Calcium extraction method, carbon dioxide immobilization method, and carbon dioxide immobilization device

Abstract

A method for immobilizing carbon dioxide according to one embodiment of the present invention comprises: a circulation step for circulating a solvent containing a polyol compound through a slag layer formed by filling a container with calcium-containing slag; an aeration step for aerating a gas containing carbon dioxide into the calcium extract obtained by passing the solvent through the slag layer in the circulation step; and a separation step for solid-liquid separation of a precipitate precipitated from the liquid mixture obtained in the aeration step, and in the circulation step, the solvent is circulated at a speed at which the slag layer does not flow.

Description

Technical Field

[0001] The invention relates to a calcium extraction method, a carbon dioxide fixation method and a carbon dioxide fixation device. Background Art

[0002] In recent years, climate change caused by global warming has become a problem. Carbon dioxide (CO2) in the atmosphere is one of the greenhouse gases and is considered to be the main cause of global warming. Therefore, there is a demand for reducing CO2 emissions, etc.

[0003] As one of the means to reduce CO 2 emission, there is a technology to fix CO 2. A CO 2 fixation method using a substance containing alkaline earth metals such as slag as a target for CO 2 fixation is known (Japanese Patent Application Laid-Open No. 2005-097072).

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2005-097072 Summary of the invention

[0007] Problems to be solved by the invention

[0008] In Patent Document 1, the above-mentioned substance containing alkaline earth metals is added to an aqueous solution containing a salt of a weak base and a strong acid placed in a first reaction container and stirred, and the stirred aqueous solution containing calcium chloride (CaCl2) is transferred to a second reaction container and aerated with carbon dioxide, thereby generating calcium carbonate (CaCO3) to fix CO2 and obtain carbonate at the same time.

[0009] In Patent Document 1, the alkaline earth metal-containing substance powder may be mixed in the aqueous solution due to stirring. The aqueous solution and the obtained carbonate after the carbon dioxide aeration may be mixed with the powder, resulting in reduced purity and limited use. In addition, since the stirring and aeration are performed in different reaction vessels, the operation of fixing carbon dioxide may become complicated.

[0010] In view of such circumstances, the object of the present invention is to provide a calcium extraction method capable of suppressing the generation of fine powder in slag and effectively extracting calcium in the slag into a solvent, as well as to provide a carbon dioxide fixation method and a carbon dioxide fixation device capable of easily fixing carbon dioxide in a calcium extract extracted by this extraction method and capable of improving the purity of the solvent and carbonate after the carbon dioxide is fixed.

[0011] Means of solving the problem

[0012] A calcium extraction method according to one embodiment of the present invention for solving the above-mentioned problems comprises a circulation step for circulating a solvent containing a polyol compound in a slag layer formed by filling a container with calcium-containing slag, wherein the solvent is circulated at a speed at which the slag layer does not flow.

[0013] Another embodiment of the carbon dioxide fixation method of the present invention for solving the above-mentioned problems comprises the following steps: a circulation step of circulating a solvent containing a polyol compound in a slag layer formed by filling a container with calcium-containing slag; an aeration step of aerating a gas containing carbon dioxide into a calcium extract obtained by passing the solvent through the slag layer in the circulation step; and a separation step of performing solid-liquid separation on a precipitate precipitated from the mixed solution obtained in the aeration step, wherein in the circulation step, the solvent is circulated at a speed at which the slag layer does not flow.

[0014] Another embodiment of the present invention for solving the above-mentioned problems is a carbon dioxide fixation device, comprising: a container for filling calcium-containing slag to form a slag layer; a supply section for supplying a solvent containing a polyol compound to the container; an adjustment section for adjusting the supply amount of the above-mentioned solvent so as to reach a speed that does not cause the above-mentioned slag layer to flow; a storage section for storing the calcium extraction liquid discharged from the above-mentioned container through the above-mentioned slag layer; an aeration section for aerating the above-mentioned extraction liquid stored in the storage section with a gas containing carbon dioxide; and a separation section for performing solid-liquid separation on the precipitate in the mixed liquid obtained by aeration through the above-mentioned aeration section.

[0015] Effects of the Invention

[0016] The calcium extraction method of the present invention can suppress the generation of fine powder in slag and can efficiently extract calcium in slag into a solvent. The carbon dioxide fixation method and carbon dioxide fixation device of the present invention can easily fix carbon dioxide in the calcium extract extracted by the above extraction method and can improve the purity of the solvent and carbonate after the carbon dioxide is fixed. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a conceptual diagram showing a carbon dioxide fixation device according to one embodiment of the present invention.

