is made to adsorb phosphorus by immersing the adsorbent in an aqueous solution containing phosphorus (aqueous phosphorus solution). In step S115, the adsorbent may simply be immersed in the phosphorus aqueous solution, or the same processes as in steps S107 to S109 may be performed while the adsorbent is immersed in the phosphorus aqueous solution.

The organic materials used in step S101 include raw trees (including thinned wood such as broad-leaved trees, coniferous trees, and bamboo, and forest waste), and waste materials from sawmills or wood processing factories (sawdust, bark waste, chip waste, and cut wood). ), vegetable husks, building demolition materials, or wooden scraps of furniture. The charcoal produced in step S101 is, for example, charcoal or bamboo charcoal. The charcoal may include white charcoal, black charcoal, sawdust charcoal, coconut charcoal, rice husk charcoal, and pulverized charcoal, in addition to bamboo charcoal.

The carbonization temperature of the organic substance in step S101 is 400° C. to 1200° C., 500° C. to 1100° C., 600° C. to 1000° C., or 700° C. to 900° C. The atmosphere for carbonizing the organic substance is an inert gas atmosphere such as nitrogen gas or argon gas, an oxygen-free atmosphere, a reducing atmosphere, or a reduced pressure atmosphere. When the carbonization of organic matter is carried out in a reduced pressure atmosphere, the gauge pressure is usually zero, and the gauge pressure is -101200 Pa or more and 1300 Pa or less in a low vacuum state, -101299.9 Pa or more and 101200 Pa or less in a medium vacuum state, -101299.99999 Pa or more-. It can be carried out in a high vacuum state of 101299.9 Pa or less or an ultra-high vacuum state of -101299.99999 Pa or less. In addition, when pressurizing after decompression, it can be carried out at a gauge pressure of -101.3 MPa or more and 0.8987 MPa or less, or -101.3 MPa or more and 0.3987 MPa or less as a gauge pressure with the atmospheric pressure as zero. The carbonization time of the organic substance is 10 minutes or more and 10 days or less, and 10 minutes or more and 5 hours or less. Further, when the carbonization of organic matter is performed in a low-oxygen atmosphere, the oxygen concentration can be 0.01% or more and 3% or less, or 0.1% or more and 1% or less. Carbonization of organic matter can be internal combustion or external heat, batch open or closed charcoal kiln, continuous rotary kiln or oscillating carbonization furnace, screw furnace, heating chamber, covered refractory vessel (crucible). ).

In this embodiment, the method of obtaining the carrier 100 by carbonizing the organic matter in step S101 is illustrated, but a commercially available carbide may be used as the carrier 100.

The mass percent concentration of iron contained in the solution 120 used in step S103 is 0.1 wt % or more and 50 wt % or less, 1 wt % or more and 40 wt % or less, or 3 wt % or more and 30 wt % or less. The time for which the carrier 100 is immersed in the solution 120 in step S103 is 10 seconds or more and 24 hours or less, 1 minute or more and 5 hours or less, or 2 minutes or more and 1 hour or less. When the pressure is reduced after immersing the carbide in a pressure vessel, or when immersing after decompression, the gauge pressure is usually -0.101 MPa or more -0.02 MPa or less, -0.101 MPa or more -0. 04 MPa or less, or −0.101 MPa or more and −0.08 MPa or less. In addition, when pressurizing after decompression, it can be carried out at a gauge pressure of -101.3 MPa or more and 0.8987 MPa or less, or -101.3 MPa or more and 0.3987 MPa or less as a gauge pressure with the atmospheric pressure as zero. In this case, the reduced pressure immersion time may be shorter than usual, and any time can be adopted after reaching a predetermined gauge pressure, but preferably 1 second or more and 1 hour or less, 10 seconds or more and 10 minutes or less, or 30 minutes or less. The time may be appropriately selected from seconds to 5 minutes.

Organic solvents such as water, methanol, ethanol, phenol, benzene, and hexane are used as solvents for the solution 120 used in step S103. In this embodiment, the method of preparing the solution 120 in step S103 is exemplified, but the solution 120 may be a commercially available product.

