CN112110769A

CN112110769A - Fertilizer

Info

Publication number: CN112110769A
Application number: CN202010553219.XA
Authority: CN
Inventors: 横山茂辉; 袋昭太; 仓泽响
Original assignee: Japanese Fujita Co ltd
Current assignee: Japanese Fujita Co ltd
Priority date: 2019-06-19
Filing date: 2020-06-17
Publication date: 2020-12-22
Also published as: JP7330772B2; JP2021001085A

Abstract

The invention aims to provide a fertilizer which can utilize fertilizer effective components for crops for a long time. The fertilizer of the present invention comprises a carrier carrying phosphorus and iron, wherein the rate of citrate-soluble phosphoric acid to total phosphoric acid in the fertilizer is 18% or more, and the rate of water-soluble phosphoric acid to total phosphoric acid in the carrier is 1% or less. The carrier may be a porous body. The porous body may contain carbide. The total phosphoric acid, citric acid and water-soluble phosphoric acid can be determined by ammonium vanadium molybdate absorptiometry.

Description

Fertilizer

Technical Field

The invention relates to a fertilizer. In particular, the invention relates to a fertilizer bearing phosphorus and iron.

Background

There is known a technique for improving soil properties such as water permeability of soil by mixing charcoal into soil. For example, a technique for improving soil quality by using carbide obtained by carbonizing biomass (bioglass) such as trees and crops is known. In this technique, oxygen atoms and hydrogen atoms are removed from biomass by heating the biomass in a state of excluding oxygen to generate carbide composed of a carbon component and an ash component.

However, in view of the cost required for producing the carbide as described above, the carbide is used only for improving the soil texture of the soil, and is not cost-effective for the production cost.

On the other hand, it is known that carbide is a porous material and has a very large surface area. By utilizing the large surface area, carbides are used as adsorbents for various substances. For example, a technique has been developed for using phosphorus-adsorbed carbide as a fertilizer by adsorbing phosphorus using calcium-bearing carbide and burying the phosphorus-adsorbed carbide in agricultural land.

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, an example of phosphoric acid used as a phosphoric acid fertilizer is phosphoric acid in an orthophosphoric acid state.

(prior art documents)

(patent document)

Patent document 1: japanese laid-open patent publication No. 10-017390

Disclosure of Invention

(problems to be solved by the invention)

Orthophosphoric acid is bonded to metals in soil such as calcium, iron, and aluminum to form a sparingly soluble salt, and is in a so-called hardly supplied state (i.e., a state in which nutrients in soil are not easily absorbed by crops). Therefore, orthophosphoric acid, which is a fertilizer effective component of crops, is used in low efficiency of approximately 10 to 15% as a phosphate fertilizer applied to soil, and the remaining approximately 90 to 85% of the phosphate fertilizer becomes insoluble in soil. Therefore, orthophosphoric acid is inefficient for use as a fertilizer component for agricultural crops. In addition, even when the technique described in patent document 1 is used, since the phosphate of patent document 1 has water solubility, when the phosphate is buried in soil as a fertilizer, the phosphate is easily dissolved in water and flows out, and the fertilizer efficiency is not maintained.

The present invention has been made in view of the above problems, and an object of one embodiment of the present invention is to provide a fertilizer capable of utilizing fertilizer effective components for agricultural crops for a long period of time.

(means for solving the problems)

The fertilizer according to one embodiment of the present invention is a fertilizer comprising a carrier carrying phosphorus and iron. The fertilizer has a citrate-soluble phosphoric acid content of 18% or more relative to the total phosphoric acid (total phosphoric acid content), and has a water-soluble phosphoric acid content of 1% or less relative to the total phosphoric acid content.

The carrier may be a porous body.

The porous body may include carbide.

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

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

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

The ratio of citrate-soluble phosphoric acid to the fertilizer may be 0.03 mass% or more and 15 mass% or less.

The total phosphoric acid, citric acid and water-soluble phosphoric acid can be determined by ammonium vanadium molybdate absorptiometry.

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

The soluble phosphoric acid can be determined by ammonium molybdic acid vanadium absorptiometry.

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

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

(effect of the invention)

According to one embodiment of the present invention, a fertilizer that can utilize fertilizer components for agricultural crops for a long period of time can be provided.

Drawings

Fig. 1 is a view showing a sectional configuration of a fertilizer according to an embodiment of the present invention.

Fig. 2 is a flowchart showing a manufacturing method of a fertilizer according to an embodiment of the present invention.

Fig. 3 is a cross-sectional view showing the shape of pores of a porous material used for a carrier according to an embodiment of the present invention.

(description of reference numerals)

10: a fertilizer; 100: a carrier; 200: holes (macro holes); 201: an inner wall;

210: a meso (well) well; 220: micro (micro) pores; 600: adsorbing iron by phosphorus; 610: a linear body;

800: iron oxide; 900: iron sulfide

Detailed Description

Hereinafter, a fertilizer and a method for producing a fertilizer according to an embodiment of the present invention will be described with reference to the drawings. However, the fertilizer and the method for producing the fertilizer according to one embodiment of the present invention can be carried out in various different modes, and the present invention is not limited to the description of the examples shown below. In the drawings referred to in the present embodiment, the same reference numerals or letters may be attached to the same parts or parts having the same functions, and the repetitive description thereof may be omitted.

In the following embodiments, the structure of carbide obtained by carbonizing wood is exemplified as the carrier of phosphorus and iron used for the fertilizer, but the structure is not limited to this structure. For example, a carbide obtained by carbonizing an organic material other than wood may be used as the carrier. In addition, a porous member other than carbide may be used as the support. In addition, the techniques of the different embodiments can be combined as long as no technical contradiction particularly occurs.