[0018] Figure 2 This is a conceptual diagram showing a test device used in Examples of the present invention.

[0019] Figure 3 It is shown in Figure 2 A graph showing the relationship between the superficial velocity of the solvent flowing through the slag layer formed in the container of the test device and the pressure loss. DETAILED DESCRIPTION

[0020] A calcium extraction method according to one embodiment of the present invention comprises a circulation step of circulating a solvent containing a polyol compound in a slag layer formed by filling a container with calcium-containing slag, wherein in the circulation step, the solvent is circulated at a speed at which the slag layer does not flow.

[0021] The calcium extraction method (hereinafter also referred to as "the extraction method") is to allow a solvent containing a polyol compound to flow through a slag layer of calcium (Ca)-containing slag to contact the slag layer. Therefore, the calcium can be effectively extracted as calcium ions in the solvent. The solvent is circulated at a speed at which the slag layer does not flow, so that fine powder (slag flakes) generated by collision of the slags in the solvent can be suppressed.

[0022] Another embodiment of the carbon dioxide fixation method of the present invention comprises the following steps: a circulation step of circulating a solvent containing a polyol compound in a slag layer formed by filling a container with calcium-containing slag; an aeration step of aerating a gas containing carbon dioxide into a calcium extract obtained by passing the solvent through the slag layer in the circulation step; and a separation step of performing solid-liquid separation on a precipitate precipitated from the mixed solution obtained in the aeration step, wherein in the circulation step, the solvent is circulated at a speed at which the slag layer does not flow.

[0023] The carbon dioxide fixing method can effectively extract calcium in the slag in the extraction process, so more carbon dioxide can be fixed to the calcium. In addition, in the extraction process, since the generation of slag pieces can be suppressed, the purity of the solvent after the carbon dioxide is fixed and the purity of the carbonate obtained by fixing the carbon dioxide can be suppressed.

[0024] The carbon dioxide fixation method may further include a recycling step of recycling the separated liquid separated in the separation step as at least a part of the solvent in the circulation step. In this way, the carbon dioxide fixation method can be performed at a low cost by recycling the solvent.

[0025] In the circulation step, the solvent may be circulated so that a pressure loss of the solvent flowing through the slag layer is 14 kPa / m or less. In this way, the generation of slag flakes can be further suppressed.

[0026] In the circulation step, the solvent may be circulated so that the superficial velocity of the solvent flowing through the slag layer is 0.4 mm / s or less. In this way, the generation of slag flakes can be further suppressed.

[0027] The polyol compound may be a diol compound or a triol compound. In this way, the calcium in the slag can be extracted more efficiently as calcium ions.

[0028] The diol compound may be one or more selected from the group consisting of ethylene glycol, propylene glycol and diethylene glycol. In this way, the calcium in the slag can be extracted more effectively as calcium ions.

[0029] The triol compound may be glycerol. In this way, the calcium in the slag can be extracted more effectively as calcium ions.

[0030] Another embodiment of the carbon dioxide fixation device of the present invention comprises: a container, which is used to fill calcium-containing slag to form a slag layer; a supply unit, which supplies a solvent containing a polyol compound to the container; an adjustment unit, which is used to adjust the supply amount of the above-mentioned solvent so as to reach a speed that does not cause the above-mentioned slag layer to flow; a storage unit, which stores the calcium extraction liquid that passes through the above-mentioned slag layer and is discharged from the above-mentioned container; an aeration unit, which aerates the above-mentioned extraction liquid stored in the storage unit with a gas containing carbon dioxide; and a separation unit, which performs solid-liquid separation on the precipitate in the mixed liquid obtained by aeration through the above-mentioned aeration unit.

[0031] Since the carbon dioxide fixing device includes the adjustment unit that adjusts the supply amount of the solvent to the slag layer to an amount at which the slag does not flow, the generation of slag flakes can be suppressed and carbon dioxide can be effectively fixed.

[0032] Here, the term "polyol compound" refers to an organic compound having a plurality of alcoholic hydroxyl groups (a group in which hydrogen atoms of aliphatic hydrocarbons are substituted with hydroxyl groups (-OH)). Similarly, the term "diol compound" refers to an organic compound having two of the above alcoholic hydroxyl groups, and the term "triol compound" refers to an organic compound having three of the above alcoholic hydroxyl groups.