In addition, a dispersant may be added to the solution 120 to facilitate the dispersion of the iron ions 110 . As the dispersant, for example, a surfactant can be used. Using anionic (anionic) surfactants, cationic (cationic) surfactants, amphoteric (zwitterionic) surfactants, nonionic (nonionic) surfactants, and polymeric surfactants as surfactants can be done. As an anionic surfactant, fatty acid sodium, monoalkylsulfate, alkylpolyoxyethylenesulfate, alkylbenzenesulfonate, alkylethersulfate, triethanolamine alkylsulfate, and alkylbenzenesulfonate can be used. Alkyltrimethylammonium salts, dialkyldimethylammonium chlorides, alkylpyridium chlorides, and alkylbenzyldimethylammonium salts can be used as cationic surfactants. Alkyldimethylamine oxides and alkylcarboxybetaines can be used as amphoteric surfactants. As nonionic surfactants, polyoxyethylene alkyl ethers, fatty acid sorbitan esters, alkyl polyglucosides, fatty acid diethanolamides, octylphenol ethoxylates, and alkyl monoglyceryl ethers can be used. Polyacrylate, polystyrene sulfonate, polyvinyl alcohol, and polyethyleneimine can be used as polymeric surfactants. The concentration of the dispersant is 0.01% or more and 20% or less, or 0.01% or more and 1% or less. Note that the carbonized material is hydrophobic (non-hydrophilic) unless it is carbonized at a high temperature, so water does not easily enter inside. Therefore, by including a surfactant in the solution 120 , the solution 120 can easily permeate the interior of the carrier 100 .

In steps S105 and S115, before the carrier 100 is immersed in the solution 120, the carrier 100 may be supplied with the surfactant. The surfactant may be supplied by coating the upper surface of the carrier 100, or by immersing the carrier 100 in a solution containing the surfactant. Further, as in step S107, degassing may be performed while the surfactant is supplied to the carrier 100. FIG.

Further, the carrier 100 does not have to be immersed in the solution 120 or the phosphorus aqueous solution. For example, the solution 120 may be permeated into the pores of the carrier 100 by applying the solution 120 or an aqueous solution of phosphorus to the surface of the carrier 100 .

In step S107, vibration may be applied during degassing in order to diffuse the air bubbles 130 out of the holes more efficiently. This vibration may be an ultrasonic vibration. Further, the carrier 100 may be heated during degassing. Also, the carrier 100 may be tilted or rotated in the solution 120 during degassing. The pressure at the time of degassing is normally -0.101 MPa or more and -0.03 MPa or less as gauge pressure with atmospheric pressure as zero, and the degassing time is 10 seconds or more and 1 hour or less, or 30 seconds or more and 10 minutes or less. .

When a carbide is used as the carrier 100, the solution 120 containing the iron ions 110 or the aqueous phosphorus solution may not easily permeate into the pores of the carrier 100 because the carbide is hydrophobic. In such a case, most of the carrier 100 floats on the liquid surface due to air present in the pores of the carrier 100 (macropores 200, mesopores 210, and micropores 220). Even in such a state, by reducing the pressure, the air existing in the pores can be pulled out of the carrier 100 and discharged out of the solution 120 or the aqueous phosphorus solution. As a result, in the pores of the carrier 100, the regions where the bubbles 130 existed can be filled with the solution 120 containing the iron ions 110 or the phosphorus aqueous solution.

The above steps S105 to S111 may be repeated multiple times. Further, the steps S107 and S109 may be repeated multiple times. Further, the process of step S115 may be repeated multiple times. Further, the drying in step S111 may be performed while the pressure is reduced without going through the step of returning to the atmospheric pressure in step S109. In that case, the pressure may be returned to the atmospheric pressure after the drying, or the reduction in step S113 may be performed while the pressure is reduced. Also, the above drying and reduction may be performed in the same step. By repeating the above steps multiple times, the amount of the iron compound 111 attached to the carrier 100 can be increased.

The reduction temperature of the iron compound 111 in step S113 should be at least 500° C. or higher. The range of the reduction temperature is, for example, 500°C to 1200°C, 500°C to 1000°C, 500°C to 900°C, or 700°C to 900°C. The reducing gas used for the reduction treatment of the iron compound 111 is carbon monoxide gas, hydrogen gas, hydrogen sulfide gas, sulfur dioxide gas, or hydrocarbon gas. The advantage of introducing these gases from the outside is that the yield of the adsorbent after reduction is increased compared to the case where carbon, oxygen, sulfur, hydrogen, etc. adhering to the carrier 100 react by heating to generate reducing gas. is also one of the effects of the present invention. Alternatively, a reducing gas such as carbon monoxide and hydrogen may be mixed. Furthermore, since many reducing gases are difficult to handle from the viewpoint of explosiveness and combustibility, they may be diluted with an inert gas. For example, it can be diluted with nitrogen gas so that the carbon monoxide concentration is 1% or more and 20% or less (that is, the nitrogen concentration is 99% or less and 80% or more). The reduction time is 1 minute or more and 10 hours or less, and 10 minutes or more and 2 hours or less. The reduction may be of either a batch type or a continuous type, and a tube furnace or a box furnace may be appropriately used as long as it has a structure that allows heating and the introduction of a reducing gas (which may be mixed with an inert gas). can. When carbon monoxide gas is used as the reducing gas, the reduction temperature should be at least 500° C. or higher. The range of the reduction temperature in this case can be, for example, 500° C. to 1200° C., 500° C. to 1000° C., 500° C. to 900° C., or 700° C. to 900° C. Moreover, when hydrogen gas is used as the reducing gas, the reduction temperature should be at least 100° C. or higher. The range of the reduction temperature in this case can be, for example, 100° C. or higher and 1200° C. or lower, 100° C. or higher and 900° C. or lower, or 700° C. or higher and 900° C. or lower.

