Method for endothermically reacting solids and method for producing oxides

Abstract

The invention provides a method for causing an endothermic reaction of a solid and a method for producing an oxide. It is required that the purity of an oxide obtained by firing limestone or the like is increased, and it has been concerned that the emission of carbon dioxide is reduced in a production method for achieving a carbon-free society. An oxide of Ca and / or Mg in a light-emitting state in which light is continuously emitted due to thermal radiation is irradiated with laser light, and the Ca and / or Mg is irradiated with the laser light by means of heat from the oxide in the light-emitting state by absorbing the laser light. A method for endothermically reacting a solid adjacent to the oxide in the light-emitting state, and a method for producing a corresponding oxide from a carbonate of Ca and / or Mg as the solid.

Description

Technical Field

[0001] The present invention relates to a method for causing a solid to undergo an endothermic reaction using heat from an oxide containing Ca and / or Mg which is in a luminescent state due to thermal radiation, and a method for producing the oxide. Background Art

[0002] Oxides obtained from carbonates and hydroxides containing Ca or Mg, such as limestone, dolomite, and magnesite, are used in a wide range of applications that support the core of industrial technology, such as steelmaking, cement raw materials, papermaking, building materials, desiccants, fertilizers, and food additives.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2012-201571 Summary of the invention

[0006] In the prior art, the oxide can be produced by heating its carbonate using a firing furnace such as a Maerz kiln, but the oxide produced using the prior art contains impurities such as sulfur or ash derived from the fuel. In recent years, higher purity has been continuously required for use in the above-mentioned industrial technology applications that require high quality.

[0007] In addition, large-scale equipment such as Maerz kiln is not suitable for burning fine-grained limestone with a diameter of less than 10 mm remaining in mines, nor is it suitable for obtaining high-quality quicklime with less impurities. However, if there is a method to burn fine-grained limestone with high quality in a short time, it is believed to be useful to effectively utilize limestone resources and meet various industrial needs.

[0008] Furthermore, in recent years, in order to realize a carbon-free society, the storage of surplus electricity generated due to imbalance in electricity supply and demand has also become an important issue and has received attention.

[0009] In recent years, in order to realize a carbon-free society, reducing carbon dioxide emissions has attracted attention as an important issue. In firing furnaces such as Maerz kilns, a large amount of carbon dioxide is emitted due to the use of fossil fuels such as heavy oil. It is generally believed that not using fossil fuels as a fuel for firing limestone can help reduce carbon dioxide emissions.

[0010] The limestone powder particles less than 1.0 mm left in the mines will only become quicklime less than 1.0 mm even if they are fired in a firing furnace, and their uses are limited. In the above industrial and technical uses, not only quicklime less than 1.0 mm but also granular quicklime of about 10 mm is required. It is generally believed that as long as the limestone powder particles can be fired into quicklime of about 10 mm in size, the limestone resources can be effectively utilized.

[0011] The present invention includes the following methods 1 to 9:

[0012] (Method 1) A method for causing a solid to undergo an endothermic reaction, comprising irradiating a laser beam to an oxide of Ca and / or Mg in a luminescent state accompanied by continuous luminescence due to thermal radiation, and using heat from the oxide in the luminescent state that has absorbed the laser beam to cause an endothermic reaction in a solid adjacent to the oxide in the luminescent state.

[0013] (Mode 2) In the method described in Mode 1, the oxide in the light-emitting state is generated by absorbing laser light.

[0014] (Mode 3) A method for producing an oxide, comprising producing the corresponding oxide from a carbonate of Ca and / or Mg as the solid using the method described in Mode 1 or Mode 2.

[0015] (Mode 4) A method for producing an oxide, comprising producing a corresponding oxide from a hydroxide of Ca and / or Mg as the solid using the method described in Mode 1 or 2.

[0016] (Aspect 5) A thermal storage medium comprising an oxide produced by the production method described in aspect 3.

[0017] (Aspect 6) An energy storage method using the oxide produced by the production method described in aspect 4 as a thermal storage medium.

[0018] (Method 7) A method for producing an oxide, comprising: using the method described in Method 1 or 2, from the solid granular carbonate of Ca and / or Mg, while forming agglomerates having a particle size larger than the particles, and producing an oxide corresponding to the carbonate of Ca and / or Mg.

[0019] (Form 8) A carbon dioxide absorber comprising a hydroxide obtained by a hydration reaction of an oxide produced by the production method described in Form 3.

[0020] (Method 9) A method for recovering carbon dioxide, characterized in that: the hydroxide obtained by hydration reaction of the oxide produced by the production method described in Method 3 absorbs the carbon dioxide existing around the hydroxide.