In the following embodiments, the size of the pores of the porous material is referred to as the pore diameter, and the size of the particulate matter is referred to as the particle diameter. Unless otherwise specified, pore diameter refers to the size of a pore in a cross-section orthogonal to the direction in which the pore extends. However, when the hole has a shape other than a long shape, the hole diameter refers to the size of the hole in an arbitrary cross section. The pore diameter may be the equivalent circular diameter of the pore in any cross section, and may also be the maximum diameter or average diameter in that cross section. Similarly, the particle diameter may be an equivalent circular diameter of the particulate matter in any cross-sectional view or projection plane, and may be a maximum diameter or an average diameter in the cross-sectional view or projection plane.

In the following embodiments, "total phosphoric acid (total amount of phosphoric acid)", "citrate soluble phosphoric acid", "water soluble phosphoric acid" and "soluble phosphoric acid" represent values obtained by ammonium vanadate absorptiometry, unless otherwise specified. Citric acid refers to phosphoric acid that is insoluble in water but soluble in a 2% citric acid solution. Citrate-soluble phosphoric acid is not immediately soluble in a weak acid of the degree of root acid secreted from the roots of crops but is soluble in an acid slightly stronger than root acid. Therefore, the fertilizer is slowly dissolved out of the fertilizer, and a long-term fertilizer effect can be obtained. Water-soluble phosphoric acid refers to phosphoric acid dissolved in water. The water-soluble phosphoric acid is quickly dissolved in water contained in the soil and absorbed by the crops. Therefore, a high and quick-acting fertilizer effect can be obtained. Soluble phosphoric acid refers to phosphoric acid that is insoluble in water but soluble in the root acid secreted from the root. Soluble phosphoric acid, although less rapid acting than water soluble phosphoric acid, is absorbed by crops more rapidly than citrate soluble phosphoric acid. For example, the ratio of the mass of total phosphoric acid or the like to the mass of the fertilizer is the ratio of the mass of total phosphoric acid to the mass of carbide in a state in which phosphorus and iron are supported, and represents total phosphoric acid (P) obtained by the above-described ammonium vanadium molybdate absorptiometry₂O₅) The ratio of mass of (a).

[ ammonium vanadium molybdate absorptiometry ]

The ammonium molybdate vanadium absorption photometry is a test method based on a test method (2018) of fertilizers and the like (available from the agricultural, forestry and aquatic product consumption safety technical center of independent administrative law). The test method for fertilizers and the like is a test method (evaluation method) established by agriculture, forestry and aquatic products provinces, and is a test method in which reagents, instruments and the like used for the test are specified according to JIS standards and the like. The total phosphoric acid, citric acid, water-soluble phosphoric acid, and soluble phosphoric acid described in the following embodiments are values obtained by the method described in the ammonium molybdate vanadium absorptiometry of the above-described test methods (2018) for fertilizers and the like (details will be described later).

[ constitution of Fertilizer 10 ]

The structure of the fertilizer 10 according to the present embodiment will be described with reference to fig. 1 and 2. In the present embodiment, a description will be given of a structure in which a carbide (porous body) obtained by carbonizing wood is used as the carrier 100 used for the fertilizer 10.

Fig. 1 is a view showing a sectional configuration of a fertilizer relating to an embodiment of the present invention. The cross-sectional view shown in fig. 1 is a cross-sectional view orthogonal 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 includes a carrier 100, iron having phosphorus adsorbed thereon (hereinafter referred to as "phosphorus-adsorbed iron 600"), iron oxide 800, and/or iron sulfide 900. The phosphorus-adsorbed iron 600 is present inside the pores 200 (macro-pores 200 described below) of the carrier 100. In other words, the carrier 100 carries phosphorus and iron. The phosphorus-adsorbing iron 600 adheres to the inner wall 201 of the hole 200.

The phosphorus-adsorbing iron 600 is fibrous in shape. The fibrous phosphorus-adsorbing iron 600 is composed of a plurality of linear bodies 610. There are cases where one or both ends of the linear body 610 are attached to the inner wall 201. Alternatively, one or both ends of the linear body 610 may be fixed to the inner wall 201. The phosphorus-adsorbing iron 600 is held inside the hole 200 by fixing one end or both ends of the wire-shaped body 610 to the inner wall 201. Since a large number of the linear bodies 610 exist inside the hole 200, the phosphorus-adsorbing iron 600 has a fibrous shape. That is, in the following description, the linear body 610 is a part of the fibrous phosphorus-adsorbed iron 600. In addition, the phosphorus-adsorbed iron 600 drawn inside the hole 200 in the lower side of fig. 1 is omitted for convenience of explanation.

Since the phosphorus-adsorbing iron 600 inside the pores 200 is fibrous, the inside of the pores 200 is not completely filled with the phosphorus-adsorbing iron 600, and a space where the phosphorus-adsorbing iron 600 does not exist continuously extends in the extending direction of the pores 200. In addition, since the iron 600 for phosphorus adsorption is fibrous, the iron 600 for phosphorus adsorption exists not only on the inner wall of the hole 200 but also in the internal space of the hole 200. Here, since the hole 200 and the phosphorus-adsorbed iron 600 extend in the depth direction of the drawing, when the hole 200 is viewed from the extension direction of the hole 200, the phosphorus-adsorbed iron 600 existing in the depth direction appears to overlap with each other, and thus the phosphorus-adsorbed iron 600 appears to fill the internal space of the hole 200.