[0033] [Details of Modes for Carrying Out the Invention]

[0034] Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. In addition, the accompanying drawings are explanatory drawings, which are conceptual drawings describing each structure (each component), and their shapes, scales, etc. are different from the actual situation, and components such as pumps for transferring liquids (solvents described later) or valves for transferring liquids at appropriate times are omitted. In addition, in this specification, multiple upper limits and multiple lower limits are described as the numerical range of the composition of the present invention. The multiple upper limits and multiple lower limits describe that one of each can be arbitrarily selected or arbitrarily combined.

[0035] [Carbon dioxide fixation method]

[0036] The carbon dioxide fixation method comprises the following steps: a circulation step of circulating a solvent containing a polyol compound in a slag layer formed by filling a container with calcium-containing slag; an aeration step of aerating a gas containing carbon dioxide into a calcium extract obtained by passing the solvent through the slag layer in the circulation step; and a separation step of performing solid-liquid separation on a precipitate precipitated from a mixed solution obtained in the aeration step, wherein in the circulation step, the solvent is circulated at a speed at which the slag layer does not flow.

[0037] The carbon dioxide fixation method may further include a recycling step of recycling the separated liquid separated in the separation step as at least a part of the solvent in the circulation step. Figure 1 Such a carbon dioxide fixation device is shown.

[0038] <Carbon dioxide fixation device>

[0039] The carbon dioxide fixing device mainly comprises the following: a container 1, which is used to fill calcium-containing slag to form a slag layer S; a supply part 2, which supplies a solvent M containing a polyol compound to the container 1; an adjustment part 3, which is used to adjust the supply amount of the above-mentioned solvent M to reach a speed at which the slag layer S does not flow; a storage part 4, which stores the calcium extraction liquid M1 that passes through the above-mentioned slag layer S and is discharged from the above-mentioned container 1; an aeration part 5, which aerates the above-mentioned extraction liquid M1 stored in the storage part 4 with a gas C containing carbon dioxide; and a separation part 6, which performs solid-liquid separation on the precipitate D in the mixed liquid M2 obtained by aeration through the above-mentioned aeration part 5.

[0040] The carbon dioxide fixation device further includes a circulation unit 7 that circulates the separated liquid M3 from which the precipitate D is separated in the separation unit 6 to the supply unit 2 .

[0041] <Slag>

[0042] The slag is not particularly limited as long as it contains calcium, and examples thereof include blast furnace slag, steelmaking slag, cement, concrete waste, glass waste, coal ash, and sludge incineration ash. The blast furnace slag is slag produced in the process of ironmaking, and the steelmaking slag is slag produced in the process of steelmaking such as converter slag or electric furnace slag. In these slags, calcium exists in the form of calcium oxide (CaO), for example.

[0043] <Solvent>

[0044] The solvent M contains a polyol compound. The polyol compound is a medium for extracting calcium from the slag. The polyol compound is an organic compound having a plurality of alcohol hydroxyl groups. The alcohol hydroxyl group is a hydroxyl group that replaces a hydrogen atom in an aliphatic hydrocarbon, and does not include a hydroxyl group that replaces a hydrogen atom in a hydrocarbon that constitutes an aromatic ring (for example, a hydroxyl group in phenols).

[0045] The polyol compound is not particularly limited as long as it is an organic compound having a plurality of alcoholic hydroxyl groups, but a diol compound or a triol compound is preferred.

[0046] The diol compound is not particularly limited as long as it is an organic compound having two alcoholic hydroxyl groups, and examples thereof include ethylene glycol, propylene glycol, diethylene glycol, butylene glycol, and diethanolamine. Among them, the diol compound is preferably one or more selected from the group consisting of ethylene glycol, propylene glycol, and diethylene glycol.

[0047] For example, it is generally known that the solubility of calcium in ethylene glycol is about 10 times that in water. In other words, the solubility of calcium in diol compounds is much greater than that in water. Therefore, the diol compound is one or more selected from the above group, and calcium can be extracted more effectively from the slag layer S.

[0048] The triol compound is not particularly limited as long as it is an organic compound having three alcoholic hydroxyl groups, but glycerol is preferred. By using glycerol, calcium can be extracted from the slag layer S more efficiently.

