JP2021159846A - Production method of adsorbent - Google Patents

Abstract

To provide a production method of an adsorbent in which a used amount of reducing gas is reduced; and to provide a production method of an adsorbent capable of producing the adsorbent without restricting the size of a raw material carbide.SOLUTION: In a production method of an adsorbent, a carbide, an iron compound and an organic binder are mixed together and kneaded, and granulated into a granulated material of the specified size, and then the granulated material is fired under a reduction atmosphere. Further, in the production method of the adsorbent, the organic binder is kneaded together with a mixture of the carbide and the iron compound, and granulated into a granulated material of the specified size, and then the granulated material is fired under the reduction atmosphere.SELECTED DRAWING: Figure 2

Description

The present invention relates to a method for producing an adsorbent. In particular, the present invention relates to a method for producing an adsorbent that adsorbs phosphorus.

In order to reduce the amount of carbon dioxide in the atmosphere, a technique for artificially recovering carbon dioxide and storing it in the ground is known. For example, it is possible to absorb carbon dioxide in the atmosphere by using biomass such as wood or agricultural products and fix the carbon dioxide as organic carbon. However, since these biomasses are organic substances, even if they are stored in the ground as they are, they will only decompose or decompose and will re-release carbon dioxide into the atmosphere. On the other hand, when biomass is heated in a state where oxygen is blocked, oxygen atoms and hydrogen atoms are desorbed, and carbides composed of carbon and ash can be produced. Since this carbide is a mass of carbon that does not contain sugar chains or amino acids that are decomposed by microorganisms, it is extremely stable in the environment (underground) and is hardly decomposed. Carbonized biomass has been used in agricultural land for a long time, and it is also recognized as a soil conditioner under the Soil Strengthening Law. Therefore, by applying fertilizer to agricultural land, carbon dioxide can be isolated and stored in the ground. can. In other words, the agricultural use of biomass carbide leads to a reduction in the amount of carbon dioxide in the atmosphere. However, considering the cost of producing carbides and the current carbon pricing, simply using carbides solely to improve soil quality is not worth the production costs.

On the other hand, carbides are known to have a very large surface area because they are porous. Taking advantage of this large surface area, carbides are used as adsorbents for various substances. For example, Patent Document 1 describes a phosphorus recovery material using a carbide supporting calcium. By adsorbing phosphorus using such a phosphorus recovery material, it is possible to suppress water pollution due to the discharge of phosphorus into natural waters. Further, when the phosphorus recovery material adsorbing phosphorus is buried in the agricultural land, the phosphorus adsorbed on the phosphorus recovery material is dissolved by the organic acid released from the roots of the crop. Since this phosphorus functions as a fertilizer for crops, it is possible to improve the yield of farmland in which phosphorus recovery material is buried, or to grow good quality crops.

In this way, not only for improving the soil quality of soil, for example, carbides that can suppress environmental pollution by adsorbing certain substances, or carbides that can apply the harmful substances to other uses. Demand is increasing.

JP-A-2007-75706 JP-A-2020-11211

However, in the phosphorus recovery material of Patent Document 1, it is necessary to use a material containing a large amount of silicon such as rice husk or diatomaceous earth. When a material containing a large amount of silicon is used, there is a limit to the amount of phosphorus recovery material produced. In addition, there is a limit to the allowable amount of substances such as phosphorus that can be adsorbed.

Further, Patent Document 2 describes an adsorbent made of a carbide containing iron. A reducing gas is used in the production of an adsorbent, but many of the reducing gases are difficult to handle from the viewpoint of explosiveness and flammability, and the production cost is also reduced. Therefore, it is required to reduce the amount of reducing gas used as much as possible. Further, if the sizes of the adsorbents are to be matched, only carbides having a predetermined size can be used as raw materials. Therefore, carbides that cannot be used as adsorbents have to be disposed of at a high cost.

One embodiment of the present invention has been made in view of the above problems, and one of the problems is to provide a method for producing an adsorbent in which the amount of reducing gas used is reduced. Another object of the present invention is to provide a method for producing an adsorbent, which can produce an adsorbent without limiting the size of the carbide of the raw material.

In the method for producing an adsorbent according to an embodiment of the present invention, a carbide, an iron compound, and an organic binder are mixed and then kneaded, granulated into a granulated product having a predetermined size, and the granulated product has a reducing atmosphere. Bake under.

In the method for producing an adsorbent according to an embodiment of the present invention, an organic binder is kneaded with a mixture of a carbide and an iron compound, granulated into a granulated product having a predetermined size, and the granulated product is subjected to a reducing atmosphere. Bake below.