[ ratio of phosphoric acid in Fertilizer 10 ]

The ratio of citrate soluble phosphoric acid to the total phosphoric acid in the fertilizer 10 (citrate 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 the water-soluble phosphoric acid to the total phosphoric acid in the fertilizer 10 (the ratio of the water-soluble phosphoric acid) is 1% or less, 0.8% or less, 0.6% or less, or 0.5% or less. Alternatively, the citric acid soluble phosphoric 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 phosphoric acid and citric acid are values obtained by the ammonium vanadium molybdate absorptiometry as described above. Thus, in the fertilizer 10 relating to the present embodiment, the citrate-soluble phosphoric acid ratio is greater than the water-soluble phosphoric acid ratio.

As described above, citric soluble phosphoric acid is gradually dissolved out from the fertilizer, and thus a long-term fertilizer effect can be obtained. Since the citric acid-soluble phosphoric acid ratio is higher than the water-soluble phosphoric acid ratio, the fertilizer 10 according to the present embodiment can utilize the fertilizer effect components of the fertilizer 10 for crops for a long time. When the citric acid ratio is less than the lower limit value, a sufficient fertilizer efficiency may not be obtained as a fertilizer. When the water-soluble phosphoric acid ratio is higher than the above upper limit, phosphorus is immediately dissolved and flows out of the fertilizer when the fertilizer is buried in soil, and thus the fertilizer efficiency may not be sufficiently sustained.

The ratio of iron contained in the phosphorus-adsorbed iron 600 to the fertilizer 10 is 1 mass% or more and 50 mass% or less, 3 mass% or more and 30 mass% or less, 5 mass% or more and 25 mass% or less, 10 mass% or more and 20 mass% or less. The mass of the iron contained in the fertilizer 10 can be determined by means of, for example, an inductively coupled plasma mass spectrometer (ICP-MS). The ratio of iron contained in the phosphorus-adsorbed iron 600 to the fertilizer 10 is in the above range, so that the content of phosphoric acid in the fertilizer 10 increases and a sufficient carrier is contained to improve the soil improvement effect, and therefore, the phosphate fertilizer effect can be improved and the soil improvement effect can be provided.

The ratio of the total phosphoric acid to the fertilizer 10 is 1 mass% or more and 20 mass% or less, 3 mass% or more and 20 mass% or less, 5 mass% or more and 20 mass% or less, 10 mass% or more and 20 mass% or less. Alternatively, in the ratio of iron to the ratio of total phosphoric acid with respect to the fertilizer 10, the ratio of a relatively large ratio value to a relatively small ratio value is 5 times or less, 3 times or less, 2 times or less, or 1.5 times or less.

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

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

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

The phosphorus supported on the carrier 100 includes inorganic phosphorus and organic phosphorus. Inorganic phosphorus includes orthophosphoric acid and polyphosphoric acid. The organic phosphorus includes particulate organic phosphorus and soluble organic phosphorus.

[ constitution of Carrier 100 ]

One configuration of the carrier 100, the phosphorus-adsorbing iron 600, the iron oxide 800, and the iron sulfide 900 will be described in detail with reference to fig. 1.

The pore diameter of the pores 200 in a cross section perpendicular to the elongation direction of the pores 200 is 100 μm or less, 50 μm or less, 30 μm or less, or 20 μm or less.

The length of the linear body 610 from one side position to the other side position of the inner wall of the 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 filament 610 (the thickness of the filament 610 in a cross section perpendicular to the extension direction (or the 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 or less.

The particle diameter of the carrier 100 in a cross section perpendicular to the direction of elongation of the pores 200 is 10mm or less, 5mm or less, 3mm or less, or 2mm or less.

Since it was confirmed that the filament 610 is iron having crystallinity, the filament 610 is considered to be a product of crystal growth. That is, the length and thickness are very small as described above as compared with a linear or fibrous metal formed by processing, for example, a metal material.

Iron oxide 800 and/or iron sulfide 900 are present at least on the surface of the support 100. The iron oxide 800 is fibrous. The iron sulfide 900 is in the form of granules. The range in which the iron oxide 800 is formed is wider than that of the iron sulfide 900. The iron sulfide 900 has an equivalent circle diameter of 50 μm or less, 30 μm or less, 20 μm or less, or 10 μm or less.

[ Material of Components ]

As the carrier 100 used for the fertilizer 10, a carbide obtained by carbonizing biomass, typically, a carbide obtained by carbonizing lignocellulose, can be used. As the lignocellulose, one or more materials selected from the group consisting of wood, particle board, sawdust, agricultural waste, sewage, silage, grasses, chaff, bagasse, cotton, jute, hemp, flax, bamboo, sisal, abaca, straw, wheat straw, corn cobs, corn stover, switchgrass, alfalfa, hay, coconut hair, seaweed, algae, and mixtures thereof can be used.

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

The iron (the linear body 610) 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 may be crystalline iron sulfide.

As described above, the fertilizer 10 according to the present embodiment can be formed by adsorbing phosphorus to crystalline fibrous iron (the filament 610) present inside the pores 200 of the carrier 100. That is, the fertilizer 10 may have a structure in which the phosphorus-adsorbed iron 600 is present inside the pores 200 of the carrier 100 and the iron oxide 800 and the iron sulfide 900 are present on the surface of the carrier 100, wherein the phosphorus-adsorbed iron 600 has crystallinity and is in a fiber form, and the iron oxide 800 and the iron sulfide 900 have crystallinity. A detailed manufacturing method of the fertilizer 10 will be described later, but high-temperature heat treatment (reduction treatment) is necessary to form zero-valent iron (the filament 610) for adsorbing phosphorus inside the hole 200. When iron inside the pores 200 is oxidized or sulfurized by the reduction treatment, the phosphorus adsorption performance to iron is lowered. As a result, the amount of total phosphoric acid, particularly citrate soluble phosphoric acid, in the carrier 100 is reduced. Therefore, it is preferable to suppress oxidation or sulfidation of iron inside the pores 200 when the reduction treatment is performed.