[0049] As the upper limit of the concentration of the above-mentioned polyol compound in the solvent M circulating in the slag layer S, it is preferably 60% by mass, more preferably 50% by mass, and further preferably 40% by mass. If the above-mentioned polyol compound concentration is higher than the above-mentioned upper limit, the precipitation of the precipitate (carbonate) in the aeration process described later may be reduced. That is, the efficiency of fixing carbon dioxide may be reduced. As the lower limit of the concentration of the above-mentioned polyol compound in the solvent M in the circulation process, it is preferably 20% by mass, and more preferably 30% by mass. If the above-mentioned polyol compound concentration is lower than the above-mentioned lower limit, it may be impossible to dissolve a sufficient amount of calcium from the slag layer S into the solvent M.

[0050] The solvent M preferably further contains water. The diol compound and the triol compound are usually in liquid form at normal temperature and pressure, and thus can be mixed with the water relatively easily and circulated in the slag layer S. The water is a proton (H2) for ionizing carbon dioxide (ionizing carbon dioxide). ＋ ) supply source. In addition, in the circulation process described later, the calcium ions extracted from the polyol compound move (diffusion) in the water, and the carbon dioxide is used as the carbonate ion (CO3 2－) is dissolved in the water. As a result, calcium ions and carbonate ions react with the water as a reaction site, and calcium carbonate is precipitated. Such water is not particularly limited as long as it functions in a catalytic manner as described above, and for example, pure water can be cited.

[0051] 〔Distribution Process〕

[0052] In the circulation step, the solvent M containing the polyol compound is circulated in the slag layer S formed by filling the calcium-containing slag into the container 1. The container 1 is not particularly limited as long as it can be filled with slag to form the slag layer S and the solvent M containing the polyol compound can be circulated in the slag layer S.

[0053] In the circulation process, the solvent M is circulated at a speed at which the slag layer S does not flow. That is, the solvent M is circulated at a circulation speed at which the slag in the slag layer S does not move and collide with each other in the container 1. If the slags collide with each other due to the circulation of the solvent M, their fragments (slag flakes) are mixed into the solvent M discharged from the container 1. The mixing of the above-mentioned slag flakes into the solvent M will cause the purity of the solvent M after the carbon dioxide fixation treatment to decrease, and the use or reuse of the use may be limited. In addition, carbonates can be obtained by fixing carbon dioxide using the solvent M discharged from the container 1, but the above-mentioned slag flakes will also be mixed into the carbonates, the purity is reduced, and the use of the use may be limited. In order to improve the purity of the solvent M discharged from the container 1, it is necessary to remove the above-mentioned slag flakes, and the cost of using or reusing the solvent M and the above-mentioned carbonates discharged from the container 1 may increase.

[0054] The carbon dioxide fixing device includes a supply unit 2 for supplying a solvent M, and an adjustment unit 3 for adjusting the supply amount of the solvent M. The adjustment unit 3 adjusts the flow rate of the solvent M supplied from the supply unit 2 to the container 1, and controls the flow rate of the solvent M in the container 1 in such a way that the slag layer S does not flow. The supply unit 2 is not particularly limited, and is, for example, a pump for liquid. The adjustment unit 3 is not particularly limited, and is, for example, a regulating valve capable of changing the opening diameter. The adjustment unit 3 is provided in a solvent supply pipe P1 connecting the container 1 and the supply unit 2.

[0055] In the circulation step, the solvent M is preferably circulated in such a manner that the pressure loss of the solvent M circulating in the slag layer S is 14 kPa / m or less. The upper limit of the pressure loss of the solvent M circulating in the slag layer S is more preferably 12 kPa / m, further preferably 10 kPa / m, and particularly preferably 6 kPa / m. If the pressure loss of the solvent M circulating in the slag layer S is higher than the upper limit, the slag in the slag layer S may move relative to each other in the container 1, causing collisions, etc.

[0056] In addition, in the circulation step, the solvent M is preferably circulated in such a manner that the superficial velocity of the solvent M circulating in the slag layer S is 0.4 mm / s or less. The upper limit of the superficial velocity of the solvent M circulating in the slag layer S is more preferably 0.3 mm / s. If the superficial velocity of the solvent M circulating in the slag layer S is higher than the upper limit, the slag in the slag layer S may move mutually in the container 1 and collide with each other. The lower limit of the superficial velocity of the solvent M circulating in the slag layer S is not particularly limited, and is, for example, 0.08 mm / s.