The carbide may be porous.

The iron compound may be iron oxide.

The organic binder is at least one selected from sugar honey, waste sugar honey, starch, dextrin, corn starch, rice bran, polyvinyl alcohol, pulp effluent, lignin sulfonate, carboxymethyl cellulose, hydroxypropyl methyl cellulose, sodium alginate, phenolic resin, and tar pitch. May contain seeds.

The granulated product may be granulated to a predetermined size using a granulator.

The granulated product may have a pellet shape having a diameter of 1 mm or more and 20 mm or less.

The reducing atmosphere may include hydrogen, carbon monoxide, or hydrocarbons.

The granulated product may be fired at a firing temperature of 400 ° C. or higher and 900 ° C. or lower.

The amount of the organic binder to be kneaded may be larger than the amount of carbides in the mixture. Further, the amount of the organic binder to be kneaded may be 1.2 times or more and 2.0 times or less the amount of carbides in the mixture.

The organic binder to be kneaded may have a weight ratio of organic carbon contained in the organic binder of 20 times or more and 150 times or less of that of iron contained in the iron compound.

In the step of firing the granulated product in a reducing atmosphere, 50% or more and 95% of the organic carbon contained in the organic binder may be volatilized.

The adsorbent may adsorb phosphorus.

According to the method for producing an adsorbent according to an embodiment of the present invention, the amount of reducing gas used can be reduced, so that the safety of producing the adsorbent can be enhanced. Further, since the adsorbent can be produced without limiting the size of the carbide of the raw material, the production cost of the adsorbent can be suppressed, and an inexpensive adsorbent can be provided.

It is a schematic diagram of the adsorbent produced by the method of manufacturing the adsorbent which concerns on one Embodiment of this invention. It is a flowchart which shows the manufacturing method of the adsorbent which concerns on one Embodiment of this invention. It is a figure explaining the manufacturing method of the adsorbent which concerns on one Embodiment of this invention.

Hereinafter, the adsorbent and the method for producing the adsorbent according to the embodiment of the present invention will be described with reference to the drawings. However, the adsorbent and the method for producing the adsorbent in one embodiment of the present invention can be carried out in many different modes, and are not construed as being limited to the contents of the examples shown below. In the drawings referred to in the present embodiment, the same parts or parts having the same functions are designated by the same reference numerals or the same reference numerals followed by alphabets, and the repeated description thereof will be omitted.

[1. Composition of Adsorbent 10]
The configuration of the adsorbent 10 will be described with reference to FIG.

FIG. 1 is a schematic view of an adsorbent 10 produced by the method for producing an adsorbent according to an embodiment of the present invention. As shown in FIG. 1, the adsorbent 10 contains a first carbide 100, an iron 110, and a second carbide 120. In the adsorbent 10, the first carbide 100 and the second carbide 120 may be the same carbide or different carbides. Although the details will be described later, the raw materials of the first carbide 100 and the second carbide 120 are different. Therefore, in the following, for convenience, the first carbide 100 and the second carbide 120 will be described separately based on the difference in raw materials.

The adsorbent 10 has a pellet shape. Here, the pellet shape means a shape having a certain height. The pellet shape of the adsorbent 10 is, for example, a substantially cylindrical column, a substantially elliptical column, a substantially polygonal column, or the like. The pellet shape of the adsorbent 10 is generally determined by the shape of the granulated product 20 described later, but the height of the pellet shape is 1 mm or more and 20 mm or less, preferably 3 mm or more and 15 mm or less, and more preferably 6 mm. It is 12 mm or more and 12 mm or less. The diameter of the pellet shape (maximum width in the direction perpendicular to the height) is 1 mm or more and 20 mm or less, preferably 2 mm or more and 10 mm or less, and more preferably 3 mm or more and 6 mm or less. In the method for producing the adsorbent 10 according to the present embodiment, the size of the adsorbent can be controlled. Therefore, it is preferable that the size of the adsorbent 10 fits in the above range, which is easy to use and has a high adsorption effect.

The adsorbent 10 may be porous. That is, the first carbide 100 and the second carbide 120 may be porous. In the adsorbent 10, iron 110 is contained in the porosity of the first carbide 100 and the second carbide 120.

[2. Manufacturing method of adsorbent 10]

A method for producing the adsorbent 10 according to the embodiment of the present invention will be described with reference to FIGS. 2 and 3.

FIG. 2 is a flowchart showing a method for manufacturing the adsorbent 10 according to the embodiment of the present invention. Further, FIG. 3 is a diagram illustrating a method for manufacturing the adsorbent 10 according to the embodiment of the present invention.