In addition, since the phosphorus-adsorbed iron 600 inside the pores 200 of the carrier 100 is fibrous, the surface area of the phosphorus-adsorbed iron 600 inside the pores 200 can be increased, and the total phosphoric acid contained in the fertilizer 10 can be increased. Further, since the phosphorus-adsorbed iron 600 is fibrous, it takes time for phosphoric acid to elute from the phosphorus-adsorbed iron 600 present in the deep part of the pores 200. Therefore, the fertilizer effect component of the fertilizer 10 to crops can be prolonged.

In addition to phosphorus, iron, and sulfur, the fertilizer 10 may further contain one or more other components, for example, at least one component selected from the group consisting of plant-essential nutrients such as nitrogen, potassium, calcium, magnesium, boron, chlorine, manganese, zinc, copper, molybdenum, and nickel, flavonoids (flavonoids), organic acids, amino acids, peptides, nucleosides, nucleotides, nucleic acid bases, sugars, monohydric alcohols, nonionic surfactants, food additives, microbial extracts, plant hormones, nodulation factors, i.e., lipo-chitooligosaccharides, synthetic lipo-chitooligosaccharides, chitin compounds, linoleic acid or derivatives thereof, linolenic acid or derivatives thereof, karrikin(s) (plant seed germination signal promoting molecules), acyl homoserine lactone derivatives, betaine compounds, and phenolic compounds.

[ method for producing Fertilizer 10 ]

A method for producing the fertilizer 10 according to the present embodiment will be described with reference to fig. 2 and 3. In the present embodiment, as a method of introducing an iron compound into pores of carbide, a method of impregnating carbide in a solution containing iron is used. By this impregnation, the iron compound adhering to the pores of the carbide is reduced, and the zero-valent iron particles are arranged in the pores of the carbide.

Fig. 2 is a flowchart showing a method for manufacturing a fertilizer according to an embodiment of the present invention. Fig. 3 is a cross-sectional view showing the pore shape of a porous material used in a fertilizer according to an embodiment of the present invention.

As shown in fig. 2, the organic matter is carbonized in step S101. In the present embodiment, wood is used as the organic matter. The organic material is carbonized by heat treatment in an atmosphere having an oxygen ratio smaller than that of the atmospheric atmosphere.

There are two main types of carbonization furnaces, and a carbonization furnace that supplies heat required for carbonization from the outside is called an external heating type, and a carbonization furnace that obtains heat from a material is called an internal combustion type. The external heat type is used for carbonization while excluding oxygen, and the internal heat type supplies oxygen necessary for combustion to ensure the minimum amount of heat required for carbonization. That is, basically, the treatment of heating at a high temperature under reducing conditions is called carbonization. If the organic matter is heated under reducing conditions, the components in the organic matter begin to decompose during the temperature increase (e.g., approximately 280 ℃). By the decomposition of the components, oxygen and hydrogen in the organic matter are volatilized in the form of gases such as carbon dioxide, carbon monoxide, hydrogen and hydrocarbons, and become amorphous carbon rich in carbon components. Further, the heating is continued at a high temperature, so that oxygen and hydrogen in the organic matter are further reduced to form carbide composed of high-purity fixed carbon and ash. By this change, the organic matter becomes carbide. Since moisture and components in the organic material are desorbed in the form of volatile gas or the like and a certain amount of carbon remains, a large number of continuous pores of various sizes are formed in the carbide formed by the carbonization of the organic material. The carbide formed by carbonization with an increase in carbonization temperature has properties such as heat resistance (fire resistance), adsorptivity, and conductivity. A carbide formed by carbonization of an organic substance is an example of the support 100. In which case the carrier 100 is electrically conductive.

The pore shape of the carrier 100 in the case where carbide is used as the carrier 100 will be described with reference to fig. 3. As shown in fig. 3, the support 100 has macro pores 200 (corresponding to the pores 200 of fig. 1), mesopores 210, and micropores 220. The macro pores 200 are pores connected to the surface of the carrier 100. Inside the support 100, the macro pores 200 are subdivided to form mesopores 210, and the mesopores 210 are further subdivided to form micropores 220. The macro pores 200 have a size of 100 μm or less, 50 μm or less, 30 μm or less, or 20 μm or less. The size of the mesopores 210 is approximately 2nm or more and 50nm or less. The size of the micropores 220 is approximately 0.5nm to 2 nm.

As shown in fig. 2, carbonization of the organic matter is performed in step S101, and preparation of an iron-containing solution containing iron or an iron compound is performed in step S103. In the present embodiment, an iron-containing aqueous solution is used as the iron-containing solution. Specifically, as the iron-containing solution, an aqueous ferrous chloride solution (FeCl) in which inorganic iron or an inorganic iron compound is dissolved is used₂) FeCl (FeCl)₃) Ferrous nitrate aqueous solution (Fe (NO)₃)₂) And an aqueous ferric nitrate solution (Fe (NO)₃)₃) Ferrous sulfate aqueous solution (FeSO)₄) Or an aqueous iron sulfate solution (Fe)₂(SO₄)₃). Alternatively, as the iron-containing solution, a solution in which heme iron bound to a protein as an organic iron compound is dissolved can be used. Waste products such as blood of animals containing heme iron can be used. In thatWhen these solutions are not particularly distinguished, they are sometimes simply referred to as iron solutions. The iron-containing solution is not limited to the iron solution described above, and may be an iron-containing solution other than the iron solution described above. The solvent of the solution may be not only water but also an organic solvent such as methanol, ethanol, phenol, benzene, hexane, or the like.

