Carbon dioxide treatment agent and its manufacturing method

Abstract

To provide a carbon dioxide treatment agent capable of fixing and decomposing carbon dioxide without heat treatment, and a method of producing a carbon dioxide treatment agent that contains oxygen-deficient magnetite without requiring heat treatment under a hydrogen gas atmosphere.SOLUTION: A carbon dioxide treatment agent contains magnesium oxide, oxygen-deficient magnetite, and zeolite. A method for producing a carbon dioxide treatment agent comprises the steps of: mixing and stirring magnetite and zeolite to obtain a mixed powder in which magnetite is filled into the pores of zeolite; adding water to the mixed powder to obtain a mixture; and attaching fine magnesium oxide powder to the mixture, followed by the drying thereof.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a carbon dioxide treating agent and a method for producing the same. [Background technology]

[0002] One of the causes of global warming is the increase in carbon dioxide emissions from facilities that use fossil fuels, such as power plants, factories, and automobiles. Although efforts are being made to use natural energy sources to reduce carbon dioxide emissions, it is expected that the use of fossil fuels will remain necessary. For this reason, there is a need to develop technologies for decomposing and removing emitted carbon dioxide, as well as technologies for fixing it.

[0003] Various methods have been proposed as carbon dioxide decomposition and removal or fixation techniques, including semiconductor photocatalysis, photochemical reduction using metal colloid catalysts, metal complexes, enzymes, etc., electrochemical reduction, and chemical fixation and conversion. In addition, a method of decomposing carbon dioxide using oxygen-deficient magnetite has also been proposed (for example, Patent Document 1 and Non-Patent Document 1). According to Patent Document 1 and Non-Patent Document 1, carbon dioxide can be decomposed into carbon by heating it in the presence of oxygen-deficient magnetite. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 05-163023 [Non-patent literature]

[0005] [Non-Patent Document 1] Yutaka Tamaura, "Decomposition and removal of CO2 using magnetite and its conversion into fuel", Journal of the Japan Paper and Pulp Technology Association, 45(5), 540-547, 1991 Summary of the Invention [Problem to be solved by the invention]

[0006] As in Patent Document 1 and Non-Patent Document 1, the method of decomposing carbon dioxide using oxygen-deficient magnetite can be carried out in a relatively low-temperature environment, but requires thermal energy of 150°C or higher, preferably 250°C or higher.

[0007] It is also necessary to obtain oxygen-deficient magnetite, but in order to obtain oxygen-deficient magnetite from magnetite, it is necessary to heat treat the magnetite at 290° C. or higher in a hydrogen gas atmosphere.

[0008] The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide a carbon dioxide treatment agent that can fix and decompose carbon dioxide without requiring heat treatment, and a method for producing a carbon dioxide treatment agent that contains oxygen-deficient magnetite without requiring heat treatment in a hydrogen gas atmosphere. [Means for solving the problem]

[0010] The carbon dioxide treating agent according to the first aspect of the present invention comprises: Contains magnesium oxide, oxygen-deficient magnetite, and zeolite, The content of the magnesium oxide in the total amount of the magnesium oxide, the oxygen-deficient magnetite, and the zeolite is 3 to 75% by weight, the content of the oxygen-deficient magnetite is 10 to 90% by weight, and the content of the zeolite is 0.1 to 20% by weight. 、 It is characterized by:

[0011] It is also preferable that the content of the magnesium oxide in the total amount of the magnesium oxide, the oxygen-deficient magnetite, and the zeolite is 40 to 60% by weight, the content of the oxygen-deficient magnetite is 25 to 35% by weight, and the content of the zeolite is 1 to 17% by weight.

[0012] It is also preferable that the carbon powder is contained in an amount of 3 to 20% by weight.

[0013] It is also preferable that the calcium compound powder is contained in an amount of 3 to 20% by weight.

[0014] It is also preferable that the aluminum powder is contained in an amount of 3 to 20% by weight.

[0015] It is also preferable that the silicon powder is contained in an amount of 3 to 20% by weight.