[0021] The solid adjacent to the oxide in the light-emitting state may be another solid configured in contact with the oxide in the light-emitting state, or may be the following solid portion: a solid that forms an integral substance with the oxide in the light-emitting state before it becomes a light-emitting state, and constitutes a peripheral region that is in contact with the outer edge of the oxide in the light-emitting state formed locally in the integral substance.

[0022] In addition, in claim 6 of the claims, the heat storage medium according to the present invention is expressed as a manufacturing method, but this is based on the following situation: at the time of filing the application, it is impossible or almost impossible to directly determine from its structure or characteristics whether the object is manufactured by the manufacturing method of claim 4. In addition, in claim 8 of the claims, the carbon dioxide absorber according to the present invention is expressed as a manufacturing method, but this is based on the following situation: at the time of filing the application, it is impossible or almost impossible to directly determine from its structure or characteristics whether the object is manufactured by the manufacturing method of claim 3.

[0023] The oxides of Ca and / or Mg are preferably minerals or rocks containing quicklime (CaO), MgO, or CaO·MgO.

[0024] As the carbonate of Ca and / or Mg, limestone (CaCO 3 ), magnesite (MgCO 3 ) or dolomite (CaMg(CO 3 ) 2 ) and other minerals or rocks.

[0025] When the oxide of Ca and / or Mg is an oxide of Ca, the quicklime in the light emitting state accompanied by continuous light emission due to the heat radiation is preferably generated by limestone absorbing laser light.

[0026] When the oxide of Ca and / or Mg is an oxide of Mg, it is preferred that the oxide of Mg in a light-emitting state accompanied by continuous light emission due to the thermal radiation is generated due to magnesite absorbing laser light.

[0027] When the oxide of Ca and / or Mg is an oxide of Ca and Mg, it is preferred that the oxide of Ca and Mg in a luminescent state accompanied by continuous luminescence due to the thermal radiation is generated due to dolomite absorbing laser light.

[0028] The particle size of the particles is preferably 0.1 mm to 1.0 mm, and more preferably 0.3 mm to 0.8 mm.

[0029] As the solid, the hydroxide of Ca and / or Mg is preferably composed of slaked lime (Ca(OH) 2 ) of substances.

[0030] As the solid, the hydroxide of Ca and / or Mg preferably contains magnesium hydroxide (Mg(OH) 2 ) of substances.

[0031] As the solid, the hydroxide of Ca and / or Mg is preferably composed of hydroxide dolomite (Ca(OH) 2 Mg(OH) 2 ) of substances.

[0032] Effects of the Invention

[0033] According to the present invention, a new endothermic reaction accompanied by continuous strong thermoluminescence can be realized.

[0034] According to the present invention, it is possible to provide a method for converting CO 2 High-purity Ca and / or Mg oxides whose residual amount is suppressed to 10 mass % or less.

[0035] In addition, impurities such as sulfur and ash (main components are iron, nickel, vanadium, and silicon dioxide) derived from fuel mixed during production can be eliminated in advance, thereby designing a method for producing Ca and / or Mg oxides with higher purity.

[0036] According to the present invention, by using limestone as carbonate of Ca and / or Mg, high-purity quicklime can be produced, and high-quality raw materials supporting basic industries such as steelmaking, cement, and papermaking can be provided.

[0037] According to the present invention, by using magnesite as carbonate of Ca and / or Mg, high-purity oxide of magnesite obtained by firing can be produced, and high-quality raw materials supporting basic industries such as steelmaking can be provided.

[0038] According to the present invention, by using dolomite as a carbonate of Ca and / or Mg, a high-purity oxide of dolomite obtained by firing can be produced, and a high-quality raw material supporting basic industries such as steelmaking can be provided.

[0039] Furthermore, by using the oxides of Ca and / or Mg obtained by the present invention, a high-purity heat storage medium can be obtained, and a highly accurate energy storage system can be realized.

[0040] By using electricity generated from renewable energy instead of fossil fuels for firing, carbon dioxide emissions can be significantly reduced.

[0041] According to the present invention, the method for producing the corresponding oxide from the carbonate of Ca can also be applied to the process of producing the corresponding oxide from the carbonate of Ca by an endothermic reaction during cement production.

[0042] By using the hydroxide obtained by the hydration reaction of the Ca and / or Mg oxides obtained by the present invention, a carbon dioxide recovery system can be realized. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 This is a stereoscopic photograph showing the appearance of a block sample formed into a plate shape used in the examples, and shows a sample formed of limestone as an example.

[0044] Figure 2 (a) is a diagram showing the structure of a firing device for performing laser firing according to the present invention, Figure 2 (b) shows a condition where the light beam is formed into a ring pattern.