In step S105, the carbide formed in step S101 is immersed in the iron-containing solution formed in step S103.

In step S107, the atmosphere (environment) in which the carrier 100 is disposed is depressurized (degassed) in a state in which the carrier is immersed in the iron-containing solution. Alternatively, the atmosphere may be depressurized in a state where the carrier 100 is disposed, and thereafter, the carrier 100 may be impregnated with the iron-containing solution by injecting the iron-containing solution. Alternatively, a method of impregnating the support 100 and depressurizing, followed by pressurizing, may be employed. This decompression process can eliminate the phenomenon that air bubbles remain inside the holes. If such a phenomenon does not occur or if the characteristic of the fertilizer 10 is not greatly affected by such a phenomenon, the pressure reduction treatment may be omitted.

In step S109, the atmosphere depressurized in step S107 is returned to the atmospheric pressure, and the carriers 100 are taken out from the iron-containing solution. As a method for taking out the carrier 100 from the iron-containing solution, a known method such as liquid removal by centrifugal separation can be used. The drying of the support 100 impregnated with the iron-containing solution is performed at step S111. The liquid contained in the iron-containing solution is removed by this drying. In addition, by this drying, the iron compound adheres to the pores of the carrier 100 and the surface thereof. This drying is performed while heating the carrier 100. In addition, when drying the carrier 100, the humidity of the environment in which the carrier 100 is disposed may be adjusted. The drying may be performed simultaneously with the heat treatment of the reduction treatment of the next step.

In step S113 of fig. 2, the iron compound attached to the pores and the surface of the carrier 100 is subjected to a reduction treatment. In other words, the iron compound is reduced in a state of being attached to the inner wall of at least one of the macro pores 200, the mesopores 210, and the micro pores 220. The reduction treatment is performed by heat treatment in a reducing gas atmosphere. By this reduction treatment, the divalent or trivalent iron compound is reduced to zero-valent iron. Further, by the above heat treatment, a part of the iron compound is thermally decomposed to form iron oxide and/or iron sulfide. Thereafter, a part of the iron oxide and/or iron sulfide is reduced to metallic iron. In this way, the adsorbent relating to the previous stage of the fertilizer 10 of the present embodiment is manufactured.

In step S115 of fig. 2, phosphorus is adsorbed to the iron contained in the adsorbent. Specifically, the above-mentioned adsorbent is immersed in a phosphorus-containing aqueous solution (phosphorus aqueous solution) to adsorb phosphorus to the above-mentioned iron. In step S115, only the adsorbent may be immersed in the phosphorus aqueous solution, but the same processing as in steps S107 to S109 may be performed in a state where the adsorbent is immersed in the phosphorus aqueous solution.

Further, as the organic matter used in step S101, it is possible to use living trees (including hardwood trees, softwood trees, intermediate cut woods of bamboo, etc., woodland waste), waste of a sawmill or a wood processing factory (including sawdust, bark chips, shavings), vegetable shells, and wooden waste of building demolition materials or furniture materials. The carbide generated in step S101 is, for example, charcoal or bamboo charcoal. The charcoal can be white charcoal, black charcoal, sawdust charcoal, coconut shell charcoal, rice husk charcoal, and powdered charcoal besides bamboo charcoal.

The carbonization temperature of the organic material in step S101 is 400 ℃ to 1200 ℃, 500 ℃ to 1100 ℃, 600 ℃ to 1000 ℃, or 700 ℃ to 900 ℃. The carbonization atmosphere of the organic substance is an inert gas atmosphere such as nitrogen or argon, an oxygen-free atmosphere, a reducing atmosphere, or a reduced pressure atmosphere. When the organic material is carbonized in a reduced pressure atmosphere, the organic material can be carbonized in a low vacuum state of-101200 Pa or more and-1300 Pa or less, a medium vacuum state of-101299.9 Pa or more and-101200 Pa or less, a high vacuum state of-101299.99999 Pa or more and-101299.9 Pa or less, or an ultrahigh vacuum state of-101299.99999 Pa or less, as measured by a gauge pressure at which the normal atmospheric pressure is zero. When the pressure is increased after the pressure reduction, the pressure can be increased from-101.3 MPa to 0.8987MPa, from-101.3 MPa to 0.3987MPa in terms of gauge pressure when the normal atmospheric pressure is zero. The carbonization time of the organic matter is 10 minutes to 10 days, or 10 minutes to 5 hours. In addition, when the organic material is carbonized in a low-oxygen atmosphere, the organic material can be carbonized in a range of an oxygen concentration of 0.01% to 3%, or 0.1% to 1%. The carbonization of organic substances is carried out by internal combustion or external heating, and can be carried out using an intermittent open or closed carbon kiln, a continuous rotary kiln, a swing carbonization furnace, a spiral furnace, a heating chamber, and a heat-resistant container (crucible) with a lid.

In the present embodiment, the method of carbonizing the organic material to obtain the support 100 in step S101 is exemplified, but commercially available carbide may be used as the support 100.