[0016] Also contains aluminum silicate, The weight ratio of the total amount of the magnesium oxide, the oxygen-deficient magnetite, and the zeolite to the aluminum silicate is preferably 99.1:1 to 65:35.

[0017] A carbon dioxide treating agent according to a second aspect of the present invention comprises: Contains magnesium oxide, oxygen-deficient magnetite, and zeolite, Contains 3 to 20 wt% carbon powder; It is characterized by: A carbon dioxide treating agent according to a third aspect of the present invention comprises: Contains magnesium oxide, oxygen-deficient magnetite, and zeolite, Contains 3 to 20% by weight of calcium compound powder, It is characterized by: A carbon dioxide treating agent according to a fourth aspect of the present invention comprises: Contains magnesium oxide, oxygen-deficient magnetite, and zeolite, Contains 3 to 20 wt% aluminum powder. It is characterized by: A carbon dioxide treating agent according to a fifth aspect of the present invention comprises: Contains magnesium oxide, oxygen-deficient magnetite, and zeolite, Contains 3 to 20% by weight of silicon powder; It is characterized by: A carbon dioxide treating agent according to a sixth aspect of the present invention comprises: Contains magnesium oxide, oxygen-deficient magnetite, and zeolite, Contains aluminum silicate, a weight ratio of the total amount of the magnesium oxide, the oxygen-deficient magnetite, and the zeolite to the aluminum silicate is 99.1:1 to 65:35; It is characterized by: The present invention 7 The method for producing a carbon dioxide treating agent according to the above aspect includes the steps of: a step of mixing and stirring magnetite and zeolite to obtain a mixed powder in which the magnetite is filled in the pores of the zeolite; a step of adding water to the mixed powder to obtain a mixture; and adhering magnesium oxide fine powder to the mixture and drying the mixture. It is characterized by: [Effects of the Invention]

[0018] According to the present invention, it is possible to provide a carbon dioxide treatment agent that can fix and decompose carbon dioxide without requiring heat treatment, and a method for producing a carbon dioxide treatment agent that contains oxygen-deficient magnetite without requiring heat treatment in a hydrogen gas atmosphere. DETAILED DESCRIPTION OF THE INVENTION

[0019] (Carbon dioxide treatment agent) The carbon dioxide treating agent contains magnesium oxide, oxygen-deficient magnetite, and zeolite. The carbon dioxide treating agent has oxygen-deficient magnetite embedded in and bonded to the pores of porous zeolite, and magnesium oxide attached thereto. Carbon dioxide is efficiently adsorbed and captured mainly by the magnesium oxide, and the captured carbon dioxide is decomposed by the oxygen-deficient magnetite to release oxygen. The carbon dioxide treating agent can decompose carbon dioxide and release oxygen even at room temperature, so heat treatment is not necessary.

[0020] The content of magnesium oxide in the magnesium oxide, oxygen-deficient magnetite, and zeolite is 3 to 75% by weight, preferably 20 to 60% by weight, and more preferably 40 to 60% by weight. If the amount of magnesium oxide is too small, it is difficult to promote the adsorption and capture of carbon dioxide, while if the amount of magnesium oxide is too large, the content of oxygen-deficient magnetite becomes relatively small, making it difficult to proceed with the decomposition of carbon dioxide.

[0021] The content of magnesium oxide, oxygen-deficient magnetite, and oxygen-deficient magnetite in the zeolite is 10 to 90% by weight, preferably 25 to 70% by weight, and more preferably 25 to 55% by weight.

[0022] The content of magnesium oxide, oxygen-deficient magnetite, and zeolite in the zeolite is 0.1 to 20% by weight, preferably 1 to 17% by weight, and more preferably 1 to 15% by weight.

[0023] Zeolite is not particularly limited to LTA type, FAU type, etc., but structurally, LTA type, which has an 8-membered ring opening and small pores, is desirable. Zeolite types include amicites, analcimes, and valerite, but hexagonal, orthorhombic, cubic, and tetragonal crystal structures are desirable. Specific examples of zeolites include analcimes, chamferite, paulinite, berberite, edingtonite, erionite, faujasite, and gallonite.