As shown in FIG. 2, the method for producing the adsorbent 10 includes a mixing step (S110), a kneading step (S120), a granulation step (S130), and a firing step (S140). Hereinafter, each step will be described.

[2-1. Mixing step (S110)]
In the mixing step (S110), as shown in FIG. 3A, the carbide 200 and the iron compound 210 are mixed.

The carbide 200 is, for example, charcoal, bamboo charcoal, white charcoal, black charcoal, oga charcoal, coconut shell charcoal, rice husk charcoal, or pulverized coal. The charcoal 200 is a living tree (including thinned wood such as hardwood, softwood, bamboo, and forest waste), waste from a sawmill or wood processing factory (including sawdust, bark, chip, and scrap wood), and vegetable waste. It can be produced by carbonizing organic substances such as shells, building demolition materials, or wood-based waste materials for furniture materials.

Carbonization of organic matter is carried out by heating the organic matter in an inert gas atmosphere such as nitrogen gas or argon gas, an oxygen-free atmosphere, a low oxygen atmosphere, a reducing atmosphere, or a reduced pressure atmosphere. When performing carbonization of the organic matter in the vacuum atmosphere, 100Pa over ¹⁰ 5 Pa or lower vacuum, 0.1Pa or 100Pa following vacuum ^{inside, 10} -5 Pa or more 0.1Pa or less high vacuum state or ^10-5, It can be performed in an ultra-high vacuum state of Pa or less. When carbonizing an organic substance 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. The heating temperature for carbonizing organic matter is 400 ° C. or higher and 1200 ° C. or lower, preferably 500 ° C. or higher and 1100 ° C. or lower, more preferably 600 ° C. or higher and 1000 ° C. or lower, and particularly preferably 700 ° C. or higher and 900 ° C. or lower. be. The heating time is 10 minutes or more and 10 days or less, preferably 10 minutes or more and 5 hours or less.

Carbonization of organic matter is internal or external heating, batch open or closed coal kilns, continuous rotary kilns or rocking carbonizations, screw furnaces, heating chambers, or covered heat-resistant vessels ( It can be done using a fire pot). The internal heat type is a carbonization furnace that secures the heat required for carbonization from the material, and can carbonize organic substances by supplying oxygen required for burning the material. The external heat type is a carbonization furnace that supplies heat required for carbonization from the outside, and can carbonize organic substances by blocking oxygen.

When the organic matter is heated under reducing conditions, the compositional decomposition of the organic matter begins during the temperature rise (for example, about 280 ° C.), and the oxygen or hydrogen in the organic matter becomes a gas such as carbon dioxide, carbon monoxide, hydrogen, or hydrocarbon. The organic matter changes to amorphous carbon with a large amount of carbon. By continuing to heat at a higher temperature, oxygen or hydrogen in the organic matter is further reduced, and carbide 200 composed of high-purity fixed carbon and ash is produced. Since the water or constituents in the organic matter are desorbed as a volatile gas or the like, the carbide 200 produced by the carbonization of the organic matter becomes porous in which a large number of continuous pores of various sizes are formed. Further, the carbide 200 produced by the progress of carbonization as the carbonization temperature rises has heat resistance (fire resistance), adsorptivity, or conductivity. Therefore, the carbide 200 may be porous and may have heat resistance (fire resistance), adsorptive properties, or conductive properties.

The iron compound 210 may be a divalent iron compound or a trivalent iron compound. As the iron compound 210, iron oxide, iron chloride, iron nitrate, iron sulfate, iron acetate, iron oxalate and the like can be used. Of these, iron oxide, which has stable properties and is inexpensive, is preferable as the iron compound 210. Iron oxides are, for example, FeO (Wustite), Fe ₂ O ₃ (hematite or _{magnetite), or Fe 3} O ₄ (Magnetite). The iron compound 210 may be one kind of compound or may contain a plurality of compounds.

Further, a metal compound other than iron can be used instead of the iron compound 210. As the metal other than iron, for example, aluminum, vanadium, nickel, cobalt, manganese, magnesium, calcium or alloys thereof can be used.

The carbide 200 often contains water, and the water content varies depending on the type of carbide 200. Therefore, in calculating the mixing ratio of the carbide 200 and the iron compound 210, the amount of the solid component of the carbide 200 is used as a reference. For example, when 100 g of carbide 200 contains 5% water, the amount of solid component of carbide 200 can be calculated as 100 × 0.95 = 95 (g).