The mass percent concentration of iron contained in the iron-containing solution 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 support 100 is immersed in the iron-containing solution 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 carbide is placed in a pressure vessel and the pressure is reduced after the impregnation, or when the impregnation is performed after the pressure is reduced, the carbide can be set to-0.101 MPa or more and-0.02 MPa or less, -0.101MPa or more and-0.04 MPa or less, or-0.101 MPa or more and-0.08 MPa or less in terms of gauge pressure when the normal atmospheric pressure is zero. When the pressure is increased after the pressure reduction, the pressure can be increased at-101.3 MPa to 0.8987MPa and-101.3 MPa to 0.3987MPa in terms of gauge pressure when the normal atmospheric pressure is zero. In this case, the reduced-pressure impregnation time may be shorter than usual and may be any time after the predetermined gauge pressure is reached, but is preferably appropriately selected within a range of 1 second to 1 hour, 10 seconds to 10 minutes, or 30 seconds to 5 minutes.

As the solvent of the iron-containing solution used in step S103, an organic solvent such as water, methanol, ethanol, phenol, benzene, hexane, or the like is used. Further, in the present embodiment, the method of preparing the iron-containing solution in step S103 is exemplified, but a commercially available iron-containing solution may be used.

In addition, a dispersant that promotes dispersion of iron ions may be added to the iron-containing solution used in step S103. As the dispersant, for example, a surfactant can be used. As the surfactant, an anionic (Anion) surfactant, a cationic (Cation) surfactant, an Amphoteric (Amphoteric) surfactant, a nonionic (Non ionic) surfactant, and a polymer surfactant can be used. As the anionic surfactant, sodium fatty acid, monoalkyl sulfate, alkyl polyoxyethylene sulfate, alkylbenzene sulfonate, alkyl ether sulfate, triethanolamine alkylsulfate, and alkylbenzene sulfonate can be used. As the cationic surfactant, alkyltrimethylammonium salts, dialkyldimethylammonium chloride, alkylpyridinium chloride, and alkylbenzyldimethylammonium salts can be used. As amphoteric surfactants, alkyldimethylamine oxides and alkylcarboxy betaines can be used. As the nonionic surfactant, polyoxyethylene alkyl ether, sorbitan fatty acid ester, alkyl polyglucoside, fatty acid diethanolamide, octylphenol ethoxylate, and alkyl monoglyceryl ether can be used. As the polymer surfactant, polyacrylate, polystyrene sulfonate, polyvinyl alcohol, and polyethyleneimine can be used. The concentration of the dispersant is 0.01% or more and 20% or less or 0.01% or more and 1% or less. Further, since carbide is hydrophobic (non-hydrophilic) unless it is carbonized at high temperature, water hardly enters the inside of the pores. Therefore, by including the surfactant in the above-described iron-containing solution, the iron-containing solution can be easily infiltrated into the inside of the pores of the carrier 100.

In steps S105, S115, the above-described surfactant may be supplied to the carrier 100 before the carrier 100 is immersed in the iron-containing solution. The supply of the surfactant may be performed by coating the upper surface of the carrier 100, or may be performed by immersing the carrier 100 in a solution containing the surfactant. In addition, degassing may be performed in a state where the surfactant is supplied to the carrier 100, as in step S107.

The support 100 may not be immersed in the iron-containing solution or the phosphorus-containing aqueous solution. For example, the iron-containing solution may also be infiltrated into the pores of the support 100 by coating the surface of the support 100 with the iron-containing solution or the phosphorus aqueous solution.

In step S107, vibration may also be applied when degassing is performed to more effectively diffuse the bubbles 130 to the outside of the pores. The vibrations may be ultrasonic vibrations. In addition, the carrier 100 may be heated during degassing. In addition, the carrier 100 may be tilted or rotated in the iron-containing solution while degassing is performed. The pressure at the time of degassing is-0.101 MPa or more and-0.03 MPa or less, and the degassing time is 10 seconds or more and 1 hour or less, or 30 seconds or more and 10 minutes or less, in terms of gauge pressure when the normal atmospheric pressure is zero.

In the case where carbide is used as the support 100, since carbide has hydrophobicity, there is a case where an iron-containing solution or a phosphorus aqueous solution containing iron ions is difficult to be impregnated into pores of the support 100. In this case, most of the carriers 100 float on the liquid surface due to the air existing in the pores (macro pores 200, medium pores 210, micro pores 220) of the carriers 100. Even in this state, the air present in the pores can be drawn out to the outside of the carrier 100 and discharged to the outside of the iron-containing solution or the phosphorus-containing aqueous solution by pressure reduction. Thereby, in the pores of the carrier 100, an iron-containing solution or a phosphorus aqueous solution containing iron ions can be filled into the region where the bubbles 130 were present.

The steps S105 to S111 may be repeated a plurality of times. The steps of step S107 and step S109 may be repeated a plurality of times. The process of step S115 may be repeated a plurality of times. The drying in step S111 may be performed in a state of being decompressed without going through the step of returning to the atmospheric pressure in step S109. In this case, the atmospheric pressure may be returned after the drying is performed, and the reduction of step S113 may also be performed in a state of still being decompressed. The drying and the reduction may be performed in the same step. The amount of the iron compound attached to the carrier 100 can be increased by repeating the above-described process several times.