[0045] Figure 3 This is a graph showing the temperature change of the laser irradiated portion when the laser is continuously irradiated at a fixed point of a limestone sample for 24 seconds.

[0046] Figure 4 Graph of heat input due to intense thermoluminescence modeled as a function of temperature via heat flux.

[0047] Figure 5 Shows the fixed point irradiation Figure 3 The temperature measurement results are reproduced by unsteady-state heat transfer analysis.

[0048] Figure 6 This is a photograph showing the state of strong thermal luminescence generated when a massive limestone sample is irradiated with laser light.

[0049] Figure 7 The CO of the sample in the area subjected to laser sintering 2 Residue measurement results, the vertical axis represents the laser output power, and the horizontal axis represents the laser scanning speed.

[0050] Figure 8 The results of observing the temperature distribution of the limestone surface using an infrared camera under the irradiation conditions when the laser was scanned in the case where strong thermoluminescence was generated during the irradiation and the case where strong thermoluminescence was not generated are shown.

[0051] Fig. 9 The following shows the XRD results of a sample obtained by irradiating granular limestone with laser light and firing it with intense thermal emission.

[0052] Fig.10 The surface of the limestone sample observed by Raman spectroscopy at around 900°C when it was fired in a non-luminescent intermediate state and when it was fired in a strong thermoluminescent state ( Fig.10 (a)) and cross section ( Fig.10 The result of (b)).

[0053] Fig.11 This is a diagram for explaining a state in which a sample to which a carbon coating treatment is applied to a 5 mm distance from the end of a block limestone sample is irradiated with a laser beam starting from the coated portion of the coated sample and scanning toward the opposite side of the sample.

[0054] Fig.12 is based on Figure 7 The CO2 content of the sample in the area after laser burning of the sample treated with carbon coating under the conditions of laser output power and laser scanning speed 2 Residue measurement results, the vertical axis represents the laser output power, and the horizontal axis represents the laser scanning speed.

[0055] Fig.13 This is a schematic diagram showing an apparatus for firing a granular sample by irradiating it with laser light from above.

[0056] Fig.14 This is a schematic diagram of a firing vessel used for laser firing of a granular sample.

[0057] Fig.15 This is a photograph showing the state of strong thermal luminescence generated when a granular limestone sample is irradiated with laser light.

[0058] Fig.16 (a) shows an enlarged image of limestone powder particles before laser irradiation, Fig.16 (c) shows an enlarged image of the quicklime aggregate after firing, which is accompanied by continuous strong thermal luminescence due to laser irradiation. Fig.16 (b) shows an enlarged image of a powder particle after non-luminescent intermediate firing in which no luminescence was observed during laser irradiation.

[0059] Fig.17 This is a graph showing the temperature change of the laser irradiated portion when the laser is continuously irradiated for 60 seconds at a fixed point on granular slaked lime.

[0060] Fig.18 This is a photograph showing an agglomerate obtained by subjecting granular slaked lime to laser firing accompanied by strong thermal emission.

[0061] Fig.19 This is a graph showing the temperature change of the laser irradiated portion when the laser is continuously irradiated at a fixed point on dolomite for 60 seconds.

[0062] Fig. 20 This means that if continuous strong thermal luminescence is observed when laser sintering is performed on dolomite, 10 mass % or less of CO can be observed in the obtained oxide. 2 A diagram showing the status of the residual amount.

[0063] Fig.21 This is a graph showing the temperature change of the laser irradiated portion when magnesite is irradiated with laser light for 350 seconds at a fixed point.

[0064] Fig. 22 This means that when laser sintering is performed on magnesite and continuous strong thermal luminescence is observed, 10 mass % or less of CO can be observed in the obtained oxide. 2 A diagram showing the status of the residual amount.

[0065] Fig.23 The XRD results of oxides of slaked lime obtained by firing accompanied by strong thermal emission due to laser irradiation are shown.

[0066] Fig.24 Shown are XRD results of dolomite oxides obtained by firing accompanied by strong thermal luminescence due to laser irradiation.

[0067] Fig.25 The XRD results of the oxide of magnesite obtained by firing accompanied by strong thermal luminescence due to laser irradiation are shown.

[0068] Fig.26 This is a photograph showing an agglomerate obtained by subjecting granular dolomite to laser firing accompanied by strong thermoluminescence.

[0069] Fig. 27 This is a photograph showing an agglomerate obtained by subjecting granular magnesite to laser firing accompanied by strong thermoluminescence. DETAILED DESCRIPTION

[0070] Hereinafter, although the Example of this invention is described concretely, this invention is not limited to the Example described below.

[0071] (Example 1)

[0072] (1) Temperature changes caused by laser burning at fixed points

[0073] In this embodiment, description is made using limestone formed of carbonate of Ca as an example.