When reducing the iron compound 111, in addition to the reducing gas, carbon dioxide gas, oxygen gas, and water vapor are added to activate, thereby increasing fine pores in the carrier 100 at the same time as reduction (activating carbonization). can be done. By subjecting the carrier 100 to active carbonization, the surface area of the carrier 100 can be increased.

In step S113, when the carbon, oxygen, sulfur, hydrogen, etc. attached to the carrier 100 react by heating to generate a reducing gas, the gas is used to remove the iron compound attached to the inside of the pores of the carrier 100 and the surface thereof. 111 reduction treatment may be performed. In this case, an inert gas, rare gas, or the like may be introduced into the heating device.

In addition, when the fertilizer 10 contains other components besides phosphorus, iron, and sulfur, the raw materials may be further added.

In this embodiment, after the mesopores 210 and micropores 220 are formed in the carrier 100, the iron-containing solution 120 is soaked into the pores of the carrier 100 and dried to reduce the iron compound 111. The fertilizer 10 can be realized by forming the phosphorus adsorbent as described above and allowing the phosphorus adsorbent to adsorb phosphorus.

Moreover, in the present embodiment, since the reduction is performed by a heat treatment different from the carbonization, the conditions suitable for the reduction can be appropriately selected. For example, the carbonization and reduction treatments can be performed in different apparatuses. Alternatively, the carbonization temperature and the reduction temperature can be treated at different temperatures and times. Alternatively, carbonization and reduction treatment can be performed in different atmospheres.

When the carrier 100 is a carbide, the carbide has a high electrical conductivity, so that electron exchange is rapidly performed between the carbide and the crystal particles of zero-valent iron adhering in the pores thereof. Therefore, when a carbide containing crystal particles of zero-valent iron is placed in water, the zero-valent iron is rapidly ionized on the surface of the porous body to produce hydroxides such as iron oxyhydroxide (FeOOH), It can react with the phosphate ions present in the iron to form iron phosphate, which can be adsorbed and fixed on the carbide. Phosphorus can be efficiently adsorbed by using a conductive material as the carrier 100 in the same manner as described above. As a result, the fertilizer 10 having the characteristics as described above can be formed.

Although one embodiment of the present invention has been described above with reference to the drawings, the present invention is not limited to the above-described embodiment, and can be modified as appropriate without departing from the scope of the present invention. For example, based on the fertilizer of the present embodiment, additions, deletions, or design changes made by those skilled in the art as appropriate are also included in the scope of the present invention as long as they have the gist of the present invention. Furthermore, the embodiments described above can be appropriately combined as long as there is no contradiction, and technical matters common to each embodiment are included in each embodiment without explicit description.

Even if there are other effects that are different from the effects brought about by the aspects of each embodiment described above, those that are obvious from the description of this specification or those that can be easily predicted by those skilled in the art are of course It is understood that it is provided by the present invention.

Examples of the fertilizer according to the above embodiment will be described below. Fertilizers according to the following examples are fertilizers in which a carbonized product obtained by carbonizing wood is used as a carrier. Table 1 shows specific manufacturing conditions for the carrier in the examples.

As shown in Table 1, the manufacturing conditions for the fertilizers according to the examples include pretreatment, immersion treatment, and phosphorus adsorption treatment.

Pretreatment is a carbide cleaning treatment performed prior to step 105 of FIG. The washing liquid, washing temperature, washing time, and drying temperature in the pretreatment are the same in all examples.