The reduction temperature of the iron compound in step S113 may be at least 500 ℃. The reduction temperature range is, for example, 500 ℃ or more and 1200 ℃ or less, 500 ℃ or more and 1000 ℃ or less, 500 ℃ or more and 900 ℃ or less, or 700 ℃ or more and 900 ℃ or less. The reducing gas used for the reduction treatment of the iron compound is carbon monoxide gas, hydrogen sulfide gas, sulfur dioxide gas, or hydrocarbon gas. The introduction of these gases from the outside has an advantage in that the yield of the reduced adsorbent is higher than the case where carbon, oxygen, sulfur, hydrogen, etc. attached to the carrier 100 are reacted by heating and a reducing gas is generated, which is also one of the effects of the present invention. Alternatively, a reducing gas such as carbon monoxide and hydrogen may be mixed. Further, since the reducing gas is often a gas that is difficult to handle from the viewpoint of explosiveness and combustibility, these gases may be diluted with an inert gas. For example, the carbon monoxide concentration can be reduced to 1% or more and 20% or less (that is, the nitrogen concentration can be 99% or less and 80% or more) by diluting with nitrogen gas. The reduction time is 1 minute to 10 hours, or 10 minutes to 2 hours. The reduction may be performed by a batch (batch) method or a continuous method, and a tube furnace or a box furnace may be used as appropriate as long as the structure can heat and introduce a reducing gas (a gas mixed with an inert gas). When carbon monoxide gas is used as the reducing gas, the reducing temperature may be at least 500 ℃. The reduction temperature in this case can be set to, for example, 500 ℃ to 1200 ℃, 500 ℃ to 1000 ℃, 500 ℃ to 900 ℃, or 700 ℃ to 900 ℃. In addition, when hydrogen is used as the reducing gas, the reducing temperature may be at least 100 ℃. The reduction temperature in this case can be set to, for example, 100 ℃ to 1200 ℃, 100 ℃ to 900 ℃, or 700 ℃ to 900 ℃.

In addition, when the iron compound is reduced, carbon dioxide gas, oxygen gas, and water vapor are added in addition to the reducing gas to activate the iron compound, whereby fine pores can be increased in the carrier 100 (active carbonization) while the reduction is performed. By active carbonization of the carrier 100, the surface area of the carrier 100 can be further increased.

In step S113, when carbon, oxygen, sulfur, hydrogen, or the like attached to the carrier 100 reacts by heating to generate a reducing gas, the iron compound attached to the pores and the surface of the carrier 100 may be subjected to a reduction treatment using the gas. In this case, an inert gas, a rare gas, or the like may also be introduced into the heating device.

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

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

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

In the case where the carrier 100 is a carbide, since the carbide has high conductivity, electron exchange rapidly proceeds between the carbide and the crystal particles of zero-valent iron attached to the pores thereof. Therefore, when a carbide containing crystalline particles of zero-valent iron is put into water, the zero-valent iron is rapidly ionized on the surface of the porous body to generate a hydroxide such as iron oxyhydroxide (FeOOH), and reacts with phosphate ions present in the water to form iron phosphate, which can be adsorbed and fixed to the carbide. As described above, the carrier 100 is made of a material having conductivity, so that phosphorus can be effectively adsorbed. As a result, the fertilizer 10 having the above-described characteristics can be formed.

While one embodiment of the present invention has been described above with reference to the drawings, the present invention is not limited to the above embodiment, and can be modified as appropriate within a scope not departing from the spirit of the present invention. For example, addition, deletion, or design modification of the constituent elements appropriately performed by those skilled in the art based on the fertilizer of the present embodiment is also included in the scope of the present invention as long as the gist of the present invention is achieved. Further, the above-described embodiments can be combined and implemented as appropriate as long as they are not contradictory to each other, and technical matters common to the embodiments are included in the embodiments even if they are not explicitly described.

The effects that are obvious from the description of the present specification or can be easily predicted by those skilled in the art are naturally understood to be the effects of the present invention even if the effects are other than the effects by the features of the above-described embodiments.

[ examples ]

Examples of fertilizers relating to the above embodiments are explained below. The fertilizers according to the following examples were those using carbides obtained by carbonizing wood as carriers. Table 1 shows specific manufacturing conditions of the carriers in the examples.

[ Table 1]

As shown in table 1, the manufacturing conditions of the fertilizer related to the examples include pretreatment, impregnation treatment, and phosphorus adsorption treatment.

The pretreatment is a cleaning treatment of carbide performed before step 105 of fig. 2. The conditions of the cleaning liquid, the cleaning temperature, the cleaning time, and the drying temperature in the pretreatment are the same in all the examples.

The immersion conditions correspond to the processing in step S105 of fig. 2. The conditions of the iron-containing aqueous solution, the degassing pressure, the degassing time, and the drying time in the impregnation treatment were the same in all examples. On the other hand, in example 1 and example 2, the liquid amount of the aqueous iron-containing solution and the liquid amount of carbide cleaning water in the dipping treatment were different. Specifically, the amount of the iron-containing aqueous solution and the amount of the carbide cleaning water in example 1 were both larger than those in example 2. It is to be noted that the amount of the carbide cleaning water in example 1 is excessive, and it is considered that most of the iron compound adhered to the carbide in example 1 is lost by the dipping treatment.

[ ratio of phosphoric acid contained in Fertilizer ]

The fertilizers prepared under the above conditions involving examples 1 and 2 were evaluated using ammonium molybdate vanadates absorptiometry based on the test methods of fertilizers and the like (2018). First, the method for measuring total phosphoric acid, soluble phosphoric acid, citrate soluble phosphoric acid, and water soluble phosphoric acid using ammonium molybdate vanadium absorptiometry was summarized based on the test method (2018) for fertilizers and the like.