[0074] like Figure 1 As shown, the limestone sample used was a block sample formed into a plate shape of 25 mm×25 mm×10 mm.

[0075] The limestone sample was installed in Figure 2 The firing device shown in (a) performs firing by laser.

[0076] The laser oscillator uses a continuous wave single-mode fiber laser that can output near-infrared light with a wavelength of 1090nm. The light output by the oscillator is transmitted through the optical fiber. An isolator is provided to prevent the light returning from the sample from damaging the oscillator. An axicon lens and a focusing lens are provided to make the shape of the light beam into a ring mode. In order to perform laser scanning on the limestone sample, the sample fixed to the fixture is moved at an arbitrary speed by an X, Y, and Z automatic stage. Laser irradiation and stage scanning are controlled by a trigger using a relay circuit. The size of the light beam is a size that removes less processing than a Gaussian mode (the laser irradiation range is a solid, roughly circular mode) (a ring mode with an outer diameter of 2.0 to 3.0 mm and an inner diameter of 1.0 to 1.5 mm). By making the shape of the light beam as follows Figure 2 The annular pattern shown in (b) makes it easier to control the temperature of the laser irradiation surface and enables control of the burning area and removal processing.

[0077] Figure 3 This is a graph showing the temperature change of the laser irradiated portion when a ring mode laser with an outer diameter of 2.0 mm and an inner diameter of 1.0 mm is irradiated to a limestone sample at a fixed point for 24 seconds without scanning. Figure 1 The block limestone sample shown. Figure 3 As shown in FIG. 1 , when limestone is irradiated with laser light under certain conditions, the firing temperature of the limestone sample will stagnate at around 1000°C for a certain period of time. By continuing to irradiate with laser light, it can emit light due to thermal radiation (hereinafter referred to as strong thermal emission) and generate a high temperature of 1900°C. In addition, strong thermal emission cannot be confirmed from the limestone sample when the firing temperature is stagnant at around 1000°C (hereinafter referred to as non-luminescent intermediate firing).

[0078] The mechanism of heat input to the sample when this strong thermoluminescence is generated is examined. Figure 4 The graph shows the result of modeling the heat input caused by strong thermoluminescence by heat flux as a variable of temperature. In the temperature variation model of the heat flux, the strong thermoluminescence is attempted to be reproduced by rapidly applying the heat flux from 1000°C and rapidly reducing the heat flux after reaching 1900°C. Figure 5 Show that Figure 3 The temperature measurement results are reproduced by unsteady-state heat conduction analysis. Figure 5It can be seen that the temperature stagnation at about 1000°C and the temperature during strong thermoluminescence can be reproduced. Since the output of the laser is constant, it is considered that the strong thermoluminescence can cause a change in the absorptivity of the laser light in the laser irradiated portion that is equivalent to the change in heat flux, thereby achieving a new endothermic reaction. In addition, according to the present invention, due to the generation of strong thermoluminescence, the region adjacent to the oxide in the strong thermoluminescent state, as a specific example, the solid portion of the peripheral region that is in contact with and integrally formed with the outer edge of the oxide in the strong thermoluminescent state, or other solids that are arranged in contact with the oxide in the strong thermoluminescent state can produce a sintering effect due to the new endothermic reaction.

[0079] Based on the above description, it can be inferred that when strong thermoluminescence is generated, not only is there heat input from the irradiated laser, but also the sample's absorptivity to the laser also increases, and there is also heat input from the strong thermoluminescence. Therefore, it can be considered that the firing temperature of the sample can reach a temperature that is significantly higher than the firing temperature of the previous firing furnace.

[0080] also, Figure 6 Shown in Figure 1 The intense thermal luminescence generated when a limestone sample is irradiated with laser. When irradiated with high power density laser, light is emitted from the laser irradiation surface.

[0081] (Example 2)

[0082] (1) Firing and CO by laser scanning 2 Residue measurement

[0083] Next, the conditions of driving the automatic stage to scan the laser on the limestone sample and generating strong thermoluminescence and not generating strong thermoluminescence were explored, and CO in quicklime as an oxide corresponding to the limestone fired under various conditions was measured. 2 As the laser scanning conditions, a ring mode laser with an outer diameter of 3.0 mm and an inner diameter of 1.5 mm was used, and scanning was performed in a manner such that the pitch was kept constant at a distance (3.0 mm) so that the beams would not overlap.

[0084] In addition, the quicklime in the fired area was collected by installing a flat-end milling cutter with a blade diameter of 6 mm on a milling machine and scraping from the surface of the sample to a depth of 1.0 mm. The collected sample was evaluated for CO by the infrared absorption method specified in JIS R9011. 2 In addition, the limestone sample used in this example contains about 44% by mass of CO 2 .