The mixing ratio of the amount of the solid component (α) of the carbide 200 and the amount of the iron compound (β) is α: β = 10: 0.1 to 8, preferably α: β = 10: 1 to 5. , More preferably α: β = 10: 2-4. When the mixing ratio is in the above range, the carbide 200 and the iron compound 210 are uniformly mixed without agglutination of the carbide 200 and the iron compound 210.

When mixing the carbide 200 and the iron compound 210, the particle sizes of the carbide 200 and the iron compound 210 may be adjusted. By adjusting the particle size of each of the carbide 200 and the iron compound 210, the carbide 200 and the iron compound 210 can be uniformly mixed. The particle size of each of the carbide 200 and the iron compound 210 can be adjusted by crushing the carbide 200 or the iron compound 210. In particular, since the particle size of the carbide 200 is often larger than the particle size of the iron compound 210, the carbide 200 may be crushed to match the particle size of the carbide 200 with the particle size of the iron compound 210.

Although the carbide 200 and the iron compound 210 can be crushed in the kneading step (S120) described later, it is difficult to finely adjust the particle size in the kneading step (S120). Therefore, when adjusting the particle sizes of the carbide 200 and the iron compound 210, it is preferable to adjust the particle sizes of the carbide 200 and the iron compound 210 in advance in the mixing step (S110).

The sizes of the carbide 200 and the iron compound 210 are not particularly limited, but preferably the carbide 200 has a particle size of 10 μm or more and 50 mm or less, iron oxide has a particle size of 10 μm to 10 mm or less, and more preferably the carbide 200 has a particle size of 50 μm to 2 mm or less and oxidation. Iron has a particle size of 100 μm to 1 mm or less. When the sizes of the carbide 200 and the iron compound 210 are in the above range, not only the carbide 200 and the iron compound 210 are uniformly mixed, but also the carbide 200 and the iron are contained in the organic binder 220 in the kneading step described later. Compound 210 can be uniformly dispersed.

In the mixing of the carbide 200 and the iron compound 210, a certain amount of water may be added. By adding water, it is possible to prevent the generation of dust in the mixing step (S110), and the carbide 200 and the iron compound 210 can be uniformly kneaded in the kneading step (S120) described later.

By the above mixing step (S110), a mixture of the carbide 200 and the iron compound 210 is produced.

[2-2. Kneading step (S120)]
In the kneading step (S120), as shown in FIG. 3B, an organic binder 220 is added to the mixture (carbide 200 and iron compound 210) and kneaded to produce a paste.

Examples of the organic binder 220 include sugar honey, waste sugar honey, starch, dextrin, cornstarch, rice bran, polyvinyl alcohol, pulp waste liquid, lignin sulfonate, carboxymethyl cellulose, hydroxypropyl methyl cellulose, sodium alginate, phenol resin, tar pitch and the like. Can be used. The organic binder 220 may contain one kind of material or may contain a plurality of kinds of materials. In particular, as the organic binder 220, molasses or molasses is preferable. Molasses has a large amount of solid components, so it is easy to harden the paste. Further, since molasses contains a large amount of carbon components, the granulated product can be efficiently reduced in the baking step (S140) described later. Further, molasses is inexpensive and has few harmful components, so that the production cost of the adsorbent can be suppressed, and the produced adsorbent can be used as a safe fertilizer.

The viscosity of the organic binder 220 can be adjusted as needed. For example, water or an organic solvent can be added to the organic binder 220 to adjust the viscosity of the organic binder 220. If the viscosity of the organic binder 220 is too high, it becomes difficult to knead. If the viscosity of the organic binder 220 is too small, the viscosity of the paste must be adjusted before the granulation step (S130) described later. The viscosity of the paste is adjusted by evaporating the added water or organic solvent, which not only requires the step of evaporating the water or organic solvent, but also the carbides 200 and the iron compound by evaporating the water or organic solvent. Aggregation of 210 occurs, and the dispersibility of the carbide 200 and the iron compound 210 in the organic binder 220 is reduced. Therefore, the viscosity of the organic binder 220 is preferably adjusted before kneading with the mixture.

The amount of the organic binder 220 added is also based on the amount of the solid component of the carbide 200. The ratio of the amount of the solid component (α) of the carbide 200 to the amount of the organic binder 220 (γ) is α: γ = 100: 10 to 1000, preferably α: γ = 100: 100 to 500. More preferably, α: γ = 100: 100 to 300.