[0024] (Other ingredients) The carbon dioxide treating agent may contain other components in addition to the above components, such as carbon powder and calcium compound powder, each of which may be contained in an amount of 3 to 20% by weight.

[0025] The carbon dioxide treating agent may also contain aluminum powder, silicon powder, etc. The content of each of these components in the carbon dioxide treating agent is preferably 0.1 to 20% by weight, more preferably 3 to 20% by weight, even more preferably 3 to 5% by weight, and most preferably 4 to 5% by weight. When aluminum and silicon components are contained, the agent may be amorphous aluminum silicate in which the ratio of aluminum to silicon is 0.7 to 1 when the aluminum is taken as 1. Amorphous aluminum silicate is widely known as a carbon dioxide adsorbent. When aluminum silicate is contained, the weight ratio of the total amount of magnesium oxide, oxygen-deficient magnetite, and zeolite to the aluminum silicate is preferably 99.1:1 to 65:35, and more preferably 97:3 to 25:75.

[0026] (Method of manufacturing carbon dioxide treatment agent) The carbon dioxide treating agent can be produced, for example, as follows.

[0027] (Process 1) Zeolite and magnetite are mixed and mechanical energy is applied to allow the magnetite to penetrate the zeolite's micropores. To apply mechanical energy, for example, the zeolite and magnetite are mixed in a stirring vessel with a hemispherical base and a cylindrical body, and the vessel's rotating shaft is multiaxial, i.e., the rotating shaft rotates while the rotating shaft is further rotated. Specifically, this can be done using a device such as a planetary mixer, a planetary mixer, or a stirring / defoaming machine. The centrifugal force generated by these devices creates material convection and shear stress, which mix the zeolite and magnetite and apply high mechanical energy. This allows the magnetite to penetrate the zeolite's micropores. Furthermore, it is desirable to maintain the relative humidity in the vessel at around 50% (±5%).

[0028] (Process 2) Water is added to the mixed powder obtained in step 1. Dried zeolite absorbs water and generates heat, but zeolite has a microstructure, and large amounts of heat are generated locally within that microstructure. Furthermore, when zeolite is immersed in water, it generates hydrogen. This mechanism of heat generation and hydrogen generation converts the magnetite mixed in the zeolite into oxygen-deficient magnetite. The amount of water added to the mixed powder should be 40 to 60% by weight, preferably about 50% by weight.

[0029] (Step 3) Magnesium oxide is adhered to the mixture obtained in step 2. Any method may be used as long as it allows magnesium oxide to be adhered uniformly to the mixture, and for example, this can be done by adding water to the mixed powder in step 2, and then sprinkling magnesium oxide powder onto the mixture that has been spread out into a flat surface. The magnesium oxide powder is preferably in the form of a fine powder, and for example, has an average particle size of 20 μm or less, preferably 10 μm or less.

[0030] (Step 4) The carbon dioxide treating agent is then produced by drying the coated carbon dioxide particles while the magnesium oxide is still attached to the coated carbon dioxide particles. The drying may be carried out by heating or by natural drying.

[0031] In the method for producing a carbon dioxide treatment agent of the present embodiment, a carbon dioxide treatment agent containing oxygen-deficient magnetite can be produced even at room temperature, so heat treatment in a hydrogen gas atmosphere as in the conventional method is not required, and the production cost is excellent.

[0032] The obtained carbon dioxide treating agent may be crushed into granules or powder for use. The carbon dioxide treating agent may be used alone or by being mixed into or applied to a substrate or material. Examples of substrates and materials include, but are not limited to, road materials such as asphalt, paints and other coating materials, coating materials, colorants, adhesives, cement, building materials, exterior materials, interior materials, and ceiling materials.

[0033] When obtaining a carbon dioxide treating agent containing other components such as the above-mentioned carbon, calcium compounds, aluminum, silicon, aluminum silicate, etc., powders of these may be added together with the magnesium oxide powder in the above-mentioned step 3, or may be added and mixed after the magnesium oxide powder has been attached and dried in step 3. The blending amount of each component conforms to the blending amount of the above-mentioned carbon dioxide treating agent (for the blending amount of magnetite to be mixed, the blending amount of oxygen-deficient magnetite). [Example]

[0034] (Experiment 1) Magnesium oxide, magnetite, and zeolite were mixed in the mixing ratios shown in Table 1 to produce the samples (samples No. 1 to 23).