[0085] Figure 7 The CO of the sample in the area subjected to laser sintering is shown. 2Residue measurement results. Figure 7 The vertical axis is the laser output power, and the horizontal axis is the scanning speed. Figure 7 In the figure, a circle indicates that continuous strong thermoluminescence was observed during laser irradiation, a triangle indicates that flickering strong thermoluminescence was observed, and a cross indicates that no strong thermoluminescence was generated.

[0086] in addition, Figure 7 CO is shown on the upper right of each symbol. 2 The results of residual measurement. Under the condition of continuous strong thermal luminescence (output power of 80W, scanning speed of 0.050~0.100mm / s), CO 2 The residual amount is 2.0 mass % or less, and quicklime equivalent to JIS special grade is obtained. However, if the laser output power is reduced or the scanning speed is increased, the sample is converted into a state where strong thermal luminescence is generated from flickering, and CO 2 The residual amount becomes 15 mass % to 39 mass %. Furthermore, if the laser output power is further reduced or the scanning speed is increased from the conditions for generating flickering intense thermal luminescence, intense thermal luminescence is no longer generated, and CO 2 The residual amount increased to 37% to 41% by mass. Except for the conditions that produce continuous strong thermal luminescence, CO 2 The residual amount was reduced to 2.0 mass % or less.

[0087] Figure 8 The results of observing the temperature distribution of the limestone surface using an infrared camera under the irradiation conditions when the laser is scanned are shown in the case where strong thermoluminescence is generated during irradiation and when strong thermoluminescence is not generated. The limestone sample was laser scanned under the same conditions (output power of 80W, outer diameter of 3.0mm and inner diameter of 1.5mm) regardless of whether strong thermoluminescence is generated or not. Figure 8 , without producing strong thermal luminescence, the maximum temperature is about 1000℃ (compared to Figure 7 The cross mark corresponds to )( Figure 8 The right side shows only the white area of ​​about 1000°C), while in the case of strong thermal luminescence, the maximum temperature rises to about 1800°C (similar to Figure 7 The circle marks correspond to )( Figure 8 The black portion in the center of the left side is about 1800°C).

[0088] Conventionally, when quicklime is produced from limestone by firing, it is produced by heating to 900°C to 1000°C using a Maerz kiln or the like. Figure 7 An endothermic reaction also occurs in the region from the cross mark to the circle mark, from the limestone as the carbonate of Ca to the quicklime as the oxide of Ca.

[0089] in addition, Fig. 9 The XRD results of the sample after sintering with laser irradiation accompanied by strong thermal luminescence are shown. Fig. 9 It is known that quicklime (CaO), which is an oxide of limestone, is produced from limestone by firing accompanied by strong thermal emission due to laser irradiation.

[0090] The above-mentioned method for manufacturing quicklime is described in terms of steps, and includes: a step of irradiating a processing object containing calcium carbonate with laser light; and a step of generating calcium oxide from the calcium carbonate contained in the processing object by an endothermic reaction caused by the irradiated laser light, in a manner accompanied by continuous light emission due to heat radiation. Moreover, it can also be called a method for processing calcium carbonate, characterized in that it includes the step of causing other calcium carbonates adjacent to the calcium oxide accompanied by continuous light emission to undergo an endothermic reaction by utilizing the endothermic reaction from the calcium oxide accompanied by continuous light emission. Moreover, it can also be called a method for manufacturing quicklime by utilizing the method for processing calcium carbonate.

[0091] Fig.10 The surface of the limestone sample observed by Raman spectroscopy at around 900°C when it was fired in a non-luminescent intermediate state and when it was fired in a strong thermoluminescent state ( Fig.10 (a)) and cross section ( Fig.10 The result of (b)).

[0092] according to Fig.10 (a) It can be confirmed that, with respect to the surface, the increase ratio of the fired width in the case of strong thermal luminescence is about 2.1% compared with the case of non-luminescence. Fig.10 As shown in (b), in terms of the cross section, the firing depth is 0.6 mm in the case of non-luminescence, while it increases by 185% to 1.71 mm in the case of strong thermoluminescence. It can be considered that this is because the surface temperature rises due to the strong thermoluminescence, thereby greatly increasing the firing depth. As a result, heat is applied from the part where the strong thermoluminescence is generated to the surrounding area adjacent to it, achieving the so-called special sintering effect of applying a firing method different from that of the laser, which can be considered to achieve high-heat firing that cannot be achieved in the firing performed by the previous firing furnace.