In the kneading step (S120), the parameter that determines the dispersibility of the carbide 200 and the iron compound 210 in the organic binder 220 is not only the mixing ratio of the mixture and the organic binder 220. The dispersibility in the mixing step (S110) can also be controlled by parameters such as the temperature and time of the kneader. Therefore, the kneading machine will be described below.

A kneader can be used for kneading the mixture and the organic binder 220. As the kneader, for example, a single-screw kneader, a twin-screw kneader, a mixing roll, a kneader, a Banbury mixer, or the like can be used.

A kneading machine having a mixing function may be used. In that case, the mixing step (S110) and the kneading step (S120) can be continuously performed. For example, the carbide 200 and the iron compound 210 are put into a kneader and mixed. Subsequently, the organic binder 220 is put into the kneader and kneaded with the mixture. The carbide 200, the iron compound 210, and the organic binder 220 can be put into the kneader all at once and mixed and kneaded, but the carbide 200 and the iron compound 210 are likely to aggregate and bubbles are likely to be generated. .. Therefore, it is preferable that the mixing step (S110) and the kneading step (S120) are performed separately. Further, in the kneading step (S120), by using a kneading machine, a certain amount of the organic binder 220 can be added to the mixture at a constant speed.

The kneading temperature can be arbitrarily set, but is 0 ° C. or higher and 50 ° C. or lower, preferably 10 ° C. or higher and 40 ° C. or lower. The kneading time is preferably 1 second or more and 1 hour or less, preferably 1 minute or more and 30 minutes or less, and more preferably 1 minute or more and 15 minutes or less. By setting the parameters of the kneading step (S120) in the above range, the dispersibility of the carbide 200 and the iron compound 210 in the organic binder 220 can be optimized.

By the above kneading step (S120), a paste in which the carbide 200 and the iron compound 210 are dispersed is produced in the organic binder 220.

[2-3. Granulation process (S130)]
In the granulation step (S130), as shown in FIG. 3C, the paste is granulated to produce a granulated product 20 containing a carbide 200, an iron compound 210, and an organic binder 220.

The granulation product 20 can be produced by using a granulation machine. As the granulation machine, for example, a compression type granulation machine, an extrusion type granulation machine, a roll type granulation machine, a blade type granulation machine, a fusion type granulation machine, a spray type granulation machine, or the like can be used. .. It is preferable to use an extrusion type granulator in the production of the columnar granulated product 20. Here, the production of the granulated product 20 using the extrusion type granulator will be described.

In the extrusion type granulator, the paste formed into a predetermined shape is extruded from the mounted die. The extruded paste is cut to a predetermined length to produce pellet-shaped granules 20 having an extrusion direction in the height direction. The length (height of the pellet shape) of the granulated product 20 can be adjusted by adjusting the cutting speed (rotational speed in the case of the rotary cutting method) of the extrusion type granulator. Further, by adjusting the opening diameter of the die, the diameter of the granulated product 20 (the diameter when the cross-sectional shape is circular) can be adjusted. Therefore, by using an extrusion type granulator, it is possible to generate a granulated product 20 having a pellet shape (for example, a columnar shape) whose size is controlled.

The length of the granulated product 20 is 1 mm or more and 20 mm or less, preferably 3 mm or more and 15 mm or less, and more preferably 3 mm or more and 12 mm or less. The diameter of the granulated product 20 is 1 mm or more and 20 mm or less, preferably 2 mm or more and 10 mm or less, and more preferably 3 mm or more and 6 mm or less. When the size of the granulated product 20 is within the above range, the iron compound 210 can be sufficiently reduced in the firing step (S140) described later, so that the adsorption effect of the adsorbent 10 can be enhanced.

The cross-sectional shape of the granulated product 20 is not limited to a circular shape. By changing the opening shape of the die, the cross-sectional shape of the granulated product can also be changed. The cross-sectional shape of the granulated product may be, for example, an ellipse or a polygon. That is, the granulated product 20 may have a pellet shape of an elliptical column or a polygonal column as well as a cylinder.

In the granulation step (S130), an auxiliary agent may be added so that the pellet shape of the granulated product 20 is stabilized. As the auxiliary agent, for example, an organic resin such as polyester resin, acrylic resin, phenol resin, epoxy resin, silicone resin, polyimide resin, polystyrene resin, or urethane resin can be used. In the firing step (S140) described later, these organic resins are carbonized, and the carbides can also function as an adsorbent.

By the above granulation step (S130), a granulated product 20 containing a carbide 200, an iron compound 210, and an organic binder 220 is produced.

[2-4. Baking step (S140)]
In the firing step (S140), the granulated product 20 is fired to produce the adsorbent 10.