[0035] Each sample was prepared as follows. Zeolite and magnetite were mixed in a stirring vessel with a hemispherical base and a cylindrical body. The stirring vessel was then set on a planetary centrifugal mixer and stirred. The relative humidity inside the vessel was kept at 50%. Water (50% by weight based on the mixed powder) was added to the resulting mixed powder and stirred to obtain a mixture that was stretched into a flat surface. Magnesium oxide was evenly distributed in a rectangular parallelepiped container. Holes of approximately 0.5 mm in diameter were drilled at equal intervals at the bottom of the container, and an aluminum shielding plate was attached to the bottom. The container containing the magnesium oxide was placed on top of the mixture, which had been flattened out. The shielding plate was then removed, and the container was shuffled horizontally back and forth and side to side, while magnesium oxide powder was sprinkled evenly on top of the mixture. Magnesium oxide powder was sprinkled on the surface and then dried in this state to produce each sample.

[0036] For each of the produced samples, a verification experiment for carbon dioxide decomposition and oxygen generation was carried out as follows. A sample (300 g) was placed in a test tray, and 300 mL of distilled water was added and stirred. After the test vat was placed in a bag and sealed, a fixed amount of carbon monoxide and carbon dioxide were sequentially injected through the gas injection port. After the gas injection, the carbon dioxide concentration, carbon monoxide concentration, and oxygen concentration inside the bag were measured using an infrared absorption carbon dioxide concentration meter, a non-dispersive infrared absorption carbon monoxide concentration meter, and a zirconia oxygen concentration meter, respectively. The initial concentrations of carbon dioxide, oxygen, and carbon monoxide in the bag were as follows: Initial carbon dioxide concentration: 21,400 ppm Initial oxygen concentration: 129,700 ppm Initial carbon monoxide concentration: 32 ppm The bag was then left as is for 24 hours. After 24 hours, the carbon dioxide, oxygen, and carbon monoxide concentrations in the bag were measured using the same methods as above. The concentrations of each gas in the bag after 24 hours are shown in Table 1.

[0037] [Table 1]

[0038] A decrease in carbon dioxide concentration was observed in all samples. In particular, a significant decrease in carbon dioxide concentration was observed in samples with a magnesium oxide content of 40% by weight or more (Nos. 4, 6, 7, 8, 11 to 23).

[0039] Additionally, an increase in oxygen concentration was also observed in Samples Nos. 5, 7, 12 to 16, 19, 20, and 23. The increase was particularly large in Samples Nos. 12 to 16, 19, and 20. Although there was some variability in the results, it is generally believed that samples obtained with a blending ratio of 40 to 60% by weight of magnesium oxide, 32 to 47% by weight of magnetite, and 1 to 13% by weight of zeolite were highly effective in decomposing carbon dioxide and generating oxygen.

[0040] It should be noted that the carbon monoxide concentration did not increase in any of the samples, indicating that carbon dioxide was not decomposed into carbon monoxide, and oxygen was produced.

[0041] In this way, it has been proven that a carbon dioxide treatment agent that fixes and decomposes carbon dioxide and generates oxygen can be provided even when carbon dioxide and a carbon dioxide treatment agent are present in a room temperature environment, and that because this carbon dioxide treatment agent is produced at room temperature, a carbon dioxide treatment agent containing oxygen-deficient magnetite can be produced without the need for heat treatment in a hydrogen gas atmosphere.

[0042] (Experiment 2) Aluminum silicate was added to a sample (sample No. 15 in Experiment 1) containing 60 wt % magnesium oxide, 32 wt % magnetite, and 8 wt % zeolite, and the effect was examined.

[0043] Sample No. 15 and aluminum silicate were blended in the blending ratios shown in Tables 2 and 3 to prepare the samples (samples Nos. 31 to 74).