[0093] Moreover, from Fig.10(b) shows that a certain firing depth is observed in the case of non-luminescent intermediate firing, but a semi-elliptical firing area is observed with the laser scanning line as the center when strong thermoluminescence is generated. It can be considered that this is because, when strong thermoluminescence is not generated, a temperature distribution with a lower temperature in the center of the ring is formed due to the heat input caused by the laser alone, but when strong thermoluminescence is generated, the heat input caused by the strong thermoluminescence is increased, and the temperature in the center of the ring becomes higher, thereby forming a semi-elliptical firing area. Therefore, it can be seen that the temperature distribution is quite different when strong thermoluminescence is generated and when it is not generated. By performing this control, the characteristics of the annular mode can be fully utilized to avoid local heat input for firing.

[0094] However, the shape of the light beam that can be used in the present invention is not limited to the annular shape, and a Gaussian shape or other shapes can also be used.

[0095] As is clear from the above description, as long as laser irradiation is used and accompanied by strong thermal emission for firing, it will greatly help the firing, making CO 2 The residual amount is reduced, the firing width and firing depth are increased, etc.

[0096] Moreover, quicklime is obtained by burning limestone to make it thermally decompose. 2 The smaller the residual amount, the higher the grade. JIS R9001 stipulates that 2.0 mass % or less is a special grade.

[0097] In addition, special quicklime can be used in steelmaking. If high-quality quicklime is used as an alkaline flux to remove impurities such as sulfur and phosphorus from main raw materials such as molten iron or scrap iron, better quality steelmaking can be achieved.

[0098] By utilizing the heat input caused by the strong thermoluminescence, quicklime equivalent to JIS special grade can be fired. In addition, according to the present invention, the oxides of Ca and / or Mg as products can be provided without mixing impurities such as sulfur or ash (mainly composed of iron, nickel, vanadium, and silicon dioxide) derived from the fuel, and a high-purity oxide product can be provided, thus becoming an excellent firing method that is environmentally friendly.

[0099] (Example 3)

[0100] A carbon coating treatment was performed on a 5 mm portion of the block limestone sample from the end thereof using a black body sprayer THI-1B (manufactured by Tasco Corporation, Japan) (hereinafter referred to as a coated sample).

[0101] The laser in the same annular mode as in Example 2 was irradiated from the coating portion of the coating sample. Fig.11The laser output and scanning speed are controlled by the laser beam. Figure 7 The same change in firing method results in Fig.12 Shown in.

[0102] As a result, continuous strong thermal luminescence was confirmed under some conditions of the strong thermal luminescence flash in Example 2. The CO of the sample after firing was measured in the same manner as in Example 2. 2 Residue, such as Fig.12 As shown in FIG. 1 , although not all of them are below 2.0 mass %, it is possible to obtain a CO content of 10 mass % or less. 2 On the other hand, in this embodiment, when the strong thermal luminescence flashes or does not produce strong thermal luminescence, the CO 2 The residual amount is more than 10% by mass.

[0103] In addition, by increasing the absorptivity of the limestone sample to the laser, it is possible to promote strong thermoluminescence. In addition, even if the laser scans from the carbon-coated area to the carbon-uncoated area, it can be confirmed that the strong thermoluminescence state continues to be continuously generated without changing. Therefore, as the main reason for the generation of strong thermoluminescence, the first important point is that the temperature rises due to the heat input caused by the laser. Moreover, in order to make the strong thermoluminescence continue, it is considered important that the temperature near the laser irradiation part rises due to the heat input caused by the laser and the heat input caused by the strong thermoluminescence itself.

[0104] (Example 4)

[0105] In addition, by using Fig.13 The device shown in the figure can also be changed to irradiate laser from above, and can also deal with granular limestone. In addition, by setting the supply of limestone and the discharge device of the fired quicklime, it can also become a structure capable of continuous firing.

[0106] Furthermore, it has been found that a unique feature of firing of powder particles accompanied by strong thermoluminescence is that agglomerates of oxide particles can be formed after firing. One example of this is described in detail below.

[0107] The samples for laser irradiation are limestone particles with a particle size of 0.3 mm to 0.8 mm. Fig.14 The calcined ware shown is put into a state of assembly, and the Fig.13 The laser device shown was irradiated with laser light while stirring the powder particles while vibrating (total amplitude: 0.145 mm, vibration speed: 54.0 mm / s, vibration frequency: 120 Hz).

[0108] As a result, even limestone powder particles can be Fig.15 As shown, strong thermal luminescence was confirmed.

[0109] and, Fig.16 An enlarged image showing limestone powder particles before laser irradiation ( Fig.16 (a)), and an enlarged image of the lime aggregate after burning accompanied by continuous strong thermal luminescence due to laser irradiation ( Fig.16 (c)). In addition, Fig.16 (b) shows an enlarged image of a powder particle after non-luminescent intermediate firing in which no luminescence was observed during laser irradiation.