[0057] The slag from which calcium has been removed in the circulation process, for example, when the slag is steelmaking slag, is taken out from the container 1 and dried, and can be utilized as a resource such as a roadbed material (road material), fertilizer, etc.

[0058] 〔Aeration process〕

[0059] In the aeration process, the gas C containing carbon dioxide is aerated into the calcium extract obtained by passing the solvent M through the slag layer S in the above-mentioned circulation process. Specifically, the solvent (calcium extract) M1 discharged from the container 1 is stored in the storage section 4, and the gas C containing carbon dioxide is aerated into the stored calcium extract M1. The storage section 4 is a tank for storing the calcium extract M1 supplied from the container 1 via the extract supply pipe P2. The aeration section 5 aerates the gas C into the calcium extract M1 stored in the storage section 4. The aeration section 5 is not particularly limited, and is, for example, a known gas blowing device. The aeration of the gas C by the aeration section 5 is preferably performed while stirring the calcium extract M1 in the storage section 4.

[0060] The solvent M containing the polyol compound is in contact with the slag as a solvent containing a large amount of calcium ions (Ca 2＋ ) is discharged from the container 1. By aerating the calcium extract M1 with a gas C containing carbon dioxide, carbon dioxide is dissolved in the calcium extract M1 as carbonate ions. When the calcium ions react with the carbonate ions, carbonate (calcium carbonate: CaCO3) is precipitated as a precipitate. Since the calcium extract M1 contains a large amount of calcium ions, this carbon dioxide fixation method can fix a large amount of carbon dioxide.

[0061] As the gas C containing carbon dioxide, it is preferable to use waste gas containing carbon dioxide discharged from industrial activities such as factories, power plants, and transportation. The concentration of carbon dioxide in the gas C is not particularly limited, and may be the same concentration as that in the atmosphere or the waste gas, or may be a concentration obtained by diluting or concentrating the concentration. The gas C may also be a gas consisting only of carbon dioxide.

[0062] 〔Separation process〕

[0063] The separation step is to perform solid-liquid separation on the precipitate D precipitated from the mixed solution M2 obtained by the aeration step. Specifically, in the separation unit 6, the calcium extract (mixed solution) M2 after the aeration step supplied via the mixed solution supply pipe P3 is solid-liquid separated into a solid (precipitate D) and a liquid (separated solution M3). The separation unit 6 is not particularly limited, and is, for example, a well-known centrifugal separator.

[0064] The precipitate D and the separated liquid M3 separated by the separation unit 6 have high purity because the mixing of slag flakes is suppressed, and can be used or reused in a wide range of applications. The separated liquid M3 can be reused as part of the solvent M in the above-mentioned circulation process, for example, as described later. The precipitate D (carbonate) can be used as a filler for a resin, for example.

[0065] 〔Recycling process〕

[0066] In the recycling process, the separated separation liquid M3 is reused as at least a part of the solvent M in the circulation process. The separation liquid M3 is circulated from the circulation unit 7 to the supply unit 2 and used as a part of the solvent mixed liquid in contact with the slag layer S. The circulation unit 7 includes a separation liquid supply pipe P4. The circulating separation liquid M3 has the same quality as the solvent M before contacting the slag layer S because the mixing of slag pieces is suppressed and the precipitate D is removed in the separation process.

[0067] 〔advantage〕

[0068] This carbon dioxide fixing method can effectively extract calcium from the slag by circulating a solvent containing a polyol compound in the calcium-containing slag through a circulation process. Therefore, the calcium content of the slag after the circulation of the solvent is reduced and can be effectively used or reused. The solvent after contacting the slag contains a large amount of calcium, and carbon dioxide can be effectively fixed by aerating a gas containing carbon dioxide. In addition, this carbon dioxide fixing method can suppress the mixing of slag flakes of the slag into the circulated solvent by circulating the solvent at a speed at which the slag does not flow in the circulation process. Therefore, the precipitate precipitated by the aeration and the solvent after the aeration have high purity, and the precipitate and the solvent after the aeration can be used or reused at low cost and in a wide range of applications.

[0069] [Other embodiments]

[0070] The embodiments do not limit the configuration of the present invention. Therefore, the embodiments may omit, replace or add constituent elements of each part of the embodiments based on the description of this specification and technical common sense, and all of these should be interpreted as belonging to the scope of the present invention.