[0044] Then, a verification experiment for carbon dioxide decomposition and oxygen generation was conducted using the same method as in Experiment 1. The concentrations of each gas in the bag after 24 hours are shown in Tables 2 and 3. The initial concentrations of carbon dioxide, oxygen, and carbon monoxide in the bag were as follows: Initial carbon dioxide concentration: 21,400 ppm Initial oxygen concentration: 129,700 ppm Initial carbon monoxide concentration: 32 ppm

[0045] [Table 2]

[0046] [Table 3]

[0047] In all samples (samples No. 31 to 74), the carbon dioxide concentration decreased significantly and the oxygen concentration increased. In particular, the increase in oxygen concentration was large in samples No. 42 to 58, indicating that an aluminum silicate content of 3 to 25 wt% is particularly preferable. Furthermore, the carbon monoxide concentration did not increase in any of the samples, indicating that carbon dioxide was not decomposed into carbon monoxide, but oxygen was produced.

Claims

1. A method for producing a magnetite-based composite material, comprising: magnesium oxide, oxygen-deficient magnetite, and zeolite; the content of the magnesium oxide relative to the total amount of the magnesium oxide, the oxygen-deficient magnetite, and the zeolite is 3 to 75% by weight, the content of the oxygen-deficient magnetite is 10 to 90% by weight, and the content of the zeolite is 0.1 to 20% by weight; A carbon dioxide treatment agent characterized by:

2. the content of the magnesium oxide relative to the total amount of the magnesium oxide, the oxygen-deficient magnetite, and the zeolite is 40 to 60% by weight, the content of the oxygen-deficient magnetite is 25 to 55% by weight, and the content of the zeolite is 1 to 17% by weight; The carbon dioxide treating agent according to claim 1 .

3. Contains 3 to 20 wt % carbon powder; 3. The carbon dioxide treating agent according to claim 1 or 2.

4. Contains 3 to 20% by weight of calcium compound powder. The carbon dioxide treating agent according to any one of claims 1 to 3.

5. Contains 3 to 20 wt% aluminum powder; The carbon dioxide treating agent according to any one of claims 1 to 4.

6. Contains 3 to 20 wt% silicon powder; The carbon dioxide treating agent according to any one of claims 1 to 5.

7. Contains aluminum silicate, a weight ratio of the total amount of the magnesium oxide, the oxygen-deficient magnetite, and the zeolite to the aluminum silicate is 99.1:1 to 65:35; The carbon dioxide treating agent according to any one of claims 1 to 6.

8. A method for producing a magnetite-based composite material, comprising: magnesium oxide, oxygen-deficient magnetite, and zeolite; Contains 3 to 20 wt % carbon powder; A carbon dioxide treatment agent characterized by:

9. A method for producing a magnetite-based composite material, comprising: magnesium oxide, oxygen-deficient magnetite, and zeolite; Contains 3 to 20% by weight of calcium compound powder. A carbon dioxide treatment agent characterized by:

10. A method for producing a magnetite-based composite material, comprising: magnesium oxide, oxygen-deficient magnetite, and zeolite; Contains 3 to 20 wt% aluminum powder; A carbon dioxide treatment agent characterized by:

11. A method for producing a magnetite-based composite material, comprising: magnesium oxide, oxygen-deficient magnetite, and zeolite; Contains 3 to 20 wt% silicon powder; A carbon dioxide treatment agent characterized by:

12. A method for producing a magnetite-based composite material, comprising: magnesium oxide, oxygen-deficient magnetite, and zeolite; Contains aluminum silicate, a weight ratio of the total amount of the magnesium oxide, the oxygen-deficient magnetite, and the zeolite to the aluminum silicate is 99.1:1 to 65:35; A carbon dioxide treatment agent characterized by:

13. a step of mixing and stirring magnetite and zeolite to obtain a mixed powder in which the magnetite is filled in the pores of the zeolite; a step of adding water to the mixed powder to obtain a mixture; and adhering magnesium oxide fine powder to the mixture and drying the mixture. A method for producing a carbon dioxide treating agent, comprising:

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