The firing of the granulated product 20 is performed by heating the granulated product 20 in a reducing atmosphere. The granulated product 20 contains an organic binder 220. When the organic binder 220 is heated, a reducing gas such as carbon monoxide gas, hydrogen gas, hydrogen sulfide gas, sulfur dioxide gas, or hydrocarbon gas is generated. Therefore, a reducing atmosphere can be formed by using the reducing gas generated from the granulated product 20 without separately introducing the reducing gas. That is, the iron compound 210 can be reduced by using the reducing gas generated from the granulated product 20. Moreover, since the reducing gas can be generated inside the granulated product 20, the iron compound 210 inside the granulated product 20 can be sufficiently reduced. Further, the iron compound 210 is reduced to the iron 110 by the reducing gas from the organic binder 220 around the iron compound 210, so that the iron 110 of the adsorbent 10 after firing is made of the porous second carbide 120. It has the structure contained therein. Therefore, the amount of adsorption of the adsorbent 10 can be increased.

Many reducing gases are difficult to handle from the viewpoint of explosiveness and flammability. Therefore, since the generated reducing gas is diluted and exhausted, an inert gas can be contained in the firing of the granulated product 20. As the inert gas, for example, nitrogen gas or argon gas can be used. When an inert gas is used, for example, nitrogen gas can be flowed so that the concentration of carbon monoxide in the firing furnace is 1% to 20%.

Further, not only the reducing gas generated from the organic binder 220, but also a reducing gas such as carbon monoxide gas, hydrogen gas, hydrogen sulfide gas, sulfur dioxide gas, hydrocarbon gas, or a mixed gas thereof is used. It is also possible to form a reducing atmosphere. However, even in this case, the amount of reducing gas can be reduced as compared with the conventional method for producing an adsorbent.

The heating temperature in firing the granulated product 20 is 400 ° C. or higher and 1200 ° C. or lower, preferably 400 ° C. or higher and 900 ° C. or lower, and more preferably 700 ° C. or higher and 900 ° C. or lower. The heating time is 1 minute or more and 10 hours or less, preferably 10 minutes or more and 5 hours or less. In the method for producing the adsorbent 10 according to the present embodiment, the iron compound 210 can be reduced by using the reducing gas generated from the organic binder 220, so that the iron compound 210 is heated as compared with the usual method for producing the adsorbent. It is possible to lower the temperature or shorten the heating time.

By firing the granulated product 20, the carbide 200 is changed to the first carbide 100, the iron compound 210 is changed to iron 110, and the organic binder 220 is changed to the second carbide 120.

By the above firing step, the adsorbent 10 containing iron 110 is produced.

As described above, for convenience of explanation, the first carbide 100 and the second carbide 120 contained in the produced adsorbent 10 were distinguished based on the difference in the raw materials, but the first carbide 100 and the second carbide 120 were distinguished. Are all carbides (characteristically different from carbides 200), and may not be clearly distinguished in the adsorbent 10. In other words, it can be said that the adsorbent 10 is a carbide containing iron. However, the adsorbent 10 has a different manufacturing method from the conventional carbide containing iron, and although the mechanism is not clear, it has properties different from those of the conventional carbide containing iron.

According to the method for producing the adsorbent 10 according to the present embodiment, the adsorbent 10 can be easily produced without using special manufacturing equipment. Therefore, the manufacturing cost can be suppressed and the inexpensive adsorbent 10 can be manufactured.

[2-5. evaluation]
The adsorbent 10 according to the present embodiment can adsorb phosphorus, arsenic, lead and the like. Among them, the adsorbent 10 is excellent in phosphorus adsorption. The evaluation of the adsorptivity of phosphorus in the adsorbent 10 can be performed by a batch test. The batch test is a method of calculating the amount of phosphorus adsorbed from the difference between the concentration of the added phosphorus solution and the concentration of the supernatant after the reaction. Phosphorus solution is obtained by dissolving diphosphorus pentoxide (P ₂ O ₅ ) in water. In the following examples, the amount of _{P 2} O ₅ per 1 L of water is used as the description of the concentration of the phosphorus solution. That is, the concentration of a phosphorus solution in which 200 g of P ₂ O _{5 is dissolved in 1 L of water is described as 200 g / L.} Further, as the amount of phosphorus adsorbed on the adsorbent 10, the amount of phosphorus adsorbed per 1 g of the adsorbent (amount of adsorbed phosphorus (mg-P) / 1 g of adsorbent) is described.

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to the following examples.