[0071] In the above-mentioned embodiment, the carbon dioxide fixation device is described as including a supply unit and an adjustment unit, but the supply unit may be built in the adjustment unit. That is, a supply unit integrated with the adjustment unit may be used.

[0072] The solvent may also contain other solutions and additives other than polyol compounds and water within the range that does not hinder the calcium extraction efficiency in the slag. As other solutions, for example, hydrophilic solutions etc. As hydrophilic solutions, ethanol or methanol etc. may be cited. In addition, in the circulation process, it may also be used as a mixed solution of an aqueous solution in which a polyol compound and an additive other than a solvent are dissolved in water.

[0073] The above-mentioned recycling step is not an essential step of the carbon dioxide fixation method, and the separated liquid can also be used for other purposes.

[0074] As a method of filling the container of the carbon dioxide fixation device with slag, supply of the solvent may be started after the slag is filled into the container, or the slag and the solvent may be supplied (filled) into the container at the same time.

[0075] In addition, the solvent may be supplied to the container at a fixed flow rate or at a variable flow rate. In addition, the solvent may be supplied continuously or intermittently.

[0076] Obstacles may also be provided in the container to prevent the solvent from flowing linearly. That is, obstacles may be provided in the container to cause the solvent to form turbulent flow partially or entirely in the container.

[0077] Example

[0078] The present invention is further described below by way of examples, but the present invention is not limited to these examples.

[0079] use Figure 2 The test apparatus shown below conducted the following comparative test: As slag, 450 g of steelmaking slag adjusted to a particle size of 10 mm or less by a sieve was filled into a container 11 having an inner diameter of 42 mm and a height of 230 mm to form a slag layer S1.

[0080] The property of the slag is that f-CaO is 13% by mass. Here, f-CaO refers to unreacted calcium oxide (CaO) and unreacted calcium hydroxide (Ca(OH)2). The component contents of the slag are shown in Table 1. The contents are rounded off to 3 decimal places.

[0081]

Table 1

[0082]

[0083] As a solvent M11 containing a polyol compound, a solvent having a concentration of 40% by mass of glycerol (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., with a purity higher than 99.5%) and water was prepared. In Test Example 1 and Test Example 2 described later, the solvent M11 was supplied to a container 11 and circulated in the slag layer S1 to extract calcium. The solvent M11 was stored in a solvent container 12, and nitrogen N was applied to the solvent container 12 to supply it to the container 11. In Test Example 1 and Test Example 2, the flow rate (supply speed) of the solvent M1 was controlled by the supply amount of the nitrogen N to achieve different empty tower velocities. The supply amount of the nitrogen N was adjusted by a valve V while being confirmed by a flow meter 13.

[0084] The solvent (calcium extraction liquid) M12 discharged from the container 11 where the slag layer S1 is formed is sampled at predetermined time intervals, and the calcium ion concentration in the solution is measured to calculate the calcium extraction rate E. The calcium extraction rate E [%] is calculated using the following formula 1.

[0085] E=B / S×100 …(1)

[0086] Here, B is the calcium [mol] in the calcium extract, and S is the calcium [mol] in the slag.

[0087] In Test Example 3, 400 g of the solvent M11 and 40 g of the slag were put into another container (beaker) and stirred to extract calcium. The stirring was carried out at room temperature and nitrogen atmosphere at 300 rpm using a stirrer for 1.5 hours. The stirred solvent (calcium extract) was filtered under reduced pressure (filter material: filter paper 5 types A), and the calcium concentration in the filtrate was quantified to calculate the extraction rate.

[0088] The presence or absence of fine powder (slag flakes) in the calcium extracts of Test Examples 1, 2, and 3 was checked visually for turbidity of the calcium extracts. The evaluation of Test Examples 1, 2, and 3 is shown in Table 2.

[0089]

Table 2

[0090]

[0091] In Test Example 3, the calcium extraction rate is the same as that in Test Example 1, but there are fine powders in the calcium extract, so in order to use or reuse the calcium extract, it is necessary to remove the fine powders. On the other hand, in Test Examples 1 and 2, since there are very few fine powders in the calcium extract, the calcium extract can be reduced to a solvent and used or reused without removing the fine powders.