[0110] according to Fig.16 Before laser firing, the particles are not bonded to each other and are in a state where they can be freely dispersed on a plane. By subjecting such powder particles to laser firing accompanied by strong thermal luminescence, agglomerates with a particle size of 6 mm to 8 mm formed by the particles bonding to each other can be obtained. Therefore, a unique effect of laser firing of powder particles accompanied by continuous strong thermal luminescence is that quicklime with a larger size than the limestone particles used as the raw material can be manufactured and provided. On the other hand, the particles after the non-luminescent intermediate firing are in a state where they can be freely dispersed, just like the particles before laser irradiation, and no agglomerates can be obtained.

[0111] (Example 5)

[0112] In this embodiment, the method of the present invention is used to burn slaked lime (Ca(OH) 2 ) is explained.

[0113] The samples were prepared by mixing Ca(OH) 2 The powder raw material is crushed to form Ca(OH) with a particle size of about 0.8 mm. 2 Sample. Ca(OH) 2 The samples were collected in large quantities in a firing vessel and placed in a Fig.13 Laser irradiation device.

[0114] Laser irradiation conditions were as follows: a Gaussian mode laser with an outer diameter of 2.2 mm and an output power of 80 W was applied to Ca(OH) 2 The fixed point on the sample was continuously irradiated for 60 seconds without scanning. During the laser irradiation, the sample was stirred by applying vibration (total amplitude of 0.145 mm, vibration speed of 54.0 mm / s, vibration frequency of 120 Hz) using an exciter.

[0115] Fig.17 The temperature change of the fired part is shown. 2When laser sintering is performed, the temperature rise temporarily stops at around 600°C, and then it is observed that the temperature rises to around 2000°C accompanied by strong thermal luminescence. 2 Continuous strong thermal luminescence was confirmed. Fig.23 It is shown that by Ca(OH) 2 The Ca(OH) obtained by irradiation with laser light and sintering with strong thermal luminescence 2 XRD results of oxides. Fig.23 It is known that by sintering with laser irradiation accompanied by strong thermal luminescence, Ca(OH) 2 Producing its oxide (CaO).

[0116] In addition, it can also be obtained from Ca(OH) 2 The powder obtained agglomerates ( Fig.18 ).

[0117] (Example 6)

[0118] (1) Laser sintering of dolomite and magnesite

[0119] Furthermore, when dolomite and magnesite were laser sintered under the same conditions as in Example 1, it was observed that, similar to limestone, the temperature rise temporarily stagnated at around 700°C to 900°C, and then the temperature rose to around 1900°C by continuous laser irradiation. Fig.19 The temperature rise in the case of dolomite is shown. Fig.21 The temperature rise in the case of magnesite is shown. In addition, in the case of dolomite, continuous strong thermal luminescence of more than 45 seconds can be confirmed ( Fig.19 ), in the case of magnesite, continuous strong thermal luminescence of more than 300 seconds can be confirmed ( Fig.21 ). If the measurement can confirm the continuous strong thermal luminescence of CO in the oxide 2 When the residual amount is less than 10 mass %, a high purity oxide of less than 10 mass % can be generated. When the laser is irradiated for a longer time, a very high purity oxide of less than 2.0 mass % can be generated in any sample ( Fig. 20 and Fig. 22 ).

[0120] in addition, Fig.24 The XRD results of the oxide of the dolomite obtained by firing accompanied by strong thermal luminescence due to laser irradiation are shown. Fig.24 It is known that the oxide (CaO·MgO) is generated from dolomite by firing accompanied by strong thermal luminescence due to laser irradiation.

[0121] in addition, Fig.25The XRD results of the oxide of the magnesite obtained by firing accompanied by strong thermal luminescence due to laser irradiation are shown. Fig.25 It can be seen that the oxide (MgO) is generated from magnesite by firing accompanied by strong thermal luminescence due to laser irradiation.

[0122] (2) Forming agglomerates by laser sintering granular dolomite

[0123] Fig.26 The following table shows the state of the oxide sample obtained by irradiating 0.4 g of a granular dolomite sample with a particle size of about 0.8 mm, which was stirred by an exciter (total amplitude of 0.145 mm, vibration speed of 54.0 mm / s, vibration frequency of 120 Hz), with a Gaussian mode laser with a beam diameter of 2.2 mm at an output power of 80 W for 120 seconds. Fig.26 Continuous strong thermal luminescence can be confirmed from the sample irradiated with laser under the above conditions, and agglomerates with a larger diameter than that before irradiation can be formed ( Fig.26 The particle size of the granular dolomite forming the agglomerate is preferably 0.1 mm to 1.0 mm, more preferably 0.3 mm to 0.8 mm.