<Example 1>
As a carbide, 300 g of irregularly shaped charcoal and 83.3 g of iron oxide were mixed for 3 minutes to obtain a mixture. The water content of charcoal was 7.5%, and the solid component of charcoal was 300 × 92.5% = 277.5 g. Therefore, the ratio of the amount of solid components of charcoal to the amount of iron oxide was 277.5: 83.3 = 10: 3.

Next, the mixture was put into a kneader (manufactured by Dalton Corporation, model: KDRJ-10), 465 g of molasses was added over 2 minutes at room temperature, and kneaded for 3 minutes to obtain a paste. The ratio of the amount of solid components of charcoal to the amount of molasses was 277.5: 465 = 10:17.

Next, the paste was put into a granulator (manufactured by Dalton Corporation, model: F-5) to obtain pellet-shaped granules having a diameter of 8 mm and a height of 40 mm under the condition of a rotation speed of 112 rpm.

Next, the granulated product was calcined at 750 ° C. for 3 hours in a nitrogen atmosphere to obtain an adsorbent A.

The amount of phosphorus adsorbed on the adsorbent A was evaluated using the batch method. As the phosphorus solution, 50 ml of a 200 mg / L solution was used. The amount of phosphorus adsorbed by the adsorbent A was 26 (mg-P / g). After evaluating the adsorptivity of phosphorus, it was found that the adsorbent A did not collapse and the strength in water was high.

<Example 2>
As a carbide, 300 g of irregularly shaped charcoal and 83 g of iron oxide were mixed for 3 minutes to obtain a mixture. The water content of charcoal was 7.5%, and the solid component of charcoal was 300 × 92.5% = 277.5 g. Therefore, the ratio of the amount of solid components of charcoal to the amount of iron oxide was 277.5: 83 = 10: 3.

Next, the mixture was put into a kneader, 500 g of molasses was added over 2 minutes at room temperature, and kneaded for 30 minutes to obtain a paste. The ratio of the amount of solid components of charcoal to the amount of molasses was 277.5: 500 = 10:18.

Next, the paste was put into a granulator to obtain a pellet-shaped granulated product having a diameter of 6 mm and a height of 9 mm under the condition of a rotation speed of 112 rpm.

Next, the granulated product was calcined at 750 ° C. for 3 hours in a nitrogen atmosphere to obtain an adsorbent B.

The amount of phosphorus adsorbed on the adsorbent B was evaluated using the batch method. As the phosphorus solution, 50 ml of a 200 mg / L solution was used. The amount of phosphorus adsorbed on the adsorbent B was 27.2 (mg-P / g). Further, after evaluating the adsorptivity of phosphorus, it was found that the adsorbent B did not collapse and the strength in water was high.

<Example 3>
As a carbide, 300 g of irregularly shaped charcoal and 87 g of iron oxide were mixed for 3 minutes to obtain a mixture. The water content of charcoal was 3.3%, and the solid component of charcoal was 300 × 96.7% = 290.1 g. Therefore, the ratio of the amount of solid components of charcoal to the amount of iron oxide was 290.1: 87 = 10: 3.

Next, the mixture was put into a kneader, 522 g of molasses was added over 2 minutes at room temperature, and the mixture was kneaded for 3 minutes to obtain a paste. The ratio of the amount of solid components of charcoal to the amount of molasses was 290.1: 522 = 10:18.

Next, the paste was put into a granulator to obtain a pellet-shaped granulated product having a diameter of 3 mm and a height of 3 mm under the condition of a rotation speed of 112 rpm.

Next, the granulated product was calcined at 750 ° C. for 3 hours in a nitrogen atmosphere to obtain an adsorbent C.

The amount of phosphorus adsorbed on the adsorbent C was evaluated using the batch method. As the phosphorus solution, 50 ml of a 200 mg / L solution was used. The amount of phosphorus adsorbed by the adsorbent C was 17 (mg-P / g). Further, after evaluating the adsorptivity of phosphorus, it was found that the adsorbent C did not collapse and that the strength in water was high even if the diameter was small.

<Example 4>
As a carbide, 200 g of irregularly shaped charcoal and 100 g of iron oxide were mixed for 3 minutes to obtain a mixture. The water content of charcoal was 14%, and the solid component of charcoal was 200 × 86% = 172 g. Therefore, the ratio of the amount of solid components of charcoal to the amount of iron oxide was 172: 100 = 10: 5.8.

Next, the mixture was kneaded, 60 g of molasses was added over 2 minutes at room temperature, and the mixture was kneaded for 3 minutes to obtain a paste. The ratio of the amount of solid components of charcoal to the amount of molasses was 172: 60 = 10: 3.5.