[0092] Next, as Test Example 4, the test was conducted under the same conditions as Test Example 1 except for the empty tower velocity. The empty tower velocity was changed at a speed higher than 0 mm / s and lower than 1.4 mm / s, and the test was conducted. The test was conducted in Run 1 with a faster empty tower velocity and Run 2 with a slower empty tower velocity. The pressure loss of the solvent in the container 11 was measured with a pressure gauge. The pressure loss was read by measuring the height of the liquid in the pressure gauge above the upper end of the slag layer S1 and converting it. Figure 3 2 shows the relationship between the change in the superficial velocity of the solvent and the change in the pressure loss.

[0093] Depend on Figure 3 It can be seen that there is a bending point of pressure loss when the idle speed is 0.4 mm / s. In other words, it can be seen that if the idle speed is higher than 0.4 mm / s, the slag begins to flow. Figure 3 It is understood that it is preferred that the evaporation velocity of the solvent M11 flowing through the slag layer S1 be 0.4 mm / s or less, and the pressure loss be 14 kPa / m or less.

[0094] Industrial Applicability

[0095] Since the present invention can effectively fix carbon dioxide at low cost, the calcium-containing slag can be effectively utilized, and the purity of the solvent and the precipitate in the solvent after the carbon dioxide is fixed can be improved, so the solvent and the precipitate can be easily utilized or reused. Therefore, the present invention is suitable for the fixation of carbon dioxide.

[0096] Description of Reference Numerals

[0097] 1.11 containers

[0098] 2Supply Department

[0099] 3Adjustment Department

[0100] 4 Storage Department

[0101] 5 Aeration section

[0102] 6 Separation

[0103] 7. Circulation

[0104] 12Solvent container

[0105] 13 Flow meter

[0106] D Precipitate

[0107] M, M11 solvent

[0108] M1, M12 calcium extract

[0109] M2 Mixture

[0110] M3 separation solution

[0111] N Nitrogen

[0112] P1 solvent supply pipe

[0113] P2 Extraction Liquid Supply Pipe

[0114] P3 mixed liquid supply pipe

[0115] P4 separation liquid supply tube

[0116] S, S1 slag layer

[0117] V-Valve

Claims

1. A method for extracting calcium, wherein: The method comprises a circulation step of circulating a solvent containing a polyol compound in a slag layer formed by filling a container with slag containing calcium, In the circulation step, the solvent is circulated at a speed at which the slag layer does not flow.

2. A method for fixing carbon dioxide, wherein: The following processes are available: A circulation step of circulating a solvent containing a polyol compound in a slag layer formed by filling a container with slag containing calcium; an aeration step of aerating a gas containing carbon dioxide into the calcium extract obtained by passing the solvent through the slag layer in the circulation step; a separation step of performing solid-liquid separation on a precipitate precipitated from the mixed liquid obtained in the aeration step, In the circulation step, the solvent is circulated at a speed at which the slag layer does not flow.

3. The method for fixing carbon dioxide according to claim 2, wherein: The method further comprises a recycling step of recycling the separated liquid separated in the separation step as at least a part of the solvent in the circulation step.

4. The method for fixing carbon dioxide according to claim 2, wherein: In the circulation step, the solvent is circulated so that a pressure loss of the solvent circulating in the slag layer is 14 kPa / m or less.

5. The method for fixing carbon dioxide according to claim 2 or claim 4, wherein: In the flowing step, the solvent is caused to flow so that the superficial velocity of the solvent flowing through the slag layer is 0.4 mm / s or less.

6. The method for fixing carbon dioxide according to claim 2 or claim 3, wherein: The polyol compound is a diol compound or a triol compound.

7. The method for fixing carbon dioxide according to claim 6, wherein: The diol compound is one or more selected from the group consisting of ethylene glycol, propylene glycol and diethylene glycol.

8. The method for fixing carbon dioxide according to claim 6, wherein: The triol compound is glycerol.

9. A carbon dioxide fixation device, comprising: A container, the container being used to be filled with calcium-containing slag to form a slag layer; a supply unit that supplies a solvent containing a polyol compound to the container; an adjusting unit that adjusts the supply amount of the solvent so as to achieve a speed at which the slag layer does not flow; a storage portion storing the calcium extraction liquid that passes through the slag layer and is discharged from the container; an aeration section for aerating a gas containing carbon dioxide into the extract stored in the storage section; A separation unit performs solid-liquid separation on a precipitate in a mixed liquid obtained by aeration in the aeration unit.

Images