(method of measuring Total phosphoric acid)

First, sulfuric acid, potassium sulfate, and copper (ii) sulfate pentahydrate were added to the analysis sample. Next, pretreatment is performed by the Kjeldahl decomposition method or the ashing-hydrochloric acid boiling method to convert the total phosphorus into phosphate ions. The total phosphoric acid (TP) in the analysis sample was determined by measuring the absorbance of phosphovanadomolybdate formed by the reaction with ammonium vanadate (V), hexaammonium heptamolybdate, and nitric acid.

(method of measuring soluble phosphoric acid)

First, water is added to an analysis sample and extraction is performed to obtain an extract solution 1. Next, an ammonium citrate solution was mixed into the extraction residue and extracted to obtain an extract 2. Next, a certain amount (equal amount) of the extract liquid 1 and the extract liquid 2 were mixed. Next, nitric acid (1+1) (nitric acid diluted by adding water to concentrated nitric acid at a volume ratio of 1: 1) was added and heated to hydrolyze non-orthophosphoric acid into orthophosphate ions. Next, ammonium vanadate (V), hexaammonium heptamolybdate, and nitric acid were reacted to produce phosphovanadomolybdate. The amount of soluble phosphoric acid (SP)) in the ammonia-based ammonium citrate solution in the analysis sample was determined by measuring the absorbance of phosphovanadomolybdate.

(citric acid)

First, a citric acid solution is added to an analysis sample for extraction. Next, nitric acid (1+1) is added and heated to hydrolyze non-orthophosphoric acid into orthophosphate ions. Subsequently, ammonium vanadate (V), hexaammonium heptamolybdate, and nitric acid were reacted to produce phosphovanadomolybdate. The amount of citric acid-soluble phosphoric acid (citrate-soluble phosphoric acid (CP)) in the analysis sample was determined by measuring the absorbance of phosphovanadomolybdate.

(Water-soluble phosphoric acid)

First, water is added to the analytical sample and extraction is performed. Next, nitric acid (1+1) is added and heated to hydrolyze non-orthophosphoric acid into orthophosphate ions. Subsequently, ammonium vanadate (V), hexaammonium heptamolybdate, and nitric acid were reacted to produce phosphovanadomolybdate. The amount of water-soluble phosphoric acid (WP) in the sample was determined by measuring the absorbance of phosphovanadomolybdate.

Next, table 2 shows the results of evaluation of the fertilizers relating to example 1 and example 2 using ammonium vanadium molybdate absorptiometry. In addition, as comparative examples, the results of evaluating iron (iii) phosphate n-hydrate (manufactured by FUJIFILM Wako Pure Chemical Corporation) using the same method are shown in table 2.

[ Table 2]

"total phosphoric acid (TP)", "citrate soluble phosphoric acid (CP", "water soluble phosphoric acid (WP)", and "soluble phosphoric acid (SP)" described in table 2 are results of evaluation using ammonium vanadate absorptiometry, "ratio of total phosphoric acid", "ratio of citrate soluble phosphoric acid", "ratio of water soluble phosphoric acid", "ratio of soluble phosphoric acid", and "ratio of iron" are ratios of respective masses to a mass of carbide in a state of carrying iron and phosphorus, "CP/TP" is a ratio of citrate soluble phosphoric acid (CP) to total phosphoric acid (TP), "WP/TP" is a ratio of water soluble phosphoric acid (WP) to total phosphoric acid (TP), "SP/TP" is a ratio of soluble phosphoric acid (SP) to total phosphoric acid (TP).

The "CP/TP" (21% and 51%) of examples 1 and 2 was greater than that of comparative example (16%). As described above, in example 1 in which the iron ratio was small due to an excessive amount of carbide cleaning water, the "CP/TP" value was 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 were adjusted to appropriate conditions, the value of "CP/TP" was 3 times or more the value of the comparative example. That is, in example 1 and example 2, the ratio of citrate-soluble phosphoric acid to total phosphoric acid was large, and therefore, the fertilizer efficiency was able to be obtained for a long period of time.

Claims

1. A fertilizer comprising a carrier carrying phosphorus and iron,

the rate of citrate-soluble phosphoric acid to total phosphoric acid in the fertilizer is 18% or more, and the rate of water-soluble phosphoric acid to total phosphoric acid in the fertilizer is 1% or less.

2. The fertilizer of claim 1,

the carrier is a porous body.

3. The fertilizer of claim 2,

the porous body includes a carbide.

4. The fertilizer of claim 3,

the phosphorus and iron are present in the pores of the porous body.

5. Fertilizer according to any one of claims 1 to 4, wherein,

the ratio of the iron to the fertilizer is 1 mass% or more and 50 mass% or less.

6. Fertilizer according to any one of claims 1 to 4, wherein,

the ratio of the total phosphoric acid to the fertilizer is 1 mass% or more and 20 mass% or less.

7. Fertilizer according to any one of claims 1 to 4, wherein,

the ratio of citrate-soluble phosphoric acid to the fertilizer is 0.03 to 15 mass%.

8. Fertilizer according to any one of claims 1 to 4, wherein,

the total phosphoric acid, citric acid and water-soluble phosphoric acid were determined by ammonium vanadate absorptiometry.

9. Fertilizer according to any one of claims 1 to 4, wherein,

the ratio of the soluble phosphoric acid to the fertilizer is 0.03 mass% or more and 15 mass% or less.

10. The fertilizer of claim 9,

the soluble phosphoric acid was determined by ammonium molybdic acid vanadium absorptiometry.

11. Fertilizer according to any one of claims 1 to 4, wherein,

the ratio of sulfur carried on the carrier to the fertilizer is 3% by mass or less.

12. Fertilizer according to any one of claims 1 to 4, wherein,

the phosphorus supported on the carrier includes inorganic phosphorus and organic phosphorus.