[0124] (3) Forming agglomerates by laser sintering granular magnesite

[0125] Fig. 27 The following table shows the state of the oxide sample obtained by irradiating 0.4 g of a granular magnesite sample with a particle size of about 0.8 mm, which was stirred by an exciter (total amplitude of 0.054 mm, vibration speed of 25.5 mm / s, vibration frequency of 120 Hz), with a Gaussian mode laser with a beam diameter of 2.2 mm for 360 seconds at an output power of 80 W. Fig. 27 Continuous strong thermal luminescence can be confirmed from the sample irradiated with laser under the above conditions, and agglomerates with a larger diameter than that before irradiation can be formed ( Fig. 27 The particle size of the particulate magnesite forming the agglomerate is preferably 0.1 mm to 1.0 mm, more preferably 0.3 mm to 0.8 mm.

[0126] In addition, in Examples 4 and 6, by vibrating the granular sample with an exciter when forming agglomerates, it is possible to obtain agglomerates larger than in the case of no vibration. The vibration conditions are not limited to those shown in Examples 4 and 6, as long as the sample irradiated with laser light is vibrated in a light emission state accompanied by continuous strong thermal luminescence.

[0127] According to the present invention, it is possible to provide a method for converting CO 2The residual amount is suppressed to be less than 10% by mass of high-purity Ca and / or Mg oxides. In addition, it is also possible to pre-exclude impurities such as sulfur or ash (mainly iron, nickel, vanadium, silicon dioxide) from fuel mixed in during manufacturing, so that a method for manufacturing Ca and / or Mg oxides with higher purity can be designed. Moreover, by using the Ca and / or Mg oxides obtained by the present invention, a high-purity heat storage medium can be obtained, and a high-precision energy storage system and a carbon dioxide recovery method can be realized, the carbon dioxide recovery method being characterized in that: a carbon dioxide absorber containing the Ca and / or Mg hydroxide obtained by the hydration reaction of the Ca and / or Mg oxides manufactured by the manufacturing method of the present invention is formed, and carbon dioxide located around the carbon dioxide absorber is absorbed. In addition, the solid that undergoes an endothermic reaction by the present invention can contain a metal or the like that is an object of laser processing.

[0128] (Energy storage system)

[0129] By causing the oxides of Ca and / or Mg obtained by the present invention to undergo a hydration reaction, heat can be generated and thus can be used as a heat source. Furthermore, by irradiating the hydroxide after the hydration reaction with laser light, it can be converted back into oxides by firing accompanied by strong thermal luminescence, thereby forming a cycle. A highly accurate energy storage system using the oxides of Ca and / or Mg as a heat storage medium can be constructed.

[0130] (CO 2 Recycling method)

[0131] The carbon dioxide absorber containing the hydroxide of Ca and / or Mg obtained by hydration reaction of the oxide of Ca and / or Mg can absorb carbon dioxide in the surrounding. By irradiating the carbon dioxide absorber that has absorbed carbon dioxide with laser light and performing sintering accompanied by strong thermal luminescence, a method for recovering carbon dioxide that can obtain its oxide and obtain high-concentration carbon dioxide can be realized.

Claims

1. A method for causing a solid to undergo an endothermic reaction, characterized in that: Laser light is irradiated onto an oxide of Ca and / or Mg in a luminous state accompanied by continuous light emission due to thermal radiation, and heat from the oxide in the luminous state absorbing the laser light causes an endothermic reaction in a solid adjacent to the oxide in the luminous state.

2. The method for causing a solid to undergo an endothermic reaction according to claim 1, wherein: The oxide in the light-emitting state is generated by absorbing laser light.

3. A method for producing an oxide, characterized in that: The method according to claim 1 or 2 is used to produce the corresponding oxides from carbonates of Ca and / or Mg as the solid.

4. A method for producing an oxide, characterized in that: The method according to claim 1 or 2 is used to produce the corresponding oxides from the hydroxides of Ca and / or Mg as the solid.

5. A heat storage medium, characterized in that: Contains an oxide produced by the production method according to claim 3.

6. An energy storage method, characterized in that: The oxide produced by the production method according to claim 4 is used as a thermal storage medium.

7. A method for producing an oxide, characterized in that: By using the method according to claim 1 or 2, the solid granular carbonate of Ca and / or Mg is used to form agglomerates with a particle size larger than the particles, and at the same time, an oxide corresponding to the carbonate of Ca and / or Mg is produced.

8. A carbon dioxide absorber, characterized in that: Contains a hydroxide obtained by hydration reaction of an oxide produced by the production method according to claim 3.

9. A method for recovering carbon dioxide, characterized in that: The hydroxide obtained by the hydration reaction of the oxide produced by the production method according to claim 3 absorbs carbon dioxide existing around the hydroxide.

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