The immersion conditions correspond to the process of step S105 in FIG. The iron-containing aqueous solution, depressurization, degassing time, and drying time in the immersion treatment are the same in all Examples. On the other hand, the liquid amount of the iron-containing aqueous solution and the liquid amount of the carbide washing water in the immersion treatment are different between the first embodiment and the second embodiment. Specifically, in Example 1, compared with Example 2, both the amounts of the iron-containing aqueous solution and the carbide washing water are large. The amount of the carbide cleaning water in Example 1 was excessive, and it is considered that most of the iron compounds adhering to the carbide in Example 1 were washed away by the immersion treatment.

[Ratio of phosphoric acid contained in fertilizer]
Table 2 shows the results of evaluating the fertilizers according to Examples 1 and 2 prepared under the above conditions using the ammonium vanadomolybdate spectrophotometry method. As a comparative example, Table 2 shows the results of evaluating iron (III) phosphate n-hydrate (manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd.) using the same method.

"Total phosphoric acid (TP)", "citric acid phosphoric acid (CP)", "water-soluble phosphoric acid (WP)", and "soluble phosphoric acid (SP)" described in Table 2 are molybdenum vanado These are the results of evaluation using ammonium acid absorption photometry. "Ratio of total amount of phosphoric acid", "ratio of citric soluble phosphoric acid", "ratio of water-soluble phosphoric acid", "ratio of soluble phosphoric acid", and "ratio of iron" are the states in which iron and phosphorus are supported, respectively. is the ratio of the mass of each to the mass of the carbide of "CP/TP" is the ratio of citric soluble phosphate (CP) to total phosphate (TP). "WP/TP" is the ratio of water-soluble phosphoric acid (WP) to total phosphoric acid (TP). "SP/TP" is the ratio of soluble phosphate (SP) to total phosphate (TP).

The "CP/TP" (21% and 51%) of Examples 1 and 2 are larger than the "CP/TP" (16%) of the Comparative Example. As described above, even in Example 1, in which the amount of the carbide cleaning water is excessive and the ratio of iron is small, the value of "CP/TP" is larger than that of the comparative example. In Example 2, in which the liquid amounts of the iron-containing aqueous solution and the carbide cleaning water are adjusted to appropriate conditions, the value of "CP/TP" is three times or more that of the comparative example. That is, in Examples 1 and 2, since the ratio of citric-soluble phosphoric acid to the total amount of phosphoric acid is large, a long-term fertilizing effect can be obtained.

10: Fertilizer 100: Carrier 110: Iron ion 111: Iron compound 120: Solution 130: Air bubble 200: Pore (macropore) 201: Inner wall 210: Mesopore 220: Micropore 600: Phosphorus-adsorbed iron 601: Iron 610: Linear body 611: Linear body 800: Iron oxide 810: Iron oxide 900: Iron sulfide

Claims (12)

A fertilizer comprising a crystalline carrier carrying phosphorus-adsorbed iron,
A fertilizer wherein the ratio of citric-soluble phosphoric acid to the total amount of phosphoric acid in the fertilizer is 18% or more, and the ratio of water-soluble phosphoric acid to the total amount of phosphoric acid in the fertilizer is 1% or less. The fertilizer according to claim 1, wherein said carrier is a porous body. The fertilizer according to claim 2, wherein the porous body contains carbide. 4. The fertilizer according to claim 3, wherein said crystalline phosphorus-adsorbed iron is present in the pores of said porous body. Fertilizer according to any one of claims 1 to 4, wherein the ratio of said iron to said fertilizer is between 1% and 50% by mass. The fertilizer according to any one of claims 1 to 5, wherein the ratio of the total amount of phosphoric acid to the fertilizer is 1% by mass or more and 20% by mass or less. The fertilizer according to any one of claims 1 to 6, wherein the ratio of said citric phosphate to said fertilizer is 0.03% by mass or more and 15% by mass or less. The fertilizer according to any one of claims 1 to 7, wherein the total mass of phosphoric acid, the mass of citric-soluble phosphoric acid, and the mass of water-soluble phosphoric acid are determined by ammonium vanadomolybdate spectrophotometry. . The fertilizer according to any one of claims 1 to 8, wherein the ratio of soluble phosphoric acid to said fertilizer is 0.03% by weight or more and 15% by weight or less. 10. The fertilizer of claim 9, wherein the mass of soluble phosphoric acid is determined by ammonium vanadomolybdate spectrophotometry. 11. Fertilizer according to any one of the preceding claims, wherein the ratio of sulfur supported on said carrier to said fertilizer is 3% by weight or less. 12. The fertilizer according to any one of claims 1 to 11, wherein said phosphorus supported on said carrier includes inorganic phosphorus and organic phosphorus.

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