Next, the paste was put into a granulator to obtain a pellet-shaped granulated product having a diameter of 3 mm and a height of 3 mm under the condition of a rotation speed of 112 rpm.

Next, the granulated product was calcined at 750 ° C. for 3 hours in a nitrogen atmosphere to obtain an adsorbent D.

The amount of phosphorus adsorbed on the adsorbent C was evaluated using the batch method. As the phosphorus solution, 50 ml of a 200 mg / L solution was used. The amount of phosphorus adsorbed on the adsorbent D was 12 (mg-P / g). Further, after evaluating the adsorptivity of phosphorus, it was found that the adsorbent D did not collapse and that the strength in water was high even if the diameter was small. The ratio of the amount of solid components of charcoal to the amount of molasses is 10: 3.5, and the amount of phosphorus adsorbed is reduced as compared with the adsorbents A to C. By increasing the amount of molasses to more than 3.5 with respect to the amount of solid component 10 of charcoal, the amount of phosphorus adsorbed on the adsorbent can be increased.

<Comparison example>
In order to confirm the effect of the adsorbent 10 obtained by the production method of the present embodiment, a commercially available activated carbon was used as the adsorbent, and the same evaluation as in Examples 1 to 4 was performed. Specifically, the batch method was used to evaluate the amount of phosphorus adsorbed on the activated carbon. 0.5 g of activated carbon (Osaka Gas Chemicals, Granular Shirasagi WH2x) and 250 ml of a 200 mg / L phosphorus solution were used. The amount of phosphorus adsorbed on the activated carbon was 3.5 (at mg-P / g).

As described above, by comparing Examples 1 to 4 with Comparative Example, the adsorbent 10 produced by the method for producing the adsorbent 10 according to the present embodiment does not use a separate reducing gas, and the adsorbent 10 is used. It was found that the amount of phosphorus adsorbed in the above can be significantly improved.

10: Adsorbent, 20: Granulated product, 100: First carbide, 110: Iron, 120: Second carbide, 200: Carbide, 210: Iron compound, 220: Organic binder

Claims (14)

After mixing carbides, iron compounds, and organic binders, knead and knead.
Granulate into granulated material of the specified size,
A method for producing an adsorbent, in which the granulated product is fired in a reducing atmosphere. An organic binder is kneaded into a mixture of a carbide and an iron compound, and the mixture is kneaded.
Granulate into granulated material of the specified size,
A method for producing an adsorbent, in which the granulated product is fired in a reducing atmosphere. The method for producing an adsorbent according to claim 2, wherein the amount of the organic binder to be kneaded is larger than the amount of the carbides in the mixture. The method for producing an adsorbent according to claim 2, wherein the amount of the organic binder to be kneaded is 1.2 times or more and 2.0 times or less the amount of the carbides in the mixture. The method for producing an adsorbent according to any one of claims 1 to 4, wherein the carbide is porous. The method for producing an adsorbent according to any one of claims 1 to 5, wherein the iron compound is iron oxide. The organic binder is selected from at least sugar honey, waste sugar honey, starch, dextrin, corn starch, rice bran, polyvinyl alcohol, pulp waste liquid, lignin sulfonate, carboxymethyl cellulose, hydroxypropyl methyl cellulose, sodium alginate, phenol resin, and tar pitch. The method for producing an adsorbent according to any one of claims 1 to 6, which contains one type. The method for producing an adsorbent according to any one of claims 1 to 7, wherein the granulated product is granulated to a predetermined size using a granulator. The method for producing an adsorbent according to any one of claims 1 to 8, wherein the granulated product has a pellet shape having a diameter of 1 mm or more and 20 mm or less. The method for producing an adsorbent according to any one of claims 1 to 9, wherein the reducing atmosphere contains hydrogen, carbon monoxide, or a hydrocarbon. The method for producing an adsorbent according to any one of claims 1 to 10, wherein the granulated product is fired at a firing temperature of 400 ° C. or higher and 900 ° C. or lower. The organic binder to be kneaded is any one of claims 1 to 11, wherein the organic carbon contained in the organic binder has a weight ratio of 20 times or more and 150 times or less with respect to iron contained in the iron compound. The method for producing an adsorbent according to item 1. The method for producing an adsorbent according to claim 12, wherein 50% or more and 95% of the organic carbon contained in the organic binder is volatilized in the step of firing the granulated product in a reducing atmosphere. The method for producing an adsorbent according to any one of claims 1 to 13, wherein the adsorbent adsorbs phosphorus.

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